• MEATS

• FRUITS

• MELONS

• VEGETABLES

• POULTRY

• DAIRY PRODUCTS

AGRICULTURE HANDBOOK NO. 105

U. S. DEPARTMENT OF AGRICULTURE

Agricultural Marketing Service

Washington, D. C. December 1956
Preface

This handbook for the proper care of perishable agricultural commodities

during transportation by motortruck has been prepared at the request of various

trucking groups and tlie Transportation Research Advisory Committee to the

Department of Agriculture. The authors have drawn freely upon some published

and many unpublished data and observations to bring together, in a single handbook, useful information on this subject. Until now, such information has been

obtainable only from many widely scattered sources.

Most of the information and recommendations in this handbook are based

upon the results and observations of many years of research by the Department

of Agriculture. Because knowledge is far from complete as to the exact temperature and humidity requirements of all agricultural commodities and as to

the most efficient methods of loading and handling many commodities and containers, the information presented in this report is necessarily limited.

Only the commodities and containers that are commercially most important

are covered in this report. Complete coverage of the hundreds of different commodities and containers moving in some volume by motor freight was not possible.

Moreover, new developments are constantly taking place with the introduction

and use of new commodity varieties, packages, and cooling and refrigeration

methods. The results of these innovations must be fuUy appraised by research

and experimentation before any positive recommendations regarding their use

can be made.

It is planned to issue supplements to this handbook froni time to time, as

additional information on these subjects is brought to light by the continuing

program of research by the Department of Agriculture.

An attempt has been made in this handbook to present the information as

concisely as possible and in such form that the complete information for any one

of many commodities and containers can be readily located by the user with a

minimum of cross-reference and consultation of footnotes. For this reason, the

loading descriptions and diagrams applicable to each container are presented in

each section dealing with the particular commodity shipped in that container, even

though the same container and loading methods are frequently used for several

different commodities.

The authors wish to acknowledge the assistance given them by John N. Kelley,

manager. Fruit Transportation, Fruit Dispatch Co., who provided material on

transportation requirements for bananas; and by the following people in the

Marketing Research Division, Agricultural Marketing Service: C. Elliott Garver,

Robert C. Haldeman, B. P. Rosanoff, R. W. Penney, Walter H. Redit, and

Harold T. Cook. Appreciation is expressed also to many shippers and truckers

for information on specific transportation requirements and methods in handling

many commodities. The following publications were used as reference material

in the preparation of the report:

Enslish, Harley, and Gerhardt, Fisk. Eifecl oí Carbon Dioxide and Temperature

on Decay oí Sweet Cherries under Simulated Transit Conditioris, Amer. Soc.

Hort. Sei. Proc: 40: 172-176,1942.

Gerhardt, Fisk. and Lindeil, Glenn. New Data on Chemes. Modem Packaging. Maren 1951.

Gernarat, Fisk, and Ryaii, A. Lloyd. The Storage of Sweet Cherries as Influenced

by Carbon Dioxide and Volatile Fungicides, U. S. Dept. Agrie, Technical

Bulletin, No. 631, February 1939,19 pp.

Pentzer, W. T., Asbury, C. E., and Borger. W. R. Precooling California Grapes

and Their Refrigeration in Transit, lecnnical Bulletin No. 899, U. S, Dept.

Agricy October 1945.

Wright, R. C, Rose, Dean H., and Whiteman, T. M., The Commercial Storage of

Fruits, Vegetables, and Florist and Nursery Stocks, Agriculture Handbook No.

66, U. S. Dept. Agrie, September 1954 (data on temperature and humidity

requirements).

For sale by the Superintendent of Documents. U. S. (iovernment Printing Office

Washington 25, D. C. - Price 30 cents
Protecting

PERISHABLE FOODS

During

Transportation by

TRUCK

r^

' y> /^/^^

• MEATS

• FRUITS

• MELONS

• VEGETABLES

• POULTRY

• DAIRY PRODUCTS

AGRICULTURE HANDBOOK NO. 105

U. S. DEPARTMENT OF AGRICULTURE

Agricultural Marketing Service

Washington, D. C.

December 1956
Contents

Page

Preface Page 2 of cover

Background of study 1

Important factors in protection of

perishables 2

Refrigeration 2

Refrigeration methods 3

Mechanical refrigeration 4

Air circulation 4

Humidity 4

Insulating materials 5

Estimating mobile refrigeration requirements 6

Precooling the product 6

Ice as a refrigerant 7

Dry ice as a refrigerant 7

Top ice 7

Mechanical refrigeration requirements 7

Importance of defrosting mechanical units 7

Checking your thermostat 8

Protection against cold 8

Training or driver responsibility 8

Preparation and loading of the

vehicle 9

Cleaning and sanitation requirements 9

Maintenance of interior of the

vehicle 9

Precooling and preheating of

the vehicle 10

General loading rules 11

Fresh fruits, vegetables, and

melons 13

Apples 13

Apricots 15

Artichokes (globe) 16

Asparagus 16

Avocados 17

Bananas 17

Beans (green snap) 19

Beans (lima) 19

Beets 21

Blackberries 23

Blueberries and huckleberries 23

Broccoli 24

Brüssel sprouts 24

Cabbage 24

Cantaloups 26

Carrots 27

Casaba, crenshaw, and persian

melons 29

Cauliflower 30

Celery 31

Cherries 33

Corn (sweet) 34

Page

Fresh fruits, vegetables, and

melons—Continued

Cranberries 25

Cucumbers 35

Currants 37

Dewberries 37

Eggplant 37

Endive and escarole 38

Gooseberries 39

Grapefruit (California and Arizona) 40

Grapefruit (Florida) 41

Grapes (European or vinifera)___ 42

Grapes (American or eastern)___ 42

Honeydew melons 43

Kohlrabi 44

Leeks (green) :__ 45

Lemons 45

Lettuce 45

Loganberries 47

Melons (See casaba, etc.)

Okra 47

Onions (dried) 48

Oranges (California and Arizona) 49

Oranges (Florida) 50

Peaches 52

Peas (green) 53

Peppers 53

Plums and fresh prunes 54

Potatoes (early crop) 56

Potatoes (late crop) 57

Raspberries (black and red) 58

Rhubarb 58

Rutabagas 59

Strawberries 59

Sweetpotatoes 60

Tangerines 61

Tomatoes (mature green) 61

Watermelons 64

Freezing injury to fruits and

vegetables 64

Frozen foods 65

Fresh meat and packinghouse products 65

Loading fresh beef 66

Loading fresh pork 66

Dairy and poultry products 67

Butter and margarine 67

Cheese 68

Shell eggs 68

Poultry, fresh dressed, chilled. __ 69

Canned foods (neither cold packed

nor frozen) - 70

Freezing temperatures of canned

foods 70
Protecting PERISHABLE FOODS

During Transportation by TRUCK

By Harold D. Johnson and P. L. Breakiron

Marketing Research Division, Agricultural Marketing Service

Background of Study

The transportation of perishable food products in refrigerated trucks

and trailers, known to the trade as ''reefers," has increased rapidly in

recent years. This transportation is provided by thousands of truck

operators, ranging from small owner-operators with only one or two

vehicles to large truck lines operating hundreds of units. The motor

truck movement of hundreds of food products, many of which are

fragile and easily susceptible to spoilage, freezing, overheating, contamination, and other types of damage, in many diflFerent types of

equipment in all kinds of weather has posed some serious problems for

shippers, truckers, and receivers of the products.

Growing interest in the problems of food transportation by motortruck has prompted the U. S. Department of Agriculture to carry on a

program of research in this field. Much of the information available

on this subject, including that developed in the study of transportation

of perishables in railroad refrigerator cars, is contained in reports

published by different agencies of the Department, some of which are

out of print. In addition, much other valuable information on the

specific requirements of many products and the best methods of handling them is contained in field and office reports and other unpublished

data and observations. This handbook draws upon these publications and unpublished data to bring the information together in

one book.

Motortruck equipment is available to provide the optimum temperature and humidity for perishable commodities during transportation. However, the requirements of different commodities vary

widely, and it is necessarj^ that the shipper or trucker know the specific

needs of the commodity being transported so that he may use the right

equipment in the right way. An attempt has been made, in the preparation of this report, to present that information for many perishable

commodities so that those engaged in shipping and transporting each

of these products by motortruck can quickly and easily find what thev

need.

Many improvements in the dietary standards of our population are

traceable to advances made during the 20th centur}' in transportation

and refrigeration of a wide variety of perishable foods. In addition,

significant changes have occurred in methods of food processing. The

development of new forms of processed foods, such as frozen concentrates and other types of frozen foods, has resulted in the production

and distribution of highly perishable products having rigid requirements for protection during transportation. If we are to take full

advantage of these recent technological advances in food processing,

the commodities must have full protection all the way from the producer to the consumer.
Important Factors ¡n Protection of Perishables

Refrigeration

The object of refrigeration is to keep the commodity at a temperature that will prolong its life on the store shelf and maintain its quality.

Heat is a form of energy. It is a positive, measurable factor. Cold,

on the other hand, is a lack of heat. Cold cannot be given off or

radiated. Refrigeration is not a matter of putting cold into a space,

but is a process of removing a certain amount of heat from the space

and preventing it from getting back again. Expressed in a different

way, cold is a relative term by which we mean the absence of a certain

amount of heat.

The flow of heat is always from the warmer to the cooler object. If

one hand is held close to a cake of ice, it feels cooler because the heat

is flowing from the hand to the ice. A cube of ice in a glass of water

absorbs the heat from the water. Heat continues to flow from the

warmer to the colder body that is close to it until both objects reach the

same temperature.

It should be remembered that all fresh fruits and vegetables are

living things, even though separated from the tree, the vine, or the soil,

and they continue to generate and throw ofT heat the same as the

human î^od3^ The amount of heat generated varies with the commodity and its temperature, the greatest heat development occurring

when "the commodity is at higher temperatures and decreasing as the

commodity approaches 32° F. Refrigeration, then, is required to

counteract this generation of heat, in addition to removing heat

acquired by the commodity in the field, if the commodity is to be

transported long distances in fresh condition.

The unit of measurement of heat is called the British thermal unit,

or B. t. u. This is defined as the heat required to raise the temperature of 1 pound of water 1° F. To lower the temperature of a load, so

many B. t. u.'s must be removed, just as so many gallons of water may

be removed from a tanlv.

The term ^^refrigeration ton^' is used to express the capacity of a

refrigeration system to remove heat. The amount of heat required to

melt 1 pound of ice is 144 B. t. u.'s, so that melting 1 ton of ice will

require 144 x 2,000, or 288,000 B. t. u.'s. This 288,000 B. t. u.'s is

called a refrigeration ton.

A mechanical refrigeration machine used in a motortruck trailer is

said to have 1-ton capacity when it will remove 1 refrigeration ton per

day under standard operating conditions. This is equivalent to

12,000 B. t. u.'s per hour.

A number of sources may contribute to the heat that must be

removed from the trailer by the refrigerating equipment:

(1) Heat that is in the product at the time it is loaded.

(2) Heat of respiration; as previously stated, all fresh fruits and

vegetables respire and give off heat. The more perishable products,

such as cherries, lettuce, peaches, and corn, respire at a higher rate

than the less perishable products, such as apples, oranges, and

potatoes. The rate at which heat is given off is controlled by the

temperature of the product, and it is considerably less at temperatures

near the freezing point than at normal harvest temperatures.
(3) Ambient (outside) temperature; that is, the temperature of the

air surrounding the commodity or, in the case of a commodity moving

in a motor vehicle, the air outside the truck or trailer.

(4) Radiated heat, which is that reflected back upon the underside

of the trailer from the street or highway. Many operators seem to

discount the importance of this source of heat*. The thickness of

insulation in the floor of the trailer should not be less than that in the

walls or ceiling.

(5) Solar heat, or the heat conducted through the walls or roof of

the trailer directly exposed to the rays of the sun. A dark surface

holds more heat and conducts more into the trailer than a light one ;

a highly polished, white, stainless steel or aluminum surface is preferable. However, even a trailer with such a polished surface loses much

of its resistance to solar heat if covered with dirt and grime. It is good

practice to clean the exterior of trailers regularly and often.

(6) Heat from the motor exhaust. This is an important factor,

particularly in warm weather, whether the exhaust is vented upward,

as is the case in many diesel-powered tractors, or underneath the

trailer.

Refrigeration Methods

Of the several methods used over the years for providing refrigeration at temperatures both below and above freezing, ice, ice and salt,

dry ice, holdover systems, and mechanical refrigeration are the most

prominent. The evolution of refrigeration is traced from the use

of water ice to the modern lightweight and compact mechanical

refrigeration units.

Ice is a good refrigerating medium, but it presents drawbacks when

used in over-the-road, long-distance hauling. It is heavy, requires

considerable labor to handle, and accelerates deterioration of the

truck body by its everpresent moisture. Refrigeration produced

by ice also diminishes as the ice melts, and to obtain maximum

efficiency the bunkers should be replenished frequently. Salt may be

used to obtain lower temperatures than would be provided by the ice

alone, but the resulting drip of brine from the bunkers tends to

corrode metal parts of the trailer body and produces an undesirable

discharge on the garage floor or street.

Dry ice, due to its very low temperature (—109° F.), above which it

starts to change from a solid to a gas (CO2), can be used both for low

temperatures such as those required for frozen foods and, if properly

controlled, for temperatures above the freezing point (32° F.).

Of course, the gas so released is very cold, and has high heatabsorption qualities; it will freeze fresh foods with which it comes in

direct contact. Also, it is heavier than air, and tends to settle to the

floor of the trailer. Some truck operators have used dry ice in the

transportation of frozen foods by spreading cakes of the ice over the

top of the load. This method is unsatisfactory because the packages

immediately surrounding the dry ice blocks and the pockets or spaces

in which the gas settles are very cold, while other parts of the cargo

are relatively unprotected. Consequently, little control of load

temperatures can be maintained by this method.

Only in case of emergency due to failure of the refrigerating unit

to operate should the dry-ice method be used. The only satisfactory

dry ice refrigeration systems so far developed use a forced flow of air

over a metal bunker surface, or a liquid secondary refrigerant circu-
lated through a series of coils. Both systems are thermostatically

controlled.

Wlien transporting fresh fruits or vegetables, it is important to

vent the CO2 gas from the dry ice to the outside of the truck or

trailer, as it may have an adverse effect on the product.

Mechanical Refrigeration

There are several types of mechanical refrigerating units, thermostatically controlled and made especially for motortruck transportation. Some types have the engine, condenser, and other accessories

high on the outside of the nose of the trailer, with the evaporator

coils and air-circulating fans located on the inside. Other types have

the power unit and accessories under the frame of the trailer, with

the cooling coils and air-circulating fans high inside the front end

of the trailer. These units usually have from 2-ton to 5-ton refrigerating capacity. The size of the refrigerating plant depends upon the

construction of the trailer, the amount and quality of insulation,

and the products to be transported.

Air Circulation

Regardless of the method of refrigeration used, whether it be

water ice, water ice and salt, dry ice, or mechanical refrigeration,

provision should be made for the cold air from the ice bunker or

mechanical unit to circulate around and under the load. To obtain

this free circulation of air, the inside of the trailer should have vertical

wall strips not less than ^4 inch thick spaced at 8-inch intervals on

each wall, and floor racks providing at least 2 inches of clearance

under the load (fig. 1). Provision should be made by bulkhead or

other means for adequate circulation of air at the front of the load.

The rear doors should have vertical strips (2- x 2-inches on 8-inch

center) to prevent blocking of air if packages fall against the door.

Packages should not be loaded witliin 18 inches of the ceiling. Do

not load directly in front of the air blast from the bunker or mechanical

unit.

Humidity

In protecting fresh fruits and vegetables in transit, cold air alone

will not do the job. Moisture also is required to keep the products

fresh and crisp.

Relative humidity, as used in this text, is simply a percentage

figure indicating the amount of water vapor present in the air as

related to the saturation point of the air at a given temperature.

When water ice is used in the bunkers, and fans circulate the air,

controlling the humidity does not present a problem. When mechanical refrigeration is used, however, moisture should be added by

some means, such as sprinkling the floor. Many operators who use

mechanical systems insure the humidity content and, in turn, the

crispness of the produce hauled, by blowing ''top ice^' in crushed form

up on top of the load. Because of the low temperature in the van, just

above freezing, this ice melts very slowly and yet in melting provides

the moisture needed. In produce hauling, this method is used quite

widely in connection with dry ice or mechanical systems.
FiGUKE 1.—Interior of a truck trailer equipped with adequate floor racks, side

wall strips, and air duct on ceiling of trailer. All three of these desirable

features promote adequate air circulation through and around the load.

Insulating Materials

The vehicle used to transport fresh food products must be as

nearly airtight as possible and must be constructed to retard the flow

of heat as much as possible. An example of the principle involved

here is found in the familiar thermos bottle, which is really two

containers, one inside the other, with the air removed from the space

between. The resulting vacuum gives the bottle its ability to maintain

the substance in the inner container at a nearly constant temperature,

for a vacuum offers great resistance to the transfer of heat.

Since it is impractical to build a trailer like a vacuum bottle, the

next best alternative is to fill the space between the inner and outer

walls with a substance that will retard the flow of air, since air in

motion carries the heat from the outer wall to the inner wall. The

insulating material used should be light in weight, fireproof, sagproof,

verminproof, waterproof, nonacid, noncorrosive, and, of course, it

should be a material which has a high insulating value. Insulating

quality is subject to measurement, and the unit of measure is called

the K-factor.

