United States Department of Agriculture

Agricultural Research Service

Eastern Regional Research Center 

Research Highlights 2000-2010
Foreword

This Eastern Regional Research Center (ERRC) Research Highlights volume is a compilation of articles 

published from January 2000 to December 2010 in the Agricultural Research magazine, reporting research 

findings at the Center. Established by an Act of Congress in 1938, ERRC is one of four Regional Research 

Centers of the U.S. Department of Agriculture, Agricultural Research Service. ERRC researchers conduct 

studies to benefit producers of agricultural commodities, handlers and processors of food and nonfood products, 

Federal action and regulatory agencies, and the consumer.

ERRC is home to some of the Nation’s leading scientists and engineers who help solve problems facing the 

United States today and tomorrow with fundamental, applied, and developmental research on agricultural 

commodities including milk, meat, poultry, hides, leather, wool, fats, oils, rendered protein, grains, fruits, 

vegetables, energy crops, and juices. 

New knowledge and technology ensures an abundance of high-quality agricultural commodities and products at 

reasonable prices to meet increasing needs, and provides continued improvement in the standard of living for all 

Americans. These objectives are the basis for the following research:

•	 Development of rapid methods to detect human pathogens and harmful chemicals in foods.

•	 Development of novel methods to characterize human pathogens in foods.

•	 Development of microbial predictive modeling for food safety risk assessment and management.

•	 Development of effective and innovative intervention technologies to reduce or eliminate human 

pathogens in foods.

•	 Sustainable production of biofuels and co-products from grains and biomass.

•	 Sustainable agricultural practices. 

•	 Development of new crop-derived food ingredients and nutraceuticals with health-promoting ability.

•	 Development of new dairy products with improved functionality and health benefits.

•	 Development of valuable biobased products from agricultural byproducts for biomedical, industrial, and 

commercial applications.

•	 Utilization of byproducts, particularly potential pollutants.

•	 Opening new domestic and foreign markets and expanding existing ones.

ERRC scientists have won numerous national and international awards for their work, including the 2007 

designation by the American Chemical Society as a National Historic Chemical Landmark, recognizing ERRC 

scientists’ development of the dehydration technology that resulted in reconstituted instant mashed potatoes.

For more information about ERRC, visit www.ars.usda.gov/naa/errc. 
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 1

The articles in this volume are reprinted 

from Agricultural Research magazine, 

which is published by the U.S. 

Department of Agriculture, Agricultural 

Research Service, 5601 Sunnyside Ave., 

Beltsville, MD 20705-5130; phone 

(301) 504-1651; fax (301) 504-1641. 

The magazine is available on the World 

Wide Web at ars.usda.gov/ar. 

To subscribe to Agricultural Research

by mail, please contact New Orders, 

Superintendent of Documents, P.O. Box 

371954, Pittsburgh, PA 15250-7954.

This reprint volume may report research 

involving pesticides. It does not contain 

recommendations for their use, nor does 

it imply that uses discussed herein have 

been registered. All uses of pesticides 

must be registered by appropriate state 

and/or federal agencies before they can 

be recommended.

Reference to any commercial product or 

service is made with the understanding 

that no discrimination is intended and 

no endorsement by USDA is implied.

The U.S. Department of Agriculture 

(USDA) prohibits discrimination in 

all its programs and activities on the 

basis of race, color, national origin, age, 

disability, and where applicable, sex, 

marital status, familial status, parental 

status, religion, sexual orientation, 

genetic information, political beliefs, 

reprisal, or because all or part of an 

individual’s income is derived from 

any public assistance program. (Not all 

prohibited bases apply to all programs.) 

Persons with disabilities who require 

alternative means for communication 

of program information (Braille, large 

print, audiotape, etc.) should contact 

USDA’s TARGET Center at (202) 

720-2600 (voice and TDD). To file 

a complaint of discrimination, write 

to USDA, Director, Office of Civil 

Rights, 1400 Independence Avenue, 

S.W., Washington, D.C. 20250-9410, 

or call (800) 795-3272 (voice) or (202) 

720-6382 (TDD). USDA is an equal 

opportunity provider and employer.

Issued April 2012

Contents

3 Shaking Up the Future 

4 Fabric to Dye For

6 New Technology Boosts Fiber in Foods

8 Bioenergy Today

13 New Fuels From an Ancient Crop

14 Soil Fungi Critical to Organic Success

16 Corn Coproduct Cuts Ethanol Production Costs

18 For You, the Consumer

24 Scientists Seek To Sanitize Fruits and Vegetables

26 New Milling Methods Improve Corn Ethanol Production

28 New Detection Methods Improve Food Safety

31 Protecting U.S. Troops With Fireproof Wool

32 ARS Continues Advances in Irradiation of Ready-To-Eat Foods

36 Poultry Pathogen Models for Predictive Microbiology

38 Researchers Study Microbial Threats to Shellfish Safety

41 Make Whey for Progress: New Uses for Dairy Byproducts

42 Wool Biopolishing Process Scratches the Itch Factor

44 Getting to the Root of the Solution

46 Nonthermal Food Processing Is Heating Up

48 Fueling America—Without Petroleum 

52 Pectin Extraction From Citrus and Sugar Beets

54 New Methods for Ensuring Food Safety

56 From Lubricants to Packaging Materials: ARS Scientists Just 

Say “No” to Petroleum

59 ARS National Research Program on Obesity

60 In-Demand Fish: Making Sure They’re Always Safe To Eat

Front and back cover: The broad scope of scientific efforts in the Eastern Regional 

Research Center includes research on barley, dairy products, food safety, mycorrhizal fungi, nonthermal food processing, oysters, pectin extraction from citrus and 

sugar beets, produce-washing equipment, and wool-processing techniques.
2 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

62 Edible, Water-Resistant Film from Milk Protein

63 Boosting Barley for Bioenergy

64 New Database Helps Monitor Food Pathogens

65 Cheese, Please: Recreating Unique Properties of Hispanic Cheeses

66 Biofuel Gets Less Expensive

67 New Methods for Detecting Listeria

68 Creating Novel Foods and More From Agricultural Products

69 Washing and Sanitizing Techniques Aim To Make Produce Safer

70 New Varieties and Techniques Make Barley Better For Fuel and Food

72 New Method Simplifies Biodiesel Production

73 QuEChERS Method Catches Pesticide Residues

74 Unraveling the Listeria Genome

75 Celebrating 15 Years of a Healthy School Lunch Option

76 Science Update

Contents (continued)
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 3

esults are in . . . Adults love the

taste of ARS’ reduced-sugar,

low-fat milk shakes. Thisshake

for the new millennium is a remake of the low-sugar shake

developed in the 1970s for USDA’s

school lunch program by retired researcher Virginia Holsinger, formerly

withARS’ Dairy Products Research Unit

in Wyndmoor, Pennsylvania.

The new shakes have less than half

the sugar and about 10 percent of the

fat of commercial shakes.

The concept of a lowsugar, low-fat shake was

probably ahead of its time

two decades ago. Now,

however, since the introduction of low-fat cheese

into the school lunch program and a push toward

more nutritionally balanced meals, the shake’s

time may have finally

come—in schools and

elsewhere.

Last fall, ARS opened its

doorsto about 600 youngstersfor a tastetesting of the chocolate shakes, which

are more like soft-serve ice cream. Kids,

with their “choosy” culinary tastes,

weren’t crazy about the shakes. Some

comments: “Not sweet enough,”

“There’s an aftertaste,” and “Tastes like

cereal.”

“We’re trying to reformulate the

shakes and get rid of the cereal flavor,”

says Richard Konstance, a chemical engineer in the dairy unit.

Konstance is working with cooperative research and development agreement partner Devine Foods, Inc., of

Philadelphia, Pennsylvania, to change

the shakes and further develop them as

a commercial product.

“Our goal is to provide a dessert that

contains the same nutrients as an 8-

ounce glass of chocolate milk. But it’s

easier to provide cartons of milk than

milk shakes,” Konstance says.

R

Shaking Up the Future

The new ARSdeveloped

shakes have

less than half

the sugar and

about 10 percent of the

fat of

commercial

shakes.

Chemical engineer Richard Konstance and

president of Devine Foods, Denise Devine,

discuss the nutritional value of the lowsugar, very low-fat shake and ways to

improve and develop it into a commercial

product.

PEGGY GREB (K8876-1)

“It’s more labor intensive to provide

shakes because schools need a milk

shake machine or soft-serve machine and

someone to operate it,” says Konstance.

“A hard-pack version of the shake would

be easier for schools to deal with, but

there’s a difference in formulating softserve and hardened ice cream.”

“Ultimately, we want to create a product for young children that is healthful

and great tasting,” says Denise Devine,

president of Devine Foods.

After getting kids’ opinions,ARS

took the shakes for another test

drive—this time with adults,

ages 22 to 52. The adultsloved

them! They thought they were

just sweet enough and tasted

better than many other dietary

shakes.

What’s more, the shakes

are good for you. They are

based onARS technology and

contain Devine’s patented composition, which reduces fat and

calorie content and adds fiber and

nutrients. The fiber content is about

2 to 2.2 percent, which qualifies the

shakes as a good source of fiber. A 10-

ounce shake has as much calcium, vitamins, and minerals as a serving of milk

and has fewer calories.

One more benefit: The shakes are significantly lower in lactose—good news

for those who are lactose intolerant.

“These nutritious shakes should be

available to consumers in the near

future,” says Konstance.—By Tara

Weaver-Missick, ARS.

This research is part of New Uses,

Quality, and Marketability of Plant and

Animal Products, an ARS National Program (#306) described on the World

Wide Web at http://www.nps.ars.usda.

gov/programs/cppvs.htm.

Richard P. Konstance isin the USDAARS Dairy Products Research Unit,

Eastern Regional Research Center, 600

E. Mermaid Lane, Wyndmoor, PA 19038;

phone (215) 233-6600, fax (215) 233-

6795, e-mail rkonstance@arserrc.gov.
4 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 8 Agricultural Research/November 2000

Fabric To Dye For C

Samples of wool/cotton

crosswoven blends dyed

in a single dye bath. The

solid-color swatches were

pretreated so that both the

wool and cotton yarns

would pick up the dye

evenly. In the untreated

fabrics, the cotton stayed

largely undyed.

Peggy Greb (K9139-1)

Technician Chet Sutton

studies colorfastness of

a union-dyed wool/

cotton blend.

PEGGY GREB (K9143-1)

otton may soon be afforded the same upscale

recognition as wool, thanks to new technology. ARS chemists

Jeanette M. Cardamone and William N. Marmer have found a

way to make cotton more chemically similar to its high-end

counterpart—wool—so that a fabric blend of the two can be

easily dyed.

Dyeing a cotton/wool blend is difficult because the two fibers

have different chemical makeups. Wool, which is sheep hair,

is made of animal proteins, while cotton is made of plant

cellulose—the main part of a plant’s cell wall. Normally, when

wool and cotton are blended together, two separate dye baths

are required because the wool takes up most of the dye.

“The process we developed is a new single-bath dyeing procedure called union dyeing,” says Cardamone. She and Marmer

are with the Hides, Lipids, and Wool Research Unit at ARS’

Eastern Regional Research Center (ERRC), in Wyndmoor,

Pennsylvania. “This process helps textile manufacturers overcome a major technological barrier: dyeing all-natural blends

to the same depth of shade in one step.”

In the conventional procedure, Cardamone explains, cotton

is dyed first and wool second. Wool is dyed in an acidic

environment at high temperatures, and cotton is dyed in a

nonacidic environment at lower temperatures. This difference

requires that the wool and cotton be dyed either separately, or

sequentially in one bath in which the pH and temperature levels

are changed.

“Our improved method uses pretreatments to make the

cotton as receptive to dye uptake as the wool,” she says.

Opposites Attract

Cardamone and Marmer’s simple approach is to reverse the

chemical charge of cotton from negative to positive before

dyeing; wool is already positive. To do

this, they use cationic fixatives—

positively charged ions—which are

typically used after cotton is dyed to

help it keep its color. Applying the

fixatives before dyeing gives both fiber

components of the fabric a positive

charge. Since the dye is negatively

charged—and opposites attract—the

cotton and wool dye to a uniform shade

because the dye is attracted equally to

both fibers. This union-dyeing process

uses one dye in one bath, under one

set of conditions.

Cotton industry officials are excited

about the new process. “This technology is easy to adopt,” says John

Turner, a senior chemist with Cotton

Incorporated in Cary, North Carolina.

8
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 5

“It doesn’t require elaborate equipment or expense. In the past,

there was no satisfactory method for cotton mills to dye blends.

This technology could potentially increase the use of cotton.”

Cotton Incorporated wants to expand the use of cotton and make

it more profitable for cotton farmers and the textile industry.

“This process gives cotton an upscale market. A

cotton/wool blend would

have greater value than a

100-percent cotton item,”

Turner says. “And depending on the blend level, it

could be cleaned in the

washing machine.” Cotton

Incorporated has a research

partnership with the ERRC

scientists.

The wool industry also

finds the concept appealing

because it creates a new market for wool. Approximately

66,800 sheep producers raise

7.2 million sheep and lambs,

producing about 49.2 million pounds of wool in the

United States. Even so, the

country still imports wool

from Australia and New

Zealand. This technology

could help open more markets for American wool by

increasing demand.

Keeping Colors Colorful

The ERRC scientists also use another method that helps

make dyeing wool/cotton blends possible—a durable-press

finishing resin. The resin treatment was originally developed

by chemists at the ARS Southern Regional Research Center

(SRRC) in New Orleans, Louisiana, to prevent wrinkling in

100-percent cotton. SRRC scientists further developed the

technology to increase cotton’s dyeability. SRRC chemist

Eugene Blanchard collaborated with ERRC scientists on using

the durable-press finishing resin treatment for cotton/wool

blends.

Cardamone says resin treatments, which are alternatives to

cationic fixatives, are important for good colorfastness in

laundering. Colorfastness is a textile industry standard that

determines how stable the color is in a garment. Good

colorfastness means the garment won’t fade after one washing.

Resin pretreatment is best for garments that require excellent

colorfastness. Cationic fixatives could be used for outerwear

garments where colorfastness to washing is moderate but

colorfastness to dry cleaning is high, notes Cardamone.

“Both pretreatment systems will effectively lead to uniondyeing of wool/cotton blends, but the treatment should be

selected to accommodate the anticipated end use. A wool/

cotton-blend fabric is ideal for multiseason apparel because

wool provides inherent resiliency and warmth while cotton

contributes comfort and coolness,” says Cardamone. “These

experimental textile treatments may broaden the market for

cool-weather garments made of cotton/wool blends. In

sweaters, for example, the blend’s wool component retains

body heat and imparts thickness, while cotton makes it

comfortable to wear. Both natural fibers are great at wicking

away moisture, too.”

Through a cooperative research and development agreement

between ERRC researchers and chemical specialties

manufacturer Hercules, Incorporated, other pretreatment

systems are being investigated.

Applied commercially, these technologies may cut textile

dyeing costs—savings that can be passed on to consumers

seeking versatile garments for spring and fall.—By Tara

Weaver-Missick, ARS.

This research is part of New Uses, Quality, and Marketability of Plant and Animal Products, an ARS National

Program (#306) described on the World Wide Web at http://

www.nps.ars.usda.gov.

William N. Marmer and Jeanette M. Cardamone are with

the USDA-ARS Eastern Regional Research Center, Hides, Lipids, and Wool Research Unit, 600 East Mermaid Lane, Wyndmoor, PA 19038; phone (215) 233- 6585 [Marmer], (215) 233-

6680 [Cardamone], fax (215) 233-6795, e-mail wmarmer@

arserrc.gov and jcardamone@arserrc.gov. ◆

Chemists Jeanette Cardamone

and William Marmer study

records of the effect of dyeing

regimen on dye uptake.

PEGGY GREB (K9137-3)

Technician Kimberly Baxendale dyes samples of a wool/cotton

blend fabric.

PEGGY GREB (K9140-1)
6 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

mericans fall short when it comes to eating enough

fiber each day. So what are scientists doing to help?

They have come up with a new technology that allows

them to add more fiber to foods without changing

their texture,saysfood technologist CharlesI. Onwulata, who’s

in the ARS Eastern Regional Research Center’s (ERRC) Dairy

Products Research Unit, in Wyndmoor, Pennsylvania. “Until

now, adding fiber to foods was difficult because it changed the

qualities—particularly the texture and mouth feel—of the

food,” Onwulata says.

Onwulata has filed for a patent on the new technology,

“invisible fiber,” a process that uses milk protein to envelop

the fiber and keep it from soaking up water. “The protein barrier

makes the fiber ‘invisible’ to water. The fiber doesn’t pull

moisture out of the rest of the food product,” he notes. “But

the invisible fiber envelope will dissolve during digestion,

allowing the fiber to perform its normal function in the gut.

This new, encapsulated fiber can be incorporated into food

products without changing texture or moisture. Many foods

can be modified with the invisible fiber.”

Traditionally, food manufacturers have increased fiber in

foodsin small amountsto avoid negative effectssuch as changes in texture, color, and mouth feel. In foods with high fiber

content, the fiber absorbs water from its surroundings, giving

the food a dry texture. Reducing the water-holding capacity of

the fiber improves food quality and allows more fiber to be

added without changing its texture, Onwulata says.

Onwulata and colleagues conducted baking studies to test

the moisture level, protein content, color, and hardness of foods

made with invisible fiber and compared them to recipes with

regular fiber. Fiber affects these properties, and these properties determine consumer acceptability.

The scientists-turned-chefs baked cookies and muffins

power-packed with invisible fiber. The invisible fiber improved

the goodies’ qualities.

ARS researchers are also working with industry to increase

fiber in fluid foods. They had a cooperative research and

development agreement with Verion, Inc., of Exton,

Pennsylvania, to adapt a “dynamic pulse-pressure treatment”

processfor the food industry. The technology, which is patented

by Verion, uses hydrostatic pressure—the force applied through

water—to change the moisture, density, and melting properties

of foods. The treatment was originally used for making

pharmaceuticals.

“Scientists have known for a hundred years that high pressure can be used to process foods,” says Onwulata. “Old methods take anywhere from 20 to 30 minutes to pressure-process

foods. With dynamic pulse-pressure treatment, pressureprocessed fluid foods like milk or slurries (pastelike fluid that

can pass through a nozzle) can be processed in 1 second—

faster than with anything else that’s on the market,” he says.

NEW

TECHNOLOGY

BOOSTS

FIBER IN

FOODS

Charles Onwulata, a food technologist, prepares ingredients for

high-pressure homogenization, a process that can increase fiber

content in fluid foods.

PEGGY GREB (K9309-1)

A
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 157

Foods react differently to pressure processing, since they

have varying densities and abilities to dissolve in water. In

studies at ERRC’s dairy pilot plant, a small-scale processing

facility, scientists tested several food ingredients, including

whey proteins, corn starch, wheat bran fiber, and cellulose fiber.

They found that pressure treatment modified the molecular

structure of the starches. Pressure-treated fiber had about a 40

percent reduction in its water-holding capacity. Microscopic

images revealed that pressure treatment packed the fibers into

small balls that were impervious to moisture.

“Once these technologies are fully developed and

commercialized, the food industry will greatly benefit from

them,” Onwulata says. Many companies are interested in

increasing the amount of fiber in their foods as a benefit to

consumers. The recommended fiber intake is 20 to 35 grams

per day. But on average, Americans get only about 15 grams

per day. Studiessuggest that fiber decreases heart disease,some

cancers, high blood pressure, and diabetes.

Nutritionistsstill agree that eating a variety of grains, fruits,

vegetables, and legumes is the best way to get fiber. Meanwhile, ARS researchers will continue to look at ways to boost

fiber in other foods.—By Tara Weaver-Missick, ARS.

This research is part of New Uses, Quality, and Marketability of Plant and Animal Products, an ARS National Program (#306) described on the World Wide Web at http://

www.nps.ars.usda.gov.

Charles I. Onwulata is at the USDA-ARS Eastern Regional

Research Center, Dairy Products Research Unit, 600 E. Mermaid Lane, Wyndmoor, PA; phone (215) 233-6497, fax (215)

233-6795, e-mail conwulata@arserrc.gov. 

dooF rebiF latoT eziS gnivreS

 (grams)

Apple, raw, with skin 1 medium 3.7

Baby lima beans, cooked 1/2 cup 5.4

Baked potato with skin 1 potato 4.8

Banana 1 medium 2.8

Black beans, cooked 1 cup 15.0

Broccoli, cooked 1 spear 1.1

Carrots, raw 1 carrot 2.2

Green peas, cooked 1 cup 8.8

Lentils, cooked 1 cup 15.6

Oat bran bagel 1 4-inch bagel 3.2

Orange 1 small 2.3

hcaeP muidem 1 0.2

Peanut butter, smooth 2 tablespoons 1.9

Popcorn, air-popped 1 cup 1.2

Shredded cabbage, cooked 1/2 cup 1.7

Spinach, cooked 1 cup 4.3

Whole-wheat bread 1 slice 1.9

Whole-wheat English muffin 1 muffin 4.4

Source: U.S. Department of Agriculture, Agricultural Research Service.

1999. USDA Nutrient Database for Standard Reference, Release 13. Nutrient Data Laboratory Home Page, http://www.nal.usda.gov/fnic/foodcomp.

Foods With Fiber

Dietary fiber comes from plant cell walls. There are two

main types of dietary fiber, and we need a combination of both.

Soluble fiber (gums, mucilages, pectins) forms a gel and is

found in fruits, dry beans and peas, vegetables, and some

cereals. Insoluble fiber (cellulose, hemicellulose, lignin) passes

through your digestive tract basically intact and is primarily

found in whole-grain products, like wheat bread. Insoluble fiber

helps get rid of food your body can’t use. It also gives you that

full feeling. Soluble fiber lowers blood cholesterol and helps

regulate blood sugar. Here are just a few sources of fiber:

Chemist Renee Wildermuth bakes muffins and cookies

containing “invisible fiber.”

PEGGY GREB (K9311-1)

)1-0139K( BERG YGGEP

Muffins and cookies made with invisible fiber. Muffins and cookies made with invisible fiber.
48 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 Agricultural Research/April 2002

aking the lead for the nation last

year, the U.S. Department of

Agriculture ordered all its

locations nationwide to run

vehicles and equipment on ethanol or

biodiesel blends wherever feasible.

Gasoline-operated vehicles and equipment will use a blend of at least 10

percent ethanol and 90 percent conventional gasoline. Diesel vehicles and

equipment will use B20 biodiesel, a

blend of 20 percent biodiesel and 80

percent regular diesel. The USDA fleet

includes more than 700 “flex-fuel”

vehicles, which use a blend of 85 percent

ethanol and 15 percent gasoline.

The Department’s action reflects the

federal government’s commitment to

expanding its use of biofuels and biobased

products to set an example for the private

sector. The year 2000 also saw a groundbreaking for a $20 million National

Ethanol Research Pilot Plant in Edwardsville, Illinois. When completed in

January 2003, this will be the largest

ethanol pilot plant in the country. The

Agricultural Research Service is administering the federal government’s

contribution of $14 million toward the $20

million cost of construction. Industry

considers the plant essential to meeting its

goal of increasing annual ethanol production to 16 billion gallons over the next

10 to 15 years.

The new plant is designed to enable

researchers to develop the technologies

required to improve the efficiency of

ethanol production. The more efficient the

production, the lower the costs—in terms

of both energy and money—and the more

competitive ethanol becomes. Since each

crop has its own mix of complex sugars

and starches, each requires its own techniques to be economically processed into

ethanol. The challenge is to design

methods that allow different crops to be

processed in the same facility.

Throughout the United States and in

several other nations, scores of scientists

are researching a wide variety of ways to

improve ethanol production. These

researchers include those in ARS’national

Bioenergy and Energy Alternatives

research program. At two of ARS’regional

research centers—in Illinois and Pennsylvania—their goals are to improve the

conversion of agricultural plant materials

into ethanol and valuable coproducts,

lower production costs and fuel emissions,

and enhance performance properties of

biodiesel. The Western Regional Research

T Scientists worldwide

are researching a

wide variety of ways

to improve ethanol

and biodiesel

production. The

goals are to develop

valuable

coproducts, lower

production costs

and emissions, and

enhance the

performance of

biofuels. ifferent

Bioenergy Today

KEITH WELLER (K9835-17)

At the Beltsville Agricultural Research

Center, quality assurance specialist David

Johnson examines a sample of biodiesel

while Greg Meyer, driver from a

cooperating fuel company, fills a 20,000-

gallon tank at a boiler plant, which heats

BARC’s dairy buildings.
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 Agricultural Research/April 2002 59

Biodiesel is a clean-burning alternative fuel that can be made from

materials such as vegetable oils,

animal fats, and spent cooking

greases. Typically, biodiesel is prepared by the reaction of fat or oil with

alcohol under alkaline conditions. Soybased biodiesel is the most commonly

used form.

Ethanol is an alcohol-based fuel

produced by fermenting sugars from

crop starches. Currently, 95 percent

of ethanol is produced from corn

kernels. About 5 percent of U.S.

ethanol is made from sugar- and

starch-containing materials other than

corn. These include wheat, barley, and

sorghum grains; sugarcane; cheese

whey; and wastes from paper mills,

potato processing plants, breweries,

and beverage manufacturers—or

some combination of these materials.

Originally, most ethanol was made

through wet-milling, which means the

starch is separated from the corn

germ and fiber and liquefied by cooking. The liquefying creates sugars in

a form that can be fermented with

yeast to produce ethanol and carbon

dioxide. The ethanol is then removed

from the slurry.

The number of ethanol plants has

surged in the past few years, and drymilling is now the method used for

over half of the ethanol currently produced. In this process, kernels are

ground to a fine powder, and all of it

is cooked to liquefy it, without removing the germ or fiber. Different enzymes are added at different stages

and temperatures as the mash cools,

producing ethanol and carbon dioxide.—By Don Comis, ARS.

Biofuel Basics

y

Above: In a biodieselpowered tractor, animal

caretaker Angel Santiago

heads to a dairy barn at

BARC. The center uses B20,

a common biodiesel blend,

in its entire fleet of over 150

diesel vehicles.

Left: High-voltage

electrician Alvin Coates fills

the tank of an aerial

hydraulic lift bucket truck

with soy-based diesel.

KEITH WELLER (K9842-2)

KEITH WELLER (K9842-10).
610 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 Agricultural Research/April 2002

Center, in California, focuses its biofuel

efforts on ethanol. In 1999 the national

program was expanded to include the

breeding of improved energy crops.

Seeing Is Believing

USDA alone last year used over

100,000 gallons of biodiesel fuel and expects to easily double that amount next

year. This puts practical examples of

biofuel use within driving distance of

public and private organizations around

the country.

Leading by example, USDA’s Henry

A. Wallace Beltsville (Maryland) Agricultural Research Center (BARC) uses

B20 biodiesel in its entire fleet of 150

diesel vehicles, including a tour bus (see

cover photo) for the ARS National Visitor Center, located on BARC grounds.

The center also heats some buildings

with B5 (5 percent biodiesel).

The success with biodiesel in vehicles

has encouraged commercial and public

fleets to adopt biodiesel, particularly in

Maryland. The cities of Greenbelt,

Takoma Park, and Ocean City have all

recently adopted biodiesel fuel for their

snowplows and other public-works

vehicles and equipment. Greenbelt also

uses biodiesel to run its Connector bus,

which ferries Greenbelters on short trips

within the city, filling gaps in the

Washington, D.C., metropolitan area

public transit system. These cities

learned about biodiesel by sending

representatives to BARC meetings.

Cheaper Ways To Make Ethanol

Scientists at ARS’ Eastern Regional

Research Center (ERRC), in Wyndmoor,

Pennsylvania, are working on lowering

ethanol’s price per gallon on two fronts:

developing coproducts to defray costs

and lower-cost production techniques

and materials.

They’ve developed a growing number

of valuable coproducts of processing

corn kernels for ethanol, such as

Amaizing Oil, a new corn oil that can

lower blood cholesterol levels, and a

valuable food ingredient called Zeagen,

a corn fiber gum. Both products were

found in the fibrous hull that forms the

kernel’s outermost layer, and both are

moving closer to the marketplace.

ERRC engineers have developed a

radical alternative way to produce

ethanol at a price expected to be significantly lower than is typical of conventional methods. It’s called continuous

fermentation with stripping. The method

removes, or strips, ethanol contained in

the escaping carbon dioxide, which is

then recycled back to the fermentation

vat. In the conventional process, when

the ethanol level rises too high in fermentation vats, it slows the yeast’s ability

to produce more ethanol. The new

method continuously strips ethanol from

the fermentation broth, freeing the yeast

to make additional ethanol.

The team has also developed a new

process called pervaporation, which uses

a membrane to filter ethanol out of the

broth.

Says engineer Frank Taylor, “We are

now looking for companies interested in

taking our processes off the research

bench and develop them further for commercial use.”

Andy McAloon is the team’s cost engineer. He developed a computer model

that can estimate the cost per gallon of

ethanol if a new process were used to

produce it. “This guides our research so

that we don’t spend too much time on

processes that would not yield a more

competitive product,” says Kevin Hicks,

who leads the ERRC ethanol team. “It’s

expensive to test a process at the pilotplant stage, so this model could screen

out processes not likely to be practical.”

Other researchers at ERRC are working to reduce the cost of biodiesel production. They are making biodiesel fuel

from lower quality starting materials,

such as soybean soapstock (see story on

page 9).

To help lower the cost of ethanol production, ARS scientists have developed valuable

coproducts from corn, such as Amaizing Oil, which can lower blood cholesterol levels. Here,

chemist Kevin Hicks checks the color and quality of a corn fiber oil sample.

KEITH WELLER (K7776-1)
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 Agricultural Research/April 2002 117

Enzymes for Greater Efficiency

At ARS’ Western Regional Research

Center, in Albany, California, scientists

are creating better enzymes that produce

ethanol in a more cost-effective manner.

“About 10 to 15 percent of the energy

required to make ethanol goes toward

providing the heat to cook the starch,”

says chemical engineer George Robertson. “The more energy it takes to make

ethanol, the less useful it is as a fuel

alternative. So we’re working on

enzymes that can digest the starch and

make ethanol production more efficient.

That could open up the ethanol market

to other grains, like wheat,” Robertson

says.

To construct these enzymes, the team

uses a technique developed in the pharmaceutical industry called directed

evolution. Using biotechnology, they

take apart key plant genes and reconstruct them, introducing mutations.

The mutant genes are then inserted

into yeast organisms, where they begin

to make, or express, starch-digesting

enzymes. The scientists then screen the

yeast colonies for their enzymeproducing abilities and select the best

ones for another cycle of gene mutation

and selection.

“We can do various things to direct

the evolutionary path, speeding up

development of enzymes with desired

characteristics,” says chemist Dominic

Wong.

In the laboratory, at 98.6 ̊F, their highpowered enzymes break down starch 50

times faster than the original enzymes.

And the technique shows promise of

making even better enzymes. The team

plans to use similar approaches to develop new enzymes for use in biomass

conversion.

Microbes, Too, Can Play a Role

Making biofuels, such as ethanol, economically from the whole crop instead

of just the grain is the long-range goal of

scientists in the Fermentation Biochemistry Research Unit at ARS’ National

Center for Agricultural Utilization

Research, in Peoria, Illinois.

“But our starting point is researching

fermentation of fiber in just the corn

kernel,” says ARS microbiologist

Rodney J. Bothast, who leads the project.

Currently, the kernel fiber is separated

out and used as inexpensive cattle feed

that is valued for protein, not fiber. If

technology were developed to break

down the different polymers in kernel

fiber to simple sugars, about 10 percent

more ethanol could be produced from

each bushel of wet-milled corn.

Bothast collaborates with scientists at

ERRC and in the Department of Wood

Science at the University of British

Columbia, Vancouver, in research on the

physical and chemical pretreatment of

fiber. Pretreatment frees the cellulose

from hemicellulose, starch, and lignin

components.

Cellulose fragments are more readily

converted into sugars that can be

fermented to make ethanol. The lignin

component is not fermented but can be

burned to produce energy.

