In-package ripening of blue cheese curds

A good quality loose curd blue cheese product is prepared by a novel in-package ripening process. Inoculated raw cheese curds sealed in semi-permeable polymer film packaging will cure in 10 to 14 days to provide an economical blue cheese substitute which can be delivered to the customer without further processing or packaging.

BACKGROUND AND SUMMARY OF THE INVENTION 
This application relates to a method for preparing quick ripened blue 
cheese. More particularly, this invention is directed to a method for 
preparing a loose curd blue cheese product ripened in the same flexible 
pouch package in which it is shipped, distributed to retail outlets and 
delivered to the consumer. 
The use of blue cheese in salad dressings and cheese dips has increased the 
demand for a reasonably priced blue cheese product. As with many other 
traditional food products, spiraling costs of manufacture has encouraged 
the use of blue cheese flavors as a substitute for the more expensive aged 
blue cheese product. While submerged culture fermentations have been 
developed to provide the popular blue cheese flavor, a more popular blue 
cheese substitute is the so-called "quick ripened" blue cheese where loose 
cheese curds are inoculated and cured in a loose curd form which can be 
incorporated into food preparations. Quick ripened blue cheese cures in 
approximately two weeks as compared to traditional methods which require a 
three month to one year cure time. While some sacrifice is made with 
respect to texture and flavor, quick ripened blue cheese products are an 
economical substitute for use in salad dressings, sauces and appetizers. 
Since the principal advantage offered by use of flavor/food substitutes 
lies in the economy of their production and use, research efforts continue 
toward development of time saving/cost saving procedures for production of 
such products. Such research efforts originally led to the concept of 
quick ripened loose curd blue cheese itself. 
However, the procedure for manufacture of quick ripened blue cheese still 
necessarily utilizes many of the same time consuming and costly 
processing/packaging steps involved in the manufacture of the 
traditionally aged blue cheese product. Its only advantage lies in the 
shortened time of the aging process. The process for manufacture of quick 
ripened cheese still involves the inoculation of cheese curds, storing of 
those curds during the approximately two week curing period under 
controlled conditions of humidity and temperature and finally, packaging 
the product in containers suitable for distribution to retailers and 
ultimately to the consumer. 
The present invention is directed to an improvement in the manufacture of a 
packaged quick ripened blue cheese product. Surprisingly, it has been 
discovered that the curing process for quick ripened blue cheese can be 
carried out in a sealed package comprising a semi-permeable polymeric film 
without compromising flavor development and texture of the quick ripened 
blue cheese product. Thus, loose raw cheese curds inoculated with the 
appropriate curing organism can be sealed and ripened in the same package 
used for delivering the quick ripened product to the consumer. In fact, 
the cheese curing process can take place during the distribution of the 
product to retail outlets, assuming the sealed product packages are 
maintained at a temperature conducive to organism growth during the 
distribution process. Use of the in-package blue cheese ripening method in 
accordance with the present invention will result in reduced labor and 
facilities cost for product production, and it will allow the manufacturer 
to provide more efficiently a quick ripened blue cheese product to the 
consumer. 
It is an object of the present invention, therefore, to provide a cost 
saving method for the production of quick ripened blue cheese. 
It is another object of the present invention to provide a method for 
producing quick ripened blue cheese by an accelerated in-package ripening 
process. 
It is still a further object of the present invention to identify polymeric 
film packaging materials for an in-package quick ripened blue cheese 
product. 
Those and other objects of the present invention will be readily apparent 
from the following detailed description and examples.

DETAILED DESCRIPTION OF THE INVENTION 
The present invention is directed toward preparing an in-package ripened 
blue cheese product from raw cheese curds. Raw cheese curds incorporated 
with mold spores of Penicillium roqueforti or Penicillium glaucum are 
sealed in a package or pouch formed from a semi-permeable polymeric film 
or film laminate. Packaging of the inoculated raw cheese curds is 
conducted under condition so that the void volume in the sealed package 
(headspace gases) comprises about 20 to about 30% oxygen. The sealed 
packages are stored at a temperature from about 50 to about 65.degree. F. 
for a period sufficient to allow necessary mold growth and concomitant 
flavor development (ripening) in the packaged cheese curds. 