Some of the insulating materials now in use are glass fiber, kapok,

cellular rubber, and cork board. The thickness of the material largely

depends upon the temperature desired, the kind and efficiency of the

refrigeration used, and the hauling distances involved. Thickness

of insulation, depending upon these factors and the insulating material

employed, may range anywhere from 1 inch to 6 inches, or even

7 inches in the roof. Except for frozen foods, a 3-inch thickness

of insulating material is an average minimum requirement in walls,

floor, and ceiling, when hauls of several hundred miles are involved.
Estimating Mobile Refrigeration Requirements

In an effort to arrive at the approximate amount of refrigeration

necessary to maintain proper temperatures during transit, first let us

look at the amount that would be required under ideal conditions;

that is to say, not taking into consideration such factors as the

respiratory heat given off by different commodities, the necessity for

opening doors during transit, and possible leaks in the superstructure.

These and other factors will be discussed later.

In order to estimate the amount of mobile refrigeration required, it

is necessary to take four factors into consideration. The first of these

is the temperature of the product when loaded. Second is the expected outside temperature. Third is the number of square feet on

the outside surface of the truck body to be refrigerated. And last is

the thickness and coefficient of heat transmittance (U) of the material

used for insulation.

Once we have determined these four factors, the next step is to

multiply the coefficient of transmittance times the number of square

feet of the outside surface times the number of degrees difference

between the outside and inside temperatures. The resulting figure

will be the number of B. t. u.'s or, in other words, the quantity of

heat that must be absorbed per hour by the refrigerant in order to keep

the product at the temperature loaded. A specific example of this

formula in operation is as follows : Let us assume that these conditions

prevail: (1) Loading temperature of commodity is 35° F.; (2) expected

average outside temperature is 75° F. ; (3) outside dimensions of unit are

35 feet long, 7 feet wide, 8 feet high; and (4) insulation is 3 inches thick,

with a K-factor of .33. With an outside temperature of 75° and a

commodity temperature of 35°, the temperature differential is 40°.

Since insulation K-factors are based on a thickness of 1 inch, and

since the trailer in our example has 3 inches of insulation, we now

divide the K-factor (.33) by 3 in order to arrive at the coefficient of

transmittance, U (.11) for the insulation in this particular trailer.

The operator may obtain from the trailer manufacturer information

as to the K-factor of the insulation in a particular trailer.

A trailer with the outside dimensions listed above would have an

exposed surface of 1,162 square feet. Following the formula, we find

that .11 times 1,162 times 40 gives us approximately 5,133 B. t. u.'s of

heat that must be absorbed per hour by the refrigerant.

Precooling the Product

Ai any shipments of fresh fruits and vegetables are loaded into

trailers and accepted by the carriers when the product is not at the

desired carrying temperature. This means that additional refrigeration is needed to reduce the product temperature quickly to the dedesired level for safe transport.

This precooling may be accomplished by using commercial portable

mechanical units, by hydrocoohng, or by the vehicle's own method of

refrigeration, provided it has ample capacity.

In order to estimate the amount of refrigeration necessary to precool

a commodity to a predetermined temperature, it is necessary first to

find the amount of heat that must be removed to bring about this

reduction. The amount of heat removed will depend upon: (1)

The mitial temperature of the commodity; (2) the final temperature

desired; (3) the specific heat of the commodity to be precooled; and
(4) the total weight of the commodity and containers. Generally

precooling should be done before shipment, since truck-trailer ''reefers''

are primarily for transportation and are not a substitute for a ''cold

room'' in a packing plant.

The specific heats of individual commodities vary substantially

Fui'ther, the rates of evolution of heat are different for (^ach commodity, and vary according to commodity temperature at the time

the refrigeration is applied. Consequently, it is impracticable to

furnish complete data in this handbook to enable operators to calculate

exact refrigeration requirements on all the commodities carried under

all the widely varying conditions that might be encountered. If

specific information concerning given conditions should be desired,

it will be furnished upon request to the Transportation and Facilities

Branch, Agricultural Marketing Service, U. S. Department of Ao-riculture, Washington 25, D. C. ^

Ice as a Refrigerant

In order to melt 1 pound of ice, 144 B.t.u.'s of heat must be absorbed.

Therefore, to find the amount of ice necessary to refrigerate the trailer

used in the example given, we simply divide 5,113 (amount of heat

that will pass through our insulation (see p. 6)) by 144 to arrive at

approximately 35 pounds, or the amount of ice that will be consumed

per hour.

Dry Ice as a Refrigerant

Dry ice requirements can be estimated in essentially the same way

as those for water ice. The rate of heat consumption of dry ice has

been estimated at about 270 B.t.u.'s per pound for products held at

temperatures above 15° and 250 B.t.u.'s for those held below this

figure. Therefore, using the same trailer example as before, approximately 19 pounds of dry ice per hour (5,113 B.t.u.'s divided by 270)

would be necessary to maintain a temperature of 35°.

Top Ice

When crushed or top ice is used inside the containers or over the

top of the load, be careful that the crushed ice is not so cold that it will

freeze the part of the product with which it may come in contact.

Ice may come out of a storage room with a temperature as low as 25

degrees.

Mechanical Refrigeration Requirements

Mechanical refrigeration units are rated according to the amount of

heat units they can absorb per hour, and also in terms of ''standard

tons of refrigeration.'' A standard ton of refrigeration is a term used

to express the ability of the unit to absorb 12,000 heat units (B.t.u.'s)

per hour, or 288,000 heat units per day. In other words, a standard

ton of refrigeration has about the same cooling power as a ton of

water ice.

Importance of Defrosting Mechanical Units

It is possible that the evaporator of a mechanical unit will become so

frosted by moisture from the load and atmosphere that the refrigerating effect is severely reduced. This is due to the fact that ice itself has

390008"—5G 2 7
certain insulating properties, and when a heavy coating of ice forms on

the evaporator it will prevent heat from being absorbed properly by

the refrigerant. In order to insure proper operating efficiency of the

unit, this ice coating should be removed whenever it becomes too

thick. Under adverse conditions it may be necessary to defrost the

unit at intervals of from 2 to 4 hours.

Checking Your Thermostat

The thermostat on a refrigerating unit is the nerve center of the

system, and the unit will produce only the amount of refrigeration

called for by the setting of this instrument. If the thermostat is out

of adjustment several degrees on the low-temperature side due to road

vibration, it may cause freezing damage to the load. If it is off on the

opposite side it may cause damage by not providing sufficient refrigeration.

As a safety precaution, to protect various commodities against

freezing damage that may result from temperature variation in

different parts of the load, or from the thermostat or mechanical

refrigeration units being out of adjustment, it is recommended that the

thermostat be set at least 3° above the freezing point.

The thermostats on all types of refrigerating systems should be

calibrated at least every 60 days to be sure that the proper amount of

refrigeration is being furnished.

Protection Against Cold

In the protection of fresh, perishable, agricultural products in

transit, refrigeration is only part of the problem. There are times

when shipments may move under ventilation during the early spring

and late fall. However, on shipments moving during the cold winter

season, these fresh products must be protected from freezing damage.

There are a number of types of portable heaters that may be used.

The thermostatically controlled alcohol and propane heaters give

satisfactory results.

Secure the heater to the floor and operate the blower fan to circulate

the heat around and under the load. Otherwise, freezing temperatures

may be found in the floor packages and unfavorably high temperatures

in the top of the load.

Training or Driver Responsibility

It takes a great deal of training and experience to protect and transport perishable products properly. Each driver is responsible for the

truck and the cargo while it is in transit, and he should know the

refrigeration requirements of the commodities he hauls.

The driver should be thoroughly familiar with the operation of the

refrigeration unit in his trailer, and he should be provided with a list

of servicing points along his route in the event of mechanical failure.

All mechanical repairs should be made by persons authorized or

qualified to do so. Any adjustments by the driver ordinarily should be

limited to those of a routine nature, unless he is thoroughly familiar

with the operation and maintenance of the unit and has been properly

trained to repair and service it. Tampering with mechanical refrigera8
tion units by unqualified personnel may frequently result in serious

damage to the units or get them further out of adjustment.

Preparation and Loading of the Vehicle

Cleaning and Sanitation Requirements

The first step, and one of the most important, in the preparation of

the truck or trailer body for loading is cleaning. All loose debris from

previous shipments should be removed and the floor swept clean. For

loading some commodities, such as fresh meat and packinghouse

products, certain important sanitary requirements governing their

transportation must be complied with. In such instances, cleanino- of

the loading area with steam or hot water or fumigation with gas may

be required.

Cleanliness is particularly important if serious damage to food

products is to be avoided. Relatively small quantities or residues of

some products, such as salt, fertilizers, insecticides, and other chemicals, can easily contaminate or cause extensive damage to some

commodities. A residue of certain fertilizers and other chemicals

remaining on the floor or walls of the truck or trailer body can easily

result in serious burns to many commodities like potatoes, onions, and

melons which are not protected by heavy containers. Some chemicals

also cause rapid weakening and deterioration of paper and burlap bags

and similar containers. The possibility of chemical damage is always

greater when moisture is present. Many agricultural commodities

contain considerable moisture and some are shipped with crushed ice

on the load.

A number of perishable food products, such as butter, margarine,

and bananas, are easily contaminated by strong odors from other

products or the residues of them. Thorough cleaning of the interior of

vehicles previously used for hauling fish, cabbage, or other odorous

products is necessary if contamination of commodities absorbing these

odors is to be avoided. Even after a trailer is thoroughly cleaned with

hot water and detergents, the odors of such products as fish may

persist for some time.

Maintenance of Interior of the Vehicle

All protruding nails and staples should be removed from the floors

and walls of the vehicle and these surfaces should be kept in good

repair. Rough or splintered floor racks and side walls and protruding

nails or staples on these surfaces may cause damage to commodities

shipped in bulk or in bags. Rough or broken linings also provide

lodging points for dust or residue of flour, feed, or grain that may

result in infestations by weevils or other insects. For certain commodities, such as watermelons, bananas, and bulk shipments of some

meat products, it is sometimes desirable that interior walls of the truck

or trailer body be lined with paper or other protective material to

prevent friction bruising or chafing of the commodities. Fresh meat

should be protected from rubbing against aluminum trailer walls

because of the resulting discoloration of the meat.

The forward end wall or bunker bulkhead at the front of the truck or

trailer body should be kept straight and even. If this wall is bowed

or out of line, it is diflScult to maintain good stack alinement in the
load.^ Unless the containers in the first stack are loaded in tight

contact with the front end wall, they may shift forward during transit,

permitting the load to become slack. Maintenance of the forward

end wall in a straight and even condition and loading all containers in

the first stack tightly against that wall are the first steps that must be

taken to construct a tight, solid load to hold down container movement and damage during transit.

Precooling and Preheating of Vehicle

For shipments of frozen foods and other commodities that require

exceptionally low temperatures during transit, the interior of the

vehicle should be precooled before loading. If the truck or trailer is

equipped with a mechanical refrigeration unit, the unit should be

placed in operation, with the doors closed, and the temperature of the

interior of the vehicle should be reduced as nearly as possible to the

FIGURE 2.—Side view of a load in a motortruck semitrailer, showing arrangement

of containers in rows, stacks, and layers.

recommended transit temperature of the product being shipped. If

Avater ice or dry ice is used for refrigeration, the air circulating fans

should be placed in operation after the ice bunker has been filled and

the doors closed.

When commodities like potatoes or onions are shipped during

subfreezing weather, the interior of the vehicle should be preheated

before loading. If the vehicle is equipped with a built-in heater, it

should be placed in operation sufl5ciently in advance of loading to raise

the air temperature of the interior to or near the recommended temperature of the product to be loaded. In vehicles not equipped with

heaters, preheating may be accomplished with various types of portable

heaters. During subfreezing weather, if the truck or trailer is being

loaded in an unenclosed area, it is desirable to keep the heaters in

operation to help maintain the desired temperatures during loading.

1 Definition of loading terms (see fig. 2) :

A row is a line of containers extending lengthwise of the truck, 1 container in

width and as high as the load itself.

A layer is a course or stratum of containers one container high, usually extending

the length and width of the truck. ^

A stack is a pile of containers extending from one side wall to the other and

trom the top to the bottom of the load, parallel to the end of the vehicle and one

contamer m length.

]0
Gênerai Loading Rules

Transference of heat from the commodity to the circulatmg air in

the vehicle body is affected by a number of factors. Some of the more

important of these are: (1) The type of material used in the containers

(2) the size and number of openings in the containers, and (3) the

type of load used for the containers. The trucker cannot do much

about the hrst two factors, but he can control the loading However

in consideration of the importance of the second factor care should

be taken to see that the containers are arranged in the load so that the

ventilation openings m the containers are exposed to the ventilation

channels, or flues, m the load to the greatest possible extent The

need for loadmg the containers in a pattern providing for maximum

circulation of air around and through the packages to facilitate

refrigeration is particularly important in the transportation of commodities containing considerable amounts of field heat when loaded

and those generating comparatively large amounts of heat bv respiration. -^ ^

In loading frozen food or commodities which have been thorouo-hly

precooled before shipment, the objective is different than in loadinocommodities from which field heat or substantial heat from respiration

must be removed during transit. As the temperatures of the frozen

or precooled products are usually at or near the desired levels for

transportation, the objective should be to insulate effectively as many

packages as possible from contact with the air or walls of the vehicle.

Consequently, the packages should be loaded together as tightly as

possible and contact between the packages and walls of the vehicle

should be held to a minimum.

For safe shipment of bulk and bagged commodities which are

susceptible to bruising from overhead weight, liberal quantities of

straw or similar cushioning material should be used on the floor of the

vehicle. The need for bedding or cushioning material is greater if the

floors are slotted, grooved, or in rough, uneven condition. If loose

cushioning material such as straw is placed on the floor racks, the

racks should be covered with heavy paper or large sheets of fiberb'oard

to keep the loose material from falling through the floor racks and

blocking the air movement under the load. During cold weather,

such cushioning or bedding material also serves as an effective insulator and will help protect the load from freezing injury at the point

where it is most likely to occur. However, the most effective method

of preventing freezing of the product during transit is to maintain the

circulation ol heated air around and under the load.

In loads where vertical ventilation channels are to be maintained

between the rows of containers to facilitate refrigeration or ventilation

of the commodity, it is important that the containers be in tight contact with one another lengthwise of the vehicle body. Tight contact

between the containers in each stack helps to hold them in row alinement. If crosswise stripping of each layer, or alternate layers, of the

load is used to maintain row alinement, or if the side wall rows are not

in tight contact with the side walls, the strips in each stack should

alternately abut the sides of the vehicle body. If vertical spacing

units are used to maintain row alinement, it is also desirable that the

load be tight lengthwise of the truck or trailer body, as the spacing

units will not remain in place should slackness develop in the load

during transit.

n
Continuous lengthwise channels between the rows of containers in

the low er layers of the load which are blocked off vertically by the

upper layers do not provide as effective air circulation through the

load as vertical channels which are continuous from top to bottom.

This is due to the fact that air will circulate more freely from the top

to the bottom of the load than lengthwise of the load. Chimney-type

loads, or loads in which the containers are arranged around continuous

vertical shafts extending from the bottom to the top of the loads, also

are not as effective from a ventilation standpoint as loads with continuous vertical ventilation channels between the rows.

All containers should be loaded in such a way that maximum advantage will be taken of their inherent strength. Not all containers

can be handled or stacked in the same way because of their design,

method of packing, or the material used in their construction. Consequently, they usually will withstand more pressure or weight on one

face than on another without collapse or damage to contents. Containers that are packed with a substantial bulge on one or more faces

ordinarily should not be loaded on those faces.

^Vlien different types of containers are used in the same load, they

should be segregated in such a way that one t3^pe will not damage

another. Preferably, they should be separated by full stacks. If

separation by stacks is not possible, the containers made of lighter

material, such as fiberboard, always should be loaded on top of the

heavier wood containers. ^VTien part of the load is removed for partial

delivery at some point in transit, the remainder of the load should be

stepped down to secure properly the remaining part of the load. In

mixed loads of two or more commodities, products which have been

cooled and which require low temperatures should not be loaded

directly in contact, with warm commodities. The stacks of different

commodities may be separated by a bulkhead or sheets of fiberboard.

The product requiring the lowest temperature should if possible, be

loaded toward the front of the truck or trailer.

Many kinds of containers need to be braced or otherwise secured at

the rear of the load to prevent the containers in the last stack from

falling backward against the rear doors. This is more likely to happen

with containers of odd shapes or sizes, such as baskets. Falling of

packages, upon opening of the rear doors of the vehicle for unloading

or inspection, may result in container damage or personal injury. If

the load is stepped down at the rear end of the vehicle (that is, if the

last several stacks are not loaded as high as the forward part of the

load), there is less danger of loose packages in the upper layers of the

load shifting or falling backward against the rear doors. However,

stepping down the load at this point is not always desirable, particularly if a proper distribution of the weight of the load, providing for the

maximum permissible weight on each axle, is to be obtained. Various

methods of securing the rear stack of containers are used with good

results by many truckers. These include use of rope, wood strips,

or adjustable aluminum rods or bulkheads anchored to the side walls

of the vehicle, or other tie-down devices.

The choice of loading method, or arrangement of containers in any

one type of load, is governed or limited by several factors other than

the type, size, and shape of the containers themselves. The more

miportant of these factors are: (1) The interior dimensions of the

vehicle, (2) the weight or density of the commodity, (3) the need for

the proper weight distribution that wül provide the maximum per12
missible axle loadings, and (4) the specific refrigeration, ventilation

or heating requirements of the commodity being shipped. '

These conditions vary widely as between different types and sizes

of truck or trailer bodies, different sizes and types of containers, different commodities, and different seasons of the j^ear. Therefore, it is

not possible to recommend or illustrate any one loading method or

arrangement for any one commodity or container that will work

ideally in all motortruck shipments of a given product. The recommended loading methods for the individual commodities and containers

described and illustrated in this manual must be considered in the

light of these limitations. It will remain for the individual vehicle

operator to choose the particular loading method that will best meet

his particular needs.