“So far, the most effective way we’ve

found to break down the fiber is to

pretreat it with mild acid and then with

alkaline hydrogen peroxide,” says

Bothast.

The pretreated fiber contains sugars,

mainly arabinose and xylose and some

glucose. Normally, ethanol-producing

microbes eat the glucose first, leaving

little appetite for the other sugars. Nancy

N. Nichols, microbiologist, and Bruce S.

Dien, chemical engineer, have developed

genetically engineered microorganisms

that consume the sugars at nearly equal

rates.

These researchers are collaborating

with others at the University of British

Columbia, Purdue University, and

Williams Energy Service, in Pekin,

Illinois—the second largest ethanol

producer in the country—to test these

new microbes on kernel fiber converted

to sugars by industrial processes.

Microbiologist Rodney Bothast (left) and technician Loren Iten add starter microorganisms

to pilot-plant-size bioreactors in which ethanol is brewed from sugar mixtures derived from

corn fiber.

KEITH WELLER (K7408-6)
812 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 Agricultural Research/April 2002

Value-Added Products

As the scientists seek ways to increase

ethanol production efficiency, they’re

mindful of coproducts that might help

make ethanol crops more economically

successful. For example, other microbes

developed by Nichols and Dien convert

the sugars derived from kernel fiber into

lactic acid. Biobased companies use lactic acid to produce solvents and biodegradable plastics.

Badal Saha, an ARS chemist, and microbiologist Timothy Leathers have developed yeasts that convert the xylose

derived from corn fiber into xylitol, a

low-calorie sweetener. Xylitol, which has

a minty-cool taste, is used in some mints

and gum and sells for about $3 per

pound. It’s made from birch wood by an

expensive, energy-intensive process.

Saha and Leathers have also

discovered fungi that produce enzymes

especially well suited for converting corn

fiber into sugars. Use of enzymes decreases the amount of acid needed to

convert corn fiber to sugars, and that

makes ethanol an even more environmentally friendly fuel.

And Out on the Range . . .

Instead of making ethanol from the

sugars and starches in plants, Ken Vogel,

with ARS in Lincoln, Nebraska, is

experimenting with using cellulose and

hemicellulose from switchgrass as

another source of ethanol. Vogel’s hope

is that farmers might be able to grow this

native prairie grass on highly erodible

soils —including those set aside for

USDA’s Conservation Reserve Program—harvest the grass periodically for

ethanol production, and reap conservation benefits, such as reduced soil

erosion and enhanced carbon storage.

Vogel and colleagues are breeding

new switchgrasses for biofuel use.

They’re genetically improving the grass

for conversion to ethanol and conducting

on-farm trials to obtain economic information on production costs. Ron Follett,

at Fort Collins, Colorado, is working

with Vogel and ARS scientists at Mandan, North Dakota, to study carbon

storage on lands grown for biofuel crops.

Plant geneticist JoAnn Lamb and

colleagues at the ARS Plant Science

Research Unit in St. Paul, Minnesota, are

looking at alfalfa as another cellulose

source for producing ethanol. They

received $288,000 from ARS’ new $2.4

million in funding for developing

bioenergy crops.

They are breeding a new alfalfa variety specifically to double as a high-quality livestock feed and a bioenergy crop.

They’ll incorporate genes from southern

European varieties to give the plant a

thicker, almost woody, stem. This means

more cellulose for ethanol production.

The humid East might prefer alfalfa

to switchgrass as an ethanol source, but

switchgrass is ideally suited for the arid

West, because it needs very little rainfall

to grow. Both alfalfa and switchgrass can

also be burned to generate electricity.

There are obstacles to overcome when

making ethanol from cellulose in plants

like switchgrass or alfalfa, such as

finding ways to convert the complex

sugars in cellulose into simple ones that

can be fermented to produce ethanol.

Facilities to do this conversion will have

to be built. Equipment for this purpose

could be tested at the new Illinois pilot

ethanol plant when it is up and running,

as could equipment for the new continuous fermentation stripping process.—By Don Comis, ARS. Ben

Hardin and Kathryn Barry Stelljes,

both formerly with ARS, also contributed

to this story.

This research is part of Quality and

Utilization of Agricultural Products

(#306) and Bioenergy and Energy Alternatives (#307), two ARS National Programs described on the World Wide Web

at http://www.nps.ars.usda.gov.

To reach scientists mentioned in this

article, contact Don Comis, USDA-ARS

Information Staff, 5601 Sunnyside Ave.,

Beltsville, MD 20705-5129; phone (301)

504-1625, fax (301) 504-1641. ◆

Scientists are creating enzymes that

produce ethanol in a more cost-effective

manner. Technician Tina Williams and

chemist Charles Lee use an automated

liquid handler and a microplate reader to

measure enzyme activity.

SCOTT BAUER (K9844-1)

At WRRC, technician Sarah Batt uses a

robot to pick yeast colonies and transfer

them onto starch plates, where they’ll be

screened for desirable enzyme production.

SCOTT BAUER (K9843-1)
Barley has been cultivated 

for thousands of years, yet 

it doesn’t always make the 

list when energy experts 

discuss potential biofuel 

crops. And bio-oil—a liquid 

fuel generated when heat 

breaks down plant matter—

is still a low-profile energy 

alternative. But research 

by Agricultural Research 

Service scientists at the 

Eastern Regional Research 

Center (ERRC) in Wyndmoor, 

Pennsylvania, could give a 

big boost to producing bio-oil 

from barley feedstocks.

As a renewable transportation fuel, bio-oil made 

from barley byproducts—or 

any other biofeedstock—has 

several advantages. The fuel 

can potentially be refined, 

stored, and distributed with 

the infrastructure already in 

place for the petroleum fuel 

industry. And perhaps in the 

future, consumers will be 

able to fill up their cars with 

gasoline or diesel derived 

from bio-oil without needing 

special adaptations in their 

fuel systems.

ERRC lead scientist and 

chemical engineer Akwasi 

Boateng worked with chemist Charles Mullen, mechanical engineer Neil Goldberg, 

chemist Robert Moreau, and research leader Kevin Hicks on studies 

that evaluated the yields of bio-oil from barley straw, hulls, and 

dried distillers grains (DDGS). All three feedstocks are byproducts 

of fermentation of barley grain for ethanol—a biofuel option that 

is slowly gaining ground in the Middle Atlantic States and the 

Southeast, where farmers could cash in on the production of winter 

barley cover crops while continuing to raise corn and other food 

crops in the summer.

The researchers produced bio-oil from all three barley byproducts 

via “fast pyrolysis,” an intense burst of heat delivered in the absence 

of oxygen. In the lab, a kilogram of barley straw and hulls yielded 

about half a kilogram of bio-oil with an energy content about half 

that of No. 2 fuel oil.

New Fuels From an Ancient Crop

The energy content of biooil from barley DDGS—including DDGS contaminated 

with mycotoxins, which can’t 

be used to supplement livestock feed—was even higher, 

about two-thirds that of No. 2 

diesel fuel oil. But it was more 

viscous and had a shorter shelf 

life than the bio-oils produced 

from straw or hulls.

The fast-pyrolysis process 

also creates a solid byproduct 

called “biochar,” which might 

improve the water-holding 

capacity and nutrient content 

of soils. Amending soils with 

biochar can sequester carbon 

in the soil for thousands of 

years.

Based on these studies, 

the scientists suggest that 

colocating fast-pyrolysis 

units in commercial barley 

grain ethanol plants could 

be a win-win proposition for 

farmers in the Middle Atlantic 

States. Barley grain could be 

used to produce ethanol, and 

the byproducts could be used 

to produce bio-oil either for 

transportation fuels or for 

producing heat and power 

needed for the grain-toethanol conversion.

Growing winter barley 

would also help reduce soil 

erosion and nitrogen leaching, 

both major concerns for farmers in the Chesapeake Bay Watershed. 

Adding biochar as a soil amendment could further benefit food crop 

production and carbon sequestration efforts—all of which shows that 

even venerable old crops can be used to help solve current energy 

challenges.—By Ann Perry, ARS.

This research supports the U.S. Department of Agriculture 

priority of developing new sources of bioenergy and is part of 

Bioenergy (#213), an ARS national program described at www.

nps.ars.usda.gov.

To reach scientists mentioned in this story, contact Ann Perry, 

USDA-ARS Information Staff, 5601 Sunnyside Ave., Beltsville, MD 

20705-5129; (301) 504-1628, ann.perry@ars.usda.gov.*

Chemical engineer Akwasi Boateng (right) and mechanical engineer Neil 

Goldberg (center) adjust pyrolysis process conditions while chemist Charles 

Mullen (left) loads the reactor with bioenergy feedstock.

PEGGY GREB (D1985-1)

Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 13
14 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

Soil Fungi Critical to Organic Success

ne casualty ofAmerica’s agricultural revolution were

valuable native soil fungi that enabled crops to grow

well with less water, nutrients, and pesticides.

Increased agricultural productivity has been largely

dependent on high levels of chemical fertilizers and synthetic

pesticides. There is a growing interest in reducing this dependency by encouraging biologically based systems to enhance

productivity and product quality on farms.

That’s exactly what ARS chemist Philip E. Pfeffer and his

co-workers hope to accomplish by helping farmers reestablish

the beneficial soil organisms called mycorrhizal fungi. Pfeffer

is at the Agricultural Research Service’s Eastern Regional Research Center (ERRC) in Wyndmoor, Pennsylvania.

Mycorrhizal fungi live within the roots of most plants in a

mutually beneficial relationship (symbiosis). They help roots

scavenge more nutrients and water from the soil in exchange

for sugar to make the molecules they need to live and grow.

These fungi extend long threads, called hyphae, outside the

roots. The hyphae transport phosphorus and other nutrients into

plant roots. Mycorrhizae also enable plants to use water more

efficiently and resist pests.

Pfeffer and co-workers study the most common type of

mycorrhizae, which are called endomycorrhizae because the

fungi live inside—rather than between—root cells. They are

also called arbuscular mycorrhizae because of the treelike

structures (see photo above), or arbuscules, they build within

the cells. The branches transfer nutrients to the plant cells in

exchange for sugar for the fungi. The trunks of the arbuscules

attach to the hyphae.

Today, farmers who grow row crops, like corn and soybeans,

must rely on whatever soil fungi survived the decades of high

chemical application that began when American agricultural

production intensified in the 1950s.

Horticultural crop producers fare better because they can

buy potting mixes with beneficial fungi added. Home gardeners

can buy the fungi as soil inoculants from seed catalogs. But it’s

impractical for farmers to buy and apply the large quantities of

fungi they’d need for farm fields.

On-Farm Fungi Production

One member of the ARS team, David D. Douds, is

supervising experiments to find practical ways for farmers to

grow and apply their own mycorrhizal fungi. At the Rodale

Institute Experimental Farm in Kutztown, Pennsylvania—a

long-time proponent of organic farming—and at nearby

Stoneleigh Estate, Douds has tried growing the fungi in

compost. That would enable farmers to apply the fungi along

O

Soil Fungi Critical to Organic Success

Fields may eventually have colonies of beneficial microbes rivaling those of yesteryear.

At Stoneleigh Estate in Villanova, Pennsylvania, chemist Philip

Pfeffer (left) and microbiologist David Douds inspect a tropical

grass planted to produce compost-based inoculum.

PEGGY GREB (K9434-1)

(K9438-1)

Micrograph of fungal

arbuscules (treelike

structures) in the cells of 

leek roots.
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 15

with compost with no extra effort or cost.

Douds planted a tropical grass in the

compost after inoculating its roots with

arbuscular mycorrhizal fungi. He hoped the

roots would harbor the fungi and spread

them throughout the compost, but the fungi

didn’t spread well enough.

“We think the compost was so rich in nutrients that the grass roots didn’t encourage

the fungi to proliferate, because their help

wasn’t needed for getting nutrients,” he says.

This spring, Douds and his colleagues will

try mixing the compost with a less nutrientrich soil to see if that promotes fungal proliferation.

The researchers’ goal is to have suppliers sell farmers colonized host plants for

planting—not as a crop, but to start colonies of the fungi in soil, compost, or a compost/soil mix. Then, after the fungi have had time to multiply,

farmers would apply the colonized soil in manure spreaders

along with their compost.

“Instead of farmers having to buy and transport a whole

field’s worth of inoculum, they could buy a small fraction

packed in with host seedlings. Then, they’d plant the mycorrhizal seedlings and increase the inoculum on their own,”

Douds explains. Farmers would eventually have crop fields

with colonies of beneficial microbes rivaling those of yesteryear.

How Host Roots Communicate With

Mycorrhizal Fungi

Another member of theARS team, chemist Gerald Nagahashi, has found that plant

roots release signals to encourage or discourage proliferation during at least two of

the fungi’s seven life stages. He found that

in the firststage, when the fungalsporesstart

growing hyphae in the soil, roots exude

compounds that encourage prolific hyphal

growth. This helps the fungus find the root,

colonize it, and produce the arbuscules.

“We used carrot roots for these studies

because they’re a good model and can be

grown easily in liquid culture,” Nagahashi

says. The scientists have improved techniques for growing the fungi with carrot

roots in petri dishes and hope to do this

someday without the roots.

Nagahashi also did an experiment using

light and found it triggered more fungal

hyphal branching. “We predicted that

exposing inoculum to light would increase

colonization of corn seedlings by the fungi,

and that’s exactly what happened,” he says.

The team isstudying the basic physiology

of the mycorrhizal fungi and their interactions with plants so they can find a way to

grow fungal colonies without host plants.

This would permit large-scale production of

inoculum for field application.

“We also need to find out what nutrients

and other conditions have to be met so the

fungi grow through all seven life stages and

multiply,” Pfeffer says. “Using specially

marked molecules and nuclear magnetic

resonance spectroscopy to analyze a

mycorrhizal system in a petri dish, we’ve

learned a great deal about how carbon—in

the form of carbohydrates—flows from the

plant to the fungi. We’ve also learned that at certain stages of

the life cycle—such as during spore germination—the fungi

can take carbon directly from the soil without getting it from

plants, which encourages us.

“However, we need to find out why the spores are unable to

utilize this carbon to replenish their lipid stores, which are needed for completion of their life cycle,” says Pfeffer. “We’d like

to be able to feed the fungi glucose in the laboratory and have

them reproduce in mass quantities in fermentation vats, as we

do with bacteria and other fungi.”

In collaboration with Yair Shachar-Hill

and Peter Lammers at New Mexico State

University, the ERRC team is also examining

gene expression of these fungi at each lifecycle stage. With this information the

researchers hope to turn on the mechanisms

necessary for the fungi to complete their life

cycle in the absence of the host plant.—By

Don Comis, ARS.

This research is part of Soil Resource

Management (#202) and Plant Biological

and Molecular Processes (#302), two ARS

National Programs described on the World

Wide Web at http://www.nps.ars.usda.gov.

The ARS scientists mentioned in this

article are at the ARS Eastern Regional

Research Center, 600 East Mermaid Lane,

Wyndmoor, PA 19038; phone (215) 233-

6400, fax (215) 233-6581, e-mail

ppfeffer@arserrc.gov

ddouds@arserrc.gov

gnagahashi@arserrc.gov. 

Chemist Gerald Nagahashi transfers

roots into liquid medium. Compounds

released into the medium by these

roots will be used for in vitro studies.

Microbiologist David Douds inspects

carrot root culture system used to

study in vitro interactions of the host

plant and mycorrhizal fungi.

)1-5349K( BERG YGGEP PEGGY GREB (K9436-1)
1620 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 Agricultural Research/April 2002

he United States is the world’s leading corn-growing

country, with more than 40 percent of global production. More than 9 billion bushels were produced in

2001—the third highest yield on record, according to

USDA’s National Agricultural Statistics Service.

Where does all this corn end up? Most is used in livestock

feed, but it is also processed into many food and industrial products. These include starch, sweeteners, corn oil, beverage and

industrial alcohol, and ethanol fuel.

Corn is an abundant and renewable resource, and the search

for energy alternatives makes it a natural choice as a fuel source.

The high starch content of corn can be converted to sugar and

then fermented to ethanol fuel by brewer’s yeast.

Combining ethanol with gasoline lifts the octane level and

makes a cleaner-burning fuel. In the 2000-2001 season, about

620 million bushels of corn were used in ethanol production,

according to figures from USDA’s Economic Research Service. This number could increase 10 percent in the 2001-2002

season. A federal tax exemption keeps ethanol economically

competitive with petroleum fuel products but is due to expire

in 2007.

Cheaper Zein Means Cheaper Ethanol

Ethanol production from corn creates a surplus of byproducts that are increasingly difficult to sell. Engineers at the Eastern Regional Research Center in Wyndmoor, Pennsylvania, saw

the potential to lower production costs of ethanol by making

these byproducts more valuable, which could create new markets. The researchers believed one approach was to develop a

less expensive process to separate a valuable protein—zein—

from corn.

Zein is the main storage protein in the corn endosperm and

makes up more than half the total mass of the seed protein. It is

currently extracted from corn gluten. It is used mostly as an

edible, water-resistant coating for nuts, confectionery products,

or pharmaceutical tablets. Little zein is sold because it sells for

about $10 a pound.

“In the dry-milling ethanol process, zein is found in dried

distillers grain—or DDG—which is mostly sold as a protein

supplement in livestock feed,” says James C. Craig, the recently

retired former head of the Engineering Science Research Unit,

where the project originated. But as ethanol production expands,

the supply of DDG is expected to far exceed demand. “We

believed we could develop a process to extract the zein at a

cost that makes it attractive as a commodity.”

The researchers engineered and built a pilot ethanol plant at

ERRC to find ways to improve the economic return of

commercial corn-fermentation plants. The team broke the cost

barrier for affordable zein with a system for bulk extraction.

Their approach was to use the ethanol as a solvent to extract

zein from dry-milled corn.

“A key cost-savings in this process is that the solvent,

ethanol, is already present, since it’s the primary product,” Craig

says. “After fermentation, part of the ethanol produced can be

recycled to the extraction step, used, and then returned

downstream for separation.”

This method gives corn-ethanol plant owners an option of

producing a value-added coproduct, zein, which would provide

more revenue and reduce the overall cost of ethanol production.

Efforts are now under way to determine the maximum

concentration of zein that can be directly extracted from corn.

The pilot plant work was carried out under the supervision

of chemical engineer Leland C. Dickey. Pilot plants model

CORN

COPRODUCT

CUTS ETHANOL

PRODUCTION

COSTS

T

Chemist Nick Parris spraying zein-lipid mixture onto brown kraft

paper. These mixtures can be used to replace waxes made from

refined petroleum-based products.

PEGGY GREB (K9840-1)
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 Agricultural Research/April 2002 2117

commercial processes so that innovations can be evaluated in

a realistic setting.

Finding Added Value in Corn Kernels

Traditionally, films made from commercial zein are too

brittle and their tensile strength too low for most applications.

Chemist Nicholas Parris is finding ways to improve the

properties of zein isolated from ground corn.

Recently, ERRC scientists isolated a zein-and-lipid mixture

from dry-milled corn that costs about $1 a pound to produce.

While not as pure as the zein currently on the market, it is still

well suited for many applications. The lipid in the mixture

replaces refined petroleum-based products that are used to make

wax paper and wax-coated packaging. The mixture is an

excellent material for coatings, according to Parris, because

the zein portion resists grease, and the fatty acids repel water.

Because lipids eliminate use of paraffin wax, the paper can be

recycled. Unlike petroleum-derived waxes, the zein-lipid

mixture is biodegradable.

In the past, synthetic plasticizers have been used to improve

the mechanical properties of films made from commercial zein.

But Parris found that the presence of free fatty acids in the

zein-lipid complex could have the same effect.

A computer simulation model was designed to make cost

estimates for production from commercial plants. The models

are based on data from ethanol producers, engineering firms,

equipment manufacturers, and other sources. ARS cost engineer

Andy McAloon provides support to scientists and engineers to

determine research direction and the costs of possible

alternatives to standard industry practices. He uses the program

to predict the economic impact of the research.

About 620 million bushels

of corn were used in ethanol

production in the 2000-2001

growing season.

ERRC researchers are seeking cooperators who have specific

commercial requirements. The team can develop a process to

extract zein with the purity and characteristics for a specific

application at an affordable cost.—By Jim Core, ARS.

This research is part of Quality and Utilization of

Agricultural Products (#306) and Bioenergy and Energy

Alternatives (#307), two ARS National Programs described on

the World Wide Web at http://www.nps.ars.usda.gov.

Leland C. Dickey is in the USDA-ARS Crop Conversion

Science and Engineering Research Unit, Eastern Regional

Research Center, 600 East Mermaid Ln., Wyndmoor, PA 19038-

8598; phone (215) 233-6640, fax (215) 233-6406, e-mail

ldickey@arserrc.gov. ◆

Using a small-scale laboratory tank, chemical engineer Leland

Dickey separates corn and extract liquid. The extract liquid will be

further processed to separate out the zein.

PEGGY GREB (K9839-1)
18 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

bundant, affordable, safe, vast variety—it’s the

American way when it comes to shopping. What

isn’t found on any store shelf is an Agricultural

Research Service brand name. But many products

that people use every day could justifiably carry the stamp

“Courtesy of ARS Research.”

Pharmaceuticals, cosmetics, roach and termite controls,

leather, shampoos, and processed foods, not to mention a proverbial cornucopia of fruits, vegetables, berries, meats, and nuts,

all come to a store near you by way of ARS laboratories. Of

course, there are essential stops along the way for technology

transfer to the companies that turn out the actual products.

But without the work that ARS invests in research—often

long-term, high-risk research—there are whole industries of

products that might never have gotten off the ground. Some

products make it tastier to balance your diet. Some keep you

warm and fashionable. Some improve recreation and athletics,

and others keep you safe and healthy.

A

)01-7427K( REUAB TTOCS

Irradiated ground beef from Omaha Steaks.

)1-50001K( SUMSUA NEHPETS

All these products make use of soybeans. When ARS research develops new uses for agricultural commodities, it benefits both consumers

and farmers.

For You,the Consumer
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 19

One product in that last category ofsafety and health to which

consumers now have access as a result of ARS research is

irradiated hamburger free of Escherichia coli O157:H7, bacteria

that can cause serious, even life-threatening illness. Ground

beef is especially vulnerable because more than just the surface

of the meat may potentially have been exposed to bacterial

contamination.

The term “irradiated” refers to treatment with ionizing radiation from gamma rays produced by cobalt and cesium atoms,

machine-produced X-rays, or electron beams. Treated meat in

no way becomes radioactive.

Omaha Steaks, for example, began offering irradiated hamburger patties and ground beef in November 2000. Today, all

the 6.5 million pounds of ground beef they sell each year in

their retail and bulk food service operations is irradiated.

Bruce Simon, president of Omaha Steaks, feelsstrongly that,

with irradiation, research has developed a way to provide consumers with an extra measure of food safety for ground beef.

“We know we were among the first beef companies to make

use of irradiation. Whenever we can add another safeguard to

make sure that there is less possibility that anyone, especially

a child, could be exposed to E. coli, it’s a step we just have to

take,” Simon explains.

Consumers won’t see ARS’ name where it says “Treated by

Irradiation” on Omaha Steaks’ hamburger packaging. But much

of the research to prove irradiation an effective and safe method to sanitize ground beef came from the laboratory headed by

ARS microbiologist Donald W. Thayer.

“When you look at the docket that wassubmitted to the Food

and Drug Administration and the Food Safety and Inspection

Service to get approval for irradiation of red meat, many of the

papers they cite are from ARS,” Thayer says. Final approval

for irradiation treatment of meat came in February 2000.

Products that protect people from illness are not new accomplishments for ARS. In 1954, ARS developed N,N-diethylmeta-toluamide for the Department of Defense to protect

Tasty Juice

Sixty years ago, orange juice came either freshly squeezed in season or

canned—and tasting like the can. But in

1948, ARS scientists collaborated with

Florida Citrus Commission researchers

to perfect a method to produce a practical, flavorful frozen concentrate with all

its vitamins and minerals. Today, U.S.

consumption of orange juice from frozen

concentrate, still made using these methods, comes to more than 1.07 billion gallons a year.

)31-7327K( REUAB TTOCS

An abundance of useful products from ARS research

benefits consumers and farmers alike.
20 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

soldiers from disease-carrying insects. Now best known simply

as DEET, it remains the most effective mosquito repellant

available. About 230 products containing DEET are currently

registered with the U.S. Environmental Protection Agency.

World Health Organization statistics report that mosquitoes

spread about 4 million malaria cases, causing about 1 million

deaths globally each year. These insects also spread dengue

fever-related illnesses, which lead to 24,000 deaths annually.

More recently, the spread in the United States of West Nile

virus, also mosquito borne, hasfocused new attention on DEET.

West Nile virus has been reported in 36 states plus Washington

D.C., and it is expected to spread to all 50 states.

The Centers for Disease Control and Prevention recommend

that people in affected areas always wear an insect repellant

containing DEET when they go outside during mosquito season as the best protection against being exposed to West Nile

virus.

Some possible concerns about DEET posing a health risk

have been raised. EPA has reviewed the data and determined

“normal use of DEET does not

present a health concern.”

Several changes have been

made in the label directions to

ensure DEET is safely applied,

principally to avoid oversaturating skin or clothing and

not to spray infants.

Many antibiotics could also

bear the ARS stamp. In 1941,

British scientists, overwhelmed

by World War II, requested U.S.

help to find a way to produce

penicillin in mass quantities.

The problem was given to Andrew J. Moyer and others at the

National Center for Agricultural Utilization Research, then

called the Northern Regional Research Center (NRRC), in Peoria, Illinois.

Work began in July 1941. By November, Moyer had succeeded in increasing the yield of penicillin by creating a better

growth medium with the addition of corn steep liquor, an inexpensive byproduct of wet corn milling, and milk sugar. The

team’s development of deep vat techniques to grow the mold

cultures, called deep fermentation, added the missing piece of

the production puzzle.

Eight days after the bombing of Pearl Harbor, NRRC

representatives met with U.S. drug companies, which agreed

to attempt large-scale production of penicillin using the new

methods. The combined work of many researchers, including

ARS scientists, resulted in making penicillin available in mass

quantities by June 6, 1944, just in time to treat Allied soldiers

wounded on D-Day. Infection has always been one of the largest

causes of death in war, more so than direct battle injuries.

Mass-produced penicillin saved many lives during World

War II and continues to do so. And the improved growth media

and deep-fermentation methods and their outgrowths have since

been used in development of many other important antibiotics.

In 1987, Moyer became the first federal government scientist

inducted into the National Inventors Hall of Fame.

Filling the Cornucopia

Any time they shop for produce, people are very likely to be

buying a result of ARS research. The agency’s successes in

breeding new fruit, vegetable, nut, and berry varieties have had

an incredible impact on what consumers eat. New flavors,

extended harvest seasons, increased growing range, and better

shelf life are just a few of the improvements ARS researchers

have made.

Almost all the blueberries

and cranberries in commercial

production were either developed by ARS or bred from

ARS varieties. ARS also

brought consumers supersweetstrawberry varieties with

longer shelf life. Southerngrown fresh peaches would

probably not be readily available to consumers in eastern

U.S. markets if ARS had not

developed improved peach varieties as well as the Guardian

rootstock.

Citrus—fresh and processed—also hasARS’ fingerprints all over it. More than 80 percent of the citrus grown in

the United States are rootstock or fruit varieties developed by

ARS. When you buy a sweet red grapefruit, chances are pretty

good that it will be a Flame grapefruit from ARS. Most of the

early-season tangerines—about a $100 million annual retail

product—are ARS varieties Sunburst and Fallglo.

Red seedless grapes were all but unknown to the U.S. consumer before ARS released the Flame variety in 1973. Release

of another ARS variety, Crimson, in 1989 further increased

thistable grape’s popularity. The two varieties alone, now grown

extensively by both domestic and foreign producers, make up

a major portion of today’s consumer market.

Sweetpotato varieties released by ARS are the standard,

keeping the price of this crop affordable, the quality high, and

Insect repellants made from DEET, an ARS-developed

compound.

 SCOTT BAUER (K7243-7)
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 21

the supply steady. The same can be said for cantaloupe, watermelon, broccoli, nectarines, plums, lettuce, peppers, onions,

carrots...the list of fruits and vegetables that ARS research has

improved is almost endless.

In addition to whole foods like apples and oranges, ARS

has also developed many ingredients that people buy every day

as part of processed foods. On a wide variety of food ingredient

lists appear some form of the words “hydrolyzed oat flour” or

“hydrolyzed oat bran.” A lot of that is actually ARS’ patented

Oatrim, a calorie- and cholesterol-lowering replacer for

shortening made from enzyme-treated oats and barley.

Oatrim has been licensed to several companies, including

Quaker Oats, Inc., which uses Oatrim in foods like some

Healthy Choice dinners. Oatrim production was estimated to

be in excess of 20 million pounds in 1999, resulting in more

than $1 billion in retail sales.

Nutrim, another ARS development similar to Oatrim, has

recently led to a new, niche-market consumer product: gourmet

vegan chocolate truffles. Mrs. Mudd’s, Inc., of Oceanside,

California, worked out a way to make tasty chocolate truffles

with a great mouth feel without any dairy ingredients. When

mixed with water, Nutrim flows like heavy dairy cream or

coconut cream.

“It took 2 years to work out the right formula,” says company president Jan Mudd. “But our dark chocolate truffles are

certified organic and completely vegan, so they are the perfect

choice for people who are watching their cholesterol or those

who do not eat dairy products.”

Xanthan gum, discovered by ARS in the 1960s, is another

food ingredient that appears in a whole host of consumer

products. This natural product comes from fermenting corn

sugar with the microorganism Xanthomonas campestris. Even

a partial list of functions provides insight into why it is a

ubiquitous ingredient: it thickens liquids, provides good cling,

provides easy pourability and pumpability; controls crystallization, increases baking volume, provides temperature

stability, and suspends active ingredients.

Lactose-Free Milk

One-quarter of all adults cannot digest dairy

products. But ARS used a bacterium to produce an

enzyme that breaks down the milk sugar responsible for the problem. Today, consumers have access

to lactose-free products like milk, cheese, and ice

cream as well as Lactaid tablets, which let lactosesensitive people have dairy products. Lactose-free

milk is now 1 percent of all fluid milk sales, about

40 million gallons a year.

Strawberries, blackberries, and blueberries have all

been improved by ARS research.

SCOTT BAUER (K7229-21)

PEGGY GREB (K10141-1)

Gourmet vegan chocolates made with Nutrim, an ARS-developed

product that can substitute for dairy products in baking.
22 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

Salad dressings, instant soups, chocolate sauces, ice cream,

cake mixes, yogurt, and squeezable chewing gum are just a

few of the food products that make use of xanthan gum. It is

also in products like toothpastes, cosmetics, rust removers,

water-based paints, and antidiarrheal medicines.

Green Side Up

ARS is not an acronym you think of in connection with the

NFL, PGA, or even your neighborhood soccer field. But ARS’

bermuda grass varieties are taking over recreation fields and

golf courses, especially in the southern part of the country.

Tifsport, developed and released in 1997 by ARS plant

geneticist Wayne Hanna in Tifton, Georgia, has a whole team

roster of beneficial traits.

“We managed to breed in all the important traits—excellent

cold tolerance, uniform dark green color, aggressive establishment, improved pest tolerance, earlier spring green-up, and an

ability to tolerate frequent lower mowing,” Hanna explains.

“But most importantly, Tifsport can stand up to the stress and

demands of big-time sports, to the wear and tear of football

and soccer cleats, to the punishment of baseball spikes, and to

constant heavy foot traffic.”

Professional sports teams, universities, high schools, and

local recreation departments across the South have installed

Tifsport on athletic fields. Texas A&M recently planted about

97,000 square feet of Tifsport turf to give the Aggie soccer

team a new playing field.

The NFL Tennessee Titans football team installed Tifsport

when Adelphia Coliseum was built. A league-wide player

Neem Me Up

ARS researchers developed an environmentally friendly alternative to synthetic pesticides

from the oil of neem tree seeds that controls about 20 different plant pests and diseases.