Use of the method in accordance with this invention minimizes the risk of 
unwanted microbial contamination of the cheese prior to packaging. 
Important, too, under controlled distribution conditions, the product 
ripening process can be allowed to take place in whole or in part during 
the product distribution process or just prior to product shipment. The 
present method allows the cheese manufacturer a more efficient utilization 
of manufacturing and storage space. 
The raw cheese curds used in the present method are prepared in accordance 
with standard cheese making techniques from pasteurized, homogenized raw 
milk. To provide a suitable volume to surface area ratio, the cheese curds 
are usually cut into small pieces having a volume of about 0.125 cc to 
about 7 cc. The cheese curdsd are inoculated with mold spores selected 
from Penicillium roqueforti or Penicillium glaucum either after they are 
formed from the cheese milk, or the spores are added to the cheese milk 
prior to curd formation. Inoculation after raw curd formation is 
accomplished by mixing the sized curds with about 0.1 to about 1% by 
weight of mold spores. 
The inoculated loose raw cheese curds are transferred under controlled 
atmospheric conditions selected to minimize microbial contamination into 
pouches or envelopes of a food acceptable packaging material selected from 
known semi-permeable polymeric films or film laminates. The pouches are 
hermetically sealed using heat, adhesives or other commercially acceptable 
sealing techniques. 
The polymeric film packaging materials should exhibit some permeability to 
gases such as carbon dioxide and oxygen to allow the ripening cheese curd 
sealed within the packages to "breathe" during the ripening process. 
Exemplary of such materials are low density polyethylene ("LDPE"), 
polypropylene ("PP") and ethylene vinyl acetate ("EVA"). Preferred 
packaging materials for use in accordance with this invention are low 
density polyethylene and polypropylene with low density polyethylene being 
most preferred. Ethylene vinyl acetate ("EVA") has properties which vary 
according to the percentages of the monomeric components used to form the 
polymer. A blend containing 90% ethylene will exhibit gas/water vapor 
permeability properties close to those measured for polyethylene. Film 
thicknesses typically range from about 0.5 mil to about 2 mil with about 
0.8-1 mil polymeric film being preferred. 
Table 1 compares oxygen and moisture transmission rates between EVA and 
LDPE. Although EVA has a higher permeability rate that LDPE in some 
instances curds packaged in LDPE ripened sooner than curds in EVA. The two 
polymers share some similar characteristics, i.e. stretch, cling, and 
static, but their physical/chemical properties are quite different. The 
barrier properties of LDPE provided an "in-package" atmosphere conducive 
to ripening the curds faster than EVA. 
TABLE 1 
______________________________________ 
OXYGEN AND MOISTURE VAPOR TRANSMISSION 
OF EVA AND LDPE 
OXYGEN 
TRANSMISSION MOISTURE VAPOR 
RATE TRANSMISSION RATE 
POLYMER cc/100 in.sup.2 /24 hrs 
g mil/100 in.sup.2 /24 hrs 
______________________________________ 
EVA 2220 35.5 
LDPE 1930 25.5 
______________________________________ 
Polyethylene and polypropylene are more hydrophobic than other polymer 
films; water vapor is quite insoluble in the film and hence penetrates 
only to a limited degree. This particular property is of considerable 
value in the packaging of items requiring a low moisture loss, while 
maintaining the ability to "breathe" with the passage of significant 
amounts of oxygen or carbon dioxide. 
The polymeric film packaging material is typically formed as an envelope or 
pouch adapted to be sealed by application of heat or adhesives approved 
for use in packaging of food products. 
The composition of the headspace gas in the sealed package at the time of 
packaging has been found to affect the ripening process. Higher 
concentrations of oxygen tend to accelerate mold growth while high 
concentrations of carbon dioxide tend to hinder mold growth and the 
ripening process. Thus while acceptable ripening will take place in bags 
packaged under ambient conditions with air (about 21% oxygen) as the 
headspace gas, gas flush packaging techniques can also be used to provide 
headspace gases enriched in oxygen. The initial headspace gas composition 
should comprise about 18 to about 30% oxygen. 