Fresh FruitS/ Vegetables/ and Melons

Apples

Recommended protective services:

Desired temperature 30° to 32° F.

Desired relative humidity 85 to 90 percent.

Average freezing point 28.4°.

Bunker icing, or mechanical refrigeration with cooling and heating

cycles.

Apples loaded warm immediately after harvest should be precooled

and refrigerated during transit in order to preserve the natural quality

of the fruit until it reaches the consumer. It is particularly important

that the fruit be cooled as ranidly as possible after harvest and kept

adequately cooled during transit if it is going to be held in cold storage

for some time after shipment or if the shipment will be on the road more

than 8 to 10 hours. Since apples ripen twice as fast at 40° as they do

at 32°, they should be held as close to 32° as possible.

Shipments of warm fruit should be loaded in such a way that the air

can circulate between the rows of containers to facilitate precooling

or in-transit refrigeration. Fruit that has been in cold storage for some

time and that is already cold enough for transportation can be safely

loaded tightly in the vehicle, with provision made for circulation of air

around and under the load. As apples are quite susceptible to freezing

injury, shipments during subfreezing weather should be heated. ThermostaticaUy controlled heaters are recommended to prevent both overheating and freezing. Apples absorb odors quite readily and should

therefore not be shipped in mLxed loads with commodities like onions

or cabbage, or loaded in trucks that have recently been used to

transport odorous products like fish.

Recommended loading methods:

Baskets {bushel tubs).—1. End-to-end offset method for shipments

of warm fruit requiring considerable refrigeration (fig. 3).

2. Alternately inverted method for precooled fruit (at 30-32° F.)

in tight packs with pads under covers and covers fastened at all four

points. This method gives a tight load with a high degree of density

(fig. 4).

Western apple boxes (1-busheL nailed).—1. Lengthwise on sides in

straight continuous rows with cover bulges of all boxes facing one side

wall of trailer (fig. 5).

13
SSilSffilSiK^iSSKSwm^

¡in<'#e^iilMnni,linijnnAMlMnHjjm,l^^

¡JI^^^^Ë^sU^^^i^&S iS^^S.

FIGURE 3.—Side and end views of end-to-end offset load of bushel baskets of

apples, showing arrangement of containers in load.

2. Upriglit-on-end method for precooled fruit in cool weather when

refrigeration requirements are not heavy.

Open-mesh hags (5- and 7-lh. hags, not in master containers).—Loaded

in bulk. Floor or floor racks should be well padded with several inches

of straw or with excelsior pads or similar padding material to prevent

bruising. If loose material like straw is used for cushioning on floor

racks, the racks should first be covered with heavy paper or fiberboard

to keep the loose material from falling through the racks and blocking

the circulation of air under the load, thereby interfering with refrigeration or heating. It is seldom safe to load fruit in bags to very great

heights because of danger of bruising in bottom layers due to overhead

weight. Uneven, scarred, or splintered side walls of the trailer should

be lined with paper or other protective material to prevent rubbing

or scuffing of the fruit.

Fiherhoard cartons Oi- or l-hushel).—Lengthwise or crosswise on

bottoms. If the fruit being shipped has been removed from cold

storage and its temperature is about 35° or lower, the cartons should

be stowed together as tightly as possible (fig. 6). If the fruit is warni,

it is desirable that the cartons be loaded in a pattern that will permit

the air to circulate through the load. This may be done by arranging

the cartons in such a manner that there are two vertical ventilation

flues in each stack or by loading the containers in straight rows with

ventilation channels K inch or more in width between the rows.

Eastern apple hoxes (1%-hushel, nailed, fiherhoard covers).—^Loaded

lengthwise on bottoms. The load may be crosswise, offset by layers

to stabilize it, but all boxes should be kept in stack alinement crosswise

of the vehicle body.

Si!r:9;HiiiMiii)iiiiilllii>iiiiniiiinnJiliiiiiiiiiHiiTmiWiilfniWiiim

FIGURE 4.—Side and end views of alternately inverted load of bushel baskets of

apples. This high-density load should be used only for precooled fruit in baskets

equipped with cover pads and with the covers tightly fastened at all four

points on the basket rims.

14
L

I

1

L — ^ _s;

FIGURE 5.—Side and end views of lengthwise-on-sides load of bushel western

apple boxes. For shipments moving relatively long distances in warm weather,

this load should be used only for precooled fruit.

U

FIGURE 6.—Side and end view^s of a lengthwise-on-bottoms load of apples in

1-bushel fiberboard cartons. This type of load should be used only for precoded fruit or fruit shipped from cold storage.

Wirebound crates.—^Lengthwise-on-bottoms (fig. 7). If the fruit has

been precooled before shipment, the crates may be stowed closely

together, but for long-distance shipments of warm fruit, a load with

ventilation channels between the crates in at least the lower two layers

of the load should be used. The crates should all be kept in good stack

alinement so that the weight of crates in the upper layers of the load

will be borne by end cleats of crates in the lower layers.

^

I; »•t.tj; ==:==: === ====== === === === === ==--«—— -»—-«--

FIGURE 7.—Side and end views of a lengthwise-on-bottoms load of wirebound

crates of apples. The channels betw^een the rows of crates in the lower two

layers are for circulation of cold air through the load.

Apricots

Recommended protective services:

Desired temperature: 31° to 32°.

Desired relative humidity: 85 to 90 percent.

Average freezing point: 28.1°.

Bunker icing (no top ice); or mechanical refrigeration.

390608*»—se- is
Whenever possible, apricots should be precooled before loading.

When the fruit is loaded warm, the refrigerating unit or fans should

be operated as soon as loading is completed. Frequent re-icing during

precooling will be necessary to absorb the field heat in the product.

The containers should be loaded with spaces between the rows for

air circulation over the fruit; otherwise, decay may develop due to the

heat in the fruit.

Recommended methods of loading:

Sofi fruit lugs (nailed rectangular).—Lengthwise on bottoms, with

bottoms of boxes in all upper layers bearing on cover cleats of boxes in

lower layers. The lugs should be kept in good row alinement and

succeeding stacks of containers loaded in line and in tight contact

with the containers in the preceding stacks. Shipments of fruit not

precooled before loading should be loaded with continuous channels

at least one-half inch wide between the rows of continers. The load

should be crosswise stripped on each layer to hold the lugs in row

alinement.

Artichokes—Globe

Recommended protective services:

Desired temperature: 31° to 32°.

Desired humidity: 90 to 95 percent.

Average freezing point: 29°.

Top ice. Artichokes are generally packed in boxes and the usual

practice is to cover the containers with crushed ice.

Recommended loading methods:

Artichoke boxes (nailed, rectangular).—^Lengthwise on sides, with all

covers facing one sidewall of trailer. One or more stacks of boxes may

also be loaded on end to make load come out even in relation to interior

length of vehicle. It is advisable not to have these upright-on-end

stacks at rear of load next to trailer doors, as they are unstable and

may tilt against doors and fall out when doors are opened.

Asparagus

Recommended protective services:

Desired temperature: 34°.

Desired relative humidity: 85 to 90 percent.

Average freezing point: 29.8°.

Bunker icing. No top ice.

Thermostat setting 34° F.

Asparagus should be precooled before loading or just after loading

has been completed.

Recommended loading methods:

Asparagus crates (pyramid type, nailed).—Lengthwise on bottoms,

with all containers in good stack alinement. Containers in succeeding

stacks should be loaded in tight contact with those in preceding stacks.

The load may be crosswise offset by layers in order to distribute the

crosswise space evenly and to stabilize the load crosswise of the vehicle.

As the stalks of asparagus are always packed in an upright position

and tops are easily damaged, the crates should always be loaded,

stacked, and handled in an upright position.

16
Avocados

Eecommended prptectivejoryices:

Desired temperature, 45°.

Desired,^relative humidity, 85 to 90 percent.

Average freezing point, 27.2°.

. BunkerTjcing or mechanical refrigeration.

Most varietiesi.of, avocados should be held at 45 degrees durinotransportation, except the West Indian varieties, which should be

transported at 55 degrees. If avocados are in transit for extended

periods at substantially higher temperatures, they will ripen rapidly

and become soft. Therefore, it is important that provisions be made

for adequate refrigeration of the commodity during transit. As

avociados will not ripen satisfactorily if they are held long at temperatures below 45 degrees, shipments during subfreezing weather should

be heated.

fecommended loading methods:

,, Avocado wooden lugs.—Lengthwise on bottoms, with containers in

^ood stack alinement. Containers in the lower layers of the load

Should be in continuous rows with channels between about 2 inches

wide. At least 2 or 3 layers of containers at the top of the load may

be loaded 1 additional row in width, or offset crosswise olf the vehicle

body. This will stabilize the load and hold the .containers in the

lower layers in row ahnement. If the load is constructed in this

manner, it will not be necessary to strip the load öfesswse of the vehicle to maintain row alinement, except possibly one or two stacks at

the rear of the trailer that ordinarily are subject to some severe shifting

in transit.

Fiberboard cartons.—Same as described above for nailed lugs except

•that crosswise stripping should never be used as it may cause severe

creasing of fiberboard containers.

Bananas

Recommended protective services:

Gremfndt on stalks:

Desired temperature, 54° to 60°.

Desired relative humidity, 95 percent.

RipenedJruit (boxed):

Desired temperature, 56° to 58°.

Desired relative humidity, 80 to 85 percent.

The lowest temperature at which green bananas can be safely

transported is 54° F. Prolonged exposure of bananas to temperatures

below this point will cause chilling injury to the peel of the fruit. If

carried above 60° F., green fruit will ripen rapidly. Water ice refrigeration is preferable to mechanical refrigeration for bananas because of the higher humidity obtainable with water ice. It is desirable

that air circulating fans be used in conjunction with the water ice to

maintain uniform temperature and humidity through the interior of

the vehicle. During cold weather, floor heating of the vehicle is

desirable for maintenance of uniform temperatures. If other types

of heaters are used, forced air circulation should be provided.

17
FIGURE 8.—Cross section of a load of green bananas showing arrangement of

the stalks in the load. Each stalk in this load is covered with a polyethylene

bag to protect the fruit against friction bruising.

Recommended loading methods:

Bananas are one of the few perishable commodities loaded in bulk.

The stalks in the first layer should be loaded upright with the hands

of bananas pointing downward (fig. 8). At the rear of the vehicle

several stalks may be loaded crosswise on sides in order to hold the

upright stalks in place. Stalks in the upper layers should be loaded

crosswise on sides with the butts toward the side walls of the vehicle.

Unless the fruit is very small, such as 6 or 7 hand bunches, no more

than 2 layers should be loaded on sides on top of the upright stalks.

If the fruit is small, 3 or 4 layers may be loaded crosswise of the vehicle.

If the floor or side walls of the truck' body are rough or uneven, they

18
should be padded or lined with heavy paper or similar material to

prevent rubbmg or scuffing of the fruit. As bananas are easily contammated by strong odors, they should not be carried in trucks which

have been used to carry such products as fish or cabbage.

Beans (Green Snap)

Recommended protective services:

Desired temperature, 45° to 50°.

Desired relative humidity, 85 to 90 percent.

Average freezing point, 29.7°.

Bunker icing (no top ice) or mechanical refrigeration unit with

heating and cooling cycles.

To prevent wilting, the relative humidity should not be lower than

85 percent, and the containers should be arranged in such a manner

in the vehicle as to allow adequate air circulation around and through

the load.

If the hampers are stacked close together, blocking the air from

circulating through, the heat given off by the beans stimulates decay.

Great quantities of green beans are grown in the Southern States

during the winter season, and are transported to northern markets.

Protection against cold should be provided to prevent freezing damage in the containers on the floor.

Beans generally are packed in bushel hampers.

Recommended loading methods :

Bushel hampers (alternately inverted method).—Upright on bottoms,

with alternate stacks, rows, and layers inverted. Containers in each

stack should be loaded in tight contact with those in preceding stacks

to prevent the hampers from tilting. There are two variations of this

type of load. One is the so-called winter load in which the hampers

are stowed together tightly lengthwise and crosswise of the vehicle to

produce a solid, compact load with very small openings between the

hampers (fig. 9). The second variation is the summer, or warmweather, load in which the alternately inverted hampers are arranged

in rows with ventilation openings between (fig. 10).

DN858

FIGURE 9.—Side and end views of alternately inverted load of bushel hampers

of green or snap beans. This load should be used only during cool weather.

Beans (Lima/ in Pods)

Recommended protective services:

Desired temperature 32° to 40°.

Desired relative humidity 85 to 90 percent.

Average freezing point 30.1°.

19
BN 2528

FIGURE 10.—Summer, or warm-weather, load of 1-bushel hampers of beans.

Note space between rows of hampers to permit circulation of air through load.

Bunker icing or mechanical refrigeration.

Practically all lima beans are shipped in bushel hampers or bushel

baskets.

For lima beans to retain their fresh appearance and to prevent

wilting, the humidity should be maintained between 85 and 90 percent, and in warm weather packages should be loaded so as to allow

air circulation between the rows and stacks.

Recommended loading methods:

Bushel hampers (alternately inverted 7nethod),—Hampers upright and

mverted m alternate stacks, rows, and layers. Containers in each

stack should be loaded in tight contact with those in precedini>' stacks

to prevent the hampers from tilting. °

There are two variations of this type of load. One is the so-called

winter load m which the hampers are stowed together tightly lengthwise and crosswise of the vehicle to produce a solid, compact load

with very small openings between the hampers (fig. 9).

The second variation is the summer, or warm-weather, load in

20
FIGURE 11.—Side and end views of end-to-end offset load of bushel baskets of

lima beans, showing arrangement of containers in load.

which the alternately inverted hampers are arranged in rows with

ventilation openings between (fig. 10).

Baskets (bushel tubs),—End-to-end offset method foi shipments

moving long distances in warm weather (fig. 11).

Beets

Recommended protective services:

Beets (bunched):

Desired temperature 32°.

Desired relative humidity 90 to 95 percent.

Average freezing point 26.9°.

Ice in the containers and top ice.

The freezing point of beets is 26.9°; however, the tops will freeze

at tempeiatures below 32°.

To minimize the generation of heat in beets and tops when they

are in closed packages, crushed ice should be placed in the containers

and on top of the load. Additional top ice should be blown over the

load while in transit during the heat of the summer.

Beets (vnthoul tops):

Desired temperature 32°.

Desired relative humidity 90 to 95 percent.

Average freezing point 26.9°.

Top icing and bunker icing.

Beets without tops generally are precooled, being placed in storage

soon after harvesting. They usually are packed in bushel baskets or

50-pound open mesh bags.

On long trips, it is good practice to cover the load with crushed

ice to retain quahty and fresh appearance.

Recommended loading methods:

Beets (bunched):

Bushel baskets.—End-to-end offset, with baskets stowed tightly

against those in preceding stacks in order to prevent shifting of load

(ng. 12). Use of a guide row along one side wall of trailer from the

front of the trailer to the rear will be of help in building a tight, solid

load. This load should be used only for non-top-iced shipments moving relatively short distances in cool weather. The alternately inverted

load (fig. 13) should be used for top-iced shipments in warm weather.

21
FIGURE 12.—Side and end views of end-to-end offset load of bushel baskets of

bunched beets, showing arrangement of baskets in load.

^

lllílllllllllll/lllíl'WtftiW^lim^^ m&m^^mm'^^s^'^'^m^^^mmmmm

msmmmmmmmmmmmmmmwMmmm

U'M,.'i,rMV,lM-,i

FIGURE 13.—Side and end views of alternately inverted load of bushel baskets of

bunched beets, showing arrangement of containers in load. This high-density

load, in which the baskets fit together tightly, should not be used for shipments

moving long distances in warm weather unless they are adequately top-iced.

FIGURE 14.—Side and end views of lengthwise-on-sides load of wirebound crates

of bunched beets. Loads of this commodity should be top iced and have adequate ice between the rows of containers.

FIGURE 15.—Side and end views of a combination lengthwise-crosswise load of

5U-pound open-mesh bags of topped beets. Loads of this commodity should

be top-iced for long-distance shipment in warm weather

22
In this high-density load, the baskets are in better position to support

the overhead weight of the ice.

Wirebound crates—Lengthwise on sides. It is desirable that o-ood

row alignment be maintained in loads of this container, so there^^will

be a uniforni space between rows to permit adequate refrigeration of

the commodity by the top ice. One or more stacks of crates of this

commodity may also be loaded upright on-end in order to make the

load come out even in relation to the length of the trailer (fig. 14).

Beets (without tops):

Bushel baskets.—Same as for beets with tops (bunched beets) ffio-s.

12 and 13).

Open-mesh bags, 60-pound.—Lengthwise on sides, with straight rows

that may or may not be offset by alternate layers.

A combination lengthwise method may be used in which bags in

alternate layers are loaded crosswise of trailer (fig. 15). Lono--distance

shipments in warm weather should be top-iced.

Blackberries

Recommended protective services:

Desired temperature 31° to 32°.

Desired relative humidity 85 to 90 percent.

Average freezing point 28.9°.

Bunker ice (no top ice) ; or mechanical refrigeration.

Recommended loading methods:

Nailed and wirebound carrier crates.—^Lengthwise on bottoms. In

shipments moving relatively long distances in warm weather, vertical

ventilation channels one-half inch or more in width should be maintained between the rows of crates to facilitate refrigeration. In loads

of this type, the crates should be held in row alinement by two crosswise strips on each layer of each stack. For shipments moving short

distances to market, a crosswise offset load in which no stripping is

required usually will be satisfactory. The crates never should be

loaded, stacked, or handled on their sides or tops, because such

handling spills or jumbles the berries.

Blueberries and Huckleberries

Recommended protective services:

Desired temperature 31° to 32°.

Desired relative humidity 85 to 90 percent.

Average freezing point 28.9°.