For home gardeners, it is sold under the Green Light Company name. “It appealed to the

organic garden market from the first; now it is being well accepted by all types of home

gardeners,” says Bing McClellan, Green Light director of marketing.

Tifsport, a tough turfgrass developed by ARS, is used for sports fields by some high schools, universities, recreation departments, golf

courses, and professional sports teams. Here, the Tennessee Titans play the Washington Redskins on Tifsport in their Nashville stadium.

SNATIT/SENOJ NNOD©
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 23

survey in 2001 rated the coliseum as the fourth best playing

surface in the National Football League.

“Tifsport has great leaf texture and good dark green color.

But the best thing is that the grass stands up well to use; it

shearsrather than divotsso it lastslonger,” explains Terry Porch,

sports field manager for the Titans.

Southern golfers not only play on fairways planted with

Tifsport; many also putt on Tifeagle, a triploid bermuda grass

variety Hanna released in 1999. At last count, there are Tifeagle

greens in 14 states and 7 countries. Tifeagle can be mowed to

one tenth of an inch daily to provide a smooth, fast putting

surface. The previous standard for southern golf greens, Tifdwarf, also an ARS development, can only be mowed to three

sixteenths of an inch.

The beautiful blooms of crape myrtle are now common in many

U.S. gardens because of improved cold tolerance and disease

resistance provided by ARS.

KEITH WELLER (K3560-3)

ARS has been responsible for the bermuda grass standards

for southern sports fields, golf courses, commercial landscaping, and home lawns since grass breeder Glenn Burton started

the program in 1952. “Golfers were playing on sand or at best

rough common bermuda grasses before ARS developed the improved triploid hybrid ones,” Hanna says.

Gardeners also benefit from ARS research. Breeding successeslike camellias with better cold tolerance,American elms

resistant to Dutch elm disease, and later flowering magnolias

have given landscapers and gardeners important new choices.

One ARS advance consumers buy in droves every year are

crape myrtles developed to resist powdery mildew in the South

and colder temperature in the North, making the shrubs one of

the country’s most popular. “Within its current hardiness zone

range—which is now pretty much Baltimore south because of

ARS introductions—there is hardly a major landscape project

today that doesn’t include one or more crape myrtles. ARS

changed the crape myrtle world,” says Marc Byers of Byers

Wholesale Nurseries of Huntsville, Alabama.

Byers sells tens of thousands of crape myrtles each year and

a significant percentage are ARS-developed varieties. Natchez,

released by ARS in 1978, continues to be the standard by which

all other white crape myrtles are judged. Twenty-four years is

a long time for any one woody plant variety to remain the standard for landscapers, Byers points out.

Permanent Research

You may even be wearing ARS research as you read this

article. In 1958, wash-and-wear cotton clothes hit the consumer

market. Since the 1950s, ARS scientists have played key roles

in the research to develop durable press treatments, usually

called permanent press, that give cotton and cotton blends

wrinkle resistance. And durable press plays a key role in the

continued popularity of cotton and cotton-blend fabrics.

“Trousers represent the largest single apparel market for

cotton today, and I estimate that when we exclude jeans, more

than half of all mens’, boys’, and ladies’ trousers are made from

durable press-treated fabrics,” says Andrew Jordan, director,

technicalservicesfor the National Cotton Council. “ARS’ work

was fundamental to putting together the technology.”

Other ARS research on cotton has reached the consumer in

the form of fiber-reactive dyestuff groups that allow cotton to

be dyed more bright colors and better flame-retardant

treatments, including new-on-the-market, fire-resistant cotton

carpet.—J. Kim Kaplan, ARS.

To reach people mentioned in this article, contact Kim

Kaplan, USDA-ARS Information Staff, 5601 Sunnyside Ave.,

Beltsville, MD 20705-5128; phone (301) 504-1637, fax (301)

504-1648, e-mail kaplan@ars.usda.gov. ★

Lactose-free milk and milk products, for people who cannot

digest dairy products.

SCOTT BAUER (K7222-13)
24 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

Scientists Seek To Sanitize 

Fruits and Vegetables

gricultural advances, improved distribution, and increased imports have made it

possible for people in every

state to enjoy fresh fruits and vegetables

year-round. Americans know the health

benefits of a diet high in produce and are

taking advantage of this increased

availability and variety.

But occasionally, raw produce can

become contaminated with diseasecausing organisms such as Escherichia

coli O157:H7, Salmonella, or Listeria

monocytogenes. Although these instances are relatively uncommon, media

reports and public awareness in the last

few years have increased because scientists and public health agencies have

become better at detecting, reporting, and

determining causes of foodborne illness.

When produce is being grown, harvested, packed, and shipped, it can pick

up dust, soil, microorganisms, or chemical contaminants. Consumers should

wash fruits and vegetables to remove

those substances from surfaces.

A Clean Break

Whatever the source of contamination, more than one solution may be

needed. One area of concern is that

conventional washing methods remove

or kill only between 90 and 99 percent

of bacteria attached to the surfaces of

produce. Scientists at the Eastern

Regional Research Center (ERRC) in

Wyndmoor, Pennsylvania, are searching

for practical ways to overcome these

current limitations.

The scientists are conducting experiments on commercial-type produce

washing and sanitizing equipment to

reduce bacterial populations on fresh and

minimally processed fruits and vegetables. The tests use produce artificially

contaminated with harmless bacteria

similar in behavior to disease-causing

organisms. This research is being

conducted in a unique BSL-2 (short for

biosafety level 2) pilot plant at the

ERRC, says Gerald M. Sapers, a food

technologist with ERRC’s Food Safety

Interventions Research Unit.

Future studies will be carried out on

produce contaminated with actual

disease-causing organisms within a

containment structure equipped with its

own steam decontamination system. A

small-scale prototype was designed,

built, and validated by a team of scientists and engineers from Pennsylvania

State University and ERRC.

“Early tests with the prototype containment system have been very successful, and installation of a full-scale unit

at ERRC is nearing completion,” Sapers

says.

Paul Walker, a professor of agricultural and biological engineering at Penn

State, came to ERRC on a 15-month

sabbatical to design, build, and evaluate

research-grade produce-washing equipment for the BSL-2 pilot plant as part of

a joint venture between Penn State and

ARS, says Sapers. Walker oversaw the

design and construction of the prototype

and full-scale containment systems as

well as the newly designed, commercialscale washing equipment the lab received

from Penn State. This equipment is

operated by computer and permits

precise control of all experimental

variables. Joseph Sites, an ERRC

mechanical engineer, manages the pilot

plant, designs equipment, and conducts

experiments.

Sapers and food microbiologist

Bassam Annous are developing new

washing and sanitizing treatments in the

laboratory and then testing them in the

pilot plant. Current trials are performed

primarily with apples and cantaloupes,

using nonpathogenic surrogates for

human pathogens.

Denise Riordan, a former research

associate, and Annous compared nonpathogenic strains of E. coli with harmful

A

Engineering technician Andrew Cuthbert (foreground) gathers apples exiting a flatbed

brush washer within a containment chamber in ERRC’s new biosafety level-2 pilot plant.

Behind him, mechanical engineer Joseph Sites (middle) and food microbiologist Bassam

Annous operate the equipment.

Scientists Seek To Sanitize 

Fruits and Vegetables
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 25

strains to find surrogates with similar

traits.

ARS uses pilot plant programs to

serve as a bridge between invention and

commercialization. Industries form partnerships with ARS scientists to further

evaluate research that shows promise in

the laboratory. Effective technology can

then be transferred to produce packing

and processing industries.

Sapers says that the one-of-a-kind

equipment developed in this program

allows improvements in conventional

methods as well as novel approaches.

“The equipment must be suitable for

use in a commercial produce packing or

processing facility,” he explains.

One of the major problems that the

ERRC team is addressing is the ability

of bacteria to attach firmly to produce

surfaces, often in inaccessible locations,

and survive conventional washing and

sanitizing methods.

Packinghouses use chlorine and other

sanitizers to reduce microbe levels, but

conventional sanitizers are not able to

penetrate skin crevices, creases, or

pockets to destroy pathogens very

effectively. The trick is to find an agent

that will reach the pathogens without

damaging the appearance and texture of

the product.

Is the Solution in the Solution?

Scientists at ERRC have confirmed

the limited capabilities of conventional

washing methods, and are now looking

for methods that increase the safety of

produce while keeping the sensory qualities consumers expect in their fruits and

vegetables. Their results with experimental sanitizing treatments have been

mixed.

Washing apples in a brush washer,

even when the apples were sprayed with

very hot water, was found to be ineffective. Sapers says that total immersion in

a sanitizing solution is superior to brush

washing. However, he cautions that improper use of this “dump tank” method

for washing can lead to cross-contamination of the submerged produce.

Experimental hydrogen peroxide and

hot water treatments were applied to apples in a dip tank at different temperatures. Temperatures exceeding 60 ̊C

could not be used without causing discoloration. While such treatments were

able to eliminate up to 99.9 percent of

the bacteria, they still did not achieve the

total kill (99.999 percent) desired by the

Food and Drug Administration.

Sapers says other experimental

methods being studied involve steam

treatments or application of sanitizer

solutions under vacuum—for better

surface penetration.

“This would be a new approach for

commercial facilities,” he said. “One

challenge for researchers is to find ways

to keep the speed of the processing line

up to par, even when new sanitizing operations have been incorporated into the

process.”

Another method they are trying in

Wyndmoor involves treating apples and

other produce with acetic acid and

hydrogen peroxide vapors. Sapers said

there were large population reductions in

inoculated apples with some vapor

treatments but also some product discoloration. Work in this area is continuing.

Yet another approach involves the use

of an abrasive paste to grind pathogens

off produce surfaces while being careful

not to bruise or puncture the product.

The pilot plant program will become

fully operational when the larger containment structure is in place, permitting the

scientists to experiment with real pathogens.—By Jim Core, ARS.

This research is part of Food Safety

(Animal and Plant Products), an ARS National Program (#108) described on the

World Wide Web at http://www.nps.ars.

usda.gov.

Gerald M. Sapers is in the USDA-ARS

Food Safety Interventions Research Unit,

Eastern Regional Research Center, 600

East Mermaid Lane, Wyndmoor, PA

19038-8598; phone (215) 233-6417, fax,

(215) 233-6406, e-mail gsapers@ars

errc.gov. ◆

Food technologist Gerald Sapers (left) and

technician Donyel Jones evaluate apples

after an antimicrobial wash treatment.

PEGGY GREB (K9820-1)
1626 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 Agricultural Research/July 2004

golden kernel of corn is a rich source of many food

and industrial products, one of which is ethanol.

Ethanol production in the United States grew from

175 million gallons in 1980 to a record 2.8 billion

gallons in 2003. This boost in ethanol demand has created a

significant new market for corn.

“The United States is producing more ethanol from corn

and other domestic, renewable resources than ever before,” says

Kevin Hicks, research leader in ARS’s Crop Conversion Science

and Engineering Research Unit. “Almost 10 percent of the U.S.

corn crop is used to make fuel ethanol. That’s good for

America’s farmers. Ethanol is also good for the environment

because its use reduces greenhouse gas emissions.”

Hicks and colleagues at the ARS Eastern Regional Research

Center (ERRC), in Wyndmoor, Pennsylvania, are developing

new ways to reduce the costs of producing this important fuel

and other corn products. They’re also creating computer models to help researchers and ethanol producers estimate how different techniques might affect the bottom line.

Alternative Dry-Grind Techniques

The dry-grind process is the most common method used to

produce fuel ethanol. In it, the whole corn kernel is ground and

converted into ethanol. This method is relatively cost effective

and requires less equipment than wet milling, which separates

the fiber, germ (oil), and protein from the starch before it’s

fermented into ethanol. But the cost of making fuel ethanol

must be lowered even further before ethanol can compete favorably with gasoline.

To further lower costs for the dry-grind process, Frank

Taylor, a chemical engineer at ERRC, and Vijay Singh, a

professor from the University of Illinois at Urbana-Champaign,

developed and patented a process that permits low-cost recovery

of nonfermentable corn components, such as germ and fiber.

These can be sold as valuable co-products for food or feeds.

The process treats corn kernels with anhydrous ammonia gas

to loosen up the kernel components so they can be easily

separated and recovered.

Taylor and colleagues also developed another modified drygrind process called continuous fermentation with ethanol

stripping. It allows more efficient production of ethanol in

smaller, less expensive fermentors. (See “Bioenergy Today,”

Agricultural Research, April 2002, p. 4.)

Wet Milling Made Easier

In the wet milling process, corn is separated into its four

basic components: starch, germ, fiber, and protein, which are

each made into different products. The advantage of wet milling

is that, besides ethanol, valuable co-products such as corn oil

are also produced. The disadvantages are that the equipment is

expensive and the process uses hazardous sulfur dioxide.

During conventional wet milling, corn is steeped for 24 to

36 hours in water and sulfur dioxide to begin the separation of

the starch and protein connections. Then the corn is coarsely

ground to break the germ loose from other kernel components.

Later, the starch is separated out and converted into sweeteners or ethanol.

ERRC food technologist David B. Johnston and Singh developed a faster, cheaper way to break down the starch and

protein connections. They are using several commercially availNew Milling Methods Improve

Corn Ethanol Production

A

Food technologist David Johnston (left) and research leader Kevin

Hicks check fermentability of enzymatically milled corn.

STEPHEN AUSMUS (K11276-1)
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 Agricultural Research/July 2004 2717

able protease enzymes to do the job. This process requires much

less sulfur dioxide during the steeping stage of wet milling.

The new method includes a 6-hour soaking in water of the

corn kernels before milling. After about 3 hours of soaking,

the enzymes are added. Then normal wet-milling steps are

resumed.

Johnston says that in laboratory and pilot-scale trials, the

enzyme method separated starch and proteins faster and yielded starch equal to or greater than the conventional process.

“With sulfur dioxide, there are regulations on emissions, and

costlier equipment for processing is required,” Johnston says.

“Protease enzymes are also expensive, but we can lessen use

of harmful materials in milling and produce the starch more

quickly, using less energy.”

Predicting Costs

So, how might innovations like these affect the ethanol

producer’s bottom line? The Wyndmoor scientists recently completed several computer models to help answer that question.

Andy McAloon, head cost engineer of the Process and Cost

Simulation Group, says the models estimate the cost per gallon

to produce ethanol with various processes. The models, which

run on Aspen Plus software, are based on data from commercial

plants and current costs for equipment, materials, labor,

supplies, grain, and utilities.

McAloon and chemical engineer Winnie Yee worked with

researchers to create the models, which analyze how new

methods affect ethanol production costs. They provide support

to scientists and engineers to determine research directions and

predict the costs of possible alternatives to standard industry

practices.

“These models can save researchers and producers time and

money by simulating the many variables involved in production instead of having to actually go through the complete process each time they want to adjust a system,” McAloon says.

The scientists have just released what they believe is the

first publicly available corn wet milling process and cost model.

It was developed by McAloon, Yee, and food technologist David

Johnston, with cooperation by the Corn Refiners Association.

Johnston and co-workers plan to use it extensively in their work

with protease enzymes.

Another model, made by Yee, McAloon, and Taylor, helps

estimate costs for making ethanol by dry grind processes. For

example, they showed that the ARS-developed continuous fermentation and stripping procedure could save 3 cents per gallon. Users can examine countless other possibilities—such as

reclaiming wasted heat, converting some of the fiber to ethanol, or pulling out the germ before fermentation—to see how

they would affect the cost of making a gallon of ethanol.

The researchers recently updated their 25-million-gallon-ayear model for dry-grind ethanol producers to a 40-milliongallon version, which is available to anyone doing research or

in the initial phases of building a plant.—By Jim Core, ARS.

This research is part of Quality and Utilization of Agricultural Products (#306) and Bioenergy and Energy Alternatives

(#307), two ARS National Programs described on the World

Wide Web at www.nps.ars.usda.gov.

Kevin B. Hicks is in the USDA-ARS Crop Conversion Science and Engineering Research Unit, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, PA 19038;

phone (215) 233-6579, fax (215) 233-6406, e-mail khicks@errc.

ars.usda.gov. ★

Using a new computer model, cost engineer Andy McAloon and

chemical engineer Winnie Yee discuss different ethanol production

techniques and how they might affect costs of producing the fuel.

Chemical engineer Frank Taylor prepares to test fermentability of

corn that has been pretreated with a new “ammoniation” process.

STEPHEN AUSMUS (K11277-1)

STEPHEN AUSMUS (K11278-3)
28Agricultural Research/January 2005 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-201015

By developing new detection techniques

and processes that incorporate principles

from many different scientific disciplines, Agricultural Research Service

scientists in Wyndmoor, Pennsylvania,

are improving food safety.

Regulatory agencies and the food industry need fast, automated, cost-effective analytical methods

that are accurate, reliable, and safe and that minimize waste.

Several of the research unit’s chemists are using advanced technologies to develop methods to screen, detect, and confirm multiple chemical residues—such as veterinary drugs and

pesticides—and pathogenic bacteria and their toxins in food

products.

Shu-I Tu, research leader of the Microbial Biophysics and

Residue Chemistry Research Unit at the Eastern Regional

Research Center, oversees development of such techniques. He

says the laboratory works with state-of-the-art scientific

instrumentation and biosensor-based methods that can detect

chemical signals and provide information about specific

biological activities.

“Many procedures we use have been modified from diagnostic systems used for medical analysis,” Tu says. “We are

taking several different approaches to prevent distribution of

contaminated foods.”

One method they use, fluorescence spectroscopy, involves

recording optical spectra from molecules absorbing and emitting light. There are several ways to attach highly fluorescent

probes to make biological targets—such as pathogenic bacteria—glow. Fluorescence spectroscopic methods, which rely

on monitoring changes in the wavelengths and intensity of

the signal, have been used for decades. Researchers use

changes in the emission spectrum to achieve valuable

insight into the concentration and behavior of the

emitting molecules.

Detecting low levels of protein or DNA targets

in or on a sample is sometimes difficult and prone

to errors because specific fluorescence signals can

be low or masked by interferences. One approach

to improve detection and isolate the desired spectroscopic signal is to use what’s known as timeresolved fluorescence (TRF) and luminescence

(TRL) reagents. Time-resolved spectroscopic techniques help reduce background noise and increase

sensitivity.

Scientists Monitor Food for Residues

Some veterinary drugs are not approved for use

in food-producing animals. Others, such as betalactam antibiotics, have tolerance levels—maximum amounts of a given chemical or its breakdown

products allowed to remain in or on food commodities—

established by the U.S. Food and Drug Administration (FDA).

Time-consuming and laborious methods are currently used for

regulatory purposes to ensure that these drugs are not present

in samples.

Chemist Guoying Chen has developed a prototype of a

portable, suitcase-sized device to detect contaminants, such as

tetracycline antibiotics, in meat, milk, and fish. The 25-pound

prototype was designed for regulatory-agency investigators to

take directly to a site for field analysis. Its user-friendly custom

software is already completed and will run in a Microsoft

Windows environment.

The filter-based fluorometer uses TRL to detect trace

amounts of target chemicals by removing interference from

fluorescent background signals given off by other organic

substances present in a meat sample. The system requires 1-5 g

of meat from which to extract the antibiotics present and concentrate them into liquid solution. Testing can be conducted on

site and results provided on the spot. A quick change of filters

New Detection Methods

Improve Food Safety

Hightech

tests—

simpler,

cheaper,

faster.

Chemist Steve

Lehotay

prepares

extracts of

fruits and

vegetables for

analysis of

pesticide

residues.

STEPHEN AUSMUS (K11684-1)
16Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 Agricultural Research/January 200529

allows the user to move from one targeted drug to another. The

device is capable of analyzing key antibiotics in chicken and

beef at slaughterhouses, and it could be used to check for

contaminants in liquids, such as milk, water, or urine.

Marilyn Schneider, another chemist in the research unit, is

interested in analyzing animal-derived foods for veterinary drug

residues. She is developing assays using natural fluorescence,

as well as TRF, to screen for the presence of fluorescent

antibiotics. Schneider takes advantage of the fluorescence of a

fluoroquinolone antibiotic called enrofloxacin to first screen

muscle extracts for its presence. After two reagents are added

to this solution, the same sample can be

screened for tetracycline antibiotics,

eliminating the need for a separate

extraction.

In another approach, Schneider and

Chen use a buffer to extract samples from

chicken, clean the samples by solid phase

extraction, add TRL reagents, and then

measure the samples for tetracyclines using TRL.

“These screening assays are alternatives

to biological assays used by regulatory agencies,” Schneider

says. “The fluorescence assay is very rapid and detects the drugs

when they are at or above the tolerance level. TRL methods

require more cleanup, but have greater sensitivity.”

Chemist Steven Lehotay, along with a previously visiting

scientist, Michelangelo Anastassiades, developed the

QuEChERS method, which stands for “quick, easy, cheap,

effective, rugged, and safe” and is pronounced “catchers.” The

streamlined approach makes it easier and less expensive for

analytical chemists to examine fruits and vegetables for

pesticide residues. Lehotay says the method reduces procedural

steps—and that lessens the chance for a mistake. A single, easyto-clean Teflon tube is the only item to be washed and reused,

eliminating all the glassware used in conventional methods.

Furthermore, less than 10 mL of solvent waste is generated—

much less than the 75-450 mL generated by other methods.

“Several monitoring laboratories, including a few in FDA,

are evaluating QuEChERS for use in routine monitoring and

other approaches designed to safeguard the food supply,”

Lehotay says. He and colleagues are now working to adapt the

concept to analyze meats for veterinary drugs.

Chemist Keith Fagerquist, along with Lehotay and chemist

Alan Lightfield, developed a method to measure and confirm

beta-lactam antibiotics in pork and cattle kidney tissue. The

method—which uses liquid chromatography/tandem mass

spectrometry—is fast and looks for multiple residues in tissue

samples, where antibiotics tend to concentrate the most.

Methods Detect Pathogens and Toxins in Food

Antibodies are protein molecules that bind to antigens—

such as bacteria—and remove them from the body. Researchers can use antibodies to isolate pathogens or chemicals in food

products as well.

To detect E. coli O157:H7 in foods, chemist Shu-I Tu and

microbiologist Marsha Golden use immunomagnetic capture and

time-resolved fluorescence.

Chemist Marjorie Medina prepares egg samples for analysis of

Staphylococcus aureus enterotoxins by surface plasmon resonance.

QuEChERS

stands for

“quick, easy,

cheap, effective, rugged,

and safe.”

STEPHEN AUSMUS (D009-1)

STEPHEN AUSMUS (K11685-1)

Andrew Gehring, another chemist in the unit, is working

with Tu on a procedure that combines immunomagnetic capture

with TRF to simultaneously detect Escherichia coli and Salmonella in ground beef, ground turkey, alfalfa sprouts, and

seeds. The procedure uses magnetic beads that are coated with

pathogen-specific antibodies. The antibodies bind to the bacteria, and the magnetism pulls them out of complex mixtures of

food. Once extracted, the bacteria can be more easily detected.

Gehring is also developing a luminescence-based method

coupled with an ELISA (enzyme-linked immunosorbent assay)

to detect and confirm E. coli O157:H7. An ELISA is a sensitive laboratory test that uses antibodies and enzymes to detect

and measure specific antigens in samples. Gehring’s test can

be completed in 8 hours and can detect 1-10 bacteria per gram

of ground meat. USDA’s Food Safety Inspection Service (FSIS)

would ultimately like to be able to detect 1 bacterium in 25

grams of meat.
30Agricultural Research/January 2005 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-201017

The search for fast, inexpensive analytical food safety methods that are accurate, reliable, and safe.

Chemist Andy Gehring inserts a meat sample into a luminometer to

check for the presence of bacteria as technician Sue Reed prepares

other samples for analysis.

Chemists Marilyn Schneider and Alan Lightfield analyze veterinary

drug data from the liquid chromatograph/tandem mass

spectrometer.

The tube held by technician Sheri Mazenko contains concentrated

immunomagnetic beads coated with antibodies that bind to specific

bacteria, making it possible to detect contaminants in food.

Chemist Guoying Chen tests a portable fluorometer he designed

and built to screen for drug residues in food extracts.

STEPHEN AUSMUS (K11687-1)

STEPHEN AUSMUS (K11686-1)

STEPHEN AUSMUS (K11688-1)

 STEPHEN AUSMUS (K11689-1)

Chemist Marjorie Medina developed a biosensor immunoassay using surface plasmon resonance (SPR) to detect Staphylococcus aureus enterotoxin A (SEA) and B (SEB)—toxins that

cause gastroenteritis—in foods such as ham, milk, and eggs.

Conventional heating and processing kills the bacterium but

not its toxins. Bacteria produce toxins under stressful conditions, such as when they are too crowded or denied food or

when they’re fighting back against antibiotics.

“SPR uses light reflected off thin metal films,” Medina

explains. “Toxin molecules in the sample bind to the sensor

surface, and the refractive index at the surface changes. The

time it takes for a response from the interaction provides a

measure of how much toxin, if any, is actually present in the

food sample.”

Medina says that FSIS is interested in an alternative to the

conventional method to detect enterotoxins in whole eggs. Her

semi-automated method has several advantages over other

methods and may detect multiple bacterial toxins in a single

food sample.

Medina also developed a latex particle agglutination assay

for detection of SEA and SEB that causes the toxins to clump

together. The method takes advantage of an antibody’s ability

to bind to a unique antigen in pathogen cells. The assay is simpler to use than other methods and can detect as little as 10

parts per billion of toxin per gram of sample.—By Jim Core,

ARS.

This research is part of Food Safety (Animal and Plant Products), an ARS National Program (#108) described on the World

Wide Web at www.nps.ars.usda.gov.

Shu-I Tu is in the USDA-ARS Microbial Biophysics and Residue Chemistry Research Unit, Eastern Regional Research

Center, 600 East Mermaid Ln., Wyndmoor, PA 19038-8598;

phone (215) 233-6466, fax (215) 233-6581, e-mail stu@errc.

ars.usda.gov. ★
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 31

hough natural, untreated wool is scratchier than 

synthetic fabrics, wool is less susceptible to burning. This makes it an ideal fabric for uniforms 

worn by members of the military, firefighters, 

and others whose occupations expose them to fire.

“Wool burns with a self-extinguishing flame and produces a 

soft ash that dissipates and will not lodge in open wounds,” says 

Jeanette M. Cardamone, a chemist at the ARS Eastern Regional 

Research Center (ERRC) in Wyndmoor, Pennsylvania. “Synthetic materials, on the other hand, form hot, molten beads that 

can drip into a wound and cause trauma.”

In ERRC’s Fats, Oils, and Animal Coproducts Research Unit, 

Cardamone has discovered and patented a heat-resistant material 

that can be incorporated into wool and other fabrics to match 

the flame resistance of commercial firefighters’ uniforms. The 

material was developed at the request of the U.S. military—one 

of the largest markets for domestic wool—to offer U.S. troops 

protection against fire-related injuries.

In an earlier project, Cardamone developed biopolished wool 

that is both machine washable and itch free. Nine companies 

have expressed interest in licensing the patent for this technology, and the ARS Office of Technology Transfer has issued two 

licenses for it. This wool already has many desirable properties, 

so it’s a natural choice for developing a fabric with improved 

flame retardancy.

Working with visiting scientist Anand Kanchagar, Cardamone 

improved the flame retardancy of the biopolished wool by treating it with a heat-resistant polymer that is stable, easy to process, 

and highly tolerant of extreme temperatures. Unlike some popular 

flame retardants, the ARS material does not use the heavy metal 

zirconium, which can present a health hazard during processing. 

While natural, synthetic, and blended fibers can be treated with 

the polymer, wool is particularly suitable because of its innate 

fire resistance.

Early tests show that the burning behavior of the polymer-treated ARS wool compares to a 50/50 blend of wool and Nomex—the 

fabric currently used in protective firefighting gear.

The scientists are experimenting with different methods to enhance the wool’s heat-resistant and flame-retardant properties.

Cardamone says that the flame-retardant treatment should be 

durable to laundering.

Increasing the value and versatility of domestic wool would 

benefit the U.S. sheep industry, which produces about 40 million 

pounds of raw wool a year. In addition, U.S. consumers—including the U.S. military and many law-enforcement agencies, which 

are required to use domestic wool in their uniforms and equipment—would enjoy the benefits of home-grown, soft, shrinkproof, fire-retardant wool.—By Laura McGinnis, ARS.

This research is part of Quality and Utilization of Agricultural 

Products, an ARS national program (#306) described on the 

World Wide Web at www.nps.ars.usda.gov.

Jeanette M. Cardamone is in the USDA-ARS Fats, Oils, and 

Animal Coproducts Research Unit, Eastern Regional Research 

Center, 600 E. Mermaid Ln., Wyndmoor, PA 19038-8598; phone 

(215) 233-6680, fax (215) 233-6795, e-mail jan.cardamone@

ars.usda.gov. X

Protecting U.S. T

Troops With 

Fireproof Wool

Biopolished 

wool, developed 

at the ARS 

Eastern Regional 

Research Center 

in Wyndmoor, 

Pennsylvania, 

is displayed as 

an army neck 

gator. A new 

ARS-developed 

polymer can be 

added to this 

fabric to make it 

flame retardant.

 ERRC (D1125-2) 

 ERRC (D1125-3)

Scanning electron micrographs of untreated wool fiber (top) 

and wool fiber treated by the ARS biopolishing, shrinkproofing 

method (bottom). Magnified about 2,500x.

ERRC (D1125-1)
1032 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 Agricultural Research/February 2005

Irradiation

e are surrounded by radiation. It’s a natural part of the

electromagnetic spectrum, and we’ve harnessed its

power for our benefit.

Ionizing radiation is widely used around the world

today as a safe and effective nonthermal way to pasteurize fruits

and vegetables, ground beef, poultry, and spices. Agricultural

Research Service scientists in Wyndmoor, Pennsylvania, are

discovering more about how this valuable technology can be

used to improve food safety.

Whether from gamma rays, electron beams, or x-rays, irradiation inactivates bacteria such as Escherichia coli O157:H7,

Salmonella, Listeria, and other microorganisms and parasites

that cause some 250 types of foodborne illnesses. Symptoms

of infection can include nausea, vomiting, abdominal cramps,

and diarrhea.

Irradiation also inactivates food-spoilage organisms, including bacteria, molds, and yeasts. Irradiation modifies the genes

and cell membranes of microorganisms, killing or severely injuring them. It can lengthen the shelf life of fresh fruits and

vegetables by delaying ripening and inhibiting sprouting.

Irradiation’s effectiveness against food-spoilage organisms

was first shown in France in the 1920s. In the mid-1960s, the

U.S. Food and Drug Administration (FDA) approved use of

low-dose ionizing radiation for killing or sterilizing insects in

wheat and wheat flour and for inhibiting sprouting in potatoes.

In 1983, FDA approved using irradiation to sterilize spices.

In 1981, research programs for food irradiation were transferred from the U.S. Army to USDA’s Eastern Regional Research Center (ERRC) in Wyndmoor. Since then, ERRC

scientists have conducted genetic toxicology testing of irradiated

foods and supervised completion of the Raltech Study, the most

complete and comprehensive experiments ever conducted on

the toxicological safety of irradiated foods. These studies found

no increased risk of cancer, birth defects, or other harm from

consumption of irradiated foods.

Thanks in part to ERRC research efforts, FDA approved irradiation of poultry in 1990 and of fresh and frozen red meats,

including beef, lamb, and pork, in 1997. ERRC research also

established that ionizing radiation could inactivate E. coli

O157:H7 in red meat and poultry. Irradiated ground beef and

poultry are now sold in more than 4,000 supermarkets across

the United States.

The 2002 Farm Bill allowed, on a voluntary basis, irradiated

ground beef into the National School Lunch Program, which

USDA oversees. In 2003, Xuetong Fan, a food technologist at

ERRC, led taste panels where participants were asked to

evaluate various sensory characteristics of irradiated meats in

comparison with untreated products. The project was started to

support two USDA agencies, the Food and Nutrition Service

and the Agricultural Marketing Service, in their efforts to assure

parents and school leaders of the continued quality of school

lunches. States were permitted to offer school districts irradiated

ground beef beginning in January 2004.