During the ripening process, oxygen levels decrease and carbon dioxide 
levels increase in the package headspace. The use of "semi-permeable" 
polymer film packaging materials in accordance with this invention allows 
the headspace gases to equilibrate with the surrounding air. During the 
ripening process carbon dioxide and oxygen diffuse through the packaging 
film to allow the mold growth/ripening process to reach an acceptable 
flavor imparting endpoint. Gas impermeable packaging materials, i.e., 
materials which will not allow the diffusion of carbon dioxide from the 
package and oxygen into the package during the ripening process, do not 
permit the ripening process to proceed to a point where the in-package 
ripened blue cheese product develops acceptable flavor/textural qualities. 
Blue cheese in-package ripened in, for example, aluminum foil or foil 
laminate packaging provided a product which was considered sensorially 
unacceptable under the conditions studied. 
The addition of salt to the raw cheese curds prior to or in conjunction 
with curd inoculation and packaging also has been found to affect cheese 
ripening and flavor development. Up to about 4% salt can be added to the 
cheese curd for flavor enhancement and to inhibit unwanted microbial 
growth during the ripening process. The addition of about 0-2% salt is 
preferred. 
In-packaging blue cheese ripening in accordance with this invention is 
typically complete within 7-14 days where the packages are stored at 
temperatures ranging from about 50 to about 65.degree. F. One method of 
gauging the progress of the ripening process is to observe the extent to 
which the mold covers the surface of the packaged cheese curds. Flavor 
development to a point of threshold acceptability is typically found in 
packages where the mole has grown to the extent it covers at least 50% of 
the surface of the inoculated cheese curds. Variations in temperature 
during the present in-package ripening process will have the same effects 
as temperature variations will have during the ripening of other cheese 
products. For example, at lower temperatures the ripening process is 
inhibited. When the ripening process is judged complete, it can be 
terminated by refrigeration/freezing of the in-package ripened product. 
The present invention is further illustrated by the following 
representative examples. 
EXAMPLES 
Preparation of Cheese Curds 
Prior to salting and milling, fresh loose cheddar cheese curds were cut 
into small pieces approximately 1/4 inch cubes. P. roqueforti spores, 
(5.80 grams and 11.60 grams) and salt (0%, 1%, or 2%) were then added and 
thoroughly mixed by hand into the cheese curds (5.0 pounds). All utensils 
and surrounding areas in contact with the cheese were sanitized with a 
diluted hypo-chlorite solution to reduce potential contamination. 
The moisture content and the pH of the cheese curds were determined at the 
onset of the ripening period for each batch of cheese. 
Packaging and Storage of Cheese Curds 
The prepared loose cheese curds were packaged (1/4 lb/pkg.) into previously 
constructed flexible pouches of LDPE (1.0 mil), EVA (0.8 mil) and 
pre-formed laminated aluminum foil pouches (6".times.8-1/2"). 
These materials were chosen because of their flexible nature, their 
differing gas permeability and their ability to retain moisture. The 
transparency of LDPE and EVA permitted the ripening process to be 
monitored without the need to open the package. 
Cheese curds were packaged under ambient atmospheric conditions using LDPE 
and EVA pouches. Cheese curds were also packaged under controlled 
atmosphere conditions utilizing a gas flush of 30% oxygen and 70% nitrogen 
in LDPE, EVA and LAF pouches. 
Curds packaged in ambient conditions (LDPE and EVA) were sealed with an 
impulse heat sealer. Curds packaged in LDPE and EVA under controlled 
atmospheric conditions were sealed with twist ties while scotch tape was 
used to seal LAF pouches. Each pouch was visually inspected for leaks, 
holes, wrinkles and any other seal imperfections. 
Storage conditions were maintained at approximately 52.degree. F. and 
55-60% relative humidity (RH) for the duration of the study. 