Bunker ice (no top ice) ; or mechanical refrigeration.

Recommended loading methods:

Lengthwise on bottoms or crosswise on bottoms, with crates in good

row and stack alinement. Care should be taken to see that each flat

is stacked squarely on top of the flat in the lower layer and that the

end pieces of the flat do not bear on the cover strips of the flats

beneath it.

Flats should be arranged in the load so as to allow an abundance

of cold air to circulate over the fruit, maintaining an even, cool

temperature throughout the load. When the containers are stacked

390608 »--56 i 23
close together, blocking the free passage of air, the unfavorably high

temperatures that develop will speed deterioration and decay.

Broccoli (Italian Sprouting)

Recommended protective services:

Desired temperature 32° to 35°.

Desired relative humidity 90 to 95 percent.

Average freezing point 29.2°.

Bunker ice, top ice, and crate ice.

To keep the buds fresh and green, broccoli usually is packed with

crushed ice in the crates and crushed ice over the top of the load.

During the heat of the summer it is sometimes necessary to add

ice in the bunker, in addition to the top ice, to maintain desired

temperatures.

Recommended loading methods:

Broccoli crate {nailed, rectangular).—Lengthwise on sides. Cover

bulges of all crates should face the same side wall of vehicle, except

that crates in each side wall row should have cover bulges facing the

side walls. Each crate in each row should be directly in line and in

tight contact with the corresponding crate in the preceding stack.

Good row alinement with channels between rows for top ice are essential for effective refrigeration of the commodity.

Brüssel Sprouts

Recommended protective services:

Desired temperature 32° to 35°.

Desired relative humidity 90 to 95 percent.

When brussel sprouts are packed in drums for long hauls crushed

ice is placed in the containers and top ice over the load.

Recommended loading methods:

Drums {veneer construction).—Upright on bottoms. Loading should

be started at the front of the trailer and the first stack should be

loaded to the desired height, with all crosswise space that is not taken

up by the containers equally distributed between the containers in

the stack. In loading the second stack, the drums should be fitted

into the recesses between the drums in the first stack. The third stack

should be loaded in the same manner as the second, and so on to the

rear end of the trailer, with the drums in each stack fitted or nested

tightly into the recesses between the drums in the preceding stack.

Carrier crates {nailed and wirehound).—Lengthwise on bottoms.

Load may be crosswise, offset by layers, in order to stabilize it crosswise of the vehicle body. Long-distance shipments in warm weather

should be top-iced, in which case the crates should be loaded in row

alinement with channels between the rows to accommodate top ice.

Cabbage

Recommended protective services:

Desired temperature 32° to 35°.

Desired relative humidity 90 to 95 percent.

Average freezing point 3L2°.

24
Bunker ice and top ice, or mechanical refrigeration and top ice

Cabbage is shipped from many States, in several types of containers

and occasionally in bulk.

New cabbage, or cabbage which is freshly harvested and o-reen

packed m wooden containers or 50-pound open-mesh bags should be

covered with crushed ice, and, during warm weather, bunker ice may

be used m addition to the top ice. Adequate ventilation during cool

months, m which cabbage is usually shipped, ordinarilv will provide

suflScient protection. In exceptionally cold weather, preheating of the

trailer before loading or heating during transit is necessary to prevent

freezing injury.

Bulk shipments of new cabbage by motor carrier are not recommended during warm weather without top ice, except for short distances, as a lack of refrigeration may cause abnormal deterioration.

Open-top trucks should not be used in transporting cabbage, as

direct exposure to the sun's rays causes drying and wilting.

Recommended loading methods:

60-pound open-mesh bags.—Lengthwise or crosswise on sides (fig.

16). If top ice is used, it is desirable that the bags not be loaded too

tightly crosswise of the trailer, so that the cold air and water from the

melting ice may have free access to the bags in the lower layers. In

shipments of new green cabbage, ordinarily it is not safe to load the

commodity more than six layers high without the risk of bruising or

cracking the heads in the bottom of the load. This is true particularly in instances where substantial amounts of top ice are to be placed

on the load.

Old cabbage, or the late fall crop, which has been in dry storage for

some time prior to shiprnent, should not be top-iced. If the heads are

firm and hard, it is possible to load shipments of this crop somewhat

more heavily than shipments of green cabbage.

Wirebound boxes.—Lengthwise on sides (fig. 17). If load is not

top-iced, it may be crosswise offset by layers in order to stabilize it

and distribute the overhead weight more evenly. When top ice is

used, it is desirable in order to accommodate the ice that the containers

be loaded in straight rows with channels of at least one-half inch between the closest points of contact of containers in adjacent rows.

Nailed wooden crates,—Lengthwise on sides (fig. 18). Cover bulges

of all crates should face the same side wall of vehicle, except that

crates in each side wall row should have cover bulges facing the side

walls. Each crate in each row should be directly in line and in tight

?( \ \ I 1 ^

SL I L li^ ^\ \ \ 1 ^

fji Í Í fj

iîLJL_. t

ï^ Í Í V. M=^Mípi=Mj

FIGURE 16.—Side and end views of a combination lengthwîse-crosswîse load of

cabbage in 50-pound open-nnesh bags. Shipments of late-crop cabbage which

has been in dry storage should never be top-iced, but long-distance shipments

of the early crop should be top-iced.

25
FIGURE 17.—Side and end views of a crosswise offset load of wirebound crates

of cabbage. This type of load should be used only for short-distance shipments

in cool weather with no top-ice.

a =SR

i

i1

FIGURE 18.—Side and end views of lengthwise-on-sides load of wooden vegetable

crates of cabbage.

contact with the corresponding crate in the preceding stack. Good

row alinement with channels between rows for top ice is essential for

effective refrigeration.

Cantaloups

Recommended protective services:

Desired temperature 40° to 45°.

Desired relative humidity 85 to 90 percent.

Average freezing point 28.4°.

Bunker icing or mechanical refrigeration.

Top ice for precooling.

For the best results in transporting cantaloups over considerable

distances, they should be precooled before loading or precooled in the

vehicle with precooling fans or with crushed ice over the load.

Recommended loading methods:

Western nailed cantaloup crates (including jumbo, standard and pony

crates).—Upright on ends, with top and bottom bulges facing side

walls of trailer and sides facing front and rear of trailer. Because of

the strength limitations of this type of crate, it is usually not safe to

stack it in this position more than three layers high. The third layer

should be lengthwise on sides (fig. 19). In no case should the crates

be loaded, dropped, or handled with the weight of the crate resting on

the cover or bottom bulges. If top ice is to be used on the load, the

label ends of all crates should be loaded downward so as to prevent

defacing or loosening of the labels by the top ice.

Cantaloup crates also may be loaded lengthwise of the trailer or

truck body on their sides (fig. 20). As in the on-end load, the top and

26
bottom bulges on these crates in this position should face the sides of

the vehicle, so that they will not be exposed to pressure or overhead

weight.

However, if the cantaloups are packed tightly in the crates there

will be some bulge in the side slats. If this is the case, crosswise

stripping of each stack at each end of the crate is advisable, particularly

in the 4 or 5 stacks at the rear of the trailer over the axle, to prevent

bruising of the melons from overhead weight and road vibration. If

the load is to be transported over relatively rough roads, the lengthwise-on-sides load should not be used as there is a greater risk of bruising the melons on under sides of the crates in the lower layers.

Two-thirds crates and flat crates.—Crosswise of trailer on bottoms

with crates in good row alinement and loaded tightly against crates

in preceding stacks.

FIGURE 19.—Side and end views of upright-on-ends load of jumbo cantaloup

crates with third-layer crates lengthwise on sides. Note that the cover and

bottom bulges on all crates face the side walls of the trailer.

DN861

FIGURE 20.—Side and end views of lengthwise-on-sides load of jumbo cantaloup

crates. The cover and bottom bulges all face the side walls of the trailer.

Carrots

Recommended protective services :

Bunched with tops:

Desired temperature 32° to 34°.

Desired relative humidity 90 to 95 percent.

Average freezing point roots, 29.6°.

Ice in the containers plus top ice.

The freezing point of the carrots is 29.6°; however, the carrot tops

will freeze at temperatures below 32°.

Carrot tops generate heat when confined in a closed package. To

remove this heat, crushed ice should be placed in the containers in

addition to crushed ice over the top of the load.

27
Wifhout tops:

Desired temperature 32° to 34°.

Desired relative humidity 90 to 95 percent.

Average freezing point 29.6°.

Top ice, bunker icing, or mechanical refrigeration.

Fresh carrots without tops, packed in 50-pound open-mesh bags,

should have crushed ice blown over and through the load to preserve

their fresh and crisp appearance. Many topped carrots are packaged

in 1-pound film bags which are shipped in wirebound crates and

fiberboard cartons. The wirebound crates usually are shipped under

top ice, while the fiberboard cartons are shipped with bunker icing or

mechanical refrigeration.

Recommended loading methods:

Bunched with tops:

WGA crates {western semisquare, nailed).—Lengthwise on sides,

with crates in good row alinement (fig. 21). Crates in the two outer

rows adjacent to the side walls of the trailer should be loaded with

the cover bulges of the crates facing the side walls, as this will permit

only the apex of the cover bulge, under which there is usually some

pack ice, to contact the side walls instead of the entire surface of the

bottom of the crate. It is desirable that enough space be left between

the rows of crates for top ice on relatively long hauls. One or more

stacks of crates also may be loaded upright on ends, with the cover

bulges facing the side walls of the trailer, so that the load will come

out^even in relation to the length of the trailer. However, under no

circumstances should this type of crate be loaded or stacked on the

cover bulge.

Without tops:

50-pound open-mesh bags,—Lengthwise on sides, or combination

lengthwise-crosswise load with bags reversed in alternate layers; that

is, lengthwise in first layer, crosswise in second layer, lengthwise in

third layer, etc. (fig. 22). It is desirable that the bags not be loaded

too tightly in order that full benefit may be obtained from the top ice.

Generally speaking, the combination lengthwise-crosswise load, if

properly constructed, permits greater contact between the top ice and

the commodity in the lower layer bags.

Bushel tub baskets.—End-to-end offset or alternately inverted (figs.

23 and 24). The latter method produces a more compact load, but

it should be used only where the basket covers are tightly fastened at

all four points. In the latter method the baskets are in a better position to withstand the overhead weight of the top ice.

DN846

FIGURE 21.—Side and end views of lengthwise-on-sides load of bunched carrots

in WGA wooden crates. The channels between the rows in this type of load

should be filled with crushed ice.

28
Wirebound crates (master containers for consumír-xize ßlm bags).

Lengthwise on sides (fig. 25). It is desirable that good row alinement

be maintained in loads of this container so that there will be a uniform

amount of space between the rows to permit adequate refrigeration of

the commodity by the top ice. One or more stacks of crates of this

commodity also may be loaded upright on end so that the load will

come out even in relation to the length of the trailer.

îrnr~rT~rT-

[ Ï i l

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^^ Í Í 1

! Ï 1 1 Ï f

! ! il

fe=.,PWU^

FIGURE 22.—Side and end views of a combination lengthwisc-crosswise load of

50-pound open-mesh bags of topped carrots. Long-distance shipments should

be top-iced to provide adequate refrigeration and moisture.

^ =TTfr^

^ "N ^i

,lllUIIIHIIUlM.UMÎIjWll||llB|

IglFiHl^^^^iP^â^iill^S^^iFM

FIGURE 23.—Side and end views of end-to-end offset load of bushel baskets of

topped carrots. This type of load should be used without top ice for shipments

moving only relatively short distances.

w¥ §Sm 9Ä

FIGURE 24.—Side and end views of an alternately inverted load of bushel baskets

of topped carrots. Covers of the baskets loaded by this method should be

fastened at all four points and long-distance shipments should be top-iced.

Casaba, Crenshaw, and Persian Melons

Recommended protective services:

Desired temperature 45° to 50°.

Desired relative humidity 85 to 90 percent.

Bunker icing (no top ice) ; or mechanical refrigeration.

29
(f«««» ^SíñB-mm SS == mSm SiS ^S.iSSi SBS S=isssss

FIGURE 25.—Side and end views of a lengthwise-on-bottoms load of wirebound

crates of topped carrots. Long-distance shipments of this type of load should

be top-iced.

These melons generally are packed in flat, rectangular wooden crates

with excelsior or similar padding material in the bottom to prevent

bruising. If the melons are mature, it is particularly important that

they be refrigerated during transit, or they will ripen too fast.

Recommended loading methods:

Melon crates (nailed construction).—Lengthwise on bottoms, with

good stack alinement. It is important in loading to have each crate

stacked squarely on top of the crate directly beneath it so that the

weight of the upper layers bears on the cover cleats of the crates in

the lower layers. If the crates are permitted to shift lengthwise out

of stack alinement, the bottoms of crates in the upper layers will slip

off the cover cleats and the overhead weight of the load will bear on

the bulge of the cover slats in lower layers. Since the cover slats

usually are in direct contact with the tops of the melons, severe bruising

of melons may result. If the melons are being shipped relatively long

distances and refrigeration channels are provided between the rows

of containers, some method of holding the containers in row alinement,

including either vertical spacing units or crosswise stripping of each

layer, should be employed. Loads of precooled melons also may be

crosswise offset by layers to stabilize the load crosswise of the vehicle

(fig. 26).

FIGURE 26.—Side and end views of a crosswise offset load of melon crates, showing

arrangement of containers in load. This type of load should be used only for

shipments of precooled melons or shipments in transit not more than 24 hours.

Cauliflower

Recommended protective services:

Desired temperature 32°.

Desired relative humidity 85 to 90 percent.

Average freezing point 30°.

Top ice.

30
Recommended loading methods:

Western panel end crates (nailed construction, each containino- one

layer of heads) .—Lengthwise or crosswise of trailer on covers,''with

crates in good row and stack alinement (fig. 27). Shipments movinorelatively long distances should be top-iced and channels between the

rows should be provided for that purpose. All crosswise slack should

be evenly distributed across the trailer between the rows of crates

and between the outer rows and the sidewalls of the trailer. If top

ice is appUed evenly and uniformly over thc^ load so that all the

channels between the rows are completely filled, the commodity will

be refrigerated properly and the containers held in row alinement.

Long Island wirebound crates.—Lengthwise on sides, in o-ood row

alinement and with channels of uniform width for adeq'uate^l^op icing

(fig. 28).

Catskill cauhnower crate (whebound construction, semisquare).—

Lengthwise on sides, with good row alinement. Channels should be

provided between rows for proper distribution of top ice m longdistance shipments in warm weather (fig. 29).

FIGURE 27.—Side and end views of a length^yise-on-covers load of panel-end cauliflower crates. The lengthwise channels between the rows of these crates

should be filled with crushed ice, with additional ice over the top-layer crates.

DN 862

FIGURE 28.—Side and end views of a lengthwise-on-sides load of Long Island

wirebound cauliflower crates. Shipments moving relatively long distances

should be covered with crushed ice.

Celery

Recommended protective services:

Desired temperature 31° to 32°.

Desired relative humidity 90 to 95 percent.

Average freezing point 29.7°.

Top ice.

Celery is a highly perishable commodity and requires care in loading. The crates should be loaded with a space along the side walls

390608°—56 5 31
.. 1 1 '¡ 11^

DN865

FIGURE 29.-—Side and end views of a length\vise-on-sides load of Catskill wirebound crates of cauliflower. Long-distance shipments should be top-iced.

and between the rows. Top ice should be blown over and down

through the load to prevent the tops from heating.

Celery usually is hydrocooled in the crates before loading. Shipments adequately hydrocooled before loading ordinarily may be transported safely over long distances, but top icing is still required to

hold the product at the desired temperature and to retain moisture

in it.

On shipnients of celery moving during subfreezing weather, protection against cold should be provided.

Recommended loading methods:

Wirebound crates.—Lengthwise on sides (fig. 30). For shipments

moving relatively long distances under top ice, it is desh^able that

vertical channels at least one inch wide be maintained between rows

of crates. So that the load will come out even in relation to the

interior length of the truck or trailer body, one stack of crates at

the front or rear of the load may be loaded crosswise on sides. As

1

laM^ààÊl

DN 866

FIGURE 30.—Side and end views of a lengthwise-on-sides load of wirebound crates

ot celery Loads of this commodity should be covered with liberal quantities

of crushed ice. ^

•\

làâàc

FIGURE 31.-Side and end vieA^;s of a lengthwise-on-sides load of Sturdee crates

of celery. This load should be top-iced.

32
this particular type of container is bulged on its top and bottom

when packed, it always should be loaded on its side to prevent

crushing of the stalks.

Sturdee crates (nailed construction, umxized veneer eorrrs). Because

of cover bulges on the sturdee crates, they must be loaded on their

sides lengthwise of the truck or trailer body (fig. 31). One or more

stacks of crates may be loaded upright on ends so that tlie load will

come out even in relation to the inside length of the vehicle.

Cherries

Recommended protective services :

Desued temperature 31"^ to 32°.

Desired relative humidity 85 to 90 percent.

Average freezing points: Eastern sour cherries 22°, eastern sweet

cherries 24.7°, western sweet cherries 24.2°.

Bunker icing or mechanical refrigeration.

Cherries that will be in transit longer than 8 to 10 hours should b(^

precooled thoroughly before or immediately after loading. Full refrigeration that will reduce the temperature of the finiit to the recommended level and hold it there should be provided, whether or not

the fruit is precooled. To facilitate quick precooling and maintenance of uniform temperatures throughout the load, the containers

must be loaded so as to provide for circulation of air through the load.