So that study panelists focus only on taste, flavor, and texture, food

technologist Xuetong Fan presents samples in a specially lit room

that helps mask visual differences between samples. This study

evaluates sensory properties of irradiated ground beef for the

National School Lunch Program.

ARS Continues Advances in

of Ready-To-Eat Foods

STEPHEN AUSMUS (K11710-1)

W

Microbiologist Christopher H. Sommers is the lead scientist

for food irradiation in ERRC’s Food Safety Intervention

Technologies Research Unit. His research is directed at

improving the safety and shelf life of raw meat and ready-toeat (RTE) meat products. Sommers has done extensive work
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 33

Agricultural Research/February 2005 11

with ionizing radiation to eliminate Listeria monocytogenes

from RTE meats.

“Although RTE meats are already cooked, FDA and the meat

industry recommend reheating for some products, because they

can become contaminated between cooking and packaging.

Pathogenic bacteria such as L. monocytogenes, if present on

the product, can sometimes multiply during refrigerated storage,” Sommers says. FDA is reviewing, but has not yet approved, irradiation for RTE meats such as hotdogs, bologna,

and deli turkey and ham.

Currently, the RTE industry uses thermal and other nonthermal techniques to inactivate, if not completely kill,

microorganisms. But those treatments don’t always prevent

subsequent growth of bacteria under refrigeration. At least 90

million pounds of RTE meat products have been recalled since

1998 due to L. monocytogenes contamination. Sommers believes that for ground meats and some RTE products, irradiation

may be the only effective means of treatment, since it can be

used after packaging.

The radiation resistance of L. monocytogenes and other

pathogens depends on the product’s formulation and the genetic characteristics of the contaminating strain. Sommers has

established the radiation doses needed to inactivate L. monocytogenes in a variety of RTE meat products, and he’s determined the radiation resistance of L. monocytogenes strains

associated with foodborne illness.

Sommers has also completed studies on the roles of food

additives in inhibiting growth of injured pathogens in food

products during long-term refrigerated storage.

Food additives are commonly used to extend the shelf life

of meat products. Sommers says certain ones make Listeria

more sensitive to radiation. For instance, he determined that a

mixture of salts of acetic acid (vinegar) and lactic acid in bologna formulations decreased the radiation dose needed to inactivate 99.999 percent of L. monocytogenes inoculated onto

the meat from 3.0 to 2.5 kiloGrays (kGy). The combined treatments also prevented growth of spoilage microorganisms for 2

months. “Ionizing radiation, when combined with common food

additives, has the potential to significantly reduce the incidence

of listeriosis associated with consumption of RTE meats in the

United States,” Sommers says.

Fan and colleagues demonstrated that irradiation promoted

production of several volatile sulfur compounds associated with

unpleasant odors that can sometimes occur in irradiated or overcooked RTE turkey meat. Adding antioxidants to RTE formulations had a very limited effect in preventing production of

the compounds. In additional work with Fan and A.P. Handel

from Drexel University in Philadelphia, Sommers found that

the combination of common additives and mild heating reduced

levels of sulfur compounds in RTE turkey meat by more than

50 percent compared to irradiation alone.

Sommers collaborates with colleagues at ERRC in related

research, including irradiation of foodborne pathogens in fruits,

vegetables, and juices. He’s also examining ways to control

other major pathogens, such as E. coli, Salmonella, and Yersinia,

in other meat products. Yersinia infection most often occurs

from eating raw or undercooked pork products, such as

chitterlings. Y. enterocolitica is of great concern to researchers
1234 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 Agricultural Research/February 2005

and the meat industry because, like L. monocytogenes, it is

capable of growing at refrigeration temperatures and in highsalt environments.

To determine the radiation resistance of Y. enterocolitica in

different commercial practices, Sommers and co-researchers

studied the pathogen in ground pork at different temperatures.

They were particularly interested in the radiation dose needed

to control Y. enterocolitica in subfreezing temperatures. There

are fewer undesirable effects on some physical characteristics,

such as texture and color, of meat products at subfreezing

temperatures than those irradiated at refrigeration temperatures

at the same dose. But it takes a larger dose to pasteurize frozen

meat than nonfrozen meat. They were able to determine the

range of radiation doses required to treat the same product at

different temperatures—as commercial processors do.

At ERRC, microbiologist Glenn Boyd places a batch of hotdogs into

the gamma radiation source to rid them of foodborne pathogens.

Research on Fruits and Vegetables Improves Safety

and Quality

Brendan A. Niemira, a microbiologist and plant pathologist

at ERRC, focuses on methods to irradiate fruits, vegetables,

juices, and meat substitutes of vegetable origin, such as soy.

He is interested in finding the ideal dose of irradiation that increases safety but does not affect a given product’s quality.

Since late 2002, government regulations have permitted use

of irradiation on imported fruits and vegetables to meet phytosanitary quarantine requirements, which refers to controlling

organisms that affect plant health. Higher radiation doses could

be used to inactivate foodborne pathogenic bacteria as well.

The National Food Processors Association has petitioned FDA

to allow the higher doses on fruits and vegetables. FDA is currently evaluating the petition.

Grapes, for instance, have recently been suspected in Salmonella outbreaks. Niemira and Fan tested red and white whole

grapes and their juices after purposely inoculating them with

the pathogen. The textures of both grapes were not significantly affected by irradiation doses of up to 1 kGy—the maximum

dose approved for fresh fruits and vegetables. Although the color

of red grapes and red grape juice was influenced by treatments,

white grapes and white grape juice held up very well.

“These results demonstrate that each product responds differently to irradiation and has to be treated differently to ensure it remains appealing to the consumer,” Niemira says.

Niemira also recently studied the effectiveness of gamma

irradiation in inactivating Listeria and Salmonella placed on

the surface of lettuce. He studied four closely related but distinct

types of lettuce: Boston (butterhead), iceberg (crisphead), green

leaf, and red leaf (variants of looseleaf). The studies showed

that the radiation sensitivity of L. monocytogenes was similar

on the four lettuce types, but the sensitivity of Salmonella was

slightly different. Complexity of the leaf surface was the

underlying factor. Although irradiation was effective at reducing

pathogen numbers, subtle differences between lettuce types influenced the sensitivity of bacteria present on their surfaces.

Niemira says radiation doses would have to be tailored for each

type of lettuce to be effective.

The key to using irradiation is to eliminate foodborne pathogens without affecting product quality. Fan wants to assess the

extent of irradiation’s effect on product quality and to develop

novel ways to minimize any adverse effects. He examines

factors such as chemical composition, nutritional qualities, aroma, flavor, and texture in a variety of foods.

Major quality changes in some vegetables appeared to be

tissue browning and decreased shelf life from loss of tissue

integrity, which, in some instances, gives a soggy appearance.

Because fruits and vegetables contain so much water, they are

especially susceptible to the effects of irradiation and other nonthermal treatments.

STEPHEN AUSMUS (K11708-1)
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 Agricultural Research/February 2005 1335

Molecular biologist Chris Sommers (left) and microbiologist Glenn

Boyd vacuum-seal hotdogs to get them ready for irradiation.

Food technologist Ethan Solomon (left) and Chris Sommers

examine fluorescent micrographs of bacteria suspended in biofilms

exposed to ionizing radiation.

Fan found that irradiation and heat pasteurization of apple

and orange juice led to increased levels of several volatile sulfur compounds and aldehydes. Studies have shown that compounds such as aldehydes might contribute to off-odors in heated

and irradiated foods. Fan believes conducting the treatments at

lower temperatures, adding antioxidants, and combining irradiation with other treatments could help reduce undesirable

quality effects on juices.

Fan teamed up with collaborators to develop a method to

treat sliced apples used in fruit salads. They were interested in

reducing tissue browning, which happens when plant tissue is

cut during processing. They found

that dipping apple slices into a calcium ascorbate (a form of vitamin

C) solution before exposure to a lowdose gamma radiation treatment improved microbiological safety and

inhibited tissue browning.

Fruits and vegetables are rich in

antioxidants, which help protect us

against cancer and heart disease.

These beneficial effects are partially

due to high amounts of phenolic

compounds. Fresh and fresh-cut

fruits and vegetables are living

organisms, capable of synthesizing

novel antioxidants in response to

stresses even after they are picked

and processed. Fan showed that

irradiated iceberg and romaine

STEPHEN AUSMUS (K11706-1) STEPHEN AUSMUS (K11707-1)

lettuce and endive developed a higher antioxidant capacity than

nonirradiated vegetables during a postirradiation cold-storage

period. The higher antioxidant capacity was mostly due to the

increased content of phenolic compounds. Vitamin C content

in the fresh-cut vegetables, however, was not significantly

affected by irradiation doses as high as 1 kGy.

“In addition to the beneficial effect of foodborne pathogen

inactivation, irradiation of fresh-cut fruits and vegetables may

result in a product with enhanced antioxidant capacity,” Fan

says.—By Jim Core, ARS.

This research is part of Food Safety (Animal and Plant

Products), an ARS National

Program (#108) described on the

World Wide Web at www.nps.ars.

 usda.gov.

Christopher H. Sommers,

Brendan A. Niemira, and Xuetong

Fan are with the USDA-ARS Food

Safety Intervention Technologies

Research Unit, Eastern Regional

Research Center, 600 East

Mermaid Lane, Wyndmoor, PA

19038; phone (215) 836-3754

[Sommers], (215) 836-3784

[Niemera], (215) 836-3785 [Fan],

fax (215) 233-6445, e-mail

csommers@errc.ars.usda.gov,

bniemira@errc.ars.usda.gov,

xfan@errc.ars.usda.gov. ★

Using a texture analyzer, food technologist Xuetong Fan

and chemist Kimberly Sokorai evaluate an apple before

processing and irradiation treatments to ensure initial

product quality.

STEPHEN AUSMUS (K11709-1)
36 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

ood technologist Thomas P. Oscar wants to make poultry as 

pathogen-free as possible. His 

research focuses on modeling 

growth and survival of Salmonella and 

Campylobacter—the two most prevalent 

bacterial food pathogens—on chicken, 

the most consumed meat product in the 

United States. 

Oscar and technician Jacquelyn B. Ludwig are a two-person team at a research 

laboratory on Maryland’s Eastern Shore. 

The ARS Poultry Food Safety Research 

Laboratory is part of the Microbial Food 

Safety Research Unit of the Eastern Regional Research Center (ERRC) in Wyndmoor, Pennsylvania. But it’s 

physically located on the University of Maryland Eastern 

Shore (UMES) campus 

in Princess Anne—in 

the heart of the Delmarva Peninsula, one 

of the country’s leading poultry-producing 

regions.

Their research is part of a growing field—

known as predictive microbiology—that 

forecasts the behavior of foodborne 

pathogens in response to environmental 

conditions encountered in food production 

and processing operations. Models predict 

how long it takes for pathogens to grow 

under certain conditions and how fast 

they grow once they start. Models help 

processors make proper decisions about 

food safety and help regulatory agencies 

and scientists learn more about the 

conditions in which pathogens, such as 

Salmonella, thrive.

An estimated 1.4 million cases of salmonellosis food poisoning occur annually 

in the United States, according to the 

Centers for Disease Control and Prevention, and about 10 percent of those cases 

are from poultry. Most people 

recover without treatment, 

but some get diarrhea 

so severe that they have 

to be hospitalized. If the 

infection spreads from the 

intestines to the bloodstream, 

it can cause death unless the 

patient is treated promptly with antibiotics. The elderly, infants, and those with 

impaired immune systems are most at risk.

Poultry Pathogen Models for Predictive Microbiology

F

In a modeling study to predict growth of Salmonella on chicken, food technologist Thomas 

Oscar uses an automated counting system to count pathogen colonies (the black dots) on an 

agar medium.

PEGGY GREB (K11896-1)

Real-World Competition

“One way to better assess food safety,” 

Oscar says, “is to develop pathogen 

models that take into account real-life 

competition from other microbes present 

in food. These models would be more 

realistic, make better predictions, and help 

better ensure that the food industry doesn’t 

needlessly dispose of safe food.”

Previously, Oscar says, models were 

often developed in broth with no other 

microbes present. Researchers thought 

this would allow them to accurately predict pathogen behavior in food. Recent 

findings by Oscar and ERRC colleagues 

Mark L. Tamplin, microbiologist, and 

Andy Hwang, food technologist, indicate 

that this is not always the case.

The ARS researchers will produce more 

realistic models by using a system Oscar 

developed to rate performance of current 

models. Called the “acceptable prediction 

zone method,” it establishes criteria for 

verifying and validating models as having acceptable or unacceptable predictive 

records, classifies them to show which are 

best, and then pinpoints any changes that 

are needed. Models are evaluated under 

specific conditions to find which ones 

meet established standards and demonstrate a level of performance that could be 

used with confidence in the food industry 

to predict food safety.

Oscar thinks most current broth models are “overly fail-safe,” meaning they 

predict much higher pathogen numbers 

than would be present in real food with 

microbial competition. Still, he says, it’s 

better to over-predict the growth rate of 

a pathogen than to under-predict it. His 

laboratory is working on two promising 

techniques to improve the models.

One method is to introduce a jellyfish 

gene into Salmonella to make the bacteria 

fluoresce, or glow, so they’ll be easier to 

detect among other microorganisms on 

raw poultry. At first, the foreign DNA 

slowed Salmonella growth, making the 

models inaccurate. But Oscar and colleagues Dwayne Boucaud, assistant 

professor and microbiologist at UMES, 

1.4 million cases 

of salmonellosis food 

poisoning occur annually
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 37

and Kalpana Dulal, a graduate student, 

are working on a new way of introducing 

the foreign DNA that will allow normal 

growth.

Oscar has had more immediate success 

with the second approach. He and his 

colleagues found that a strain of antibiotic-resistant Salmonella can be a valuable tool for modeling pathogen growth. 

Salmonella typhimurium DT104 is known 

to be resistant to five different antibiotics. 

The researchers put four of those five antibiotics in an agar medium they were using 

to determine the amount of Salmonella in 

a food sample. The antibiotics killed off 

competing microorganisms on the agar 

Graduate student Kalpana Dulal (left) and microbiologist Dwayne Boucaud, of the 

University of Maryland Eastern Shore, examine expression of green fluorescent 

protein by Salmonella on agar medium. 

Technician Jacquelyn Ludwig grinds 

chicken in preparation for modeling 

experiments of Salmonella. 

PEGGY GREB (K11900-1)

PEGGY GREB (K11904-1)

plates and left just the Salmonella. The 

scientists were able to follow the surviving 

Salmonella and model its growth on raw 

poultry meat, showing how it behaves in a 

real food environment. The DT104 strain 

helped confirm their theory that models 

developed in the absence of microbial 

competition do not accurately predict 

pathogen behavior in foods that contain 

other spoilage organisms.

“One of the biggest hurdles we face 

in developing models in food with other 

microorganisms has been not having a 

valid marker pathogen strain that we could 

follow in the presence of other microorganisms,” Oscar says. “The DT104 strain, 

which exists in nature, has allowed us 

to jump over this hurdle and holds great 

promise for developing better Salmonella 

models for the food industry.”

Oscar’s study doesn’t end with Salmonella. Along with Kisun Yoon, assistant 

professor at UMES, and graduate student 

Candace Burnette, he has new findings 

on Campylobacter, the leading cause of 

bacterial food poisoning worldwide.

The three scientists recently found that 

C. jejuni died faster at room temperatures 

than at refrigeration temperatures. The 

data collected in the study was used to 

develop one of the first predictive models for C. jejuni. The new model will be 

included in ERRC’s Pathogen Modeling 

Program, a package of models available 

on the World Wide Web at www.arserrc.

gov/mfs/pathogen.htm. The availability 

of these and other food safety models 

should accelerate use of models by food 

industries and researchers interested in the 

field of predictive microbiology.—By Jim 

Core, ARS.

This research is part of Food Safety 

(Animal and Plant Products), an ARS 

National Program (#108) described on 

the World Wide Web at www.nps.ars.

usda.gov.

Thomas P. Oscar is with the USDA-ARS 

Poultry Food Safety Research Laboratory, Room 2111, Center for Food 

Science and Technology, University of 

Maryland Eastern Shore, Princess Anne, 

MD 21853; phone (410) 651-6062, fax 

(410) 651-8498, e-mail toscar@errc.ars.

usda.gov. X
38 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

hellfish can remind us of treasured times—going clam 

digging with the family, slurping down oysters on the 

half shell at a raw bar with friends, or shucking them 

yourself in the hopes of finding a pearl. Unfortunately, 

eating them is often discouraged today because of environmental 

contamination. 

In hopes of reversing this trend, scientists at the Microbial 

Safety of Aquaculture Products Center of Excellence in Dover, 

Delaware, are conducting research to provide safer shellfish. A 

field location of the ARS Eastern Regional Research Center’s 

Microbial Food Safety Research Unit in Wyndmoor, Pennsylvania, the Center of Excellence is a partnership between ARS 

and Delaware State University, one of the 1890’s Historically 

Black Colleges and Universities. ARS’s Centers of 

Excellence are intended to foster complementary 

research on problems of national and regional 

concerns and to enhance cooperative research. Established in 1999 on the university’s campus, the Dover worksite is the only 

ARS laboratory studying bacterial and viral 

safety of shellfish.

According to Gary P. Richards, a microbiologist and the center’s lead scientist, shellfish are filter feeders, so they concentrate 

pollutants, including human pathogens, from seawater.

“The laboratory focuses on developing rapid, cost-effective, 

and practical methods to detect microorganisms in oysters, 

clams, and mussels and is evaluating processing strategies to 

eliminate these potentially harmful pathogens,” Richards says.

Oysters, clams, and mussels are considered aquaculture species because of the amount of management that goes into maintaining productive molluscan shellfish beds. These shellfish are 

a concern to Richards and his colleague, microbiologist David 

H. Kingsley, because bacterial and viral pathogens can become 

concentrated within edible shellfish tissues. Many types of viral 

and bacterial pathogens that grow in the gut of infected people 

may contaminate water and food. Shellfish live along the shore, 

where they are subject to contamination with pathogens from 

improperly treated municipal waste, leaking septic systems, 

floodwaters, runoff, or overboard discharge of boat wastes. 

They may also become contaminated by unsanitized hands and 

S

surfaces at harvesting, processing, and preparation facilities.

From a food-safety standpoint, three groups of pathogens are 

of greatest concern to the molluscan shellfish trade: The noroviruses (formerly known as the Norwalk-like viruses), hepatitis 

A virus, and Vibrio bacteria.

Noroviruses, the leading cause of nonbacterial gastrointestinal 

illness in the United States, have gained recent notoriety because 

of several outbreaks on cruise ships. There are an estimated 9.2 

million cases of norovirus infection caused by food in the United 

States annually. Norovirus illness comes on rapidly, lasts only 

a few days, and is rarely life threatening.

The second agent is hepatitis A virus. It is far less prevalent 

than norovirus—about 23,000 cases of hepatitis A are reported 

each year in the United States. But this virus infects the liver and 

can be more serious than norovirus infection. Although many 

illnesses are mild and asymptomatic, some require hospitalization or lead to death. Contamination of shellfish beds by direct 

exposure to human fecal wastes can readily lead to hepatitis A 

and norovirus infections.

The third group of human pathogens are bacteria of the 

genus Vibrio. Perhaps the best-known Vibrio infection is cholera, which sickens many people in underdeveloped countries 

through contaminated food and water. In the 

United States, V. cholerae is not a problem, but 

two other vibrios are of concern: V. vulnificus

and V. parahaemolyticus. These bacteria are 

naturally found in shellfish and seawater, 

particularly when water temperatures are warm. 

“Consumption of V. vulnificus-contaminated 

oysters is not a problem for healthy individuals,” 

says Richards, “but that’s not the case for sick, 

elderly, or immunocompromised people, especially 

those with liver disease or diabetes. These groups 

should avoid eating raw shellfish because of the widespread 

presence of V. vulnificus in the marine environment.”

Mortality rates for those who acquire a V. vulnificus infection 

exceed 50 percent, with rapid disease onset and death often 

within 3-4 days. This bacterium is also a flesh-eating organism, 

which can produce major disfigurement in those who survive 

infection.

The other Vibrio pathogen found in the United States is 

V. parahaemolyticus, which causes a gastrointestinal illness that is 

generally not life threatening. Illnesses from V. parahaemolyticus

have resulted in the closure of shellfish beds on the Atlantic, 

Pacific, and Gulf coasts of the United States and have led to 

major economic hardships for the shellfish industry.

Bacterial Virulence Factors

Deaths from V. vulnificus continue to occur among immunocompromised oyster consumers. To better understand how these 

and related bacteria invade the human host, Richards focused 

Researchers Study 

Microbial Threats to 

Shellfish Safety

 Mortality rates for immunocompromised people infected 

with Vibrio vulnificus 

exceed 50 percent.
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 39

collaboratively with the Haskin Shellfish Research Laboratory, 

Rutgers University, in New Jersey to detect vibrios in oysters 

and seawater.

Virus Methods Development

Recently, Richards, working with the Centers for Disease 

Control and Prevention (CDC), developed a rapid method to 

detect a broad range of noroviruses. He combined a technique 

known as real-time reverse transcription-polymerase chain 

reaction (RT-PCR) with universal primers developed by CDC 

and was able to detect most norovirus types circulating in the 

world today.

According to Richards, “This method should be particularly 

useful to clinical, environmental, and food-testing laboratories, 

because, for the first time, analysts will be able to rapidly test 

for a wide spectrum of noroviruses in a single reaction tube.”

Other recent research in this area involved detection of noroviruses in stools of individuals who had no symptoms of illness. 

The results suggest that healthcare workers and food handlers 

could unknowingly spread noroviruses in the workplace, and 

highlight the importance of good hygienic practices, particularly 

handwashing, to reduce the threat of food contamination and 

enteric virus illness.

Kingsley and Richards have also developed a way to extract 

viral RNA from shellfish. This method permits relatively rapid 

purification of hepatitis A virus and norovirus genetic material from within shellfish tissues. To detect the virus’s genetic 

material, RT-PCR is then used to amplify the viral RNA. This 

extraction method is being evaluated by state, federal, and 

foreign laboratories to measure its performance, determine 

its cost-effectiveness, and consider it for possible adoption in 

virus-testing programs.

John Ewart (left), an aquaculture/fisheries specialist (University of 

Delaware), and ARS microbiologist Gary Richards examine freshly 

harvested oysters on board the Center for the Inland Bays’ work 

boat before transport to the laboratory. 

In studies to measure virus uptake and depletion rates, technician 

Gloria Meade inoculates a tank of oysters with hepatitis A virus. 

on identifying Vibrio enzymes that may enhance bacterial invasiveness. Leading a research group involving scientists from 

Delaware State University and the National Institutes of Health, 

Richards recently discovered and characterized an enzyme in 

V. vulnificus and identified it as phosphoglucose isomerase with 

a novel lysyl aminopeptidase activity. 

The presence of this enzyme activity signifies a potential 

mechanism that may help the spread of Vibrio. He also detected 

the enzyme in virtually all species of Vibrio tested to date, but 

not in non-Vibrio pathogens. The enzyme is capable of metabolizing substances found in human tissues and the bloodstream. 

Such metabolism produces peptides that act on the blood vessels. These could account for the low blood pressure and rapid 

spread of V. vulnificus—a hallmark of Vibrio infection in humans.

Richards also developed a quick and simple enzyme-based 

assay that will allow vibrios to be readily detected in food, 

water, and clinical samples. This assay is being evaluated 

STEPHEN AUSMUS (K11763-1)

STEPHEN AUSMUS (K11765-1)
40 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

Technician Michael Watson loads shellfish 

extracts into a real-time RT-PCR machine to 

detect the presence of norovirus RNA. 

At the ARS Microbial Safety of Aquaculture Products Center of Excellence, microbiologist 

Gary Richards injects Vibrio extract into a chromatograph to isolate enzymes that may 

influence bacterial invasiveness. 

STEPHEN AUSMUS (K11762-1)

STEPHEN AUSMUS (K11766-1)

Intervention Strategies

Some shellfish consumers prefer 

to eat shellfish raw or only lightly 

cooked, so the shellfish industry is interested in methods that can inactivate 

pathogens in their products without 

cooking. Kingsley is studying a way 

to sanitize raw shellfish and other 

virus-contaminated foods by using 

high-pressure processing (HPP), in 

which foods are subjected to extremely 

high pressure. The advantage of this 

technology is that no heat or chemicals are involved, permitting shellfish 

and other foods to retain their raw, 

uncooked flavor and character.

“HPP is being used commercially, 

for example, to pasteurize fruit juices 

in Japan and to treat sliced deli meats 

in Spain,” Kingsley says.

In the United States, some in the 

oyster industry are already using HPP 

to facilitate shucking, eliminate Vibrio

contamination, and extend product 

shelf life. These factors make HPP desirable to the processor and consumer, but 

the initial costs of the HPP units have 

prevented their widespread use.

Kingsley, working collaboratively 

with researchers from the U.S. Food and 

Drug Administration, tested the ability 

of HPP to inactivate hepatitis A virus 

from oysters. They found that 1-minute 

treatments of oysters greatly reduced 

hepatitis A virus populations.

Since it is not currently possible to 

replicate norovirus in the laboratory, 

Kingsley and Richards, in collaboration 

with researchers at the University of 

Delaware, used feline calicivirus, a cat 

virus that is genetically related to norovirus, to demonstrate that noroviruses 

may be sensitive to HPP. Kingsle hopes 

to find a way to directly study norovirus 

response to HPP in the future. Shellfish 

processors may be more willing to invest the capital needed to perform HPP 

once it’s been conclusively shown to 

inactivate norovirus.

“Our research is of direct benefit to 

state and federal regulatory agencies 

who can use the improved methods and 

to the industry and seafood processors 

who can use new and innovative processing strategies to reduce contamination in seafoods,” Richards says. “We 

will continue to evaluate these methods 

and seek partners to help validate them 

as we pursue new ways to enhance 

seafood safety.”—By Jim Core, ARS.

This research is part of Food Safety 

(Animal and Plant Products), an ARS 

National Program (#108) described 

on the World Wide Web at www.nps.

ars.usda.gov.

Gary Richards and David Kingsley are with the USDA-ARS Microbial Safety of Aquaculture Products Center of Excellence, Delaware 

State University, James W.W. Baker 

Center, Dover, DE 19901; phone 

(302) 857-6419, fax (302) 857-6451, 

e-mail grichards@errc.ars.usda.gov, 

dkingsley@errc.ars.usda.gov. u
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 41

The average American consumes more than 30 pounds of cheese every year. Every pound produced creates 

an estimated 9 pounds of whey, the liquid byproduct that remains after the curds, or solids, coagulate.

Where does all the whey go? It’s used in a range of products such as candy, pasta, baked goods, animal 

feed—and even pharmaceuticals.

Since its inception, ARS’s Dairy Processing and Products Research Unit at the Eastern Regional Research 

Center (ERRC) in Wyndmoor, Pennsylvania, has investigated uses for whey and other dairy byproducts. 

Today, thanks in part to ERRC research, cheesemakers have markets for over 1 billion pounds of whey 

every year.

New research shows that whey can also be used to create eco-friendly 

products. For example, using a process called “reactive extrusion,” food 

technologist Charles Onwulata supplements polyethylene—a common nonbiodegradable plastic—with whey proteins.

Reactive extrusion involves forcing plastic material through a heating 

chamber, where it melts and combines with a chemical agent that strengthens 

it before it’s molded into a new shape. Onwulata showed that by combining 

dairy proteins with starch during this process, it’s possible to create a biodegradable plastic product that can be mixed with polyethylene and molded 

into utensils.

Working with laboratory chief Seiichiro Isobe, of the Japanese National 

Food Research Institute, Onwulata created a bioplastic blend by combining 

whey protein isolate, cornstarch, glycerol, cellulose fiber, acetic acid, and the 

milk protein casein and molded the material into cups. Onwulata observed 

that dairy-based bioplastics were more pliable than other bioplastics, making 

them easier to mold.

Bioplastic blends can replace only about 20 percent of the polyethylene in a 

product, so resulting materials are only partially biodegradable. But Onwulata 

and his colleagues are currently applying this process to polylactide (PLA), 

a biodegradable polymer.

“Blending dairy-based bioplastics with PLA could eventually allow producers to make completely biodegradable materials,” he says.

In a separate project, research leader Peggy Tomasula and her colleagues 

have developed technology to create biodegradable films from byproducts of 

both dairy processing and biofuels production. Tomasula found that combining 

casein with water and glycerol—a byproduct of biodiesel production—produces a water-resistant film that can be used as an edible coating for groceries 

and other products.

“We use carbon dioxide as an environmentally friendly solvent to isolate 

dairy proteins from milk, instead of harsh chemicals or acids, which can be 

difficult to dispose of,” Tomasula says. Carbon dioxide is a byproduct of the 

glucose fermentation that is used to make ethanol, and she says it makes the 

edible film more water resistant.

The resulting food coatings are glossy, transparent, and completely edible. Like traditional food packaging, edible films can extend the shelf life of many foods, protect products from damage, prevent exposure 

to moisture and oxygen, and improve appearance. By using renewable resources instead of petrochemicals, 

the scientists can create more biodegradable products and reduce waste.—By Laura McGinnis, ARS.

This research is part of Quality and Utilization of Agricultural Products, an ARS National Program 

(#306) described on the World Wide Web at www.nps.ars.usda.gov.

Peggy M. Tomasula and Charles I. Onwulata are in the USDA-ARS Dairy Processing and Products Research Unit, Eastern Regional Research Center, 600 E. Mermaid Ln., Wyndmoor, PA 19038-8598; phone 

(215) 233-6703 [Tomasula], (215) 233-6497 [Onwulata], fax (215) 233-6795, e-mail peggy.tomasula@

ars.usda.gov, charles.onwulata@ars.usda.gov. X

Make Whey for Progress

New Uses for Dairy Byproducts

Food technologist 

Charles Onwulata 

inspects molded dairy 

bioplastic made from 

surplus whey proteins. 

PEGGY GREB (D793-1)
42 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

Wool F

Biopolishing Process 

Scratches the Itch Factor

Good 

news 

for

 wool 

industry 

and U.S. 

military

rom the agency that brought you 

permanent-press cotton and permanent creases in wool trousers 

in the 1960s comes an exciting 

new breakthrough.

Researchers at the ARS Eastern Regional Research Center in Wyndmoor, 

Pennsylvania, have developed a biopolishing method that makes scratchy wool 

feel silky smooth. Not only does it remove 

the itch factor, it also bleaches the wool 

to a high level of whiteness and alters 

the surface of wool fibers to make them 

shrink-proof.

According to Jeanette Cardamone, a 

textile chemist in the center’s Fats, Oils, 

and Animal Co-products Research Unit, 

their method increases smoothness and 

shine on the fabric’s surface by removing 

fiber-yarn ends projecting from it. This 

contributes to a pleasing feel, which increases wool’s appeal for fashion uses. 

The process involves two steps. First, 

an activated peroxide bleach is used to 

whiten the wool fibers and remove the 

protective lipid barrier that surrounds 

them. This step bleaches the wool at 

lower temperatures and in half the time 

as conventional techniques, which cuts 

processing costs, according to Cardamone. 

And because it removes the lipid layer, the 

peroxide treatment also makes the fibers 

more receptive to dye.

“High-temperature dyeing is traditionally used with wool because of the lipid 

barrier to dye uptake,” Cardamone says. 

“Although wool has resilient properties, 

those high temperatures weaken the fiber. 

Our process lets wool be dyed at lower 

temperatures, preserving its strength.”

The second step—enzyme treatment—

is what makes machine-washable wool a 

reality. The surface of a woolen fiber is 

covered with microscopic scales, somewhat like scales on a fish or shingles on a 

roof. Wool shrinks during machine-washing because the heat and pressure lock the 

scales in place. The enzyme treatment 

“digests” the scales so they can’t become 

locked. This controls shrinkage without 

loss of strength or elastic recovery. 