After the first 24 hours of storage, headspace gas analysis, pH and sensory 
analysis were performed on the packaged cheese curds. These analyses were 
performed on a daily basis throughout the ripening process. 
Visual changes in the cheese curds and obvious growth of contaminant 
organisms were noted throughout the duration of the study. 
Package Environment 
Initially packages were designed and filled under normal atmospheric 
conditions (approximately 21% oxygen and 79% nitrogen) utilizing a heat 
seal closure. Packages were also filled under controlled conditions within 
a glove box with an atmosphere composed of 30% oxygen and 70% nitrogen. 
Periodically, gas samples were extracted from the glove box and analyzed 
using a gas chromatograph to ensure that the right concentrations of gases 
were maintained throughout the packaging procedure. 
Cheese curds were packed under elevated levels of oxygen to determine 
whether or not the ripening rate of the cheese would be affected by 
increasing the initial oxygen level. Material thickness and package 
surface area can enhance or decrease the rate of transmission of gases 
into and out of the package. This could effect the rate of ripening. 
Therefore, careful control of material thickness and pouch surface area 
was maintained. 
Using a hygrometer inserted into a package, initial and final relative 
humidity readings confirmed that the atmosphere within the pouch headspace 
maintained a 90-95% relative humidity. 
Salt Concentrations 
Several different levels of sodium chloride (0%, 1% and 2%) were added to 
the non-ripened cheese curds prior to packaging. This was done to 
determine the effect on ripening of the spore inoculated cheese curds and 
the growth of contaminant organisms. 
Mold Concentrations 
The effect of inoculating with differing amounts of P. roqueforti spores 
was evaluated by adding 5.80 grams or 11.60 grams of spores per 5.0 pound 
batch (dry weight) of curds. P. roqueforti spores were obtained as a 
powdery, freeze dried material from Dairyland (Wisconsin). 
After the cheese curds had been prepared and stored, packages were divided 
into several different batches. As outlined below, the packaging material, 
amount of salt and/or mold, and the atmosphere in which the curds were 
packaged determined which batch the curds belonged. 
______________________________________ 
Low Density Polyethylene 
Ethylene Vinyl Acetate 
______________________________________ 
BATCH #1 (Control) 
BATCH #7 (Control) 
0% mold, 0% salt 0% mold, 0% salt 
BATCH #2 BATCH #8 
1/2% mold, 0% salt 
1/2% mold, 0% salt 
BATCH #3 BATCH #9 
1% mold, 0% salt 1% mold, 0% salt 
BATCH #4 BATCH #10 
1% mold, 2% salt 1% mold, 1% salt 
BATCH #5 BATCH #11 
l% mold, 2% salt 1% mold, 2% salt 
BATCH #6 BATCH #12 
(Controlled Atmosphere) 
(Controlled Atmosphere) 
1% mold, 2% salt 1% mold, 2% salt 
______________________________________ 
Laminated Aluminum Foil 
(Controlled Atmosphere) 
______________________________________ 
1% mold, 2% salt 
______________________________________ 
ANALYTICAL PROCEDURES 
Sampling 
Each day of the ripening process, a different package of curds from each 
material (LDPE, EVA and LAF) was obtained from the control chamber and 
used for sampling. 
Moisture Content 
The moisture content of the cheese curd was determined by the vacuum oven 
method (AOAC, 1975). Determinations were made in triplicate and performed 
initially and at appropriate stages of this study. 
pH 
pH measurements were determined by using an Orion digital pH/mV meter 
equipped with a glass electrode (Standard Methods for Examination of Dairy 
Products, 1972). The measurements were made by inserting an electrode into 
blended cheese samples for 5 minutes. Measurements were taken initially 
and continued on a daily basis throughout the ripening period for each 
batch of cheese. 
Headspace Analysis 
Headspace analysis, using gas chromatography was utilized to determine the 
concentration of carbon dioxide and oxygen in the packaged cheese curds. 