Deterioration of quality and development of decay in sweet cherries

during transit can be retarded effectively by carbon dioxide gas in

concentrations as low as 15 percent. Tests have shown that the

fruit will tolerate concentrations as high as 25 percent without harmful effects. In recent years, some shipments of cherries in lugs from

the Pacific Northwest producing areas have been sealed in polyethylene liners, within the lugs, from which part of the air was exhausted

before sealing. Respiration of the fruit diu'ing transit builds up sufficient concentrations of carbon dioxide (C°2) within the sealed hners

to aid materially in retarding quality deterioration and decay.

For long-distance shipment of cherries in unlined packages, substantially the same effect can be achieved within the trailer body by

circulating carefully controlled carbon dioxide gas produced by melting small quantities of dry ice. This method is effective only if the

truck or trailer body is almost completely air tight so as to prevent

leakage of the gas. As carbon dioxide is heavier than air, it settles

to the bottom of the load. It is exceptionally cold and may cause

freezing damage to the fruit in the bottom layers of the load unless

it is circulated throughout the load.

Recommended loading methods:

Climax splint baskets and 8- or 12-quart úherhoard baskets.—Combination lengthwise and crosswise load with containers reversed in

alternate layers (fig. 32). Containers in the first layer may be loaded

lengthwise and those in the second and each alternate layer crosswise of the vehicle body. If the baskets are not equipped with

recessible handles, the handles of the baskets in one layer will extend

upward between the baskets in the layer immediately above. In

shipments moving relatively long distances in warm weather, each

stack of containers should contain several continuous vertical openings, or flues, extending from the top to the bottom of the load, to

facilitate refrigeration.

33
Soft fruit lugs, wood construction.—'Lengthwise on bottoms. The

containers should be kept in good stack alinement crosswise of the

vehicle so that the overhead weight of the lugs in the upper layers

will be on cover cleats at each end of the covers. Shipments of precooled fruit or shipments not moving long distances may be offset

crosswise by layers. Shipments of warm fruit moving relatively long

distances should have channels between the rows of lugs to facilitate

refrigeration.

FKíURE 32.—Side and end views of a combination lengthwise-crosswise load of

fiberboard baskets of cherries. This type of load should be used only for precooled fruit or fruit not being shipped long distances.

Corn (Sweet)

Recommended protective services:

Desired temperature 31° to 32°.

Desired relative humidity 80 to 90 percent.

Average freezing point 28.9°.

Bunker ice and top ice, or mechanical refrigeration and top ice.

Because the sugar in green sweet corn changes to starch rapidly, it

is imperative that this product be cooled just as soon as possible after

harvest and be kept refrigerated during transit. When sweet corn is

loaded without precooling, packed in crates or in bags, the containers

should be covered with crushed ice during the time of loading so that

each container is practically surrounded with ice.

Some corn is hydrocooled in the crates before loading. Shipments

that have been hydrocooled adequately before loading ordinarüy may

be transported safely for long distances, but top icing is still required to

hold the product at the desired temperature and to retain moisture.

In addition, during the heat of summer, bunker icing is necessary,

with circulation of cold air through the load.

Recommended loading methods:

Wirebound crates.—Lengthwise on sides. If the commodity has

been precooled before loading, the crates may be loaded somewhat more

compactly than if it is loaded warm (fig. 33). For adequate refrigeration, nonprecooled corn in wirebound crates should be loaded with

channels between the rows sufficiently wide to accommodate top ice.

Both precooled and nonprecooled corn should be top-iced liberally

and re-top-iced every 24 hours.

50-pound ojpen-mesh bags.—Alternately reversed load (fig. 34).

Bags should be reversed in alternate layers; that is, the first layer

bags should be loaded lengthwise and the second and each alternate

layer of bags loaded crosswise. Icing and re-icing should be the same

as for wirebound crates.

34
fwmïïi

mm

FIGURE 33.—Side and end views of a lengthwise-on-sides load of wirebound crates

of sweet corn. The channels between the rows of crates should be filled and

the top of the load should be covered with liberal quantities of crushed ice.

DX 844

FIGURE 34.—Side and end views of a combination lengthwise-crosswise load of

50-pound open-mesh bags of sweet corn. Shipments of this commodity should

be top-iced.

Cranberries

Recommended protective services:

Desired temperature 36° to 40°.

Desired relative humidity 85 to 90 percent.

Average freezing point 27.3°.

Bunlver icing or mechanical refrigeration.

The most desirable temperature in transit is from 36° to 40°. Lower

temperatures increase low-temperature breakdown.

Recommended loading methods:

Fiberboard cartons.—Lengthwise or crosswise on bottoms. As most

cranberries are precooled before shipment and many are shipped from

cold-storage plants, the cartons should be loaded tightly together, to

insulate as much of the load as possible from external heat. To accomplish this, the cartons may be reversed in alternate rows, layers or

stacks to make the load compact and make it come out even in relation

to the interior dimensions of the vehicle.

Cucumbers

Recommended protective services

Desired temperature 45° to 50°.

Desired relative humidity 85 to 90 percent.

Average freezing point 30.5.

Bunker icing or mechanical refrigeration unit with cooling and heating cycles.

35
Even though the freezing point for cucumbers is 30.5°, they should

not be held below 45°, because they develop low-temperature breakdown.

During the spring and fall, cucumbers may be transported by opening the ventilators, but they must not become chilled. The ventilators

should be closed when the outside temperature falls below 45° or

rises above 50°.

Cucumbers moving during the winter should be protected against

cold weather by portable heaters.

Recommended loading methods:

Bushel tub baskets.—End-to-end offset (fig. 35) or alternately inverted (fig. 36). The latter method produces a more compact load,

but should be used only where the basket covers are tightly fastened

at all four points.

Wirebound crates.—Lengthwise on bottoms (fig. 37). To facilitate

ventilation, the load should have channels between the rows in at least

FIGURE 35.—Side and end views of end-to-end offset load of bushel baskets of

cucumbers, showing arrangement of containers in load.

FIGURE 36.—Side and end views of alternately inverted load of bushel baskets of

cucumbers.

FIGURE 37.—Side and end views of a lenglhwise-on-bottoms load of wirebound

crates of cucumbers. The chanrels between the rows in two lower layers are

contmuous from the front to the rear of the load to facilitate ventilation.

36
the lower two layers that are contiauous from the front to the rear of

the load.

Currants

Recommended protective services:

Desired temperature 34°.

Desired relative humidity 80 to 85 percent.

Average freezing point 30.2°.

Bunker ice (no top ice) ; or mechanical refrigeration.

Recommended loading methods:

Nailed and wirebound carrier crates.—Lengthwise on bottoms. Load

maj^ be crosswise, offset b}^ layers to stabilize it crosswise of the vehicle

body. For more effective refrigeration required for long-distance

shipments in warm weather, ventilation channels should be maintained

between the rows of crates.

Dewberries

Recommended protective services:

Desired temperature 31° to 32°.

Desired relative humiditv 85 to 90 percent.

Average freezing point 28.9°.

Bunker ice (no top ice); or mechanical refrigeration.

The crates should be arranged in the load to allow an abundance of

cold air to circulate over the fruit, maintaining an oven, low temperature through the load.

When the containers are stacked close together, blocking the free

passage of air, the resulting high temperatures may speed deterioration

of the fruit and development of decay.

Recommended loading methods :

Nailed and wirebound carrier crates.—LengthAvise on bottoms. In

shipments moving relativel}^ long distances, vertical channels should

be maintained between the rows to promote adequate refrigeration.

The crates should not be loaded, stacked, or handled on their sides or

tops, or the berries in the till baskets will be spilled or jumbled.

Eggplant

Recommended protective services :

Desired temperature 45° to 50°.

Desired relative humidity 85 to 90 percent.

Average freezing point 30.4°.

Bunker ice (no top ice); or mechanical refrigeration unit with

cooling and heating cycles.

Eggplant going to distant markets generally is shipped in bushel

baskets.

Since eggplant is very susceptible to freezing, protection against cold

should be provided in trucks hauling this product in winter.

37
FIGURE 38.—Side and end views of an end-to-end offset load of eggplant, showing

arrangement of baskets in load.

Recommended loading methods:

Bushel baskets.—Baskets packed with this commodity should be

loaded by the end-to-end offset method (fig. 38).

Endive and Escarole

Recommended protective services:

Desired temperature 32°.

Desired relative humidity 90 to 95 percent.

Average freezing point 30.9°.

Top ice. •

To help retain the commodity's fresh, crisp appearance and condition, crushed ice should be placed in the containers and on top of the

load. Some endive and escarole is hydrocooled in the crates before

loading. Shipments adequately hydrocooled before loading ordinarily

may be transported safely over long distances, but top icing still is

required to hold the product at the desired temperature and to retain

moisture in it.

Recommended loading methods :

Bushel baskets.—End-to-end offset method, with baskets stowed

tightly against those in preceding stacks in order to prevent shifting

of load (fig. 39). Use of a guide row along one side wall of trailer from

the front to the rear is of help in building a tight, solid load. This

type of load should be used only for shipments moving short distances

in cool weather, and may be used with bunker ice instead of top icing.

Alternately inverted method.—This method, in which alternate

baskets in each row, layer, and stack are loaded on covers, produces a

*¡AJIIíí8ííSM1SSSJ|IÍSÍÍííISS

FIGURE 39.—Side and end views of an end-to-end offset load of bushel baskets of

endive and escarole.

38
tight load that utihzes available loading space somewhat more effectively than the end-to-end offset method (fig. 40). This load should

be used for long-distance shipments, and should be covered with a

liberal quantity of crushed ice.

Wirebound crates.—Lengthwise on sides or bottoms (fig. 41). It is

desirable that good row ahnement be maintained in loads of this

container so that there will be a uniform amount of space between the

rows, permitting adequate refrigeration of the commodity by th(^ top

and body ice. One or more stacks of crates of this commodity also

may be loaded upright on end so that the load comes out even in relation to the length of the trailer.

nir?7Tnn'rrTTf'''i

ill I f I j M11111Ti r ' M ííTffi-

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FIGURE 40.—Side and end views of an alternately inverted load of bushel baskets

of endive. This commodity should be shipped under top ice.

FIGURE 41.—Side and end views of a lengthwise-on-bottoms load of wirebound

crates of endi\e. Long-distance shipments of endive and escarole should be

covered with crushed ice.

Gooseberries

Recommended protective services :

Desired temperature 31° to 32°.

Desired relative humidity 80 to 85 percent.

Average freezing point 28.9°.

Bunker ice (no top ice); or mechanical refrigeration.

The crates should be arranged in tlie load to allow an abundance of

cold air to circulate over the fruit, maintaining an even, low temperature throughout the load.

When the containers are stacked close together, blocking the free

passage of air, the resulting high temperatures may facilitate deterioration of the fruit and development of decay.

Recommended loading methods:

Nailed and wirebound crates.—Lengthwise on bottoms. The load

may be crosswise offset by layers; otherwise, channels of adequate

width should be maintained in the load to promote good refrigeration.

39
Grapefruit—California and Arizona

Recommended protective services:

Desired temperature 45° to 50°.

Desired relative humidity 85 to 90 percent.

Average freezing point 28.4°.

Ventilation, bunker icing, or mechanical refrigeration.

As Cahfornia and Arizona grapefruit are not subject to stem-end rot,

they usually can be transported safely at somewhat higher temperatures than the fruit produced in areas where stem-end rot is prevalent.

Warm fruit should be precooled before loading or precooled m the

vehicle before shipment. Fruit packed in fiberboard cartons should

be precooled before loading. Shipments that will be in transit longer

than 8 to 10 hours, and shipments during warm weather, should be

refrigerated.

Recommended loading methods:

Standard 1%-bushel nailed citrus boxes.—Upnght on ends, with the

rows paired, loaded bottom to bottom (fig. 42). Pairing of the rows

in this manner will prevent the boxes from moving out of row alinement. They are topheavy in this position, with the center of gravity

shifted toward the cover of the box. This permits them to ' Valk'' in

the direction of their bottoms. In most shipments it is possible to load

only 2 layers of boxes upright on end. Boxes in the third layer may be

loaded lengthwise on bottoms.

Fiberboard cartons.—Lengthwise or crosswise on bottoms. If the

fruit has been precooled, the cartons should be loaded together as

tightly as possible (fig. 43). If the load does not come out even in

relation to the interior width of the vehicle, it may be crosswise offset

FIGURE 42.—Side and end views of an upright-on-ends deck load of standard

nailed l^-bushel citrus boxes of grapefruit. Upright boxes in 1st and 2d

layers are "paired,'' or loaded bottoms to bottoms, to prevent crosswise

'Valking'' of the boxes.

iiiL.liLllllimigBBBgHB

FIGURE 43.—Side and end views of lengthwise-on-bottoms load of western citrus

cartons of precooled fruit.

40
by layers so as to increase the crosswise stability of the load and to

decrease the area of contact between the load and the side walls of

the vehicle body. However, il the fruit has not been precooled,

ventilation channels or flues should be provided between the rows or

stacks to facilitate refrigeration.

Grapefruit—Florida

Recommended protective services:

Desired temperature 32° to 34°.

Desired relative humidity 85 to 90 percent.

Average freezing point 28.4°.

Ventilation, bunker icing, or mechanical refrigeration.

During the early fall and late spring, shipments of grapefruit from

Florida should be precooled, and sufficient bunker ice should be used

to maintain the recommended temperatures.

The heaviest movement of citrus fruit from Florida is during the

cold weather when refrigeration service is not necessary and ventilation sometimes may be used. The ventilators on the trailers should

l3e closed when the outside temperature drops below 32° and rises

above 40°. When outside air temperatures rise above 40°, refrigeration should be furnished.

When the temperature drops to the low 20's, provision for heating

should be made to keep the containers on the floor from freezing.

Recommended loading methods:

Standard 1%-bushel nailed citrus boxes.—Upright on ends, two layers

high, with the covers facing one sidewall of the truck or trailer body.

Third-layer boxes may be loaded either crosswise or lengthwise of the

trailer on bottoms (fig. 44). The boxes in the first layers loaded

upright on ends also may be arranged bottom to bottom. This

method has the advantage of preventing 'Svalldng'' of the boxes in

the direction of their bottoms \vith consequent rubbing and breaking

of the cover straps. Good row alinement should be held in the loads

in order to assure maximum ventilation.

1%-bushel vnrebound citrus boxes.—Lengthwise on bottoms. If the

rows of containers will not come out even in relation to the interior

width of the vehicle, the remaining crosswise slack may all be left

along one side wall in alternate layers (fig. 45). The resulting crosswise offset load will stabilize the load crosswise of the vehicle bod}^ and

provide sufficient space for the circulation of air along one side of each

FIGURE 44.—Side and end views of upright-on-ends deck load of standard nailed

1^-bushel 2-compartment citrus boxes. Upright boxes in 1st and 2d layers

may also be "paired," or loaded bottoms to bottoms, in extra wide vehicles to

prevent crosswise "walking."

41
FicuRE 45.—Side and end views of crosswise offset load of 1%-biishel wirebound

boxes. Crosswise offsetting loads of these containers helps to stabilize the load

crosswise of the vehicle body and facilitate refrigeration.

layer and under and over the boxes in each layer in tight contact

with one side wall.

Fiberboard cartons.—Lengthwise or crossmse on bottoms. If the

fruit has been precooled before loading, the cartons should be loaded

together as tightly as possible. However, if the fruit is warm, a

chimney-type load should be used, or the cartons should be loaded

lengthwise in continuous rows with channels between the rows to

facilitate the circulation of cold air. In the chimney-type method the

cartons are loaded length\vise and crosswise in alternate rows and layers

so as to tie them in place around vertical ventilation flues about 4

inches in width, extending from the top to the bottom of the load.

Grapes—European or Vmifera Varieties

Recommended protective services:

Desired temperature 30° to 31°.

Desired relative humidity 85 to 90 percent.

Average freezing point 24.9°.

Bunker icing or mechanical refrigeration.

All varieties of grapes should be precooled either before or after

loading. Shipments of warm fruit (nonprecooled) that will be in

transit longer than 8 to 10 hours should be precooled in the vehicle

before shipment. Sufficient refrigeration to maintain recommended

temperatures during transit should be provided for all long-distance

shipments in warm weather, whether or not the fruit has been

precooled.

The containers should be stacked so as to provide air channels to

allow an abundance of cold air to circulate through the load.

Grapes—American or Eastern Varieties

Recommended protective services:

Desired temperature 31° to 32°.

Desired relative humidity 80 to 85 percent.

Average freezing point 27.5°.

Bunker icing or mechanical refrigeration.

Recommended loading methods:

Nailed wooden lugs.—Either lengthwise or crosswise on bottoms

(fig. 46). All containers should be stacked squarely on top of one

another so that the weight of containers in the upper layers will bear

squarely on the cover cleats of the containers beneath them. For

42
il1]l

jaci b¿dL^

DN869

FIGURE 46.—Side and end views of a lengthwise-on-bottoms load of grape lugs.

This type of load, in which there are no ventilation channels, should be used

only for precooled fruit.

nonprecooled shipments moving relatively long distances, the lengthwise-on-bottoms load with ventilation channels between rows should

be used for adequate refrigeration. Crosswise stripping of the lengthwise rows or vertical spacing units should be used in this tj^pe of load

to hold the lugs in row alinement and prevent disarrangement of the

load with consequent damage and blocking of the ventilation channels.

For shipments from cold-storage plants or precooHng rooms, the lugs

may be loaded together tightly if the commodity temperature is

about 35°, or lower, at time of loading.

Climax splint baskets and 4-, 5-, or 12-guart fiherhoard baskets.—

Combination lengthwise and crosswise load, with containers reversed

in alternate layers (fig. 47). Containers in the first layer should be

loaded lengthwise and those in the second and each alternate layer

should be loaded crosswise of the vehicle body. If the baskets do not

have recessible handles, the handles of the baskets in one layer will

extend upward between two baskets in the layer immediately above.

In shipments of fiberboard baskets with recessible handles, moving

relatively long distances in warm weather, each stack of containers

should have several continuous vertical openings or flues extending

from the top to the bottom of the load to facilitate refrigeration.