The same lipid layer that makes wool 

resistant to dye uptake would usually 

protect the scales against such an enzyme 

attack. But the bleaching step removes 

that protection. 

 PEGGY GREB (K11893-1)
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 43

Visiting scientist Anand Kanchagar (left), from the University of Georgia, and textile chemist 

Jeanette Cardamone examine the effect of ARS processing on wool fabric captured by image 

processing. The processed fabric held by Kanchagar has a biopolished, smooth surface, 

whereas the unprocessed fabric held by Cardamone has a fuzzy, wrinkled surface. 

 PEGGY GREB (K11875-1)

Technician Guoping Bao prepares 

solutions for treatment of wool fabrics with 

an ARS-developed process for whitening, 

biopolishing, and shrinkage prevention. 

PEGGY GREB (K11877-1) 

“No damage is done to the underlying 

fiber structure, and the fabric’s mechanical 

properties are not changed, because the 

enzyme activity is limited to the outside 

layer, or cuticle,” Cardamone says. An 

additive is used in both the bleach pretreatment and the enzyme treatment to 

keep the enzymes out of the fiber’s inner 

structure.

The process can be applied to everything from loose fibers to yarn, fabric, or 

completed garments. 

Good News for Wool Industry

Washable wool has been available for 

about 35 years, but the processing required 

for it is not done in the United States. Wool 

fiber and fabric are conventionally made 

shrinkage resistant by a process called 

“chlorination.” Like the new ARS method, 

chlorination alters the fiber’s cuticle. But 

chlorination is not allowed in the United 

States because it produces chemicals of 

environmental concern. So we import all 

our shrinkage-resistant wool.

In the United States, wool is mainly a 

byproduct from breeds of sheep raised 

for meat and ranges in quality from fine 

to coarse. The new method could help 

the U.S. wool industry compete against 

countries like Australia, which produces a 

fine, soft wool from Merino sheep. 

The U.S. military is interested in using biopolished wool, especially for 

manufacture of underwear for our troops. 

Cardamone says underwear garments currently being used by the military contain 

synthetic fibers that can burn and melt 

into wounds during combat situations. 

Wool, on the other hand, produces a selfextinguishing flame and a dissipating ash 

when burned.

By law, in fact, uniforms must be produced domestically or in a country with 

which the United States has a free-trade 

agreement. The Berry Amendment to 

2004’s Defense Federal Acquisition Regulation Supplement and the Buy American 

Act require the U.S. government—in 

particular, the Department of Defense—

to procure (generally) only U.S.-

manufactured textiles and apparel.

Mill trials are under way specifically 

to meet military needs. The woolen-mill 

industry is interested in licensing the process, but if it is used for the military, no 

licensing is required. Military field trials 

are also ongoing.

Concurrently, textile mills are applying 

the process to new and existing wool fabric lines to evaluate its commercial value 

as a replacement for imported, chlorinated 

wool textile products. All processing can 

be completed by wool mills within the 

United States, promoting use of domestic 

wool. 

ARS filed a patent on the technique. 

The American Wool Council, a division 

of the American Sheep Industry Association, provided partial funding for the 

research.—By Jim Core, ARS.

This research is part of Quality and 

Utilization of Agricultural Products, an 

ARS National Program (#306) described 

on the World Wide Web at www.nps.ars.

usda.gov.

For further information on U.S. Patent Application No. 10/730,208, “Methods of Improving Shrink-Resistance of 

Natural Fibers, Synthetic Fibers, or 

Mixtures Thereof, or Fabric or Yarn 

Composed of Natural Fibers, Synthetic 

Fibers, or Mixtures Thereof,” contact 

Jeanette Cardamone, USDA-ARS Fats, 

Oils, and Animal Co-products Research 

Unit, Eastern Regional Research Center, 

600 East Mermaid Ln., Wyndmoor, PA 

19038; phone (215) 233-6680, fax (215) 

233-6795, e-mail jcardamone@errc.ars.

usda.gov. X
44 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

I

t might be surprising to learn how 

little is actually known about the role 

of one of nature’s tiniest and most 

effective gardeners.

Mycorrhizal fungi are organisms that 

live inside and outside root cells and help 

them reach for nutrients by extending 

long threads called “hyphae” into the soil. 

The hyphae act as extensions of the root 

system. The plant, in exchange, gives the 

fungi glucose and possibly other organic 

materials they need to grow.

The most common mycorrhizal fungi, 

arbuscular mycorrhizal (AM) fungi, colonize most crop plant roots and enhance 

nutrient uptake, mainly phosphorus. AM 

fungi have been shown to enhance disease 

resistance, increase soil’s stability against 

erosion, maintain soil pores for air and 

water infiltration, improve soil fertility, 

and increase concentrations of organic 

matter in the soil.

Unfortunately, AM fungus populations 

in soils have been diminished by modern 

agricultural practices. But they can still 

make important contributions to productivity in systems where little or no chemical fertilizers and pesticides are used, such 

as in organic farming.

Although home gardeners can buy 

potting mix with beneficial fungi added, 

it’s impractical for farmers to buy and 

apply the amount they would need for 

their fields. A team of ARS scientists at 

the Eastern Regional Research Center 

(ERRC) in Wyndmoor, Pennsylvania, 

is examining the feasibility of on-farm 

mass production of AM fungus inoculum 

already native to a site or introduction of 

nonnative AM fungi by way of colonized 

host plants. By learning more about AM 

fungus physiology and finding ways to 

grow colonies without host plants, they 

hope to make the fungi a practical option 

for producers.

Researchers in ERRC’s Microbial Biophysics and Residue Chemistry Research 

Unit take a three-pronged approach to 

mycorrhizal research. David D. Douds, 

a microbiologist, heads the on-farm 

inoculum production. Philip E. Pfeffer, 

a chemist, is mainly investigating the 

fungi’s metabolism and molecular biolGetting to the Root of the Solution

Technician Joe Lee (left) and microbiologist David Douds examine pot cultures of bahiagrass 

and arbuscular mycorrhizal fungi in the greenhouse. 

PEGGY GREB (D365-1)
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 45

ogy. Gerald Nagahashi, a chemist/cell 

biologist, is studying the fungal life cycle.

Pfeffer and Douds collaborated with 

Michigan State University and New 

Mexico State University scientists to 

show the symbiotic relationship between 

mycorrhizal fungi and plants in nitrogen 

recycling. Nitrogen is an essential part of 

proteins, nucleic acids, and other cellular 

components of living organisms.

Though the scientists had identified 

enzyme activities in AM fungi and genes 

involved in nitrogen absorption and metabolism, little was known about how nitrogen is transported from fungus to plant 

root and in what form it is transferred.

Using nuclear magnetic resonance, 

mass spectrometry, and gene expression 

measurements, they recently established 

that nitrogen is transported as the amino 

acid arginine. It takes a novel metabolic 

route from external hyphae to fungal 

structures located in plant roots. It is then 

broken down by the fungus to ammonium, 

which is transferred to the host plant.

“Nitrogen availability often determines 

plant growth,” Pfeffer says. “Microorganisms have a central role in supporting life, 

because they are involved in most aspects 

of nitrogen availability. We’ve shown that 

mycorrhizal fungi may have a much more 

significant role in the worldwide nitrogen 

cycle than previously believed.”

One Step at a Time

Currently, researchers cannot cultivate 

the fungus without a host. The fungus 

cannot complete its life cycle without 

the organic nutrients or other stimuli it 

receives from roots. Nagahashi and his 

colleagues have been focusing on events 

that must occur before the fungus can 

colonize a host plant.

“We developed a bioassay that has allowed us to determine that chemical compounds exuding from the host’s roots, root 

caps, and root border cells induce fungal 

hyphal branching,” Nagahashi explains. 

“This is the earliest structural change in 

the fungus after spore germination. The 

increase in branching creates a greater 

potential for the fungus to find the host 

root surface, where it can attach.”

Nagahashi and Douds used in vitro 

sterile culture techniques to investigate 

how certain environmental factors—root 

compounds, blue light from the sun’s 

spectrum, and carbon dioxide—affect 

AM fungal growth. They found that these 

three factors can all work independently 

to promote growth of AM fungi but were 

even more effective when combined to 

operate in synergy. The most effective 

treatments involved the joint use of 

chemical compounds with one of the 

environmental factors.

The AM fungus life cycle’s first three 

steps have been completed in laboratories 

without a host root. Nagahashi and his 

colleagues are currently focused on the 

fourth step—formation of “penetration 

hyphae,” which enter and develop into 

a network of intercellular hyphae inside 

the root.

“This step leads to host root colonization,” Nagahashi says. “We have developed another bioassay that may allow us 

to test for host compounds, or interactions 

between host and fungus, which lead to 

this step’s completion.”

Identifying these compounds could 

eventually be used to provide researchers 

with pure fungus spores, the development 

of which is the life cycle’s final step, and 

allow them to be cultivated away from 

host plants.

AM Fungi Thrive on Organic Farms

Douds collaborates with researchers at 

the Rodale Institute in Kutztown, Pennsylvania, which for more than 25 years has 

compared conventional and low-input, or 

organic, farming systems at the same site. 

Some of Douds’s work with mycorrhizal 

fungi was conducted in Rodale’s Farming 

Systems Trial, a comprehensive study of 

organic farming techniques that began in 

1981 on 6.2 hectares, which makes it the 

longest running comparison study of its 

kind in the United States.

Of particular interest to Douds were 

results showing that plots farmed with 

two organic systems had greater AM fungi 

spore populations and produced greater 

plant root colonization than did soils from 

a conventional corn-soybean rotation system.—By Jim Core, ARS.

This research is part of Soil Resource 

Management (#202) and Plant Biological 

and Molecular Processes (#302), two ARS 

National Programs described on the World 

Wide Web at www.nps.ars.usda.gov.

David D. Douds, Philip E. Pfeffer, and 

Gerald Nagahashi are with the USDAARS Eastern Regional Research Center, 

600 East Mermaid Lane, Wyndmoor, PA 

19038; phone (215) 233-6469, fax (215) 

233-6581, e-mail ppfeffer@errc.ars.usda.

gov, ddouds@errc.ars.usda.gov, gnagahashi@errc.ars.usda.gov. X

Technician Aisha Abdul-Wakeel places samples into a gas chromatograph while chemist 

Philip Pfeffer examines mass spectral data to measure the amount of isotopically labeled 

nitrogen that has been delivered from the mycorrhizal fungus to the host plant. 

PEGGY GREB (D366-8)
46 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

he food industry wants to ensure the safety of its 

products while maintaining quality. But while the 

maxim “heat kills germs” still holds true for food 

sterilization, scientists are exploring alternative treatments for 

lowering foodborne pathogen levels. Today, new technologies 

that are faster, cheaper, and less disruptive to quality than traditional thermal processing are increasingly common.

Under the guidance of research leader Howard Zhang, scientists in the Food Safety Intervention Technologies Research 

Unit—part of ARS’s Eastern Regional Research Center (ERRC) 

at Wyndmoor, Pennsylvania—have investigated several nonthermal processing technologies. These include high-pressure 

processing, pulsed electric fields, radio-frequency electric fields, 

ultraviolet light, and irradiation.

“Some of these nonthermal techniques were developed here, 

but we have also tested and improved other technologies developed elsewhere,” Zhang says. “Our work has improved food 

safety by enabling the food industry to make better decisions 

about how to reduce or eliminate foodborne pathogens.”

For Liquids, High-Pressure and Electric Fields

High-pressure processing (HPP) treatment involves applying 

80,000-130,000 pounds per square inch of pressure to a sample. 

Imagine the pressure in the greatest depths of the ocean, then 

multiply that by 10. Applying that extreme pressure for 2-5 

minutes will kill most vegetative microorganisms—those that 

grow in foods under normal storage conditions.

ERRC researchers found that HPP treatment at 25 ̊C can 

significantly reduce E. coli populations in tomato juice and 

liquid whole eggs. Their research also suggested that multiple 

brief high-pressure treatments were more effective than one 

lengthy treatment using continuous pressure for the same total 

amount of time.

While HPP can eliminate vegetative microorganisms, it is 

not effective at killing microbial spores. And at 5-10 cents per 

pound, it is too pricey to be practical.

“We hope to develop pressure technology that is cheaper and 

more effective against spores,” Zhang says.

Another technology that ERRC scientists have improved uses 

pulsed electric fields (PEF) to kill yeasts, molds, and vegetative 

Nonthermal 

Food Processing 

Is Heating Up

Food microbiologist Dike Ukuku 

(left) and engineer Joseph Sites 

evaluate effects of high-pressure 

processing on microbial stability of 

tomato juice and liquid eggs. 

PEGGY GREB (D616-1)

T

bacteria in liquid foods. These intensive electric pulses break 

down the cell membranes of the microorganisms.

One study explored the feasibility of using PEF in making 

shelf-stable salad dressings. A model salad dressing for the study 

was formulated by Kraft Foods. ARS scientists inoculated the 

dressing with Lactobacillus plantarum, a very heat-resistant 

spoilage bacterium. The sample was then treated either by PEF 

alone or by PEF followed by mild heat. While PEF treatment 

alone significantly reduced L. plantarum, the dressing retained 

microbial shelf stability only when refrigerated. PEF plus 

mild heat exposure, however, produced shelf stability at room 

temperature.

Another study subjected applesauce samples to PEF followed 

by mild heat treatment. The processed applesauce was aseptically 

packed into plastic cups and stored at room temperature. Evaluations indicated that the processed applesauce maintained high 

sensory quality during 470 days of storage. That’s a longer shelf 

life than is currently used in commercial practice. This research 

demonstrated that following PEF with mild heat may be used in 

producing high-quality, shelf-stable applesauce products.

Like the PEF process, radio-frequency electric field (RFEF) 

technology subjects liquid foods to high electric fields. But 

this procedure—developed at 

ERRC—uses a continuous alternating current power supply, 

which costs less than a PEF 

pulse generator. 

In one study, ARS scientists 

applied RFEF for 3 seconds at 

60 ̊C to an apple juice sample 

inoculated with E. coli. The 

electrical cost of RFEF processing was about 1 cent per 

deciliter (10.5 quarts), and the 

procedure was more effective 

than conventional heating under the same conditions.

UV or Not UV? Ultraviolet 

Light and Irradiation

ERRC has also investigated 

ultraviolet (UV) light and irradiation technologies as alternatives or complements to 

thermal processing.

Scientists used UV processing on an apple cider sample 
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 47

pathogen prevention improves constantly, and with it, the safety 

of the nation’s food supply.—By Laura McGinnis, ARS.

This research is part of Food Safety, an ARS National Program (#108) described on the World Wide Web at www.nps.

ars.usda.gov.

Howard Zhang is with the USDA-ARS Eastern Regional 

Research Center, 600 E. Mermaid Lane, Wyndmoor, PA 19038; 

phone (215) 233-6583, fax (215) 233-6406, e-mail howard.

zhang@ars.usda.gov. X

In studies of methods to pasteurize liquid foods such as apple 

cider without using heat, research leader Howard Zhang (left) 

and chemical engineer David Geveke develop and evaluate pulsed 

electric field and radio frequency electric field treatments.

Food microbiologist Kathleen Rajkowski evaluates how well a 

pulsed ultraviolet light treatment inactivates bacterial pathogens on 

the surface of test media. 

PEGGY GREB (D618-1)

PEGGY GREB (D617-1)

that had been inoculated with bacteria. Heat and chemical treatments can destroy bacteria within cider, but they generally alter 

the flavor. The UV treatment reduced populations of E. coli and 

Listeria innocua by more than 99 percent without changing the 

liquid’s flavor. Scientists believe UV processing has potential to 

improve the safety of apple cider and extend its shelf life without 

diminishing its quality.

Could UV processing provide safe liquid egg products too? 

Extensive thermal pasteurization, though effective for other 

types of food, damages the functional properties of egg whites, 

so USDA’s Food Safety and Inspection Service asked ERRC 

to investigate.

ERRC researchers combined UV and heat treatments to kill 

E. coli in liquid egg whites. Whites infected with E. coli O157:

H7 were processed using a simple UV apparatus consisting 

of a low-pressure mercury lamp surrounded by a coil of UVtransparent tubing. The scientists found that UV treatment at 

room temperature can significantly reduce the heat subsequently 

required to pasteurize liquid egg whites.

Irradiation exposes food to a low level of ionizing radiation to 

kill bacteria, molds, yeasts, parasites, and other microorganisms 

that can lead to food spoilage and illness if untreated. ERRC is 

the only federally funded and operated food irradiation research 

facility in the United States.

Over the last 25 years, studies have shown that eating 

irradiated foods poses no increased health risks for consumers. 

ERRC research findings have enabled federal regulatory 

agencies to establish standards to ensure safety and quality of 

irradiated products like fruit, vegetables, juice, meat, and meat 

substitutes. At 3-5 cents per pound, irradiation is slightly more 

expensive than thermal processing, but its success in deactivating 

spores and other microorganisms has made it an option for the 

food industry.

Foodborne pathogens are varied and numerous, but thanks 

in part to contributions from ERRC scientists, knowledge of 
48 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

T

Fueling America—

Without Petroleum

Chemical engineer John Nghiem (left) and research 

leader Kevin Hicks monitor a new process for 

converting barley into fuel ethanol. 

PEGGY GREB (D768-1)

he demand for alternatives to petroleum-based fuels 

is steadily rising.

Corn and soybeans—the dominant feedstocks 

for ethanol and biodiesel production in the United 

States—grow well in the central regions of the country. But are these the only available sources? What options exist 

for U.S. growers in other regions? How can corn and soybean 

feedstocks be improved?

Scientists at the Eastern Regional Research Center (ERRC) in 

Wyndmoor, Pennsylvania, are answering these and other questions about renewable fuels production. Their research focuses on 

four major areas: biodiesel, ethanol, thermochemical processes, 

and cost analysis.

“For years, ERRC has been a committed participant in alternative fuels research,” says center director John Cherry. “This 

is a particularly exciting time, because so much of our research 

work is being adopted and used by industry.”

Biodiesel: From Grease to Glycerol

What do animal fats, rendered materials, and restaurant grease 

have in common? Besides ready availability and limited marketability, they’re all subjects of ERRC biodiesel research headed 

by research leader Bill Marmer. Scientists in his group have 

demonstrated that products of the rendering industry can be used 

as low-cost feedstocks for biodiesel production.

Biochemist Mike Haas and biologist Karen Scott are working 

with the Philadelphia Fry-o-Diesel company to demonstrate that 

trap grease—waste grease that restaurants and food companies 

collect from their drains—can be converted into a clean-burning, 

renewable fuel source.

Haas and Scott helped characterize trap-grease samples, 

advised the company on operation design, and analyzed the 

products of trial runs. They have successfully produced fatty acid 

methyl esters, the chemical compounds that make up biodiesel, 

from the grease. The esters are being tested to determine whether 

they meet accepted biodiesel standards.

These researchers are also developing a method to produce 

biodiesel directly from oil-bearing materials, including soybean 

flakes and rendered products. The oils or fats in the feedstock 

are treated with 18 percent methanol, forming biodiesel as the 

extractant. This would eliminate the need to isolate the oil before 

converting it to fuel, thereby reducing production costs, and 

would expand the amount of available fuel feedstocks.

Another objective of biodiesel research is to find uses for 

glycerol, a coproduct of biodiesel production.

“For every 100 pounds of biodiesel produced, you get 10 

pounds of glycerol,” says chemist Tom Foglia. “Current markets 

are saturated.”

Concerned that increased biodiesel production could result in 

a hyperglutted glycerol market, ERRC researchers are investigating alternative uses for the compound. Molecular biologist Dan 
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 49

Microbiologist Rick Ashby (left) and molecular biologist Dan 

Solaiman monitor bacterial growth and production of a biopolymer 

for use in plastics and other products. The bacteria are growing 

in a nutrient broth containing glycerol, a coproduct of biodiesel 

production. 

Solaiman and microbiologist Rick Ashby have found that crude 

glycerol can be used to support microbial cell growth and production of polyester biopolymers, which can be used as plastics 

or adhesives, and biosurfactants, which are used in detergents or 

as antimicrobial agents. This is particularly important because 

crude glycerol is less marketable than pure glycerol.

In related studies, chemist Victor Wyatt demonstrated that 

glycerol could be used to produce a new class of prepolymers 

for making such products as coatings, resins, foams, and agents 

for remediation of polluted environments.

These alternative uses for glycerol have proved successful on 

a trial scale. Now the scientists are testing them at an industrial 

level through a cooperative research and development agreement 

with an international consumer products company.

Ethanol: Beyond the Corn Belt

Affordable, available, and easy to work with, corn is the main 

feedstock for ethanol in the United States. As ethanol production 

increases—USDA chief economist Keith Collins estimates that 

our country could produce 12-13 billion gallons in 2009—so 

does the demand for suitable feedstocks.

To avoid overburdening the corn market, ethanol producers 

have two options: increase conversion efficiency or use an alternative crop. Several ERRC research projects have demonstrated 

how these can be done.

Food technologist David Johnston is investigating new processes using protease enzymes from microbial and fungal sources 

to produce ethanol more efficiently. In trials, Johnston found that 

adding enzymes during fermentation sped up the process and 

increased ethanol yields.

“The enzymes make more nutrients available for the yeast. 

They expedite the fermentation process and can also make it 

easier to separate liquid from solids after the ethanol has been 

removed,” Johnston says. “This is important because the more 

efficiently you separate the free liquid from the solids, the more 

energy efficient the process can be.”

Corn isn’t the only available feedstock for ethanol. Research 

leader Kevin Hicks is collaborating with biotechnology company 

Genencor International; Virginia Tech, in Blacksburg, Virginia; 

and members of the barley industry to explore barley’s potential 

as a feedstock in regions of the United States where corn is not 

the principal crop.

Hicks estimates that barley grown in North America could 

supply about 1 billion gallons of ethanol per year. The crop is 

well suited to the Mid-Atlantic, where it could be grown as a 

winter crop in rotation with soybeans and corn in 2-year cycles.

Currently, barley yields less ethanol than corn does, and the 

ethanol from barley is more expensive. Barley’s physical properties—an abrasive hull and low starch content—impede production efficiency. But Hicks and his colleagues are overcoming 

these hurdles with research.

With Genencor, the researchers are developing new enzyme 

technology that could improve the speed, efficiency, and cost of 

barley-based ethanol production.

They also collaborated with Virginia Tech researchers to develop barley varieties with higher starch content and a loose hull 

that generally falls off during harvest or grain cleaning. Initial 

studies suggest that such varieties have promise as a feedstock. 

Biologist Karen Scott 

prepares a sample 

of trap grease for 

conversion to biodiesel. 

In the foreground are 

samples of distilled 

(left) and crude (center) 

biodiesel from trap 

grease.

PEGGY GREB (D770-1)

PEGGY GREB (D769-1)

Enzymes could improve the speed, efficiency, and cost of barley-based ethanol production.
50 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

Engineers Neil Goldberg (left) and Akwasi Boateng operate a 

fluidized-bed thermochemical reactor they designed and built for 

converting crop residues into renewable bio-oils and hydrogen fuels. 

PEGGY GREB (D767-1)

Biomass—materials 

such as sawmill waste, 

straw, and cornstalks—

is heated in a reactor 

and converted into 

liquid (bio-oil) and 

synthetic gas.
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 51

Engineers Andrew McAloon (left) and Winnie Yee (right) explain the 

economic advantages of a new fuel ethanol process to ERRC director 

John Cherry. 

In one study, for example, a hull-less barley produced 2.27 gallons of ethanol per bushel, whereas hulled barley produced 1.64 

gallons per bushel.

The scientists are now studying which conditions will promote 

the most cost-effective production of barley-based ethanol.

Breaking Down the Biomass

There are two main processes, or “platforms,” for making fuels 

from biomass: sugar and thermochemical conversion. The sugar 

platform involves breaking down complex carbohydrates in the 

biomass—materials such as sawmill waste, straw, and cornstalks 

(stover). Then, yeasts metabolize, or consume, the simple sugars 

to make alcohol.

Breaking down those complex carbohydrates requires a lot of 

energy, Hicks says, and special microorganisms are required to 

convert some sugars into ethanol. And, ironically, the process 

creates a lot of carbon dioxide—the greenhouse gas that’s helping to spur the biofuels movement.

The thermochemical platform involves heating the biomass 

in a reactor and converting it into liquid (bio-oil) and synthetic 

gas (gaseous fuels comprising carbon monoxide, hydrogen, and 

low-molecular-weight hydrocarbon gases such as methane and 

ethane). Chemical engineer Akwasi Boateng has led much of 

the ERRC research on this process.

In a study with research leader Gary Banowetz and colleagues 

in Corvallis, Oregon, Boateng converted grass seed straw into 

synthetic gas using small-scale gasification reactors. Built to 

serve a farm or small community, these reactors could provide 

an environmentally friendly and economic use for the 7 million 

tons of straw produced by the grass seed industry every year in 

the Pacific Northwest.

Neither the sugar platform nor the thermochemical platform 

has been perfected yet, Hicks cautions.

“Each one has technical and economic hurdles that must be 

solved through research,” he says. “We’re trying to compare the 

processes and determine which, if perfected, would give the most 

useful energy from a given amount of biomass. We’re working 

with international experts to make intelligent decisions on where 

to focus our efforts.”

A Model Approach: Cost Analysis

Price is one of the major factors inhibiting the spread of 

biofuels. Reducing production costs would make them more 

competitive with petroleum-based fuels—but where can scientists cut costs?

Engineers Winnie Yee and Andy McAloon create technical 

models to guide research efforts toward economically feasible 

processes. With the models, they analyze every aspect of a biofuel production process and determine where cost-cutting would 

be most effective. This allows researchers to pinpoint the exact 

steps in the process that need to be modified.

“It’s important to know that our research makes economic 

sense, that these processes will be competitive enough for industry to accept them,” McAloon says.

Haas used one of McAloon’s models to analyze his efforts to 

create biodiesel from soy flakes. The model estimated that by 

first drying out the moist flakes, Haas could reduce the amount 

of methanol required later, thereby reducing the cost per gallon from $2.83 to $2.66. Haas and his colleagues are currently 

working to reduce that cost even further to a point of commercial 

competitiveness.

For about 10 years, ERRC has been providing these technical 

models for ARS scientists. Developing a model from the ground 

up is time-consuming, McAloon says, but once developed it can 

be modified to meet the needs of a specific product or process. 

Within the past year alone, he estimates, ERRC has produced 

several hundred copies of their models for researchers within 

ARS and around the world.

“Our scientists are approaching biofuels research from many 

different angles that allow us to come up with comprehensive 

solutions,” Cherry says. “We’ve made some great discoveries 

here at ERRC that have helped improve biofuel production, and 

I’m confident that we’ll see even more improvements in the 

future.”—By Laura McGinnis, ARS.

This research is part of Bioenergy and Energy Alternatives, 

an ARS National Program (#307) described on the World Wide 

Web at www.nps.ars.usda.gov.

To reach scientists mentioned in this article, contact Laura 

McGinnis, USDA-ARS Information Staff, 5601 Sunnyside Ave., 

Beltsville, MD 20705; phone (301) 504-1654, fax (301) 504-

1486, e-mail laura.mcginnis@ars.usda.gov. X

PEGGY GREB (D777-1)
52 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

extraction.” Fishman is now adapting flash extraction techniques 

to remove pectin from sugar beet pulp—which is even more 

heat-sensitive—at lower temperatures than those used to extract 

pectin from citrus. 

Brett Savary, a plant physiologist formerly at ERRC, evaluated 

enzymes from citrus fruits and sugar beet roots for use in modifying the properties of pectin and other cell wall polysaccharides. 

He has been using new proteomic technologies to rapidly identify 

and characterize these enzymes.

With cooperators at the ARS Citrus Products Laboratory in 

Winter Haven, Florida, Savary discovered a distinctive citrus 

enzyme that may be useful for commercial processing of pectin. 

They are filing a patent on the discovery and partnering with 

a U.S. manufacturer to produce the enzyme and determine its 

usefulness for manufacturing pectin with improved properties 

in food applications.

The group is also looking at using enzymes to help dry out A

Pectin Extraction 

From Citrus and 

Sugar Beets

Low-Value Pectin’s a Natural for 

Making High-Value Products

Chemists Marshall L. Fishman (left) and Hoa K. Chau prepare 

orange peels for flash extraction of pectin using microwave heating 

under pressure.

PEGGY GREB (D702-1)

t ARS’s Eastern Regional Research Center (ERRC) 

in Wyndmoor, Pennsylvania, researchers in the Crop 

Conversion Science and Engineering Research Unit 

are at work on pectin, a polysaccharide component in 

the cell walls of fruits and vegetables.

Polysaccharides are polymers made up of many 

simple carbohydrates (sugars) linked together into long, continuous molecules. Pectin is currently valued for use as a gelling and 

thickening agent, beverage stabilizer, and fat substitute.

Most commercial pectin is obtained by extraction from citrus 

peels, but sugar beet pulp is also rich in pectin. About 1.5 million 

tons of dry beet pulp—an enormous untapped source of a valuable polysaccharide—are generated annually by U.S. processors.

At present, most pulp is dried and sold as animal feed at little 

profit because of the costly energy required to dry it for storage 

and shipment.

But sugar beet pectin has different chemical features than 

citrus pectin, so it could find new uses, especially in industrial 

products. Beet pulp is also rich in other highly functional cell 

wall polysaccharides that could be isolated and put to use. To 

increase profits for sugar beet growers and processors, the Wyndmoor researchers are working on new processes to efficiently 

isolate beet pectin and associated polysaccharides and find higher 

value uses for them.

Extraction of pectin from plant material now takes an hour or 

more using conventional heating; care must be taken not to break 

down its structure—which provides thickening properties—by 

overheating. To save time and reduce cost, Marshall L. Fishman, 

an ERRC chemist, developed microwave and steam-injection 

techniques to heat fruit peels with acidified water in pressureresistant containers.

“Using these ‘flash extraction’ methods, pectin can be extracted in just 10 minutes,” Fishman explains. “They use less 

energy and yield higher quality pectin than conventional heat 
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 53

regeneration. The new, pectin-based material forms three-dimensional structures with better physical and mechanical properties 

than the tissue replacer in current use.

Other potential medical applications of these novel pectin 

materials include prosthetic medical devices and scaffolding for 

bone or cartilage repair, since pectin and other polysaccharides 

have properties that allow human cells to bind to them and 

grow. A patent application has been filed, and ARS has signed a 

cooperative research and development agreement with a private 

company to further develop the materials.

Liu has combined pectin and zein—the main storage protein 

in corn seeds—and found that the combination can be used in a

colon-specific drug-delivery system. It doesn’t degrade until it 

reaches the large intestine, allowing for controlled release.

In another human health application, plant physiologist Arland 

T. Hotchkiss and cooperators demonstrated for the first time 

that pectin fragments from orange peel have prebiotic properties. Prebiotics are nondigestible food ingredients that increase 

growth of beneficial probiotic bacteria in the large intestine. 

Probiotic bacteria stimulate health and help prevent growth of 

foodborne pathogens. 

Orange pectin prebiotics are also being evaluated by collaborators as animal-feed ingredients. This may allow reduction or 

elimination of antibiotics that are often added to feed.

Industrial Uses, Too

Microbial fermentation of sucrose or starch is used to manufacture a polymer known as “polylactic acid,” or PLA, and its 

copolymers.

At present, PLA is more expensive than petroleum-derived 

thermoplastics, and its polymers are stiff and brittle in thicker 

materials. Liu is testing sugar beet pulp as an inexpensive filler 

to reinforce PLA. The pectin and other polysaccharides in the 

pulp add tensile strength. Compression heating forms them into 

a water-resistant, thermoplastic composite material well suited 

to manufacturing diverse products, such as office supplies, 

automobile parts, and lightweight construction materials. The 

improved properties are achieved at lower cost, and the material 

is biodegradable. 

Further refinements of these ERRC-developed pectin-processing techniques should lead to more economical carbohydratebased alternatives to imported petroleum-based products.—By 

Jim Core, formerly with ARS.

This research is part of Quality and Utilization of Agricultural 

Products, an ARS National Program (#306) described on the 

World Wide Web at www.nps.ars.usda.gov.

To reach scientists mentioned in this article, contact Linda 

Tokarz, USDA-ARS Information Staff, 5601 Sunnyside Ave., 

Beltsville, MD 20705-5129; phone (301) 504-1658, fax (301) 

504-1486, e-mail linda.tokarz@ars.usda.gov. X

Chemists LinShu Liu (left) and David Coffin examine a microsphere 

made from pectin and zein. It is used as a controlled drug-delivery 

system.

Technician Andre White (left) and plant physiologist Arland 

Hotchkiss analyze the pectic fragment composition of a prebiotic 

fraction from orange peel.

PEGGY GREB (D704-1)

PEGGY GREB (D705-1)

beet pulp after sugar extraction, which would reduce processors’ energy costs. It may be possible to combine enzymes with 

Fishman’s flash extraction technologies to efficiently extract 

arabinan, another cell wall polysaccharide that could also be commercially produced from sugar beet pulp. With effective recovery 

of valuable soluble polysaccharides, much of the remaining 

material is an enriched form of cellulose that’s readily digestible 

by microbes and could be fermented to produce ethanol.

Products With Medical Uses

Recently, ERRC chemist LinShu Liu developed a material 

from natural crop polymers, including pectin, which can be 

used in biomedical materials, such as those used in human tissue 
54 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

ood news for fans of raw cookie dough. Researchers 

at ARS’s Eastern Regional Research Center (ERRC) 

in Wyndmoor, Pennsylvania, have filed a patent 

on technology that can further protect pasteurized 

liquid eggs from food safety threats. These threats 

include both naturally occurring spoilage bacteria 

and pathogens such as Salmonella enteritidis, the primary cause 

of egg-related foodborne illness in the United States. The technology has also been successfully applied to milk.

But don’t go running for that dough just yet. The U.S. Food 

and Drug Administration (FDA) still cautions against consuming any raw, unpasteurized eggs or products that contain them.

Despite adherence to pasteurization protocols prescribed by 

the U.S. Department of Agriculture, illnesses related to consumption of raw egg products still occur. About 40,000 cases of 

salmonellosis are reported in the United States each year. The 

new ARS technology, developed by ERRC scientists Sudarsan 

Mukhopadhyay, Peggy Tomasula, and John Luchansky, may 

help reduce that number.

“Current pasteurization technology is not adequate to remove 

all pathogens effectively from egg products,” says Tomasula, 

research leader of the ERRC Dairy Processing and Products 

Research Unit. “Though pasteurization eliminates heat-sensitive 

pathogens, some heat-resistant microorganisms can survive and 

spoil liquid egg whites.”

Consumers can avoid illness by properly handling and cooking eggs before consumption. But Tomasula, along with lead 

scientist Luchansky of the Microbial Food Safety Research 

Unit and chemical engineer Mukhopadhyay, has found that new 

technology can compensate for the shortcomings of thermal 

pasteurization.

The technology, called “crossflow microfiltration membrane 

separation” (CMF), removes more pathogens than thermal 

pasteurization does. And it does so without affecting the eggs’ 

ability to foam, coagulate, and emulsify—meaning that CMFtreated eggs could be safely substituted for pasteurized eggs 

in products where those characteristics are desired, such as 

angel food cake and mayonnaise. In a pilot-scale study, CMF 

was shown to remove about 99.9999 percent of inoculated S. 

enteritidis from unpasteurized liquid egg whites.

The technology can also be used to remove Bacillus anthracis

spores from egg whites. This finding adds to previous work in 

which ERRC researchers used CMF to remove 99.9999 percent 

of B. anthracis spores inoculated into fluid milk. Microfiltration 

can also protect milk from more common bacterial pathogens, 

potentially extending its shelf life.

Though effective in its own right, CMF works best when 

treated as an accompaniment to pasteurization, not a replacement 

for it, says Tomasula. Combining the two processes significantly 

reduces the pathogen load.

Plague Defense

Using antibody- and DNA-based technology, ARS researchers in the ERRC Microbial Biophysics and Residue Chemistry 

Research Unit have developed a variety of methods for targeting 

dangerous pathogens in food. They’ve used these technologies to 

detect foodborne pathogens such as Escherichia coli O157:H7, 

Salmonella, and Listeria monocytogenes. Recently, microbiologist George Paoli and his colleagues have applied some of the 

same detection techniques to Yersinia pestis, the bacterium that 

causes bubonic plague.

“Many methods used to detect more common foodborne 

pathogens can be extended or modified for detecting organisms 

that are a concern with respect to food safety,” Paoli says.

The biological makeup of individual bacterial species varies 

considerably. Though the methods used to detect them are similar, they have to be altered to suit specific pathogens. Because 

antibodies bind to specific targets, antibody-coated immunomagnetic beads (IMBs) can be used to target and remove specific 

G

New Methods for Ensuring Food Safety

Microbiologist George Paoli inspects antibody-coated magnetic 

beads and biologist Chandi Wijey analyzes DNA samples in their 

efforts to develop immunological, microbiological, and genetic-based 

methods for detection of Yersinia pestis in food.

PAUL PIERLOTT (D1452-1)

Safe and Abundant Food and Crops
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 55

pathogens. The trick to IMB technology is finding an antibody 

that attaches to one, and only one, target—for example, a Y. 

pestis antigen. Paoli and his colleagues have developed IMBs 

to capture Y. pestis, and preliminary tests in milk samples have 

been successful.

In the early stages of testing the IMB technology, ERRC 

scientists found that their beads could pick Y. pestis out of a 

food mixture, but they also captured Staphylococcus aureus. 

Further research showed that the binding of S. aureus to the IMBs 

could be overcome by plating on media that were selective for 

growth of Yersinia. Use of these plates, along with the IMBs, 

significantly reduces the danger of false-positive results in 

samples that might also contain S. aureus. 

The team is also using genetic methods that rely on a common 

DNA test known as the “polymerase chain reaction,” or PCR. 

The group has developed PCR-based methods to detect Y. pestis

and differentiate it from other foodborne bacteria, including two 

closely related Yersinia species, Y. enterocolitica and Y. pseudotuberculosis. They have also developed a PCR method that targets 

genes related to the virulence of Y. pestis. This test could be used 

to determine a particular strain’s potential public health impact.

The scientists are currently working to combine the different areas of this research—the IMB detection, microbiological 

plating media, and genetic detection and typing of Y. pestis—to 

develop a complete set of tools for detection of Y. pestis in food, 

as part of a holistic approach to food security.

Warming Up to Food Security

The likelihood of B. anthracis or Y. pestis entering the U.S. 

food supply is very small––significantly smaller than the 

relatively low risk of contamination by Salmonella or other 

naturally occurring pathogens. Should that remote possibility 

occur, however, one of the easiest, most effective food safety 

tools—heat—lies in the hands of the consumer.

Previous ERRC studies have established and validated the 

use of thermal and nonthermal technologies to reduce the risk 

of foodborne pathogens. Luchansky and colleagues Vijay Juneja 

and Anna Porto-Fett recently led studies in which they applied 

thermal technology to ground beef inoculated with B. anthracis

and Y. pestis––with encouraging results.

Patties made from inoculated ground beef were cooked on an 

open-flame gas grill and a “clam-shell” style electric grill. Both 

models are commonly used by consumers and the food industry. 

In both studies, the scientists found that cooking the ground beef 

on commercial grills, at the heat and time levels recommended 

by USDA and FDA, noticeably reduced the overall levels of both 

pathogens on or in the meat.

Research efforts like these ensure that U.S. consumers and 

food-industry professionals have the most advanced technology 

and information available to protect against potential pathogen 

threats.—By Laura McGinnis, ARS.

This research is part of Food Safety, an ARS national program 

(#108) described on the World Wide Web at www.nps.ars.usda.

gov.

To reach the scientists mentioned in this article, contact Laura 

McGinnis, USDA-ARS Information Staff, 5601 Sunnyside Ave., 

Beltsville, MD 20705-5129; phone (301) 504-1654, fax (301) 

504-1486, e-mail laura.mcginnis@ars.usda.gov. X

At ERRC, special project team members sample steaks to search 

for pathogens both before and after cooking on a commercial gas 

grill. Left to right: technician Brad Shoyer, food technologist Anna 

Porto-Fett, and microbiologists John B. Luchansky, Vijay Juneja, 

and Jeffrey Call. 

ERRC chemical engineers Sudarsan Mukhopadhyay (left) and 

Peggy Tomasula examine a ceramic membrane module for use in 

microfiltration of liquid egg whites to eliminate potential pathogens 

such as Salmonella enteritidis. 

PAUL PIERLOTT (D1451-1)

PAUL PIERLOTT (D1450-1)
56 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

S making biobased additives, ones suitable 

for use in formulating greases; crankcase, 

two-cycle, and marine engine oils; and hydraulic, transmission, and drilling fluids.

The additives would be made from

the predominant fat molecules—triglycerides—in natural oils of familiar crops 

like soybean, corn, or canola or from

lesser-knowns like pennycress, camelina, 

and crambe. Fully biodegradable, these 

vegetable-oil-based additives are just

slightly darker, and somewhat thicker, 

than the clear, light-yellow cooking oils 

used in home kitchens across America.

The additives would provide an alternative to today’s 

petroleum-based products—

and a potentially profitable 

market for growers in the

Midwest and elsewhere.

Erhan did the work while 

a chemist at the ARS National Center for Agricultural Utilization Research

in Peoria, Illinois. She’s 

now director of the agency’s Eastern

Regional Research Center in Wyndmoor, 

Pennsylvania.

The new-age additives, says Erhan,

offer many benefits and, to date, no

downside. “You can use them with either 

biobased or conventional lubricants,” she 

points out. And the novel additives meet 

all the standard criteria for a top-notch, 

antifriction, antiwear additive, namely, 

impressive viscosity and liquidity, high

flashpoint, and stability despite temperature extremes.

In small-scale laboratory tests to evaluate wear and friction, for example, the

plant-oil additives performed as well as or 

better than commercial petroleum-based 

additives. And since they’re fully biodegradable, proper disposal is fast, easy, and 

inexpensive.

What’s more, the additives can be

produced with the same equipment that

chemical companies already have in place 

for making traditional additives.

It’s no wonder that several leading

makers of petroleum-lubricant additives 

have already expressed an interest in the 

scientists’process for making the biobased

additives.

Erhan and coinvestigators Brajendra K. 

Sharma of Pennsylvania State UniversityUniversity Park, and Atanu Adhvaryu,

formerly with the university, describe the 

technology in their U.S. patent, issued

in 2007. Importantly, the procedure and 

the resulting additives are eco-friendly. 

“No harsh solvents are used, and very

ARS Scientists Just Say “No”to Petroleum

At the NCAUR lab in Peoria, chemist Sevim 

Erhan (now center director at the Eastern 

Regional Research Center in Wyndmoor, 

Pennsylvania) formulates a biodegradable 

lubricant using an ARS patented biobased 

antiwear additive. 

Wrapping Up With Dairy-Derived Ingredients

Speaking of saying “no” to petroleum-based products, many food manufacturers 

want to incorporate renewable materials into their operations to help reduce foodpackaging waste.

Most food packages are made of multilayer films that are thin, continuous sheets of 

synthetic polymers. But consumers and food retailers are concerned about the waste 

generated during the manufacture of such packaging. Many, it seems, are interested 

in replacing petroleum-based packaging with biobased packaging.

At the ARS Eastern Regional Research Center in Wyndmoor, Pennsylvania, scientists

are developing strong, biodegradable dairy-based films that are better oxygen barriers 

than petrochemical-based films. “We are involved with finding the technology to improve dairy films so that they can eventually perform as plastics,” says research leader 

Peggy Tomasula, with the center’s Dairy Processing and Products Research Unit.

NCAUR (D1643-1)

S u s t a i n a b l e 

A g r i c u l t u r e

From Lubricants to Packaging Materials

creech!

Few sounds are more nervewracking than the scraping of

metal on metal. It’s the job of 

lubricants to prevent that annoying noise by making sure that—when 

metal touches metal—everything moves 

smoothly and quietly.

Machines that have moving parts—

your car’s engine or the hydraulic pump 

of a huge earthmover, for instance—

almost always require lubricants. Most

lubricants are made of so-called “base

oil” that’s blended with additives to boost 

performance.

In the United States, the 

demand for additives, already at nearly 2 billion

pounds a year, is expected

to increase at a respectable 2 

percent a year for the next 5 

years. That’s why Sevim Z. 

Erhan and colleagues have

developed a new process for 

14 Agricultural Research/September 2009
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 57

little energy and water are required,” says 

Erhan.

In brief, the vegetable oil is allowed to 

react with several chemicals, for various 

periods of time, including a 4-hour stint 

at a boil. Savvy chemists would summarize the process as “reacting triglyceride 

oils with thiols to yield poly (hydroxy

thioether) derivatives.”

Plant Starch—Not Polystyrene

Just as the environmentally sound

additives might help lessen America’s 

dependence on petroleum, so too might 

Visiting chemist Brajendra Sharma uses a standard 

four-ball test method to measure friction and wear 

properties of vegetable-oil-based antiwear additives. 

The additives can be used in either biodegradable or 

conventional lubricants and greases. 

Close-up of the additive

being placed onto ball 

bearings before friction 

test at right.

Food technologist Artur Klamczynski (left) 

and plant physiologist Greg Glenn prepare 

batches of starch-based dough which will be 

further processed by extrusion to form heatexpandable pellets. 

PEGGY GREB (D1642-1)

PEGGY GREB (D1639-1)

PEGGY GREB (D1641-1)

She wrote “Using Dairy Ingredients To Produce Edible Films and Biodegradable 

Packaging Materials,” a book chapter in the soon-to-be-published Dairy-Derived Ingredients: Food and Nutraceutical Uses, by London-based Woodhead Publishing.

The chapter focuses on films made from dairy proteins, with an emphasis on those 

based on casein and whey, the major proteins found in milk. It also covers research 

efforts to improve the proteins’ mechanical and barrier properties so that these natural 

materials could eventually be used in a variety of applications.

As a dairy ingredient, casein shows good adhesion to different substrates. But while 

casein is an excellent barrier to oxygen, carbon dioxide, and aromas, it is a weak 

barrier to moisture. “The water-soluble nature of these proteins is a big problem,” 

says Tomasula. “Much of the research on edible casein films to date is directed to 

improving their water-vapor barrier properties. The use of dairy-based films as part 

of multilayered packaging systems will be the focus of future research.”—By Rosalie 

Marion Bliss, ARS.

starch-based foams replace polystyrene

products. An example: the rigid, custom-fit

foam pieces used inside cardboard cartons

to keep computer monitors securely in

place during shipping and storage. Those 

foam pieces could just as easily be made 

from wheat, potato, or corn starches

instead of petroleum.

That’s according to Gregory M. Glenn, 

a plant physiologist with the ARS Western Regional Research Center in Albany,

California.

Glenn and co-inventor Simon K. Hodson, formerly with EarthShell, LLC,

of Lebanon, Missouri, have patented

two “green” processes for making topperforming, starch-based foams for a 

multitude of everyday products—shipping

liners, disposable dinnerware, and more.

These biofoams, which look like familiar polystyrene foam goods, are strong, 

durable, and versatile, Glenn says. They 

can be manufactured to the same range 

of densities as conventional foams and

can be die-cut or molded into a seemingly limitless array of shapes, sizes, and 

thicknesses.

The starch-derived foams aren’t waterproof, however, so a moisture barrier 

needs to be added. But such barriers are 

nothing new and, in fact, can be derived 

from plant sources, such as corn, so that 

the finished biofoam product would still 

be made exclusively from renewable,

biodegradable natural resources.

The Shape of Things To Come

Glenn has worked with both of the new 

processes in small-scale experiments at

Agricultural Research/September 2009 15
58 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

his laboratory. Both technologies rely

on an extruder—a standard piece of

equipment—to heat and mix a doughlike blend of starch and other all-natural 

compounds.

For one process, the extruder squeezes 

out long strings of the dough, referred to 

as a “thermoplastic melt,” that are later cut 

into small beads, about half the size of a 

marble. At various points in the process, 

the beads puff and expand. That happens, 

for instance, when the beads are put into 

the cavity of a heated mold, to press them 

into the desired shape.

Expanded beads will eventually touch 

one another, creating a strong matrix that’s 

much like the bead matrix of polystyrene 

foams.

The second process that Glenn and

Hodson developed results in a mix that 

emerges from the extruder as a continuous

hollow tube. As it moves, it is slit along 

one length so that instead of being rounded, it opens flat, just like a book that’s 

opened to lie flat on a table.

The now-flat foam is then rolled up—

like a bolt of cloth—and stored. Later, it 

can be heated, unrolled, and die-cut into 

the desired product.

To enhance the strength of the foams, 

natural fibers—from a softwood such as 

southern pine—can be added to the mix 

before it goes into the extruder, reinforcing

the foam for heavy-duty jobs.

The mounting environmental costs of 

landfills increasingly stuffed with nonbiodegradable polystyrene may eventually make Earth-friendly, biobased foams 

the preferred choice for tomorrow.—By 

Marcia Wood, ARS. 

This research is part of Quality and

Utilization of Agricultural Products, an 

ARS national program (#306) described 

on the World Wide Web at www.nps.ars.

usda.gov.

To reach the scientists mentioned in this 

article, contact Marcia Wood, USDA-ARS 

Information Staff, 5601 Sunnyside Ave., 

Beltsville, MD 20705-5129; phone (301) 

504-1662, fax (301) 504-1486, e-mail

marcia.wood@ars.usda.gov. ✸

SCOTT BAUER (K5052-5)

For Sustainability Smarts: The National Agricultural Library’s 

“Sustainable Agriculture Information Tools” Website

You’re interested in learning more about sustainable farming, but you don’t want to spend 

a lot of time surfing the web.

No worries.

Expert librarians at the National Agricultural Library in Beltsville, Maryland, and Washington,

D.C., have done the homework for you, compiling handy resources at www.nal.usda.gov/afsic/

sustain.shtml.

Scroll down to the “Learn More” headings to find an interesting potpourri of clickables, 

all leading you to reliable, authoritative resources. All are carefully vetted by the pros at the 

library’s Alternative Farming Systems Information Center.

Get backgrounded quickly—and become fluent in the lingo—by skimming “Sustainable 

Agriculture: Definitions and Terms.”

Check out the comprehensive “Sustainable Agriculture Automated Database Searches.” 

Anywhere from thousands to millions of documents were sifted and winnowed to find those 

most relevant and of the highest quality.

Curious about scientific journals? You’ll want to view the library’s top picks, posted at 

“Sustainable Agriculture: Top 10 Research Journals.”

Have college-age kids or grandkids who might be interested in studying sustainable ag? 

They’ll definitely want to read “Educational and Training Opportunities in Sustainable Agriculture,” which covers everything from the nation’s longest-running undergraduate degree program

in organic farming (Washington State University-Pullman) to the University of New Hampshire’s 

new “eco-gastronomy” program, an eclectic blend of nutrition, food, and farming.

Updated frequently, the library’s sustainable agriculture website is widely regarded as among 

the best of its kind.—By Marcia Wood, ARS.

16 Agricultural Research/September 2009
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 59

Jean Mayer USDA Human Nutrition Research 

Center on Aging at Tufts University

Boston, Massachusetts

www.ars.usda.gov/naa/hnrca

Children’s Nutrition Research Center

Houston, Texas

www.ars.usda.gov/spa/cnrc

Western Human Nutrition Research Center

Davis, California

www.ars.usda.gov/pwa/davis/whnrc

Grand Forks Human Nutrition Research Center

Grand Forks, North Dakota

www.ars.usda.gov/npa/gfhnrc

Beltsville Human Nutrition Research Center

Beltsville, Maryland

www.ars.usda.gov/ba/bhnrc

Lower Mississippi Delta Nutrition Intervention 

Research Initiative 

Little Rock, Arkansas

www.ars.usda.gov/spa/littlerock/deltaniri

O

ARS National Research Program on Obesity

Arkansas Children’s Nutrition Center

Little Rock, Arkansas

www.ars.usda.gov/spa/littlerock/acnc/

U.S. Plant, Soil and Nutrition Laboratory

Ithaca, New York

www.ars.usda.gov/naa/ithaca/uspsnl

Eastern Regional Research Center

Wyndmoor, Pennsylvania

www.ars.usda.gov/naa/errc

Southern Regional Research Center

New Orleans, Louisiana

www.ars.usda.gov/msa/srrc

Western Regional Research Center

Albany, California

www.ars.usda.gov/pwa/wrrc

National Center for Agricultural Utilization 

Research

Peoria, Illinois

www.ars.usda.gov/mwa/ncaur

besity is a growing epidemic in 

the United States that is leading to 

spiraling health problems and rapidly rising health care costs. ARS 

has unique expertise and facilities 

to carry out a cohesive research program on 

obesity prevention and energy metabolism, 

both through its national program in Human 

Nutrition and in coordination with ARS crop 

and animal breeding and new product and 

food-processing research.

The agency’s obesity research program 

rises from an interlocking tripod of research 

areas: learning what people eat, what the 

body needs, and how to modify what we eat 

to be more beneficial. Results from each of 

these areas influence research in the others. A 

major facet of the research program is finding 

ways to prevent obesity in people.

ARS’s six human nutrition research centers are home to carefully controlled human studies as well as community studies, 

which provide information from diverse 

populations at various stages of growth and 

physiology. This special expertise forms a 

core capability of ARS’s obesity and human 

nutrition program.

In addition, ARS scientists at other locations across the country focus on developing 

new foods and food ingredients that may help 

solve the obesity problem. Their goal is foods 

that farmers can competitively produce, with 

taste, texture, and flavor that consumers accept. These are critical factors that must go 

along with nutritional enhancement.

To leverage resources for obesity research, 

ARS partners with other agencies, from 

USDA’s Center for Nutrition Policy and 

Promotion to the Department of Health and 

Human Services’ National Center for Health 

Statistics as well as many universities.

To further program coordination, ARS is 

developing a new obesity initiative that will 

build on the agency’s capabilities to address 

the many facets of this growing problem. A 

particularly important facet will be conducting multicenter studies with adults and children to better understand biological factors 

underlying the propensity to gain weight and 

to test dietary and physical activity strategies 

to prevent unhealthy weight gain.

Locations of ARS Centers Doing Research on Obesity
IN-DEMAND FISH: Making Sure They’re 

Popular fish like salmon, catfish, and tilapia 

are coming under the close scrutiny of 

Agricultural Research Service food-safety 

scientists Andy Hwang and Kathleen 

Rajkowski. They’re discovering more about 

how to prevent foodborne pathogens from 

contaminating these and other delicious, 

good-for-you seafood. Both scientists are 

based at the ARS Eastern Regional Research 

Center in Wyndmoor, Pennsylvania.

Hwang, a food technologist, has completed a series of studies in which he’s 

simulated—in his laboratory—commercial 

processes used today for preparing smoked 

salmon. A gourmet treat, smoked salmon 

is typically sold in vacuum packages that 

have a refrigerator shelf life of about 3 to 

8 weeks, according to Hwang. Trouble is, 

pathogenic microbes like Listeria monocytogenes can live at refrigerated temperatures, 

so it’s important to get rid of these harmful 

microbes before the product leaves the 

processing plant.

Smoked salmon, pricey and, when properly prepared, delicate in texture, is often 

served in thin slices with bagels and cream 

cheese or as an appetizer, stacked on toasttype crackers with red onion and a splash of 

lemon juice. Too, some sushi bars feature 

smoked salmon surrounded by sticky rice 

and snugly wrapped in seaweed.

Hwang is looking for ways that processors 

can protect the pleasing flavor and texture of 

smoked salmon while reducing or eliminating contamination by L. monocytogenes or 

other foodborne pathogens.

At the Smokehouse

Smoked salmon is typically prepared by 

using what’s known as “wet brining” or “dry 

brining” to cure the raw fillets before smoking. Fish cured with a wet brine are soaked 

in a solution of water, salt, and sugar, which 

preserves the fish, helps it retain moisture, 

and enhances its flavor. The brine may also 

include spices or liquid smoke, like the kind 

home chefs use for a backyard barbeque.

With dry brining, the salt and other compounds are rubbed on the fillets and later 

rinsed off before the fish is smoked.

The smoking process takes place in special smoking ovens in which wood chips 

are burned to smoke the cured fillets. Most 

processors opt for cold smoking, which uses 

temperatures of 68 ̊F to 86 ̊F to smoke—but 

not cook—the fillets. Cold-smoking takes 

about 3 to 4 days.

Hot-smoking, a lesser-used option for 

salmon, uses temperatures of about 140 ̊F 

and takes about 6 to 10 hours. Hot-smoking 

cooks the fish, giving it a different taste and 

texture than cold-smoked fish.

Researchers are 

looking for ways 

that processors can 

protect the pleasing 

flavor and texture 

of smoked salmon 

while reducing 

or eliminating 

contamination by 

L. monocytogenes

or other foodborne 

pathogens.

PEGGY GREB (D1966-1)

Food technologist Andy Hwang and technician Stacy Raleigh study the effect of smoking temperature 

on survival of Listeria monocytogenes on smoked salmon.

60 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010
 Always Safe To Eat

Many Combinations Tested

In a series of experiments, Hwang and 

colleagues Shiowshuh Sheen and Vijay 

Juneja at Wyndmoor exposed cooked 

salmon samples, prepared with various 

concentrations of salt and smoke compound 

(from burning wood chips or liquid smoke), 

to midrange temperatures—between 104 ̊F 

and 131 ̊F. “The temperatures were higher 

than those used for cold-smoking but not 

quite as warm as hot-smoking,” explains 

Hwang. “We wanted to provide a range 

of alternative smoking temperatures for 

processors to consider and to show them 

the level of Listeria inactivation they might 

be able to achieve at various temperatures 

and various combinations of salt and smoke 

compound.”

The scientists cooked the fillets for the tests 

to kill any existing microbes before inoculating the fish with Listeria. Not surprisingly, 

smoking temperature was the single most 

important factor for inactivating the microbe. 

“Every 9 ̊F increase in temperature resulted 

in a 10-fold increase in rates of inactivation 

of the Listeria,” Hwang reports.

The researchers used data from the study 

to create a new, first-of-its-kind formula, or 

mathematical model, for food processors 

and their food-safety consultants to use 

in choosing the optimal combination of 

temperature and concentrations of salt and 

smoke compound.

“Users can plug into the model the salt 

concentration, smoke-compound concentration, and smoking temperature of their choice 

to predict what effect this combination may 

have on Listeria levels,” says Hwang. “Salt 

and smoke-compound concentrations and 

smoking temperature affect taste, texture, 

and other key qualities of the smoked fish, 

so processors often have their own unique 

combination of these three factors. We constructed the model to accommodate a wide 

range of choices.”

The team’s 2009 article in the Journal of 

Food Science has details.

Now, Hwang intends to test these laboratory findings at a smokehouse and monitor 

the safety of the smoked salmon as it makes 

its way through the distribution chain, from 

wholesaler to retailer to restaurant or home.

And as a followup to a preliminary study 

that he and Sheen described in another 2009 

Journal of Food Science article, Hwang wants 

to discover more about the extent to which 

other microbes—benign or harmful—can 

colonize the fillets and help or hinder Listeria’s survival.

Powerful Tactics That Don’t Require Heat

Meanwhile, colleague Rajkowski, a 

food microbiologist, is determining how 

to prevent certain foodborne pathogens 

from contaminating fish fillets. She’s using 

tilapia and catfish fillets for this research. 

“Even though foodborne illnesses are not 

commonly associated with either of these 

fish,” says Rajkowski, “we chose them for 

our research because they are the two most 

commonly consumed kinds of fish fillets in 

the United States today.”

Microbes that she’s studying include not 

only Listeria but also Salmonella, Shigella, 

Staphylococcus, Pseudomonas, and Escherichia coli O157:H7.

In one study, Rajkowski is determining 

the correct cooking times and temperatures 

for packaged tilapia fillets. Instructions for 

cooking fillets are sometimes based on visual 

determination—what the fish looks like.

“Instructions might require you to know 

what the fillet looks like when it ‘flakes easily with a fork,’” she says. “Not everyone 

knows what’s meant by that. We want to 

provide science-based cooking instructions 

that are precise and easier for everyone, even 

beginning cooks, to follow.”

Rajkowski is continuing research on 

heat-free ways to reduce levels of harmful 

microbes. Overheating can easily ruin the 

taste and texture of fish.

In an early experiment with both frozen and 

thawed tilapia and catfish fillets, Rajkowski 

artificially inoculated the fillets with L. monocytogenes and then determined the amount 

of ionizing radiation needed to reduce the 

pathogen’s population by 90 percent. The 

dosages required to achieve that level of 

safety were nearly the same for both kinds 

of fish, Rajkowski found. Published in the 

Journal of Food Protection in 2008, the study 

was the first to identify the dosages needed to 

effectively reduce Listeria in these popular 

fish products. Her results were similar to 

those that reduce Listeria in ground beef.

Rajkowski is also testing the effects of 

ultraviolet (UV) light in combating another 

pathogen, Shigella sonnei. Like Listeria, 

Shigella can cause gastrointestinal illness. 

For one investigation, Rajkowski applied a 

solution of S. sonnei to the surface of frozen 

tilapia and then exposed the samples to UV 

light. The treatment resulted in a 99-percent 

reduction of the pathogen. In contrast, tests 

with small samples of fresh tilapia showed 

that the UV treatment did not kill the pathogen. But exposing the fillets to pulsating 

beams of high-intensity UV light reduced 

the pathogen by 99 percent. Rajkowski 

documented the study in 2007 in Ice World 

Journal.

Fish that Hwang and Rajkowski are 

investigating are a good, low-fat source of 

high-quality protein. That’s reason enough 

to make sure these fish, and others from farm 

and sea, remain pathogen-free and safe for 

us to eat.—By Marcia Wood, ARS.

This research supports the USDA priority 

of ensuring food safety and is part of Food 

Safety, an ARS national program (#108) 

described at www.nps.ars.usda.gov.

Cheng-An (Andy) Hwang and Kathleen 

Rajkowski are with the USDA-ARS Eastern 

Regional Research Center, 600 E. Mermaid 

Ln., Wyndmoor, PA 19038; (215) 233-6416 

(Hwang), (215) 233-6440 (Rajkowski), andy.

hwang@ars.usda.gov, kathleen.rajkowsi@

ars.usda.gov.*

Food microbiologist Kathleen Rajkowski places 

a frozen catfish fillet into a device for surface 

decontamination by pulse UV treatment.

PEGGY GREB (D1964-1)

Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 61
62 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

Edible, Water-Resistant 

Film from Milk Protein

new process to continuously make films from a milk 

protein could lead to edible, water-resistant coatings 

on several products commonly found in grocery-store 

dairy aisles.

The process uses the unique characteristics of casein (pronounced 

KAY-seen), a milk protein that is the 

chief nutritional ingredient in cheese. 

It is also used as a food supplement 

and as a functional component in 

nonfood products, including adhesives, finishing materials for paper 

and textiles, and paints.

Casein’s natural structure gives 

it the ability to form water-resistant 

and biodegradable films or coatings. 

Casein films could be produced as 

stand-alone sheets or as thin coatings that could adhere directly to a 

product. Either form would act as a 

barrier to outside substances while 

protecting a product from damage or contamination. The edible film locks in moisture, so it may be used to coat dairy food 

products, such as cheese, or as part of a laminate in packaging 

for cottage cheese or yogurt. Flavorings, vitamins, or minerals 

could also be added to the coatings.

The process uses an ARS-patented method developed by 

Peggy Tomasula, research leader in ERRC’s Dairy Processing 

and Products Research Unit in Wyndmoor, Pennsylvania. Her 

extraction method separates casein from milk with high-pressure 

carbon dioxide.