,

II 1 II : M II 1

II II ' 1

III M 1

II II '

II ill Í

h^^4J L ,1

FIGURE 47.—Side and end views of a combination lengthwise-crosswise load of

8-quart fiberboard baskets of grapes. This same loading pattern may be used

also for splint baskets.

Honeydew Melons

Recommended protective services:

Desired temperature 45° to 50°.

Desired relative humidity 85 to 90 percent.

Average freezing point 28.8°.

Bunker icing or mechanical refrigeration.

43
Although the freezing point of honeydew melons is 28.8°, it is not

desirable to transport them at temperatures below 36°, as they will

show low-temperature breakdown.

These melons generally are packed in wooden crates with excelsior

or some other soft material to prevent bruising.

Sufficient bunker ice to maintain the recommended temperatures

should be used.

Recommended loading methods:

Honeydew melon crate.—Lengthwise on bottoms. The crates should

be stacked squarely on top of one another so that the weight of the

crates in the upper layers will bear on the cover cleats at the ends of the

crates beneath them. If the crates in the upper layers are permitted to

shift forward or backward and the bottoms slip off the cover cleats

and rest upon the thin cover slats, the melons in the lower crates will

be bruised. For this reason, it is necessary that the crates be stacked

tightly together and held firmly in stack alinement. The load may be

crosswise offset bj^ layers to distribute properly the weight of the load

and any crosswise slack (fig. 48). For long-distance shipments in

warm weather, however, the crates should be loaded in continuous

rows separated by ventilation channels to facilitate refrigeration. In

loads of this type it wül be necessary to crosswise strip each layer of

each stack to Jfiold the crates in row alinement.

FIGURE 48.—Side and end views of a crosswise offset load of honeydew melon

crates.

Kohlrabi

Recommended protective services:

Desired temperature 32°.

Desired relative humidity 90 to 95 percent.

Average freezing point 30°.

Ice in the containers, plus top ice.

The freezing point of kohlrabi is 30°; however, the tops may freeze

at temperatures slightly below 32°.

Recommended loading methods:

Wirebound crates.—Lengthwise on bottoms. Shipments moving in

excess of 8 to 10 hours in warm weather should be top-iced. Crates

should be loaded in continuous rows with channels between the rows

to accommodate crushed ice. In loads of this type, the crates should

be stowed tightly together lengthwise of the vehicle body in good row

ahnement. For shipments moving more than 8 to 10 hours in cool

weather under ventilation, the load may be crosswise offset by layers

to distribute equally the load weight and crosswise slack.

44
Leeks (Green)

Recommended protective services:

Desired temperature 32°.

Desired relative humidity 90 to 95 fï'ercent.

Average freezing point 29.2°.

Top ice.

The containers should be arranged to allow ample air circulation to

prevent the tops from heating. Top ice should bo l)lown over the load

Recommended loading methods:

Wirebound crates.—Lengthwise on bottoms. On shipments movinofrom farm to market, where the time in transit will not exceed 8 to

10 hours, or during cool weather when no top ice is used, the crates

may be loaded crosswise offset by layers to distribute equally the

weight and any crosswise slack. Shipments moving in excess of 8

to 10 hours during warm weather should be loaded in continuous rows

with channels between the rows to accommodate top ice.

Lemons

Recommended protective services:

Desired temperature 55° to 58°.

Desired relative humidity 95 to 90 percent.

Average freezing point 28°.

Ventilation, bunker icing, or mechanical refrigeration.

Lemons should not be transported at temperatures much below

58° F., as lower temperatures produce pleating, separating of the

segments, and other types of internal breakdown. For this reason,

shipments moving during subfreezing weather should be heated.

As temperatures higher than 58 degrees materially shorten the market

life of the fruit, ventilation in cool weather and limited refrigeration

in warm weather are important to maintain the recommended temperature.

Recommended loading methods:

Fiberboard cartons.—Lengthwise or crosswise on bottoms. As

lemons do not require low temperatures for storage or transportation,

shipments during cool weather may be loaded safely with the cartons

stacked together tightly lengthwise or crosswise of the vehicle body.

Shipments of nonprecooled fruit and shipments during warm weather

should be loaded by the chimney method, which will provide vertical

flues in the load to facilitate cooling of the commodity (fig. 49). It

is important in constructing loads of this type that the cartons be

stowed together tightlv and that there be little or no slack in the

load to permit the cartons in any one layer to move about and block

the vertical ventilation flues.

Letfuce

Recommended protective services:

Desired temperature 34°.

Desired relative humidity 90 to 95 percent.

Average freezing point 31.2°.

Bunker icing or mechanical refrigeration.

45
FicuRE 49.—Side, top, and end views of a chinaney load of fiberboard cartons of

lemons, slií)winí< arrangement of containers and location of vertical ^'entilaíion

flues.

Precooled dry-packed shipments should be bunker-iced or mechanically refrigerated. Nonprecooled shipments packed in wooden

crates with package ice also should be top-iced, and in warm weather

this should be supplemented further by bunker icing or mechanical

refrigeration.

Recommended loading methods:

Fiberboard cartons.—Lengthwise on sides or bottoms (fig. 50).

Loading of cartons on sides is recommended because it minimizes

the bulging of cartons in the lower layers due to overhead weight of

the load. One or more rows or stacks, however, may be loaded on

bottoms so that the load comes out even in relation to the interior

width and length of the truck or trailer body. Top-la3^er cartons

also may be loaded on bottoms.

Wood cratesj nailed or wirebound.—Lengthwise on sides (fig. 51).

In nonprecooled shipments where top ice is used, the crates should be

loaded in continuous rows with channels to hold top ice in contact

with the containers. One or more stacks of crates may be loaded

FIGURE 50.—Side and end views of a lengthwise-on-bottoms load of fiberboard

cartons of lettuce.

46
—î

3i j=#=!

1 1

I i

s

DN846

FIGURE 51.—Side and end views of a lengthwise-on-sides load of WGA nailed

wooden crates of lettuce. This load should be top-iced and the channels

between the rows of crates completely filled with crushed ice.

crosswise on sides or upright on ends at the front or back of the load

so it will come out even with the interior length of the truck or trailer

body. The nailed crates, on which the cover bulges are higher,

should be loaded with the covers of all crates in each side wall row

facing the side walls of the vehicle to minimize the area of contact

between crates and inside walls.

Loganberries

Recommended protective services:

Desired temperature 33°.

Desired relative humidity 85 to 90 percent.

Average freezing point 29.5°.

Bunker ice (no top ice) or mechanical refrigeration.

Recommended loading methods:

Nailed and wirebound carrier crates.—Lengthwise on bottoms. In

shipments moving relatively long distances in warm weather, vertical

ventilation channels should be maintained between the rows of crates

to facihtate refrigeration. In loads of this type, the crates should

be held in row alinement by two crosswise strips on each layer of

each stack. For shipments moving short distances to market, a

crosswise offset load in which no stripping is required usually is

satisfactory. The crates never should be loaded, stacked, or handled

on their sides or tops, or the berries in the till baskets will be spilled

or jumbled.

Okra

Recommended protective services:

Desired temperature 50°.

Desired relative himaidity 85 to 90 percent.

Average freezing point 30.1°.

Bunker icing or mechanical refrigeration.

It is necessary to maintain a high humidity to keep okra from

wilting. At temperatures below 50° this product is subject to chilling

injury, which results in decay. Some protection should be provided

on shipments moving during cold weather.

Recommended loading methods:

Bushel hampers.—^Alternately inverted method. Hampers in

alternate rows, layers, and stacks should be inverted or loaded on

covers to produce a tight, solid load. In shipments moving under

47
Ventilation, however, the so-called summer load which permits

better circulation of air through the load, should be used. In this

type of load the hampers are alternately inverted by layers only,

and those on one stack are not nested between those m the preceding

stack, but are arranged in continuous rows with opemngs between

for circulation, (fig. 10).

Onions, Dried

Recommended protective services:

Desired temperature 32°.

Desired relative humidity 70 to 75 percent.

Average freezing point 30.1°. i i .

Ventilation, or mechanical refrigeration unit with cooling and heating cycles. • i X

Onions are generally held in dry cold storage for long periods at a

temperature of 32°. The reason for this low temperature is to prevent sprouting and the development of decay.

When the onions are moved from a temperature of 32 to warm outside weather, they sweat, causing dampness in the bags. For this

reason, the ventilators should remain open so the onions will dry out

in transit.

Truck trailers transporting onions m winter should provide protection against cold.

Recommended loading methods:

Open-mesh bags.—The two principal considerations in loading bagged onions are to facilitate ventilation of the commodity and, when

circumstances require, to protect the commodity against cold. It is

desirable that the bags be stacked so that the flow of air through the

load will not be impeded, ^^^hen the bags are all loaded lengthwise

or all crosswise of the truck body, they have a tendency to shake

down, or to settle into a compact load that hampers the circulation

of air through and around them.

The so-called ''log cabin'' type of load is recommended for shipments moving under ventilation (fig. 52). In this type of load, the

bags are reversed in alternate layers, those in one layer being loaded

lengthwise and those in adjacent layers, above and below, crosswise

of the truck body. Loading of the bags in this manner tends to prevent their settling together so tightly as to interfere with movement

of air through the load during transit.

In shipments moving relatively long distances during subfreezing

weather, a pyramid type of load should be used to keep the bags out

Ï

^rrz 1 I l^1

«(• Ï \ 1 J;^

ÏÏ I 1 .Jfc:

ï I : ï ií

i Í Í . -4; fe^K^Qi

FIGURE 52.—Side and end views of a combination lengthwise-crosswise load of

50-pound open-mesh bags of dry onions.

48
of contact with the side walls of the truck or trailer body, where

freezing may occur. With this type of load, the floor of the truck

should be bedded with several inches of straw and the bottom-layer

bags should be kept away from the side walls of the trailer. It is

necessary to load the bags in alternate layers crosswise of the vehicle

to tie the load together effectively and to prevent the bags in the upper

part of the load from moving out of position and coming in contact

with the side walls of the truck body.

Oranges—California and Arizona

Recommended protective services:

Desired temperature 35° to 37°.

Desired relative humidity 85 to 90 percent.

Average freezing point 28.9°.

Ice, or mechanical refrigeration, or ventilation, according to seasonal conditions.

Precooled oranges should be stacked tightly in the trailer, with

wall strips and floor racks to provide ample air circulation around and

under the load. Oranges not precooled should be loaded with channels

to provide air circulation through the load to remove the field heat.

Some means of protection should be provided against cold, to

eliminate the hazard of freezing damage in winter.

Recommended loading methods:

Standard 1%'bushel nailed citrus boxes.—Upright on ends, with the

rows paired (loaded bottom to bottom). Pairing of the rows in this

manner prevents the boxes from moving out of row alinement, as

they are topheavy in this position, with the center of gravity shifted

toward the cover of the box, permitting them to 'Svalk'' in the direction of their bottoms. In most shipments, it is possible to load only

two layers of boxes upright on end. Boxes in the third layer may be

loaded lengthwise on bottoms (fig. 53).

Fiherboard cartons.—^Lengthwise or crosswise on bottoms (fig. 54).

If the fruit has been precooled before loading, the cartons should be

loaded together as tightly as possible. If the fruit is warm, however,

a chimney-type load should be used, or the cartons should be loaded

lengthwise in continuous rows with channels. In the chimney-type

load, the cartons are loaded lengthwise and crosswise in alternate

rows and layers, so as to tie them in place around vertical ventilation

flues about 4 inches wide, extending from the top to the bottom of

the load.

FIGURE 53.—Side and end views of an upright-on-ends deck load of standard

nailed l^^-bushel citrus boxes of oranges. Upright boxes in the 1st and 2d

layers are "paired,^' or loaded bottoms-to-bottoms, to prevent crosswise

walking" with resulting cover-strap breakage.

49
^

^

yj SE-L

FIGURE 54.—Side and end views of a lengthwise-on-bottoms load of western

fibei board cartons of oranges.

Oranges—Florida

Recommended protective services:

Desired temperature 38° to 40°.

Desired relative humidity 85 to 90 percent.

Average freezing point 27.4°.

Bunker icing or mechanical refrigeration.

Oranges should be precooled to 45° to 50°, either before loading or

immediately after loading.

During the summer, the bunker should be filled with ice and the

air-circulating fan operated to maintain the recommended product

temperature.

During the late fall, early spring, and mild winter seasons when refrigeration service is not required, the ventilators of the trailer may be

opened when the outside temperature ranges between 35 and 45

degrees.

When the outside temperature reaches the low twenties, provision

should be made for heating to prevent freezing of fruit in containers

on the floor.

Recommended loading methods:

Standard 1%-bushel nailed citrus boxes.—If there is little or no crosswise slack in the load, the boxes should be loaded upright on ends,

two layers high, with the covers facing one side wall of the truck or

trailer body. Third-layer boxes may be loaded either crosswise or

lengthwise of the trailer on bottoms (fig. 55). The boxes in the first

layers loaded upright on ends should be arranged bottom to bottom

if there is about 2 inches or more crosswise slack in the load. This

method has the advantage of preventing ''walking'' or tipping of the

boxes in the direction of their bottoms with consequent rubbing and

breaking of the cover straps. Good row alinement shoidd be maintained in the loads to secure the maximum benefit of refrigeration.

1%'bushel wirebound citrus boxes.—Lengthwise on bottoms. If the

rows of containers will not come out even in relation to the interior

width of the vehicle, all the remaining crosswise slack may be left

along one side wall in alternate layers (fig. 56). The resulting crosswise offset load will stabilize the load crosswise of the vehicle body and

provide sufficient space for the circulation of air along one side of each

layer and under and over the boxes in each layer in tight contact with

one side wall.

Fiberboard cartons.—Lengthwise or crosswise on bottoms. Shipments of nonprecooled fruit that will be in transit longer than 8 to 10

hours should be loaded with ventilation channels about 1 inch wide

50
FIGURE 55.—Side and end views of an upright-on-ends deck load of IK-bushel

• Florida standard citrus boxes.

DN847

FIGURE 56.—Side and end views of crosswise offset load of 1%-bushel wirebound

citrus boxes. The air channels along the side walls facilitate cooling of the

load.

between the rows in the lower layers of the load to facilitate ventilation or refrigeration. The upper two layers of the load should be

crosswise offset to stabilize the load and hold the cartons in the lower

layers in row alinement. However, if the fruit has been adequately

precooled before shipment, the cartons may be stowed together tightly

in the load to retain the desired temperature.

5- and 8-pound open-mesh bags.—Alost truck shipments of oranges

in these consumer-size units are made in mixed loads with wirebound

crates and other types of containers. In mixed shipments of this type,

2 or 3 layers of wirebound crates or other heavier containers are

loaded on the floor of the vehicle and the small bags are loaded on top

of the larger containers.

Liberal quantities of cushioning material such as excelsior pads or

straw should be placed on top of the larger citrus containers, to protect

the fruit in the bottom-layer bags from crushing due to overhead

weight. The padding used for this purpose should be several inches

thick. Observations on test shipments b}^ motortruck have shown

that severe crushing of the fruit in bottom-layer bags occurs when the

bags are loaded more than eight layers high. Because loading bagged

fruit on top of the other containers in the load has a blanketing effect

on the circulation of air through the other containers in the bottom

part of the load, it is desirable that the rims of crates in the lower

layers be spaced about 1 inch apart to permit circulation of air between them lengthwise of the vehicle body. If straw or other loose

material is used for cushioning the bags in loads of this t3rpe, heavy

paper or sheets of fiberboard should be placed over the crates in the

bottom of the load to keep the straw from working down between the

rows and blocking the ventilation channels. In solid loads of bagged

fruit, liberal quantities of cushioning material should be used on the

floor of the trucks and the fruit should not be loaded more than eio:ht

51
layers high. If it is necessary to load more bags than can be accommodated in an eight-high load, a false deck resting on the side walls

of the vehicle should be used to separate the load vertically, to avoid

crushing of the fruit from overhead weight.

Peaches

Recommended protective services:

Desired temperature 33°.

Desired relative humidity 85 to 90 percent.

Average freeziag point 29.4°.

Bunker icing, or mechanical refrigeration.

Peaches from all shipping areas should be precooled either before

loading or immediately after loading.

When warm peaches are to be loaded, the vehicle should be iced to

capacity before loading and the air circulating fan turned on immediately after loading. Frequent re-icing may be necessary during the

first several hours of precooling.

It is very important that the load should be arranged so that the

cold air may circulate over and through the load.

Recommended loading methods:

Tub baskets, K-, %-, Yi-busheL—These baskets may be loaded by

either the crosswise offset (fig. 57) or alternately inverted method,

depending upon the temperature of the fruit at time of loading and the

length of time that it will be in transit. Shipments of fruit, adequateh^

precooled before loading, may be loaded by the alternately inverted

method. This load, however, should be used only for baskets which

have not been packed with a pronounced cover bulge and are equipped

with cover pads filled with macerated paper, with the covers securely

fastened at all four points. The alternately inverted load is of high

density and carries well under normal conditions. Shipments of nonprecooled fruit which will not be in transit longer than 8 to 10 hours

also may be loaded by the alternately inverted method. Nonprecooled fruit which will be in transit for a substantially longer period

of time should be loaded by the crosswise offset method to facilitate

refrigeration.

One-bushel baskets.—These may be loaded either by the end-to-end

offset method or the alternately inverted method.

Western peach box (nailed).—Lengthwise on bottoms. Good stack

alinement should be maintained to prevent any of the boxes in the

upper layers from slipping off the cover cleats and bearing on the light

FIGURE 57.—Side and end views of a crosswise offset load of >^-biishel baskets of

peaches, showing arrangement of baskets in load.