Tomasula found that if this casein is mixed with water and 

glycerol and left undisturbed to dry, it forms a water-resistant, 

flexible, filmlike material.

“It’s been difficult to obtain films, fibers, and molded materials 

with acceptable mechanical properties from casein,” Tomasula 

said. “That’s because moisture can dissolve it. The new material 

remains intact when exposed to water, unlike other protein-based 

films patented in the past.”

And until now, it hasn’t been known how to make such films 

on a continuous, large scale.

Michael Kozempel, who recently retired as a chemical engineer from ERRC, and Tomasula developed a pilot-plant process 

to produce the film continuously. Kozempel determined which 

feeding mechanism would spread the casein solution uniformly 

and which belt material would allow easiest removal of the dried 

films. He also specified drying conditions and temperatures for 

making the films in 3 hours.

“This process makes the films continuously, and it can be 

modified for other proteins,” Kozempel says. “It establishes the 

feasibility of commercial production of biodegradable polymer 

coatings made from dairy products.”

Kozempel also showed that up to 20 percent of the casein can 

be substituted with nonfat dry milk, which reduces the cost of 

the films with little loss in physical 

properties.

ARS has filed a patent application 

on the continuous-production process 

and is interested in finding business 

partners to move it to market.—By 

Jim Core, ARS.

This research is part of Quality and 

Utilization of Agricultural Products, 

an ARS National Program (#306) 

described on the World Wide Web at 

www.nps.ars.usda.gov.

Peggy Tomasula is in the 

USDA-ARS Dairy Processing and 

Products Research Unit, Eastern 

Regional Research Center, 600 East 

Mermaid Ln., Wyndmoor, PA 19038; 

phone (215) 233-6703, fax (215) 233-6795, e-mail ptomasula@

errc.ars.usda.gov. X

A continuous biodegradable protein film begins to 

form using the new ARS film-making process. 

PAUL PIERLOTT, USDA-ERRC/VGT (D299-1)

A

The edible film 

locks in moisture, 

so it may be used 

to coat dairy food 

products, such as 

cheese, or as part 

of a laminate in 

packaging for 

cottage cheese or 

yogurt.
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 63

way in constructing the first major barley-to-ethanol 

production facility in the United States.

Meanwhile, in Raleigh, North Carolina, Marshall 

coordinates the regional winter barley testing nursery, which has the best experimental lines from both 

public and private winter barley breeding programs in 

the United States. He and other scientists in the ARS 

Plant Science Research Unit are just a few years into 

making crosses between hull-less barley and barley 

with resistance to Ug99, a stem rust that can inflict 

crop losses of up to 100 percent.

Once the researchers have developed robust lines 

that contain both traits, they’ll begin breeding for traits 

to enhance ethanol production, such as starch content. 

“In several years, we hope to release barley varieties 

with traits for enhanced agronomic performance, good 

grain-to-ethanol qualities, and good resistance to stem 

rust,” Marshall says.—By Ann Perry, ARS.

This research is part of Plant Genetic Resources, 

Genomics, and Genetic Improvement (#301), Bioenergy and Energy Alternatives (#307), and Quality and 

Utilization of Agricultural Products (#306), three ARS 

national programs described at www.nps.ars.usda.gov.

Kevin B. Hicks is with the USDA-ARS Crop Conversion Science and Engineering Research Unit, 

Eastern Regional Research Center, 600 E. Mermaid 

Lane, Wyndmoor, PA 19038; (215) 233-6579, kevin.

hicks@ars.usda.gov.

 David S. Marshall is in the USDAARS Plant Science Research Unit, 

North Carolina State University, 3411 

Gardner Hall, Raleigh, NC 27695; 

(919) 515-6819, david.marshall@

ars.usda.gov. X

Boosting Barley for Bioenergy

OATS &

Barley

Hulled winter barley ready for harvest. 

gricultural Research Service (ARS) scientists 

Kevin Hicks and David Marshall want winter 

barley to become a prime-time player in bioenergy production.

“The 2007 Energy Independence and 

Security Act requires production and use of 36 billion 

gallons of renewable transportation fuels by 2022. 

Today we only make 9 billion,” says Hicks. “We see 

winter barley as the perfect biofeedstock for making 

biofuels on the East Coast.”

So Hicks and others in the ARS Crop Conversion 

Science and Engineering Research Unit in Wyndmoor, 

Pennsylvania, are developing new sustainable technologies to convert varieties of hulled and hull-less 

winter “energy” barley into fuel ethanol. This initiative 

also includes Virginia Polytechnic Institute and State 

University scientists Carl Griffey, Wynse Brooks, and 

Mark Vaughn, who are supervising ongoing research 

efforts to develop improved varieties of hulled and 

hull-less barley.

Their combined efforts could help farmers from 

southern Pennsylvania to South Carolina develop a 

profitable 2-year rotation of winter barley, corn, and 

soybeans. Winter barley is grown on seasonally fallow land. It acts as a cover crop by protecting soil and 

nutrients and preventing migration of fertilizers from 

crop fields to the Chesapeake Bay—which is why the 

Chesapeake Bay Commission supports the development of winter barley as an energy crop. And since 

the field would otherwise be left fallow, producing 

biofuels from winter barley would not interfere with 

food production.

Now, too, there is a major marketing opportunity 

for growers of winter barley. Osage Bio Energy, 

headquartered in Glen Allen, Virginia, is well under 

A

BILL SCRUGGS (D1661-1)
64 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

new Agricultural Research

Service initiative will help

facilitate research cooperation

among scientists studying a key food

safety issue—how pathogenic bacteria

respond to different environmental

conditions in food.

Scientists in the Eastern Regional

Research Center’s (ERRC) Microbial

Food Safety Research Unit in Wyndmoor, Pennsylvania, and the United

Kingdom’s Institute of Food Research

(IFR) have formed the world’s largest

online database of predictive microbiology information. Predictive microbiology is a growing field that estimates

behavior of microorganisms in response

to environmental conditions, including

food production and processing operations from the farm to the table. The

database, called ComBase, is designed

to help make risk assessments and model

development easier. It wasreleased at the

fourth International Predictive Modeling

in Foods Conference in June 2003 and

can be found on the World Wide Web at

wyndmoor.arserrc.gov/combase.

For more than 15 years, ERRC has

developed mathematical models of the

behavior of bacterial pathogens in food.

In February 2002, ERRC established the

Center of Excellence in Microbial Modeling and Informatics (CEMMI) to help

generate interest in forming partnerships

that advance use of predictive models of

microorganisms in food. This “virtual

laboratory” can be found at www.arserrc.

gov/cemmi.

CEMMI’s objective is to link the expertise of its members to researchers in

the food industry, government, and academia. According to coordinator Mark

L. Tamplin, the center hopes to improve

the way predictive models are developed

and then applied to various foodprocessing situations, while ensuring that

users properly interpret results. Predictive microbiology can also benefit the

risk-assessment community by solving

gapsin research data and enhancing uniformity in experimental designs, he says.

ERRC’s Pathogen Modeling Program

software, a research and instructional

tool for estimating the effects of multiple variables on growth, inactivation, or

survival of foodborne pathogens, has

been available for download since 2002

at www.arserrc.gov/mfs/pathogen.htm.

That program and the United Kingdom’s

Food MicroModel, produced by IFR and

the Foods Standards Agency, are both

majorsoftware packages used to describe

bacterial responsesto food environments.

By combining their efforts and using

ComBase to organize the thousands of

existing data sets in the hands of scientists and in the literature, ARS and IFR

have expanded the uses for this vast

amount of information.

ComBase, a CEMMI project, already

contains around 25,000 growth and survival data set records. The software lets

scientists simulate a food environment

by entering data—such as temperature,

acidity, and available water—and then

retrieves all records that match those

search criteria. Tamplin says microbiologists in academia, government, and industry are submitting data to ComBase,

thus eliminating unnecessary repetition

of experiments among laboratories, improving models, and standardizing data

sources. More than 1,000 people accessed ComBase data in the first 4 months

following its launch. Tamplin says the

ultimate success of ComBase relies on

collaborators’ willingness to deposit

more data.

“Development of models depends on

available data,” he says. “We’re

appealing to professional journals to ask

authors to submit all their raw data with

their articles, much as they already do

for papers about genomic sequences.

This would help keep the database timely

and offer users the most reliable

information.”—By Jim Core, ARS.

This research is part of Food Safety

(Animal and Plant Products), an ARS

National Program (#108) described on

the World Wide Web at www.nps.ars.

usda.gov.

Mark L. Tamplin is with the USDAARS Microbial Food Safety Research

Unit, Eastern Regional Research Center,

600 East Mermaid Lane, Wyndmoor, PA

19038; phone (215) 836-3794, fax (215)

233-6581, e-mail mtamplin@errc.ars.

usda.gov. 

New Database Helps Monitor Food Pathogens

Microbiologist Benne Marmer (left) and technician Tod Stewart use computer-assisted

laboratory methods to record growth of Listeria monocytogenes bacteria on ready-to-eat

meat products. This information is analyzed in ComBase and then converted to a model in

the ARS Pathogen Modeling Program software.

A

PAUL PIERLOTT (K11054-1)
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 65

merica’s growing Hispanic

population craves the various

types of cheese available in their

native countries. Raw milk,

which is used to produce these cheeses,

gives them distinctive flavors, textures,

and cooking properties. Even though

someAmerican companies are producing

Hispanic-style cheeses from pasteurized

milk (a U.S. requirement for cheeses aged

less than 60 days), these do not exhibit

the full range of properties of cheeses

made from raw milk.

Researchers atARS’ Eastern Regional

Research Center (ERRC) in Wyndmoor,

Pennsylvania, are studying Hispanic

cheeses to help producers meet the

increasing demand for them. Total

Hispanic-style cheese production in the

United States jumped 52 percent from

1996 to 2001, when more than 102 million pounds were sold, according to

USDA’s National Agricultural Statistics

Cheese, Please

Recreating Unique Properties of Hispanic Cheeses

Service. In fact, it is one of the fastest

growing U.S. food markets, outpacing

the growth of the cheddar and mozzarella

markets.

It’s Flavor, Not Fire

Hispanic-style cheese does not mean

hot-and-spicy cheese; other ingredients

make Hispanic dishes hot. In general, the

cheeses are white or off-white and moist.

They taste like fresh milk. They become

soft and creamy when heated but do not

lose shape, run, or separate into greasy

solids and liquids. Most cheeses are

fresh, though some are aged. Many are

mild tasting and crumbly. Others are

harder and have stronger flavor.

Chemist Diane L. Van Hekken and

colleagues in ERRC’s Dairy Processing

and Products Research Unit are studying

selected Hispanic cheeses made in

Mexico to better understand how specific

processing techniques result in their

desirable qualities. They are looking at

the cheeses’ chemical and physical

makeup to learn how these properties

relate to flavor; texture, such as chewiness and stringiness; and function, such

as the ability to melt or be sliced. They

want to find ways to duplicate these

characteristics by following U.S. practices and standards. Then, they hope to

apply the findings to improving cheeseprocessing techniques in general.

According to Van Hekken, there is not

a lot of literature available for researchers on the characteristics of these cheese

types, and so a main objective is to compile needed references.

In Search of Authenticity

The researchers are looking at four

specific cheese types. The first, Queso

Blanco, may be the most popular cheese

south of the border. It is soft and won’t

melt. Panela is mild, sweet, and crumbly. Asadero is a smooth, yellow cheese

that issomewhat tangy and good for baking. And last, Van Hekken’s research

team traveled to Mexico twice, where

they are working with a collaborator to

A

Using a torsion gelometer, chemist Diane

Van Hekken examines the fracture

properties of Hispanic-style cheeses to

establish their texture profiles.

PEGGY GREB (K10121-1)

examine Mennonite-style cheeses from

the state of Chihuahua. These semihard

cheeses—named after the Mennonite

settlers who introduced them to the region—are similar to Queso Quesadilla

and Menonita found in the United States.

“All these cheeses have been developed for specific purposes,” Van

Hekken explains. “People can’t cook a

Mexican-style dish, for example, with

American-style cheese and expect it to

taste authentic. Restaurants that want

their dishes to be traditional know this,

and they search for the right cheeses.”

A sensory evaluation board (taste

panel) at ERRC has been working since

May 2001 to define the flavor profiles

of both raw and pasteurized cheeses.

MaryAnne Drake, a professor with North

Carolina University’s Department of

Food Science, helped initiate training for

panelists to become human instruments

and to use a common terminology in

describing what they taste.

The researchers also hope to improve

the shelf life of Hispanic-style cheeses,

which will expand their marketability

here and in foreign markets and ensure

high food-safety standards.—By Jim

Core, ARS.

This research is part of New Uses,

Quality, and Marketability of Plant and

Animal Products, an ARS National Program (#306) described on the World

Wide Web at http://www.nps.ars.usda.

gov.

Diane L. Van Hekken is in the USDAARS Dairy Processing and Products

Research Unit, Eastern Regional

Research Center, 600 East Mermaid

Lane, Wyndmoor, PA 19038-8598; phone

(215) 836-3777, fax (215) 233-6795,

e-mail dvanhekken@arserrc.gov. ★
66Agricultural Research/April 2002 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-20109

Many commercially available biodiesel fuels are made from

refined soy oil and are then added to diesel, typically at levels

of 20 percent of the mixture’s volume. According to Haas,

studies show that biodiesel, used alone or in such blends, can

provide much needed lubrication to fuel systems while also

reducing production of polluting exhaust emissions. Because

of these benefits, Haas points out, there is strong interest in

this country and around the world in developing methods to

produce biodiesel from fats and oils.

Originally, methods were designed to produce biodiesel from

highly refined oils. Now Haas, Scott, and Bloomer have modified the technology to allow

use of lower value, less pure

lipids, such as soapstock, as

starting materials. This could

increase availability of biodiesel while decreasing its cost.

Soybean oil soapstock is a

plentiful and relatively inexpensive byproduct of edible-oil

refining. About 100 million

pounds are produced in the

United States every year, and

it can be had for one-tenth or

less the cost of refined vegetable oil, Haas says. Currently,

it is used mostly as a cheap

source of fat in livestock feeds.

However, by implementing

processes such as the one developed by Haas and Bloomer, the agents in soapstock could

one day serve as the source of more than 6 million gallons per

year of diesel engine fuel or fuel additives and in other applications such as cleaning agents and organic solvents.

Other ARS scientists have patented another method to

develop biodiesel and lubricants, as well as fuel and lubricant

additives. This enzymatic method, invented by ERRC

researchers Foglia, William N. Marmer, and Lloyd A. Nelson,

uses animal fats, vegetable oils, rendered fats, and restaurant

grease to produce the fatty acid esters that can be used as

biodiesel and lubricants. Because conversion of grease, in

particular, was very effective and inexpensive, grease-derived

biodiesel could be used in conjunction with soybean oil

derivatives to reduce costs.—By Jim Core, ARS.

This research is part of Bioenergy and Energy Alternatives,

an ARS National Program (#307) described on the World Wide

Web at http://www.nps.ars.usda.gov.

Michael J. Haas is in the USDA-ARS Hides, Lipids, and

Wool Research Unit, Eastern Regional Research Center, 600

East Mermaid Lane, Wyndmoor, PA 19038; phone (215) 233-

6459, fax (215) 233-6795, e-mail mhaas@arserrc.gov. ◆

B

Biofuel Gets Less Expensive

The french-fry

aroma, another

typical trait of

current biodiesel

fuels, was an

added bonus.

eing stuck in a traffic jam may be a bit more bearable if

the aroma of fresh french fries was in the air, rather

than the noxious stink of fossil fuel exhaust.

When scientists at the Eastern Regional Research

Center (ERRC) recently tested biodiesel fuel produced

from soybean soapstock—an abundant but underused byproduct of vegetable oil refining—they found its composition, engine performance, and emissions to be comparable to those of

biodiesel fuels presently on the market, which are made from

highly refined edible oils. The french-fry aroma, another typical trait of current biodiesel fuels, was an added bonus.

Biodiesel is the term given

to diesel engine fuels made

from agricultural fats and oils.

There is much interest in the

use of biodiesel throughout the

world because it is made from

renewable resources and reduces air-polluting emissions

by diesel engines.

ARS research chemist

Michael J. Haas and biologist

Karen M. Scott teamed with

research scientist Scott

Bloomer—then at the international agricultural company

Cargill in Minneapolis, Minnesota—to develop a chemical

method that converts all forms

of fatty acids found in lipids

of soybean soapstock into simple methyl esters. The researchers have applied for a patent on the method.

Haas, Thomas A. Foglia, and other ARS researchers with

ERRC’s Hides, Lipids, and Wool Research Unit in Wyndmoor,

Pennsylvania, are interested in using lower value lipids derived

from animal fats, vegetable oils, and recycled greases as raw

materials for biodiesel production. They want to make biodiesel more attractive economically while reducing use of imported

fossil fuels and increasing use of renewable, agriculture-based

products.

Biologist Karen Scott and biochemist Michael Haas prepare a

reactor of soybean-derived soapstock for conversion to biodiesel.

PEGGY GREB (K9841-1)
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 67

uick, accurate, cost-effective methods for detecting 

pathogenic bacteria are essential to ensuring a safe food 

supply. ARS scientists at the Eastern Regional Research 

Center (ERRC) in Wyndmoor, Pennsylvania, are improving methods to detect foodborne pathogens like the deadly 

Listeria monocytogenes.

The Centers for Disease Control and Prevention estimates that 

listeriosis, the disease caused by L. monocytogenes infection, 

affects around 2,500 people every year and kills about 500. Newborns, seniors, pregnant women, and individuals with compromised 

or weakened immune systems are particularly susceptible.

Most methods for detecting harmful foodborne bacteria rely on 

antibodies, proteins used by the immune system to fight infections 

and foreign bodies. Because antibodies are highly specific, researchers can use them to identify and locate specific pathogens.

Antibodies vary in their degree of specificity. For example, 

current antibody-based methods for detecting L. monocytogenes

can’t distinguish it from the mix of nonharmful bacteria found in 

most foods, says Shu-I Tu, research leader of the ERRC Microbial 

Biophysics and Residue Chemistry Research Unit.

A molecular method called “phage display” uses bacteria and 

bacterial viruses, or phages, to quickly select antibodies to detect 

pathogens. Microbiologist George C. Paoli and chemist Jeffrey D. 

Brewster have used phage display to isolate an antibody fragment 

that binds specifically to L. monocytogenes.

“This may be the first antibody to demonstrate the high 

degree of specificity required to accurately detect this 

pathogen,” Paoli says.

The researchers’ success demonstrates that antibody 

phage display can be used to select antibodies for pathogen 

detection—even where traditional methods have proved 

inadequate. Paoli is also using phage display to select antibodies targeting other difficult-to-detect bacterial pathogens 

related to food safety and security.

Paoli has since characterized the interaction of the antibody with the bacterium and has identified the part of the 

L. monocytogenes cell to which this antibody binds. Paoli 

and postdoctoral research associate Lynn Kleina also linked 

the antibody fragments to microscopic magnetic beads, 

creating an L. monocytogenes-specific immunomagnetic 

bead (IMB).

Because the antibodies bind to specific targets, the 

anti-L. monocytogenes IMBs can be used to capture just 

L. monocytogenes from the bacterial mix found in food. 

This is the first step in developing a significantly improved 

detection method for L. monocytogenes. This work will allow researchers to develop much-needed rapid tests for the 

pathogen, reducing the likelihood that contaminated food 

will reach consumers.

The Microbial Biophysics and Residue Chemistry Research 

Unit has an impressive history of pathogen detection research. 

To learn more about this work, see “New Detection Methods 

Improve Food Safety,” Agricultural Research, January 2005, 

pp. 15-17.—By Laura McGinnis, ARS.

This research is part of Food Safety, an ARS National 

Program (#108) described on the World Wide Web at www.

nps.ars.usda.gov.

Shu-I Tu is in the USDA-ARS Microbial Biophysics and 

Residue Chemistry Research Unit, Eastern Regional Research 

Center, 600 E. Mermaid Ln., Wyndmoor, PA 19038; phone 

(215) 233-6466, fax (215) 233-6581, e-mail shu-i.tu@ars.

usda.gov. X

New Methods for Detecting Listeria

From left, microbiologist George Paoli, postdoctoral research associate 

Lynn Kleina, and chemist Jeffrey Brewster examine colonies of Listeria 

monocytogenes captured with immunomagnetic beads coated with singlechain antibodies specific for the pathogen. 

Q

PEGGY GREB (D615-1)
68 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

he Eastern Regional Research Center (ERRC) in Wyndmoor, Pennsylvania, recently announced the opening 

of the Center of Excellence in Extrusion and Polymer 

Rheology (CEEPR).

The goal of the new center is to create value-added, novel 

foods, food ingredients, and nonfood or industrial biodegradable 

products from underused agricultural materials such as whey or 

corn byproducts. Current research projects cover a wide range of 

products, including snack foods, cheeses, meal replacement bars, 

pet foods, texturized proteins or meat substitutes, aquaculture 

feed, and nonfood materials such as films. 

Scientists at ERRC work to create processes for converting 

corn and other grains into food and nonfood products. The waste 

streams from these processes will provide working materials for 

CEEPR projects.

The center features a modern pilot plant where new products 

can be developed from concept to prototype and eventually to 

full market production through technology-transfer collaborations. For example, they will develop processed foods and create unique biopolymers with production-scale extruders and an 

injection molding machine at ERRC.

Extrusion is a process of converting raw materials into new 

forms. The materials are first made into a semisolid mass, then 

forced through a die’s restricted opening to create new shapes. 

According to Charles Onwulata, a food technologist in ERRC’s 

Dairy Processing and Products Research Unit and CEEPR’s 

Inset: Whey-protein enriched 

corn curls. ARS scientists have 

developed a method to modify 

whey proteins, making them 

more compatible with starch and 

therefore easier to puff. 

Left: In a modern pilot 

plant at the Eastern 

Regional Research Center in 

Wyndmoor, Pennsylvania, 

food technologist Charles 

Onwulata works on 

development of processed 

foods and creation of unique 

biopolymers with productionscale extruders and an 

injection molding machine. 

PAUL PIERLOTT (D041-1)

coordinator, the food industry uses rheology equipment, which 

helps determine the form, deformation, and flow properties 

of melted materials and the texture of resulting products. As 

Onwulata says, “The rheology of the product in the extruder 

affects the structure and texture of the finished product.”

Knowledge of polymer rheology is essential in maintaining 

uniform textures in molded products such as, for example, an 

ice cream sandwich. ERRC’s polymer work will use injection 

molding to create bioplastics from agricultural wastes. 

Onwulata says they are forming partnerships with industry, 

other research agencies, and universities. In the past, Onwulata 

has collaborated with two sister agencies at the U.S. Department 

of Agriculture. He worked with the Animal and Plant Health 

Inspection Service to develop an insect feed and with the United 

States Agency for International Development to develop an 

extruded instant emergency food product needing no further 

cooking. Onwulata is also developing new ways to use whey 

proteins in enhancing the nutrition content of extruded crunchy 

snack foods.—By Jim Core, ARS.

This research is part of Quality and Utilization of Agricultural 

Products, an ARS National Program (#306) described on the 

World Wide Web at www.nps.ars.usda.gov.

Charles Onwulata is in the USDA-ARS Dairy Processing and 

Products Research Unit, Eastern Regional Research Center, 600 

East Mermaid Ln., Wyndmoor, PA 19038; phone (215) 233-6497, 

fax (215) 233-6795, e-mail conwulata@errc.ars.usda.gov. u

PAUL PIERLOTT (D041-2)

T

Creating Novel Foods and More From Agricultural Products
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 69

resh fruits and vegetables are rich in essential vitamins 

and minerals, a quality that contributes to healthier diets. But several outbreaks of food poisoning in recent 

years have been linked to cantaloupes, sprouts, lettuce, 

tomatoes, and other fresh produce. Conventional commercial washing and sanitizing methods to remove microbial 

contaminants from produce surfaces have been found to be 

marginally effective. 

Scientists at ARS’s Eastern Regional Research Center (ERRC) 

in Wyndmoor, Pennsylvania, are conducting experiments to understand how these microorganisms survive and grow on produce 

surfaces even after exposure to sanitizing solutions like chlorine.

Says Bassam A. Annous, a microbiologist in ERRC’s Food Safety Intervention 

Technologies Research Unit, “Gaining 

knowledge of factors that permit survival 

of microbial contaminants during washing 

and sanitizing will help us develop new 

technologies for removing or inactivating 

microbes on both fresh and minimally 

processed produce.”

The human pathogen Salmonella is often 

the culprit behind produce-related outbreaks 

of foodborne illness. It’s an important concern 

in ensuring microbiological safety of freshcut cantaloupe. The bacteria quickly cling 

to the rind and form a “biofilm”—a mass of 

microbes attached to a surface and to each 

other by bacterial polymers (complex sugars).

Then, Salmonella cells present on the rind can 

be transferred to the melon’s internal tissues 

during cutting.

Annous, along with postdoctoral researcher 

Ethan Solomon, biologist Angela Burke, 

food technologist Dike Ukuku, and biologist 

Peter Cooke, recently gained new insight 

into how Salmonella forms this biofilm on cantaloupe surfaces. 

Salmonella cells produce fimbriae (hairlike structures) and 

cellulose that help them attach, colonize, and survive on the 

melon’s surface. Once attached to the outside of the rind, the 

cells grow and excrete polymers, forming the biofilm, which 

shields the bacteria from harsh sanitizing solutions.

The researchers will collaborate with scientists at the 

University of Navarra, in Spain, to determine how Salmonella

develop fimbriae as they grow and how they use them to cling to 

surfaces. They will also determine the role of specific bacterial 

polymers involved in surface attachment and biofilm formation 

by using Salmonella cells that are defective in producing fimbriae 

and/or cellulose.

But scientists are already finding ways to outsmart the bacerium. For instance, Annous and Joseph Sites, a mechanical 

engineer, recently developed a commercial-scale surfacepasteurization treatment that resulted in a 5-logs (99.999 percent) 

reduction in a population of Salmonella Poona on the surface 

of artificially contaminated cantaloupe. The process involves 

immersing melons in water at 169 ̊F for 3 minutes to kill the 

pathogens, then sealing each melon in a plastic bag before rapid 

cooling in an ice-water bath. The plastic bag prevents the fruit 

from potential recontamination in the cold water. The treatment 

not only enhances the safety of the fruit, but also extends its shelf 

life by reducing native microflora that may cause spoilage. And 

it did not harm melon quality.—By Jim Core, ARS.

This research is part of Food Safety (Animal and Plant Products), an ARS National Program (#108) described on the World 

Wide Web at www.nps.ars.usda.gov.

Bassam A. Annous is in the USDA-ARS Food Safety Intervention Technologies Research Unit, 600 East Mermaid Ln., 

Wyndmoor, PA 19038-8598; phone (215) 233-6797, fax (215) 

233-6406, e-mail bannous@errc.ars.usda.gov. X

Surface pasteurization of cantaloupes using a commercial-scale dump tank (designed at 

ARS’s Eastern Regional Research Center) in ERRC’s biosafety level-2 pilot plant. 

F

PAUL PIERLOTT, USDA-ERRC/VGT (D321-1)

Washing and Sanitizing 

Techniques Aim To Make 

Produce Safer
70 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

N ew varieties of barley could help 

solve two national problems: energy dependence and obesity. That’s 

because some parts of barley are 

excellent for making fuel ethanol, while 

other parts are nutritious and naturally 

low in calories.

High starch content is needed to produce ethanol, while soluble fibers such as 

beta-glucan and other types of fiber have 

been found to possess health benefits for 

people. Now scientists are developing 

ways to maximize the benefits found in 

some special barley varieties.

Researchers at the Eastern Regional 

Research Center (ERRC) in Wyndmoor, 

Pennsylvania, want to reduce the cost 

of fuel ethanol and make it available 

nationwide. Most ethanol production 

facilities use corn as starting material, or 

“feedstock,” and not surprisingly, they’re 

located in the Corn Belt, not on the East 

and West Coasts, where demand for fuel 

ethanol is increasing. It’s too costly for 

most coastal states to ship corn from the 

Midwest to a local ethanol plant, so it 

makes sense for these “corn-deficient” 

states to use locally grown grains as alternatives. Barley, which grows well in 

these regions, may be the answer—once 

a couple of problems are solved.

“Barley isn’t usually thought of as a 

good candidate for fuel ethanol feedstock 

because it typically has an abrasive hull 

and a lower starch content than corn,” says 

Kevin Hicks, research leader of ERRC’s 

Crop Conversion Science and Engineering 

Chemist Robert Moreau (left) and biologist Mike Powell 

prepare samples to analyze edible oils and nutraceuticals 

in barley fractions using HPLC-MS methods. 

Chemical engineer Gerry Senske (left) and research leader 

Kevin Hicks carry out a fermentation of hull-less barley to 

produce fuel ethanol. 

Research Unit. “And it 

contains a troublesome 

polysaccharide, beta-glucan, 

that makes barley mash too 

viscous to mix, ferment, and 

distill economically.”

Low starch content in most 

barley varieties—50 to 55 

percent compared to corn’s 

72 percent—results in lower 

ethanol yield. ARS researchers are helping to create new 

barley varieties with higher 

starch content. They’re also developing 

new milling processes that will separate 

low-starch barley kernels into a starchenriched stream for efficient ethanol production and a protein- and fiber-enriched 

fraction for making valuable food and feed 

co-products.

Research is needed to help growers 

select the best varieties for ethanol production and to solve technical problems 

related to milling and fermenting barley. 

ARS also wants to expand the feed applications for barley distillers dried grains 

with solubles (DDGS), the main co-product from “dry grind” ethanol production

In the process of finding solutions to all 

these needs, ARS researchers may have 

also found some ways to provide the food 

industry with nutritious ingredients.

Better Varieties for Ethanol

Production

ERRC researchers examined more than 

100 new lines of barley being developed 

by collaborators at Virginia Polytechnic 

Institute and State University for suitability in ethanol production and have 

narrowed their focus to several promising 

varieties. Lines being developed at the 

ARS Small Grains and Potato Germplasm 

Research Unit in Aberdeen, Idaho, are 

also being evaluated.

The scientists are looking at malt, 

hulled, and hull-less barley varieties 

suitable for growers in various parts of 

the country.

Most barley not selected for brewing 

is used in animal feed and sells for well 

under $2 a bushel, according to Hicks. 

Producers would like to see a higher return 

for their crop.

Barley hulls are very abrasive and cause 

expensive wear and tear on grain handling 

and milling equipment. Removing the 

hull and other nonstarch components of 

the kernel before fermentation for ethanol 

would greatly improve the production 

process. A combination of milling, grindPEGGY GREB (K11935-1)

PEGGY GREB (K11938-1)

New Varieties and 

Techniques Make 

Barley Better For Fuel 
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 71

Starch and soluble fibers are key in ARS’s 

efforts to use barley to produce ethanol and enhance 

the nutrition in food products. 

ing, and size-fractionation techniques 

could accomplish this. But perhaps an 

even better idea is to use barley varieties that are naturally hull-less, avoiding 

the need for “pearling”—a process that 

removes the hull and makes the grains 

smaller and rounder. As Rolando Flores, 

an ERRC agricultural engineer, explains, 

pearling removes the hull, divides the 

fiber into several fractions, and separates 

the protein from the starch to produce 

ethanol without wasting low-starch barley 

co-products.

Hull-less varieties lose their hull during 

harvesting. They have more starch and 

protein but less fiber than hulled varieties. Several Virginia hull-less lines look 

promising in ERRC’s program.

Hull-less barley solves the “hull” problem but not the beta-glucan viscosity issue. 

With hulled varieties, fractional milling 

techniques such as pearling help by removing beta-glucan-enriched fractions before 

fermentation. But these techniques don’t 

remove all the beta-glucan. So, for both 

hull-less and hulled varieties, beta-glucanase enzymes are used in fermentation to 

dramatically break down high-viscosity 

beta-glucans into low-viscosity oligosaccharides, solving the beta-glucan problem, 

according to Dennis O’Brien, an ERRC 

chemical engineer.

Nutrition for Feed and Food

Animal feeds rich in beta-glucan cause 

nutritional problems in poultry. Betaglucan in DDGS limits their application 

for use as feed mainly to ruminants, such 

as cattle. But high-protein DDGS fractions 

with low-levels of beta-glucan would 

make useful ingredients in poultry, swine, 

and fish feeds. The ERRC team is making 

progress in this area.

Barley fractions that are high in betaglucan might also find use in certain 

foods. Beta-glucan has been found to 

lower cholesterol levels and blood pressure and improve immune function in 

human studies.

Scientists with the Beltsville (Maryland) 

Human Nutrition Research Center’s 

(BHNRC) Diet and Human Performance 

Laboratory will study the possibility of 

using beta-glucan and other soluble fibers 

not being used in ethanol production. 

Future studies at BHNRC will include 

human feeding studies designed to test 

the health-promoting effects from foods 

prepared with the ERRC barley coproducts.

“In our previous human feeding studies, 

consumption of soluble fiber from barley 

significantly improved several risk factors 

for cardiovascular disease and diabetes,” 

says Kay Behall, a BHNRC chemist.

Robert A. Moreau, an ERRC chemist on 

the project, says fractions remaining after 

milling are also low in starch, so they’re 

low in carbohydrates and high in dietary 

fiber, oil, and protein, which makes them 

ideal nutraceuticals—ingredients added 

to food for their health benefits. Barley 

fractions could be added to pasta, breads, 

pastries, and snack foods to increase their 

fiber content and reduce starch.

Moreau and cooperators at the University of Helsinki in Finland found that 

phytosterols in grains such as barley and 

rye are concentrated in the outer layers, or “fines,” of kernels. Some studies 

have found that these plant sterols might 

contribute to a reduced risk of coronary 

heart disease. Currently, sterols are used 

to enrich products such as margarine and 

orange juice.

ARS researchers are using pearling to 

remove plant sterols and fiber-enriched 

outer layers of hull-less barley. “We found 

that fines removed from kernels contained 

two to three times as many phytosterols 

per unit weight as did whole kernels. 

These fines could serve as a new source 

of phytosterols,” Moreau says.—By Jim 

Core, ARS.

This research is part of Quality and Utilization of Agricultural Products (#306) 

and Bioenergy and Energy Alternatives 

(#307), two ARS National Programs described on the World Wide Web at www.

nps.ars.usda.gov.

Kevin Hicks is in the USDA-ARS Crop 

Conversion Science and Engineering Research Unit, Eastern Regional Research 

Center, 600 East Mermaid Ln., Wyndmoor, 

PA 19038-8598; phone (215) 233-6579, 

fax (215) 233-6406, e-mail khicks@errc.

ars.usda.gov. X

Chemical engineer Jhanel Wilson and 

agricultural engineer Rolando Flores mill 

barley kernels into starch-enriched fractions 

for ethanol production and low-starch 

fractions for food and feed. 

PEGGY GREB (K11940-1)
72 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

ARS scientists in Wyndmoor, Pennsylvania, have modified biodiesel 

production technology. Their method eliminates a step—and an airpolluting chemical—from the process of synthesizing the fuel.

Michael Haas, a biochemist with the Eastern Regional Research Center’s Fats, Oils, and Animal Coproducts Research Unit, and colleagues 

developed the new approach. 

In this country, soybean oil is the most prevalent starting material 

for biodiesel, though other vegetable oils, animal fat, and waste grease 

are used too. But soybean oil’s relatively high cost results in biodiesel 

being expensive, which discourages wider adoption of this desirable, 

renewable fuel.

In biodiesel production, hexane, a colorless, flammable liquid derived 

from petroleum, is traditionally used to extract the oil from the soybeans. 

But hexane is an air pollutant, and its release is regulated by the U.S. 

Environmental Protection Agency. Working with ERRC biologist Karen 

M. Scott and chemist Thomas A. Foglia, Haas eliminated hexane from 

the process simply by skipping the oil-extraction step that relies on it. 

Instead, Haas explains, soybean flakes are incubated with methanol 

and sodium hydroxide—the same agents that would be used to process 

extracted oil.

“In the new method, soybean flakes are incubated in alkaline 

methanol, eliminating the need to isolate and purify the oil before 

transesterification.” (“Transesterification” is a reaction between fats and 

alcohol that forms the simple fatty acid esters that are biodiesel.) The 

lipids don’t have to be isolated first because transesterification occurs 

in the raw soy flakes containing the oil.

Next, when the researchers collaborated with Andrew McAloon, a 

process modeler/cost engineer at their facility, to estimate and compare 

costs, they hit a snag. Without even accounting for the cost of the soy 

flakes or soy oil, a gallon of biodiesel produced by their new process 

was estimated to cost $3.14—versus 38 cents per gallon if produced by 

the conventional process. 

The researchers then noticed that their new method used considerably 

more methanol than is typically needed in biodiesel synthesis. They 

reasoned that the moisture naturally present in soybeans, as much as 

10 percent in soy flakes, could be the reason behind the high methanol 

requirement. They found that by drying the flakes before starting the 

biodiesel synthesis, they could greatly reduce the required methanol 

volume. As a result, the estimated cost went down to $1.02 per gallon.

Haas and his colleagues are presently refining their economic model 

to account for income from selling the lipid-free, protein-rich flakes left 

after the biodiesel reaction for use as animal feeds and to account for cost 

differences between refined-oil and flaked-soybean starting materials.

ARS has filed a patent application on the process. Haas is exploring 

use of this new method to produce biodiesel from the lipids in corn coproducts from ethanol plants that use corn as a starting material. He’s 

also investigating the suitability of canola seeds and meat and bone 

meal.—By Jim Core, ARS.

This research is part of Bioenergy and Energy Alternatives, an ARS 

National Program (#307) described on the World Wide Web at www.

nps.ars.usda.gov. 

Michael J. Haas is in the Fats, Oils, and Animal Coproducts Research 

Unit, USDA-ARS Eastern Regional Research Center, 600 East Mermaid 

Ln., Wyndmoor, PA 19038; phone (215) 233-6459, fax (215) 233-6795, 

e-mail mhaas@errc.ars.usda.gov. X

New Method 

Simplifies 

Biodiesel 

Production

Oil from soybeans 

is the usual starting 

material for 

biodiesel. 

SCOTT BAUER (K5267-6)
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 Agricultural Research/July 2003 739

uEChERS (pronounced catchers) is not a cool, new way of spelling the position we

usually associate with masked, padded, often grimy players toiling behind home

plate during baseball and softball games.

It’s actually a catchy name for a new approach to analyzing pesticide residues in

fruits and vegetables.

Steven J. Lehotay, an ARS chemist at the Microbial Biophysics and Residue

Chemistry Research Unit, Eastern Regional Research Center in Wyndmoor,

Pennsylvania, and a visiting scientist, Michelangelo Anastassiades, from a government laboratory in Stuttgart, Germany, developed the QuEChERS method,

which stands for quick, easy, cheap, effective, rugged, and safe. It can be used

with a wide range of pesticides and food types.

Current methods of extracting pesticide residues from food samples and

preparing them for analysis are time consuming, expensive, and labor intensive. The new, streamlined approach makes it easier and less expensive for

analytical chemists to examine food.

Routine monitoring serves to enforce laws, protect the consumer, provide data for risk

assessment and pesticide reregistration, ease international trade, market residue-free products, and help verify organic food labeling.

The U.S. Department of Agriculture and other organizations started the Pesticide

Data Program in May 1991 to test commodities in the U.S. food supply for pesticide residues.

Using QuEChERS, a single chemist can prepare a batch of 10 previously

chopped samples in about 30 minutes with $1 worth of materials per sample. This gives at least fourfold lower material costs and fourfold greater

sample throughput per analyst than traditional methods. Lehotay says the

method combines different steps, which means there is less chance for error.

A single, easy-to-clean Teflon tube is the only item to be washed and

reused, eliminating all the glassware used in conventional methods. Furthermore, less than 10 milliliters of solvent waste is generated—much less than the

75-450 milliliters generated by other methods.

Key to the new approach is the development of a rapid procedure called dispersive

solid-phase extraction. This technique quickly removes water and nontarget compounds

with magnesium sulfate and a primary-secondary amine sorbent.

More than half the produce samples tested in the United States typically do not

have measurable residues, and less than 1 percent of tested samples exceed tolerance

levels, according to the U.S. Food and Drug Administration (FDA). Consumers

should always wash, peel, or cook produce to help remove residues.

The term “tolerance” is used to describe the maximum amount of a given

pesticide or its breakdown products allowed to remain in or on food commodities.

The U.S. Environmental Protection Agency sets tolerance levels in the United

States, and state and federal monitoring programs enforce these legal limits.

Several monitoring laboratories, including a few in the FDA, are

evaluating QuEChERS. Lehotay believes that it will someday substantially

increase monitoring rates and lower costs of pesticide residue analysis.—

By Jim Core, ARS.

This research is part of Food Safety (Animal and Plant Products), an ARS

National Program (#108) described on the World Wide Web at www.nps.ars.usda.gov.

Steven J. Lehotay is in the USDA-ARS Microbial Biophysics and Residue Chemistry

Research Unit, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor,

PA 19038-8598; phone (215) 233-6433, fax (215) 233-6442, e-mail slehotay@arserrc.

gov. ★

QuEChERS Method Catches Pesticide Residues

Q
74 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

Unraveling the Listeria Genome 

If knowledge is power, Agricultural Research Service scientists 

are gaining the upper hand on Listeria monocytogenes.

Researchers at the ARS Eastern Regional Research Center 

(ERRC) in Wyndmoor, Pennsylvania, and the Institute for 

Genomic Research in Rockville, Maryland, sequenced four 

strains of Listeria related to foodborne listeriosis outbreaks—an 

important step toward developing a management strategy for 

this deadly bacterium.

“Researchers in the ERRC Microbial Food Safety Research 

Unit have completed whole genome sequencing and comparison 

of four genomes, which allowed us to significantly improve our 

understanding of Listeria,” says research leader John B. Luchansky. In addition to finding serotype-specific and strain-specific 

genome sequences, they found that these four Listeria strains 

have largely similar genetic content and organization.

The team believes a few unique regions could account for 

epidemiological and antigenic differences among strains. Understanding these differences will improve scientists’ ability to 

assess the risk posed by contamination of food by this bacterium.

They also confirmed that Listeria bacteria have 15 genes 

in a regulatory protein family known as “Crp/Fnr,” considerably more than most bacteria have. Luchansky and molecular 

biologists Darrell Bayles and Gaylen Uhlich are investigating 

whether these sequences influence the bacterium’s virulence or 

persistence in the food supply.

The scientists have estimated the percentage of the genome 

for which there is no known function and identified specific 

genes that warrant further investigation. They’ve also started to 

pursue proteomics and genomics studies, Luchansky says. This 

involves comparing different strains of bacteria—or the same 

strain growing under different environmental conditions—to 

determine whether there are differences in the level of gene or 

protein expression under the conditions tested.

Knowing more about the bacterium will enable regulatory 

agencies and the food industry to make better informed decisions about safety standards and control strategies, Uhlich says. 

And uncovering the genetic information that defines Listeria’s

survival, growth, persistence, and ability to cause disease will 

help scientists better understand the bacterium’s virulence, its 

presence in the environment, and its persistence in the food chain.

“Ultimately, we hope to learn enough about Listeria to prevent 

contamination, decrease prevalence, and reduce disease,” Bayles 

says. “This research puts us in a better position to make scientifically sound decisions about managing the threat of foodborne 

listeriosis.”—By Laura McGinnis, ARS.

John Luchansky, Darrell Bayles, and Gaylen Uhlich are 

with the USDA-ARS Eastern Regional Research Center, 600 E. 

Mermaid Ln., Wyndmoor, PA 19038-8598; phone (215) 233-6620 

[Luchansky,] (215) 233-6678 [Bayles], (215) 233-6740 [Uhlich], 

fax (215) 233-6581, e-mail john.luchansky@ars.usda.gov, 

darrell.bayles@ars.usda.gov, gaylen.uhlich@ars.usda.gov. X
How about cheesy pepperoni, Hawaiian pineapple and ham, or 

vegetarian pizza, all piping hot and ready to enjoy? These pizzas 

are made with reduced-fat mozzarella cheese and are offered at 

the Crossroads Café—the food-service installation at Camas High 

School in Camas, Washington.

One technology for making tasty-but-healthy cheese was 

invented by Agricultural Research Service (ARS) scientists at the 

Dairy and Functional Foods Research Unit in Wyndmoor, Pennsylvania. It became available to schools in 1995 and is used to provide 

a low-fat alternative to high-fat cheese when making pizzas. The 

ARS team included chemists Michael Tunick, Edyth Malin, and 

James Shieh, physical science technician Brien Sullivan, and Peter 

Cooke (no longer with ARS). Other team members, Virginia Holsinger and Phil Smith, are deceased.

In 2009, more than 31 million children participated in the 

USDA National School Lunch Program in more than 101,000 

schools and residential childcare institutions. With National School 

Lunch Week being observed each October, now is a good time to 

celebrate all healthy cheese options—produced using a variety of 

manufacturing methods—that are available in school lunches.

Starting in 1992, the team began exploring new ways to cut 

mozzarella’s fat content without sacrificing its flavor or stretchy 

texture, especially as a pizza topping. They worked on modifying 

the network of the milk protein casein. The result was a mozzarella 

with improved storage life and only 10 percent fat—about half the 

fat content of regular mozzarella.

Just as important, pizza-eating students give the cheese a 

thumbs-up, according to school food-service director Sarah Winans 

with the Crossroads Café. 

Martha Henry, director of food service for all schools in 

Tennessee’s Maryville City School District, agrees. “We find that 

pizza is one of school kids’ favorite lunches,” she says. “Reducedfat mozzarella cheese allows the students to enjoy pizza while 

reducing their dietary fat intake.”

The USDA Farm Service Agency’s Kansas City Commodity 

Office in Missouri began buying lower fat mozzarella cheeses in 

the early 1990s. Since 2000, that office has been buying lower fat 

mozzarellas exclusively. More than 500 million pounds of lower 

fat mozzarella cheeses—worth more than $800 million—have 

been purchased for school-related programs, according to program 

analysts David Leggett and Michael Buckley with the USDA Food 

and Nutrition Service in Alexandria, Virginia.

This research supports the USDA priority of improving children’s nutrition and health.—By Rosalie Marion Bliss, ARS.

Michael H. Tunick is with the USDA-ARS Dairy and Functional 

Foods Research Unit, Eastern Regional Research Center, 600 

E. Mermaid Lane, Wyndmoor, PA 19038-8598; (215) 233-6454, 

michael.tunick@ars.usda.gov.*

Celebrating 15 Years of a Healthy School Lunch Option

More than 31 million children 

participate in the National 

School Lunch Program during 

the school year.

Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 75
76 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

Science Update Science Update

Toward Safer Fresh-Cut 

Tomatoes, Melons

Most of the fresh-cut produce market’s 20-percent annual growth is in 

vegetables. While retailers have long 

sought a way to offer consumers freshcut tomatoes and melons, they haven’t 

pursued that market beyond local or 

regional fresh-cut processing because 

of product quality problems and food 

safety concerns caused by inadequate 

cold temperatures during distribution.

In the past, melons and tomatoes 

have been associated with Salmonella, 

which heads the list of common causes 

of food-borne illnesses. About 40,000 

cases of salmonellosis are reported annually, according to the federal Centers 

for Disease Control and Prevention in 

Atlanta, Georgia.

In a few years, supermarkets may sell 

packaged fresh-cut tomatoes, melons, 

and other fruits if researchers find 

novel methods for killing or removing 

disease- causing bacteria.

Now ARS scientists have entered 

into a 2-year cooperative research and 

development agreement with EPL 

Technologies, Inc., of Philadelphia. 

Pennsylvania, to develop novel methods 

for killing or removing disease-causing 

bacteria from fresh-cut fruits. Under the 

agreement, the scientists will seek alternatives to common sanitizing agents, 

such as chlorine, that are used to wash 

fresh-cut foods. This research should 

allow fresh-cut manufacturers to expand 

their markets and make healthy freshcut products available to a larger group. 

Successful introduction of these products will be a major boon to growers and 

shippers. Gerald M. Sapers, USDA-ARS 

Plant Science and Technology Research 

Unit, Wyndmoor, Pennsylvania; phone 

(215) 233-6417, e-mail gsapers@ars 

errc.gov.

Using Microwaves To 

Extract Pectin

Among other food uses, pectin

acts as a gelling agent in fruit jams and 

jellies and as a texturizer in premixed 

yogurt. A natural ingredient, it’s mostly 

obtained from citrus pulp, peel, and 

albedo—the white material between the 

outer peel and fruit—and from apples 

and sugar beets. To extract pectin from 

fruit, industry uses a conventional 

heating process that takes an hour or 

more per batch. Overheating sometimes 

breaks down the pectin, reducing its 

quality.

Now scientists have found a way 

to use microwave technology to extract 

this valuable food ingredient, which 

is largely imported and sells for $6 to 

$8 per pound. A faster, nondestructive 

method could reduce the cost of domestic production and provide a market for 

what is currently a low-value byproduct 

of U.S. food processing. A patent application on the technology has been filed. 

Marshall L. Fishman, USDA- ARS Plant 

Science and Technology Research Unit, 

Wyndmoor, Pennsylvania; phone (215) 

233-6450, e-mail mfishman@arserrc.

gov.

Corn Extract for Waxing 

Paper

Zein is a corn protein making up 

about half of the protein found in the 

corn ker- nel. Unlike other corn proteins, 

which are water soluble, zein repels 

water, making it an ideal coating material. It was discovered when researchers, 

at work on reducing the cost of distilling ethanol from corn, isolated it as a 

zein-lipid mixture. They found it had 

good grease resistance and water barrier 

properties.

Extracting such mixtures from 

ground corn should cost about $1 to $2 

per pound. The zein coating would be 

suitable for most packaging material 

requiring waterproofing, such as boxes 

for perishable fruits, vegetables, or fish. 

Nicholas Parris, USDA-ARS Engineering Science Research Unit, Wyndmoor, 

Pennsylvania; phone (215) 233-6453, 

e-mail nparris@arserrc.gov.

Bacteria Turn Fats and 

Oils Into Plastics

Microbial fermentation is turning vegetable oils and animal fats 

into biodegradable industrial materials. Certain microorganisms, when 

grown on fats and oils, can produce 

poly(hydroxyalkanoate) polymers, or 

PHAs. When fed excessive carbon and 

deprived of other nutrients, bacteria like 

Pseudo- monas resinovorans produce 

these plasticlike substances as a survival 

mechanism. The polymers are either 

rigid or elastomeric, depending on their 

chemical structure, the organism that 

produces them, and the fat or oil feedstock.

Since PHAs break down naturally 

over time, they are suitable for a wide 

range of environmentally friendly medical and consumer products ranging 

from adhesives to plastics and films. 
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 77

Science Update Science Update

Scientists want to control the PHA 

properties to make them suitable for 

diverse industrial uses. The properties 

vary with the fatty acid composition of 

the feedstock source. Richard D. Ashby, 

Daniel K.Y. Solaiman, USDA-ARS 

Hides, Lipids, and Wool Research Unit, 

Wyndmoor, Pennsylvania; phone (215) 

233-6483 [Ashby] -6476 [Solaiman], 

e-mail rashby@ars errc.gov, dsolaiman@

arserrc.gov.

Virtual Laboratory 

Furthers Food Safety

Predictive microbiology is a growing field that estimates the behavior of

mi- croorganisms in response to environ- mental conditions. These include 

the food production and processing opera- tions that occur from farm to table. 

Now, mathematical models 15 years in 

the making are being used to estimate 

the behavior of foodborne bacteria that 

can cause illness or disease in consumers. They have been collected on one web 

site that functions as a virtual laboratory 

to help facilitate cooperation among researchers studying one key food safety 

issue: how pathogenic bacteria in food 

behave under varying environmental 

conditions. The site is called the Center 

of Excellence in Microbial Modeling and 

Informatics, or CEMMI, for short. It can 

be accessed at http://www.arserrc.gov/ 

cemmi.

Researchers hope that the center will 

improve the way predictive models are 

developed and applied. It should help 

define existing gaps in research data and 

enhance uniformity in experimental designs. It will network laboratories, researchers, model designers, and industry, 

thus facilitating the solving of contemporary food safety and quality problems. 

Mark L. Tamplin, USDA-ARS Microbial 

Food Safety Research Unit, Wyndmoor, 

Pennsylvania; phone (215) 836-3794, 

e-mail mtamplin@arserrc. gov.

Increasing Fiber in 

Cereals and Snacks

Americans average only about 15 

grams a day of dietary fiber, even though 

the recommended intake is 20 to 35 

grams. Studies suggest that adequate 

fi- ber can decrease the risk of heart disease, some cancers, diabetes, and high 

blood pressure. One easy way to increase 

the general population’s fiber intake 

might be to add it to favorite snack 

foods, which now contain less than 3 

percent fiber.

Until now, adding plant fiber during 

the extrusion process by which many 

cereals and snacks are formed has caused 

undesirable textural changes. But by 

adding dairy proteins such as whey or 

casein as binders, ingredients hold together better, making for a more acceptable product that may eventually contain 

as much as 10 percent fiber. Other work 

is testing use of milk protein to envelop 

fibers and keep them from soaking up 

water when used in foods. Reducing 

water-holding capacity of fiber can improve food quality. Charles I. Onwulata, 

USDA-ARS Dairy Products Research 

Unit, Wyndmoor, Pennsylvania; phone 

(215) 233-6497, e-mail conwulata@

arserrc.gov.

Getting More Out of 

Corn—More Economically

After 100 years of doing it the same 

way, corn refiners will soon have another option that can potentially lower costs 

and shorten the time needed to produce 

starch, oil, and other co-products. In laboratory and pilot-scale trials, this new 

method yields as much or more starch as 

the conventional process.

Relying on protease enzymes to 

break down starch and protein and using 

less sulfur dioxide, the method requires 

just a 6-hour pretreatment of corn kernels be- fore milling. This replaces the 

24 to 36 hours of conventional steeping 

in water and sulfur dioxide that customarily start the breakdown process. 

Researchers have applied for a patent on 

the method. David B. Johnston, USDAARS Crop Conversion Science and 

Engineering Research Unit, Wyndmoor, 

Pennsylvania; phone (215) 836-3756, 

e-mail djohnston @arserc.gov.

Protective, Edible, 

Milk-Based Film

A patent has been issued for a method to modify milk proteins to make water-resistant films that may one day coat 

or package foods. It uses highly pressurized carbon dioxide to remove the 

protein known as casein from milk. The 

main protein in milk, casein solidifies 

when milk acidifies. It is already used 

as a food supplement and as an ingredient in adhesives, finishing materials for 

paper and textiles, paints, and other nonfood products. But because moisture can 

dissolve casein, it’s been difficult to use 

in films, fibers, or molded materials and 

get acceptable mechanical properties.

The new extraction method capitalizes on casein’s natural structure to form 

water-resistant films and coatings that 

can act as barriers between products and 

outside substances. The films can be 

formed either as stand-alone sheets or 

as thinner coatings that adhere directly 

to the product. Both can lock in moisture and remain intact when exposed to 

water.

Such edible coatings might be used 

on dairy food products such as cheese 

or be incorporated into packaging material. Flavorings, vitamins, or minerals 

could be added to the coating to enhance 

them. Researchers are still evaluating 

these and other potential uses, but the 

patent is available for licensing. Peggy 

M. Tomasula, USDA-ARS Dairy Processing and Products Research Unit, 

Wyndmoor, Pennsylvania; phone (215) 

233-6703, e-mail ptomasula@arserrc. 

gov.
78 Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010

Science Update Science Update

Seeking Quick Checks for 

E. Coli

Sometimes it’s really important to 

know which strain of Escherichia coli 

bacteria might be causing illness in a patient. Several strains, such as O157:H7, 

are known to provoke severe gastrointestinal problems including bloody 

diarrhea and hemorrhagic colitis and 

can lead to serious health complications, 

including kidney failure. Experts use 

serotyping to distinguish between 

E. coli strains and determine how potentially dangerous a particular one might 

be. But the laboratory procedure is labor 

intensive and time consuming.

Now scientists are developing tests 

using both conventional and real-time 

PCR (polymerase chain reaction) methods. These chemical procedures generate enough genetic material to allow 

identification and study of various E. 

coli strains. The researchers want to find 

ways to detect and identify specific E. 

coli serogroups and increase knowledge 

of each one’s potency. Pina M. Fratamico, USDA-ARS Microbial Food Safety 

Research Unit, Wyndmoor, Pennsylvania; phone (215) 233-6525, e-mail 

pfratamico@errc.ars.usda.gov.

More Protein in Snacks

Snack foods are a major dietary

component for many U.S. consumers. 

Often these crunchy favorites are made 

from high-starch products such as corn 

flour. On average, these between-meal 

items consist of 3 to 5 percent protein, 

with the rest mostly carbohydrates, fats, 

and sweeteners.

Now a way has been found to 

increase the protein in foods such as 

breakfast cereals, corn puffs, cheese 

curls, and energy bars by up to 35 percent by adding whey proteins left over 

from cheesemaking. It wasn’t easy for 

food technologists to figure out how to 

add more whey without reducing the 

crunchiness of the end product. But 

through trial and error, they found the 

right temperature and moisture at which 

to blend corn flour with whey protein 

isolate so that it would run through a 

twin-screw extruder and achieve the 

desired shape and consistency. This 

technology is available for licensing. 

Charles I. Onwulata, USDA-ARS Dairy 

Processing and Products Research Unit, 

Wyndmoor, Pennsylvania; phone (215) 

233-6497, e-mail conwulata@arserrc.

gov.

Orange Peel’s Got 

Curative Powers

There’s more good stuff lurking in an 

orange than just its vitamin C-rich juice. 

Studies show that carbohydrates in its 

peel have health-promoting effects. One 

of them, pectin, has prebiotic properties. 

Prebiotics are nondigestible foods or nutrients that increase growth of beneficial, 

probiotic bacteria in the large intestine, 

where they stimulate health and help 

curb foodborne pathogens.

Prebiotic carbohydrates, also known 

as oligosaccharides, are found in certain 

fruits and vegetables and are beginning 

to be used in food products and animal feeds. Now, antiadhesive prebiotics 

have been discovered that may prevent 

patho- gens from binding to intestinal 

walls. Work is under way to find new, 

cost-effective methods to extract pectic 

prebiotics from orange peel, a low-value, 

abundantly available processing byproduct. A commercial partner’s being 

sought to further develop and commercialize this technology. Arland T. 

Hotchkiss, USDA-ARS Crop Conversion 

Science and Engineering Research Unit, 

Wyndmoor, Pennsylvania; phone (215) 

233-6448, e-mail ahotchkiss@arserrc. 

gov.

Itch-Free, MachineWashable Wool

ARS has developed a better way to 

produce bleached, itch-free (biopolished), 

machine-washable wool suitable for use 

in military apparel and in commercial 

textile product lines where synthetic 

fibers are traditionally used. The work 

was headed by ARS chemist Jeanette 

M. Cardamone. The new process is an 

alternative to conventional chlorination 

processing, which is not environmentally 

friendly. The military is especially keen 

to have itch-free, machine-washable, 

shrink-resistant wool for clothing because 

it would be more comfortable and 

breathable than synthetics. In addition, 

this specially processed wool burns to a 

soft ash with a self-extinguishing flame, 

while synthetics melt and drip-burn to a 

hard bead that can lodge in open wounds. 

ARS washable wool technology could 

increase the demand for domestic wool. 

This work was conducted at the Fats, 

Oils, and Animal Coproducts Research 

Unit, Eastern Regional Research Center, 

Wyndmoor, Pennsylvania.

A new biopolishing woolprocessing technique can make 

wool clothing more comfortable. 

Even the U.S. military is 

interested.

Food Safety Help for 

Processors

A new Internet resource could be invaluable to food processors—especially, 

to smaller meat and poultry processing 

companies. The information it provides 

can answer food safety questions and 
Agricultural Research Reprint: Eastern Regional Research Center Research Highlights 2000-2010 79

Science Update Science Update

help food processors make science-based 

decisions to produce safe and wholesome 

products for consumers. Called the Predic-

tive Microbiology Information Portal, or 

PMIP, it offers information on research, 

regulations, and resources related to 

Listeria monocytogenes in ready-to-eat 

foods. Soon it will be expanded to include 

other pathogen and food combinations. To 

help ensure the safety of food processing 

methods, a searchable database allows 

users to find information that can be used 

to develop plans for Hazard Analysis and 

Critical Control Point inspection.

Developed in collaboration with Rut-

gers University and Decisionalysis Risk 

Consultants, Inc., of Ottawa, Ontario, the 

portal includes a tutorial with instructions 

on using and interpreting predictive mod-

els. It links to the ARS Pathogen Modeling 

Program and ComBase, which provide di-

verse resources associated with databases, 

regulatory requirements, and food safety 

principles. The PMIP Web address is 

www.ars.usda.gov/naa/errc/mfsru/portal. 

Vijay K. Juneja, USDA-ARS Microbial 

Food Safety Research Unit, Wyndmoor, 

Pennsylvania; phone (215) 233-6500, 

e-mail vijay.juneja@ars.usda.gov.

Sustainable Corn 

Production Supports 

Advanced Biofuel 

Feedstocks

Researchers have found a costeffective, energy-efficient, and envi

-

ronmentally sustainable method to use 

corn stover for gener- ating an energyrich oil called “bio-oil” and for making 

biochar to enrich soils and sequester 

carbon. The team used fast pyrolysis 

to transform corn stover and cobs into 

bio-oil and biochar. They found that the 

bio-oil captured 70 percent of the total 

energy input, and the energy density 

of the bio-oil was 5 to 16 times that of 

the feedstock. This suggests it could be 

more cost effective to produce bio-oil 

through a distributed network of small 

pyrolyzers and then transport the crude 

bio-oil to central refining plants to make 

“green gasoline” or “green diesel,” 

rather than transporting bulky stover 

to a large centralized cellulosic ethanol 

plant. About 18 percent of the feedstock 

was also converted into biochar, which 

contains most of the mineral nutrients in 

the corn residues. Amending soils with 

this biochar would return those nutri-

ents to the soil, reduce leaching of other 

nutrients, help build soil organic matter, 

and sequester carbon. Charles Mullen, 

USDA-ARS Crop Conversion Science 

and Engineering Research Unit, Wyn-

dmoor, Pennsylvania; (215) 836-6916, 

charles.mullen@ars.usda.gov.

Tanning Innovation Might

Boost Meat Safety

Microorganisms present on the hair 

of food animals at the time of slaugh-

ter—such as Escherichia coli O157:H7, 

Salmonella, and Listeria monocyto-

genes—can contaminate meat and some-

times cause illness in consumers. Re-

search shows that removing hairs from 

cattle hides before skinning significantly 

reduces the threat of meat contamina-

tion. Now, a 10-year-old hair-removal 

method has been improved to reduce 

both processing costs and environmental 

impact. The patented process begins 

with spraying a sodium sulfide solu-

tion on the carcass hide, which breaks 

protein bonds within hair fibers and al-

lows their easy removal. Then a sulfideneutralizing agent is applied. Packers 

can now remove most of the hair, split 

the hide, and send the top layer for tan-

ning and the rest for other uses. This 

saves time and money, allows earlystage inspection of the hide’s grain layer, 

and reduces shipments of low-quality 

hides to tanners. The method is being 

implemented by Future Beef Operations, 

LLC, in a new Kansas plant. Andrew G. 

Gehring, USDA-ARS Hides, Lipids, and 

Wool Research Unit, Wyndmoor, Penn-

sylvania; phone (215) 233-6491, e-mail 

agehring@arserrc.gov.
Eastern Regional Research Center

USDA-ARS

600 East Mermaid Lane

Wyndmoor, PA 19038

Phone: (215) 233-6400

Fax: (215) 233-6777

www.ars.usda.gov/naa/errc