52
covers of the boxes in the lower layers of the load. Shipments of non

precooled fruit should be loaded with ventilation channels at least 1

inch wide bet\yeen the rows of boxes to facihtate refrigeration Loads

of this type, with the boxes in continuous rows and ventilation channels

between, should be double-stripped crosswise at least on alternate

layers of each stack, to hold the boxes in row alinement. If the fruit

has been adequately precooled before loading, the boxes may be

loaded together tightly or the load may be crosswise offset by layers to

distribute the crosswise slack equally and stabilize the load crosswise

of the vehicle body.

Peas (Green)

Recommended protective services:

Desked temperature 32°.

Desired relative humidity 85 to 90 percent.

Average freezing point 30"^.

Bunker, top, and container icing.

Fresh green peas are generally packed in bushel tub baskets or

hampers, with crushed ice in the containers in addition to crushed ice

over and through the load.

The purpose of placing the crushed ice in the containers as well as

on top of the load is to lower the temperature of the product as quickly

as possible so that the pods will retain their fresh, green appearance,

and, more important, to keep the su^ar in the peas from turning to

starch.

Recommended loading methods:

Bushel tub baskets or hampers.—Alternately inverted method (fig.

58). Alternate baskets in each row, stack, and layer are loaded on

covers. Because of the semiconical shape of the baskets, this method

produces a compact, high-density load which adequately supports the

weight of the top ice used for refrigeration. Baskets should be

stacked together tightly, and care should be taken to see that all

covers are secured tightly as the baskets are placed in the load.

jiiiiiiiMiniiiiiifiiiiMiiMiillifHiiiiiiilinfiiiiiiîiri

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Blsí^ass.'SKsigsj^:;^;];:^^^

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FIGURE 58.—Side and end views of an alternately inverted load of bushel baskets

of fresh peas. The covers on these containers should be securely fastened at

all four points and the load should be covered with liberal quantities of crushed

ice.

Peppers

Recommended protective services :

Desired temperature 45° to 50°.

Desired relative humidity 85 to 90 percent.

Average freezing point 30.1°.

53
Ventilation, bunker icing, or mechanical refrigeration unit with

cooling and heating cycles.

Although the fi-eezing point of peppers is 30.1°, it is not desirable

to hold them below 45° because this will develop low-temperature

breakdown.

Shipments moving in winter should be protected against cold by a

heater.

Recommended loading methods:

Chie-bushel tub baskets.—End-to-end offset (fig. 59). The crates

should be loaded in continuous I'ows with ventilation channels between

the rows in the lower two layers of the load to facilitate ventilation.

All crates should be kept in good stack alinement so that the full

weight of the crates in the load is borne by the end cleats of the

containers.

Wirebound crates.—Lengthwise on bottoms (fig. 60). The crates

should be loaded in continuous rows with ventilation channels between

the rows in the lower two layers of the load to facilitate ventilation.

All crates should be kept in good stack alinement so that the full

weight of the crates in the load is borne by the end cleats of the

containers.

^ .^

SmSKsasjK^^

JThSHTH 1 im

mam iTari rflHnïrrnsri,iîirii^in,iiiH.iîinjiiriiFrnjii»,^

' """ ""i" 'mM iiUviiiiJi'''' iiMiMifin iiniiuíi'Miíüyj¿üMiffli^^üJ^ü¿uiüi¿

ii»

1M

DN848

FIGURE 59.—Side and end views of an end-to-end offset load of bushel baskets

of peppers.

W"" lliiMi#iii imlWllJ

FIGURE 60.—Side and end views of lergthwise-on-bottoms load of wirebound

crates of peppers. The channels between the rows of the lower two layers are

for ventilation.

Plums and Fresh Prunes

Recommended protective services:

Desired temperature 31° to 32°.

Desired relative humidity 85 to 90 percent.

Average freezing point 28°.

Bunker icing.

54
Plums and prunes should be precooled sufficiently before loadincr to

maintain the recommended temperatures in transit. *^

When warm fruit is to be shipped, precoohng should be started

immediately after loading is completed. The containers should be

loaded so as to allow an abundance of air to circulate through the containers in all parts of the load.

Recommended loading methods:

4-basket crate and soft fruit lugs.—Lengthwise on bottoms. These

containers shoidd be stacked together tightly lengthwise of the truck

or trailer body so as to prevent any lengthwise movement of the

crates in any layer. As the covers of these containers are made of

thin wood veneer with cleats at each end, severe bruising to the fruit

may result if the crates in the upper layers move forward or backward

off the cover cleats of the containers in the lower layers. If the fruit

has been precooled before loading, the containers should be placed

together in tight, compact loads. Shipments of noncooled fruit moving

relatively long distances should be loaded in continuous rows separated

by channels to aid the circulation of cold air through the load.

Tub baskets, half-bushel.—These baskets may be loaded by either

the crosswise offset (fig. 61) or alternately inverted metliod, depending

upon the temperature of the fruit at time of loading and the length of

time it will be in tra.nsit. Fruit adequately precooled before loading

may be loaded by the alternately inverted method. This load, however, should be used only for baskets which have not been packed witli

a pronounced cover bulge and are equipped ^vith cover pads filled with

macerated paper, with the covers fastened securely at all four points.

The alternately inverted method gives a high-density load which will

carry well under normal conditions. Shioments of nonprecooled

fruit which will not be in transit longer than 8 to 10 hours also may be

loaded by the alternately inverted method. Nonprecooled fruit

which will be in transit for a substantially longer time should be

loaded by the crosswise ofi*set method to facilitate refrigeration.

Climax splint baskets and ßberboard baskets, 4, 5, or 12 quarts.—

Combination lengthwise and crosswise load, with containers reversed

in alternate layers. Containers in the first and each alternate layers

should be loaded lengthwise and those in the second and each alternate

layer crosswise. If the baskets are not equipped with recessible

handles, the handles of the baskets in one layer wUl extend upward

between two baskets in tDe layer immediately above. In shipments

of fiberboard basket? with recessible handles moving relatively long

distances in warm weather, each stack or imit of containers should

have continuous vertical openings or flues extending from the top to

the bottom of the load for adequate cooling of the commodit3^

FIGURE 61.—Side and end views of a crosswise offset load of Jí-bii.sliel baskets of

fresh prunes.

55
Potafoes—Early Crop

Recommended protective services:

Desired temperature 50°.

Desired relative humidity 90 to 95 percent.

Average freezing Doint 28.9°.

Ventilation, biniker icing, or mecbanical refrigeration unit with

cooling and heating cycles.

Early crops of potatoes are harvested in the Southern States during

the winter, spring, and early summer, and move to market through

weather tliat grows increasingly cooler the fartlier north they go.

As a rule, they can be shipped satisfactorily under ventilation service.

The ventilators should remain open between 40° and 60°. Above

or below this outside temperature range, the ventilators should be

closed.

During periods of unseasonably warm weather, the bunkers in the

trailer may be filled and the ventilators may be opened as the shipment

moves northward into cooler temperatures.

When the outside temperature reackes the low twenties, some provision should be made for heating to protect the potatoes in containers

in the bottom of the load.

Recommended loading methods:

100-pound burlap bags.—Combination lengthwise-crosswise pyramid-type load (fig. 62). Because of the comparative tenderness and

susceptJibility of early potatoes to bruising, it is desirable that they

not be loaded more than six layers high. The floor of the truck or

trailer body should be bedded with several inches of straw or other

cushioning material. If straw or other loose material is used on the

floor racks of the vehicle, the racks should first be covered with heavy

paper or fiberboard to prevent the cushioning material from falling

through the floor racks and blocking the circulation of air under the

load that could result in inadequate cooling or heating. Various types

and sizes of unitized excelsior pads are commercially available for

cushioning loads of bagged commodities. Bags in the lower two layers

of the load should be spaced as far apart as possible crosswise of the

vehicle body to permit circulation of air through the load. Pyramiding of the load helps to hold the bags in the upper layers away from

the vehicle side walls, and to obtain more even distribution of overhead

weight and circulation of air around the load.

50-pound paper bags.—Lengthwise and crosswise on sides. Bags

may all be loaded crosswise, or all lengthwise, or they may be loaded

lengthwise and crosswise in alternate layers. Another variation is to

load the bags along each side wall crosswise and those in the middle

of the load lengthwise. The advantage of the last variation is that

the twist at the mouth of bags in contact with the side wall of the

truck or trailer body provides small cushions that help to prevent

rubbing damage to which bags in some shipments are exposed when

they are loaded lengthwise with their sides against the side walls of

the vehicle. The floor of the truck or trailer body should be bedded

with several inches of straw or other cushioning material to help

protect the potatoes in the bottom layer from bruising. If such loose

material is used on the floor racks of the vehicle, the racks first should

be covered with heavy paper or fiberboard to prevent the cushioning

material from falling through the floor racks and blocking the circulation of air under the load, resulting in inadequate cooling or heating.

56
Various types and sizes of iinitized excelsior pads are commercially

available for cushioning loads of bagged commodities. The load also

should be constructed with continuous channels lengthwise of the load

at least in alternate layers, to facilitate movement of air through the

load.

^ ( J . )

^ C )[ \{ ) '

i f ] Í ), ( r . ), U^i U

FIGURE 62.—Side and end views of a pyramid-type load of 100-pound bags of

early potatoes. Straw or other cushioning material should be used on the

floor of the vehicle to help prevent bruising or flattening of this tender commodity by the overhead weight of the load.

Potatoes—Late Crop

Recommended protective services:

Desired temperature 38° to 50°.

Desired relative humidity 85 to 90 percent.

Average freezing point 28.9°.

Ventilation, bunker icing, or mechanical refrigeration unit with

cooling and heating cycles.

A great part of the late potato crop moves to market during the

late fall, through the winter, and in the earh^ spring.

During the late fall and early spring, in relatively cool weather, late

potatoes can be shipped under ventilation.

The ventilators should remain open when outside temperature is

between 40° and 60°. Above or below this temperature range, the

ventilators should be closed.

In winter, trucks or trailers should be preheated if the inside

temperature is below the desired level. Heaters and air circulation

should be provided to prevent freezing damage in the bottom of the

load.

Reconunended loading methods:

100-pound burlap bags.—Lengthwise or crosswise on sides. As

late-crop potatoes are less susceptible to bruising than the early crop,

shipments ordinarily may be loaded one to two layers higher than

early-crop potatoes. The floor of the truck or trailer body should be

lined with heavy building-type paper. However, if the floor is slotted

or grooved, it should be bedded with several inches of straw or other

cushioned material. For shipments moving relatively long distances

in cold weather, liberal quantities of stra\\' on the floor and along the

l30ttom sides of the load help to protect the commodity against freezing. Pyramiding of the bags in the upper layers so as to hold them

away from the side walls also aids in preventing freezing of the commodity at that location.

50'pound paper bags.—^Lengthwise and crosswise on sides. Reversing of bags in alternate layers, especially along the side walls of

the truck or trailer body, so that the fold at the mouths of the bags

57
contacts the side walls, provides some protection against rubbing and

chafing of the bags at that point. The bags should be further protected l)y lining the floor, and also the walls to the height of the load,

with heavy building-type paper. However, if the floor is slotted or

grooved, it should be covered with several inches of straw or other

cushioning material. Liberal quantities of straw or similar material

on the floor and along the bottom sides of the load help to protect the

commodity from freezing at those points in severely cold weather.

Pyramiding of bags in the upper layers so as to hold them away from

the vehicle side wall also helps to protect the commodity from sidewall freezing.

10- and IS-pound paper hags.—Lengthwise on sides. The bags in

each layer of each stack should be reversed, with the mouths of the

bags in one layer facing the front of the vehicle and those in the next

layer facing the back of the load. As small bags of this type taper

somewhat toward the mouths, reversing the bags in alternate layers

compensates for this difference and makes it possible to build an even

and level load. Preparation of the interior of the truck or trailer

body for loading should be the same as for 50 pound paper bags.

Raspberries—Black and Red

Recommended protective services:

Desired temperature 33°.

Desired relative humidity 85 to 90 percent.

Average freezing point 29.9°.

Bunker ice (no top ice) ; or mechanical refrigeration.

The crates should be arranged in the load to allow an abundance of

cold air to circulate over the fruit, maintaining an even low temperature thi^oughout the load.

When the containers are stacked close together, blocking the free

passage of air, heat develops in the fruit, causing decay.

Recommended loading methods:

Nailed and wirehound carrier crates.—Lengthwise on bottoms. In

shipments moving relatively long distances in warm weather, vertical

ventilation channels should be maintained between the rows of crates

to facihtate refrigeration. In loads of this type the crates should be

held in row alinement by two crosswise strips on each layer of each

stack. For shipments moving short distances to market, a crosswise

offset load in which no stripping is required usually will be satisfactory.

The crates never should be loaded, stacked, or handled on their sides

or tops, or the berries in the till baskets will be spilled or jumbled.

Rhubarb

Recommended protective services:

Desired temperature 32° to 35°.

Desired relative humidity 90 to 95 percent.

Average freezing point 28.4°.

Bunker icing or mechanical refrigeration.

Recommended loading methods:

Fiberboard car/ons.—Lengthwise on bottoms. As this commoditsr

seldom is shipped in large quantities, usually it is included with other

58
vegetables in mixed shipments. In such instances, it is desiiablo to

load the cartons of rhubarb in the upper layers of the load, particularly

if the cartons are comparatively small and light.

Some refrigeration should be provided to maintain the iccoinmended temperatures either in straight loads or in mixed loads.

Rutabagas

Recommended protective services:

Desired temperature 32° to 35°.

Desired relative humidity 90 to 95 percent.

Average freezing point 29.5°.

Bunker icing or mechanical refrigeration.

Recommended loading methods:

60-pound burlap bags.—Lengthwise on sides. As rutabagas are not

easily bruised, they do not present much of a problem in loading.

Many rutabagas are fairly large, and the 50-pound bags usually cannot

be filled completely. For this reason, the individual bags are somewhat slack and have a tendency to settle in the load. Loading the

bags lengthwise with the mouths facing the rear of the truck or trailer

body faciUtates unloading, as the gathered mouths of bags can easily

be grasped to pull them from the load.

Depending on outside weather conditions, some means of either

refrigeration or ventilation should be provided to maintain the

recommended temperatures.

Strawberries

Recommended protective services:

Desired temperature 33°.

Desh'ed relative humidity 85 to 90 percent.

Average freezing point 29.9°.

Bunker ice (no top ice) or mechanical refrigeration.

The crates should be arranged in the load to allow the cold air to

circulate freely over the fruit, maintaining an even, low temperature

throughout the load.

When the containers are stacked close together, blocking the free

passage of air, the fruit develops heat, causing decay.

Recommended loading methods:

Nailed or wirebound carrier crates. Lengthwise on bottoms (fig. 63).

In shipments moving relatively long distances in warm weather, vertical ventilation channels should be maintained between the rows of

crates to assure adequate refrigeration. In loads of this type, the

crates should be held in row alinement by two crosswise strips on each

layer of each stack. For shipments moving overnight to market, a

crosswise offset load, in which no stripping is required, usually is

satisfactory. The crates never should be loaded, stacked, or handled

on their sides or tops, or the berries in the till baskets will be spilled

or jumbled.

59
\

: Pi

w^üj||1 Èi

FIGURE 63.—Side and end views of a lengthwise-on-bottoms load of wirebound

carrier crates of strawberries.

Sweetpotafoes

Recommended protective services:

Cured stock:

Desired temperature 55° to 60°.

Desired relative humidity 85 to 90 percent.

Average freezing point 28.5°.

Ventilation in cool weather; bunker icing or mechanical refrigeration

in warm weather.

Non cured stock:

Desired temperature 85°.

Desired relative humidity 90 to 95 percent.

Average freezing point 28.5°.

No ventilation; no bunker icing or mechanical refrigeration.

Sweetpotatoes generally are packed in bushel baskets or wirebound

crates. Temperatures slightly below 55 degrees may not be harmful

for short periods. However, prolonged exposure to low temperature

should be avoided. Noncured sweetpotatoes are more susceptible to

chilling injury than cured stock.

Provision should be made for protection against cold in winter.

Recommended loading methods:

Bushel baskets.—End-to-end offset (fig. 64). The covers should be

fastened securely on the baskets at all four points, and the baskets

should be stacked tightly together in the load.

Wirebound Janees crates.—Lengthwise on sides, with tops and

bottoms reversed in alternate layers. As these containers are slightly

narrower at the top than at the bottom, reversing the crates in alter-

^

FIGURE 64.—Side and end views of an end-to-end offset load of bushel baskets of

sweetpotatoes.

60
nate layers (loading with the tops of crates in one layer facing one side

of the truck body and those in the layer immediately above facing

the opposite way) compensates for the difference, making the top of

the second and all even-numbered layers come out almost level. The

crates should be stacked squarely on top of one another in good row

aUnement, with the cleats at the top and bottom of each crate bearing

squarely upon the cleats of the container directly beneath it.

Tangerines

Recommended protective services:

Desired temperature 31° to 38°.

Desired relative humidity 90 to 95 percent.

Average freezing point 28°.

Bunker icing or mechanical refrigeration.

Recommended loading methods:

Wirebound crates.—Lengthwise on sides. Crates in all lower layers

should be stacked lengthwise on sides, but top-layer crates may be

loaded lengthwise on bottoms. Crates should be stacked squarely on

top of one another and good stack alinement should be maintained so

that most of the overhead weight will be borne on the end cleats of the

crates. Keeping the crates in good row alinement also will aid proper

refrigeration of the commodity.

For the best results in transporting tangerines, which are highly

perishable, they should be precooled and should be given ample refrigeration while in transit, especially on long hauls.

Tomatoes—Mature Green

Recommended protective services:

Desired temperature 55° to 70°.

Desired relative humidity 85 to 90 percent.

Average freezing point 30.4°.

Bunker icing or mechanical refrigeration unit with cooling and heating cycles.

When transporting mature green tomatoes from producing areas in

the South to northern markets, a small amount of bunker ice may be

used to remove the field heat from the fruit. Do not reduce the

product temperatm-e below 50° F. Temperatures below this point

may cause chilling injury.

When moving through mild temperatures (50° to 60°) the ventilators should be opened.

When shipments move through low outside temperatures, truck

trailers should be equipped for protection against cold. Tests have

shown the most satisfactory results with portable thermostatically

controlled heaters.

Wall strips and ñoor racks are very important for adequate circulation of air around and under the load.

Recommended loading methods:

Nailed wooden lug boxes.—Lengthwise on bottoms (fig. 65). The

lugs should be stacked tightly together in good row alinement so that

the weight of the lugs in all upper layers will be borne by the cover

cleats of the lugs beneath them. The lugs in any layer should not be

61
free to move forward or backward, or they may slip off the cover cleats

of the lugs directly beneath, depressing the light veneer cover slats

into the fruit and ciiushig bruishig.

Wirebound 60-pounfi crater.—^Lengthwise on bottoms (fig. 66).

These crates also should })e stacked together tightly lengthwise of the

vehicle body so tliat all ovc^liead weight will l)e borne by the end

cleats of the crates.

" ~"

~i ~~" ~~

' 3L-i^S SE

FIGURE 65.—Side and end views of a lengthwise-on-bottoms load of tomato lugs.

It is important that good stack alinement be maintained in loads of this container so that the weight of the lugs in the upper layers will bear on cover

cleats of containers in the lower lajeéis.

Fiberboard cartons.—Lengthwise or crosswise on bottoms (fig. 67).

Fiberboard is a fairly good insulator, and most types of cartons used

for tomatoes do not have as many or as large openings as the nailed

or wirebound crates through which the commodity can be ventilated,

It is therefore necessary that some provision be made for the circulation

of air through the load. This can be accomplished by using a chimney-type load, or by crosswise offsetting the load by layers and having

longitudinal openings in the lower 2 or 3 layers extending the entire

length of the load. In the chimney-type load the cartons are loaded

crosswise and lengthwise in blocks, in the center of which are vertical

flues extending from top to bottom of the load.

Fiberboard baskets.—Combination lengthwise-crosswise load with

containers reversed in alternate layers. If the baskets do not have

recessible handles, the handles of the baskets in each layer, except

the top layer, will extend upward between two baskets in the layer

inamediately above (fig. 68). In shipments of fiberboard baskets

with recessible handles, moving relatively long distances in warm

weather, each stack or unit of containers should have continuous

vertical openings, or flues, extending from top to bottom of the load,

to facilitate refrigeration.

DN845

FicuRE 66.—Side and end views of a lengthwise-on-bottoms ventilated load of

wirebound tomato crates. The ventilation channels between the crates in the

I'-wer two layers of the load are continuous from the front to the rear of the load.

62
FIGURE 67.—Cross section of a lengthwise-on-bottoms load of fiberboard cartons

of tomatoes. Channels between rows in lower three layers facilitate air circulation.

FIGURE 68.—Rear view of a combination lengthwise-crosswise load of fiberboard

baskets of tomatoes.

63
Watermelons

Recommended protective services:

Desired temperature 36° to 40°.

Desired relative humidity 85 to 90 percent.

Average freezing point 29.2°.

Ventilation in transit required. No refrigeration.

Recommended loading methods:

Watermelons generally are shipped in bulk. One exception is the

so-called ''icebox watermelons/' which are small, round melons

generally shipped and handled in bushel baskets and various other

containers. The ''icebox'' melons, which were introduced commercially a few years ago, as yet are produced and shipped only in limited

quantities. Both the long-type and round-type large melons usually

are loaded lengthwise of the truck or trailer body. In this type of

load the second and each alternate layer will be one row less in width

than the first and each odd-number layer, as the melons in the second

and all upper layers are placed in the pockets between adjacent melons

in two rows of the layer directly beneath.

The side walls of the truck or trailer body should be lined with heavy

paper or other protective material to prevent rubbing or scarring of

the melons. The floor of the vehicle body should be bedded with

several inches of clean straw, excelsior, or similar cushioning materia],

to protect the bottom-layer melons from bruising. Straw or other

cushioning material should not be placed between the rows or layers

of melons as it will interfere with ventilation of the load.

Freezing Injury fo Fruits and Vegetables

On the basis of experiments, observations of produce under commercial conditions, and experience of commercial operators, various

fruits and vegetables can be grouped as follows as to their susceptibility

Approxim'ite

freezing

Moderately susceptible—Con. ° F/

Grapes 25-28

to freezing injury:

Most susceptible:

Asparagus

Avocados

Bananas

Beans, lima

Beans, snap

Berries

Cucumbers

Eggplant

Lemons

Limes

Peppers

Potatoes, white

Squash, summer

Sweetpotatoes

Tomatoes

Moderately susceptible :

Apples

Broccoli, sprouting

Cabbage, new

Celery

Cranberries

Approximate

freezing

poivt

' F.i

30

27

30

30

30

30

30

30

28

29

30

29

29

29

30

28

29

31

30

27

Lettuce 31

Onions 30

Oranges and grapefruit 28

Parsley (2)

Peaches and plums 29

Pears 28

Peas 30

Squash, winter 29

Least susceptible:

Beets 27

Brüssel sprouts (2)

Cabbage (old and Savoy).

Carrots

Cauliflower

Kale

Parsnips

Rutabagas

Salsify

Spinach.

Turnips.

31

29

30

30

30

30

29

^30

30

1 In most cases, these are the approximate average freezing points. It should be

remembered that individual specimens may freeze at slightly higher or slightly

lower temperatures.

2 Exact freezing point not known.

Source: Freezing Injury of Fruits and Vegetables, U. S. Department of Agriculture Circular No. 713.

64
Froren Foods

The National Association of Frozen Food Packers has recommended

that all frozen products be transported at 0° F.

Motortruck trailers transporting these products should have a

minimum thickness oj 6 inches oj high quality insulating material in

wallSy floorj and ceiling, and either a mechanical or dry ice refrigeratiiip;

unit with ample capacity to maintain zero temperature over long

distances.

Provision should be made in the trailers for good air circulation

around and under the load, using floor racks with a space of at least

2 inches under the load, and wall strips not less than %-incli tliick,

spaced about 8 inches apart. (See fig. 1.) All truck trailers sliould

be precooled to a temperature of not more than 10° F. before loading.

Curtains over the doorway opening, a tunnel, or other protection

from outside heat should be provided during loading to retain the

effects of the precooling.

If for any reason loading or unloading is interrupted, the rear doors

should be closed immediately and the refrigerating unit started until

work is resumed.

Because of the variety of containers used and the density of many

frozen commodities that may limit the height of the load, it is not

feasible to recommend any single method of loading. However, in

loading frozen foods the packages should be placed tightly together

in a single compact mass. It should be borne in mind that there will

be no evolution of heat in these commodities, and consequently, no

need for ventilation channels in the load. On the contrary, frozen

commodities should be loaded in a solid, tight, mass, and tlie circulation of refrigerated air at zero or below should be directed above,

under, and aroimd the load to prevent the transfer of outside heat

through walls, ceiling, and floor. The driver should supervise tlie

loading of his trailer to be sure that provision is made for adequate

air circulation around the load, and that the weight of the load is

properly distributed, eliminating the hazard of having to open the

doors to adjust the load.

Fresh Meat and Packinghouse Products

Motor carriers transporting fresh meats and packinghouse products

also have problems with their equipment. Truck trailers used in this

traffic must be designed to carry quarters of meat suspended from

meat rails in the ceding, as well as packages on the floor. The inside

of the trailer shoiúd be cleaned with hot water and detergents after

unloading at the end of each trip, in accordance with standards set

up by the U. S. Department of Agriculture, to prevent the development of harmful bacteria and offensive odors. Consequently, it is

essential that the interior of the trailer be designed to facilitate cleaning. The materials used, especially in side walls and floors, should be

resistant to the effects of heat and vapor. Corrosion-resistant metals

or plastics are recommended for this piu-pose.

These trailers should have ample insulation, and either a mechanical

or dry-ice refrigerating unit capable of maintaining the temperature

at which the product was loaded. Floor racks should be used to

insure circulation of air around the load. Wall racks also are desirable.

65
Loading Fresh Beef

During warm weather, truck trailers should be precooled to 35° to

40° F. before loading.

The quarters of beef should be chilled to 35° F. in the chilling rooms

before shipment.

Forequarters are hung with the long hooks inserted from the bone

side, usually under the 4th rib about 11 inches from the backbone so

that they will balance and hang straight.

Short hooks are used in hanging the hindquarters, the hooks being

inserted through the opening in the gambrel cord of the shank.

Loading generally is started by hanging the forequarters next to the

wall with the bone side to the wall on either side of the load (fig. 69).

More forequarters then are hung between until the stack is completed.

Care must be taken to see that quarters are paired and hung boneside

to boneside, meatside to meatside. A boneside hung next to a meatside rubs the meat and damages it. Extra quarters generally are

added at the center of the stack to tighten up the load and eliminate

crosswise slack. Hindquarters are loaded in the same manner.

M»

W f (' v' '

L I VO ^ vx\^ Ky XJ \J vAJ1^;

1 1

\s\m\m\mN\g\\\\\m\^^^^^^^^^

UNIT END MIDDLE HALF POSITION DOOR POSITION

FIGURE 69.—Side and end views of a mixed load of forequarters and hindquarters

of dressed beef.

Loading Fresh Poric

During warm weather, truck trailers should be precooled between

35° to 40° F. before loading. The product should be chilled to 35°

to 38° F. in the chilling room before being loaded. Generally, fresh

pork cuts such as loins, hams, spareribs, and trimmings are packed in

fiberboard containers. The packages should be arranged so as to

66
allow ample circulation of air around and under the load to avoid

high temperatures along the floor of the trailer, iloor and wall racks

are advisable to insure adequate air circulation.

Recommended Temperatures and Humidity for Fresh Meat and Packinghouse

Products

Beef carcass-.

Lamb carcass.

Pork carcass _.

Veal carcass-_.

FRESH MEAT CUTS

Beef..

Lamb.

Pork_-

Veal -r

Pork sausage, brains, tripe, liver

CURED ISIEATS

Bacon, derind slab

Bacon, sliced

Hams, tender cured

Dried beef

Sliced luncheon meats. _.

Frankfurters

Bologna sausage

Braunschweiger

Liver sausage

Liver loaf

Luncheon loaf

Pimento and pickle loaf.

1 Temperature Relative

' humidity

° F. Percent

35 85

35 80

35 80

35 80

33-30 80-85

33-36 75-80

33-36 75-85

33-36 75-80

26-28 75-85

26-28 70-80

32-35 90-95

32-35 75-80

38-45 70-85

26-28 70-80

26-28 70-80

26-28 70-80

26-28 70-80

26-28 70-80

26-28 1 70-80

26^28 1 70-80

26-28 ! 70-80

Dairy and Poultry Products

Butter and Margarine

Recommended protective services:

Desired temperature 35° to 38°.

Desired relative humidity 90 to 95 percent.

Bunker icing or mechanical refrigeration.

Butter and margarine generally are shipped from cold storage rooms

of creameries or from cold storage warehouses. They are packed in

fiberboard cartons with a capacity of 24 1-pound packages or 48 ^2-

pound packages. Butter and margarine have been cooled thoroughly

before shipment, and are insulated to some extent by wrapping in

foil or waxed paper and packaging in ji- and 1-pound cartons in fiberboard boxes. The commodities usually, therefore, can be exposed

to room temperature and fairly low humidity for short periods in

loading or unloading, without risk of serious damage. During

shipment, however, these products must be kept refrigerated effectively at the recommended temperatures to prevent softening or

quality deterioration.

67
Recommended loading methods:

As both butter and margarine are contaminated by strong odors,

they never should be shipped in trailers or trucks which have not been

cleaned thoroughly or decontaminated after previously being used to

haul such commodities as fish, cabbage, or onions. The cartons may

be loaded either lengthwise or crosswise on bottoms. As the products

are usually at or below the desired transit temperatures at the time

of loading, the cartons should be stacked together as tightly as possible,

to retain the benefit of previous refrigeration.

Cheese

Recommended Temperature Range for Cheese

Type of cheese Temperature

range, °r.

Type of cheese Temperature

range, °F.

Brick 30-34

30-34

30-34

32-34

32-34

30-34

32-34

Process American

Process brick.

50-70

Camembert 40-60

Cheddar

Cottage

Process limburgcr

Process Swiss

40-60

50-70

Cream Roquefort _ _ 30-34

Limburffer Swiss 30-34

N^piifoViatel Cheese foods 40-60

Shell E99S

Recommended protective services:

Desired temperature 35° to 40°.

Desired relative humidity 70 percent.

Average freezing point 27.5°.

Bunker icing or mechanical refrigeration.

Shell eggs are extremely perishable and under unfavorable conditions

they deteriorate rapidly.

The truck or trailer should be precooled to 40° before the cases are

loaded. Loading should be completed as quickly as possible so that

there will be a minimum rise of temperature of the trailer because of

the open doors. A curtain may be used over the rear doors to hold

the cold air inside.

Recommended loading methods:

Fiberboard cartons should be loaded on bottoms, those of 30-dozen

capacity lengthwise (figs. 70 and 71). As most eggs shipped long

distances have been in cold storage and the product temperature already is within the desired range, the cartons should be loaded together as tightly as possible. As shell eggs are very fragile and susceptible to cracking and breakage from vertical movement in the

load, it is highly desirable that loads be tied down in some manner to

prevent this type of movement, particularly at the rear end of the

load and over the axle area where the most severe vertical shocks are

concentrated. Extensive vertical movement of the load may be

prevented by placing cross pieces of wood over the top layer cartons

in each stack and toe-nailing or otherwise securing them to the side

68
' ï

_

— ~

mas

~

ïfl

FicuRE 70.—Side and end views of a lengthwiee-on-hottonis load of .SO-dozen-sizc

fiberboard cartons of shell ejígs.

FIGURE 71.—Side and end views of a lengthwise-on-bottoms load of 15-dozen-size

fiberboard cartons of shell eggs.

walls of the vehicle body. Another holddown method is the placement of inflated truck tire inner tubes between the top of the load and

the ceiling of the vehicle. This method is satisfactory provided the

tubes are placed so as not to interfere with the movement of air to the

rear of the trailer.

Poulfry—Fresh Dressed, Chilled

Recommended protective services:

Desired temperature 34° to 36°.

Desired relative humidity 90 to 95 percent.

Fresh dressed poultry generally is packed in wirebound wooden

containers with paper liners, with approximately 25 pounds of crushed

ice in the package. In addition to the refrigeration provided, this

keeps the birds fresh and clean. After loading is completed, the top

of the load should be covered with a blanket of crushed ice. During

loading, care should be given to the proper distribution of the weight

of the load in the trailer so as to avoid having to open the doors in

transit and rearrange the load.

Recommended loading methods:

Wirehound containers.—If the wirebound containers do not have

pronounced cover bulges, they may be loaded lengthwise on bottoms.

Continuous vertical channels should be left between the rows of containers to accommodate crushed ice. If the truck walls do not have

vertical strips, channels should be left between the outer rows of

containers and truck walls to accommodate the crushed ice.

69
Canned Foods (Neither Coldpacked Nor Frozen)

Recommended protective services:

In summer, canned food requires very little protection. However,

during the cold months protection should be provided to keep the

product from freezing. p T -i. • Canned foods moving from canneries to the place of distribution

during cold weather, if protection is not provided, are sometimes cooled

close to or even below their freezing points. This low tenaperature will

result in condensation on the cans, if they are moved directly into a

temperature of 50° F. or higher, and cause rust spots on the cans, with

staining and wrinkling of labels. If canned foods are so held for considerable periods, rust will pinhole the cans with resultant spoilage of

the commodity.

To avoid such damage, provision should be made for transit protection against cold. On shipments moving through intensely cold

weather (0° F. or below), thermostatically controlled heaters may be

used.

Recommended loading methods:

Fiberboard cartons.—Very little or no refrigeration is requh-ed by

canned food items, except those that are frozen, and the can-filled

cartons are resistant to overhead weight, so ordinarily there are not

many problems connected with loading this class of freight for motortruck shipment. The cartons may be loaded either crosswise or lengthwise of the vehicle body to produce whatever type of load pattern

will result in a tight, solid load.

Freezing Temperatures of Canned Foods

Freezing

point.

o p

Applesauce 27. 6

Asparagus 30. 2

Beans, green stringless 30. 3

Beans, Uma 29. 6

Beans, with pork 28. 8

Beans, strained 30. 6

Beans, wax, cans 30. 3

Beans, wax, glass j ars 30. 2

Beets 30. 4

Carrots 30. 3

Catsup 19. 4

Chili sauce 23. 7

Corn, creamed 29. 6

Corn in brine 29. 4

Corn, vacuum packed 29. 7

Cranberry sauce 16. 3

Grapefruit juice 30. 2

Milk, evaporated 29. 4

Mushrooms 29. 8

Freezing

point,

o p

Peaches, heavy sirup 28. 6

Peaches, light sirup 27. 6

Pears 27. 6

Peas, Alaska 31. 0

Peas, sweet 29. 3

Pea soup 27. 7

Potted meat 26. 0

Pumpkin 30. 7

Salmon 27. 2

Sardines 28. 2

Spiced meat 22. 2

Spinach 30. 8

Succotash 29.9

Sweetpotatoes 29. 2

Tomatoes 30. 8

Tomato juice 29. 8

Tomato soup 27.4

Tuna fish 26. 3

Vinegar 28. 7

70 U. S. GOVERNMENT PRINTING OFFICE: >956