Prior to packaging the curds, Dow Corning silicone rubber was deposited on 
each pouch. After the rubbery material was cured, a needle (syringe) was 
inserted through the patch without causing the pouch to tear or leak. 
The syringe was filled to the desired volume (approximately 1 cc). The 
contents of the syringe were then injected into the gas chromatograph (GC) 
(Packaging 427 Lab Manual, 1982). 
Samples were taken in duplicate after 24 hours and on daily basis 
throughout the ripening period for each batch of cheese. 
Hygrometer Analysis 
A hygrometer was used to record the relative humidity on the inside of the 
packaged cheese curds. A sensor was positioned in a LDPE pouch so as not 
to interfere with the ripening activity, then sealed with Dow Corning 
silicone rubber. 
Measurements of the relative humidity inside the package were taken after 
the first 24 hours and on the last day of the ripening process. 
Sensory Analysis 
An experienced cheese judge scored and rated individual packages of cheese. 
Flavor and color were evaluated. Scores ranged from 1-5, (1, least 
favorable to 5, most favorable). Each package of cheese was judged at the 
onset of the study and continued until all samples had been evaluated. 
Results were not statistically evaluated, but were used to indicate 
acceptability. 
Microbial Observations 
Visual inspection of each pouch was made regularly, to detect presence of 
undesirable contamination by molds, yeasts or bacteria during the ripening 
period. 
These observations were made after 24 hours and continued daily throughout 
the study. Visual examinations were instrumental in detecting mold growth 
or spoilage organisms. 
Gas headspace analysis 
The results of gas headspace analysis for representative Batches are 
depicted graphically in FIGS. 1-3. 
Moisture content 
The amount of moisture in cheese influences its rate of ripening, pH, 
flavor, and nutritive value. Moisture content is important to the consumer 
and to the cheese maker. 
Ability of cheeses to be stored is closely related to the moisture content, 
acidity, and several other factors that influence maintaining quality. 
Generally, the higher the moisture and the lower the acidity, the shorter 
the shelf life. 
According to the classification of natural cheeses by hardness and moisture 
content, commercial blue cheese is considered to be a semi-soft, high 
moisture (45-55%) cheese. 
In this study, the moisture content for each batch of cheese was determined 
at 3 stages: (1) prior to inoculation and packaging, (2) 24 hours after 
inoculation and packaging, and (3) upon completion of the ripening period. 
Results are summarized in Table 2. 
For all batches of curd, moisture ranged from 40.0% to 47.4%, from the 
beginning to the end of storage, respectively. Moisture content was 
dependent upon the manufacturing process and degree of ripening. 
The composition of mold ripened cheeses specified in the Federal Standards 
of Identity, (21 CFR, Sec. 19.565) is 42 to 46% moisture and not less than 
50% fat in the dry matter. 
The interrelationship of pH and water activity is of practical importance. 
As the mold grew, the pH increased. Initially, when the moisture content 
was high, there was not much mold production, but as the curds began to 
dry out, mold growth increased. When moisture content was at its lowest 
level, mold production was usually at its highest. 
Although salt and mold slightly influenced the moisture content, different 
permeability rates of the packaging materials had a greater influence on 
moisture. 
Sensory evaluation 
Sensory evaluation is one of the most vital tests that can be performed on 
any food product. Food products which are intended for commercial 
consumption should always be evaluated a priori. 
TABLE 2 
__________________________________________________________________________ 
Moisture Content of curds packaged in LDPE, EVA and LAF 
__________________________________________________________________________ 
Pouches 
LOW-DENSITY POLYETHYLENE 
ETHYLENE-VINYL ACETATE 
Prior to inoculation 
24 hrs after 
End of 
Prior to inoculation 
24 hrs. after 
End of 
Variables 
& packaging 
inoculation 
study 
& packaging 
inoculation 
study 
__________________________________________________________________________ 
0% MOLD BATCH 1 BATCH 7 
0% SALT 46.6% 46.6% 46.2% 
46.6% 46.4% 45.9% 
1/2% MOLD 
BATCH 2 BATCH 8 
0% SALT 47.1% 44.2% 41.2% 
46.8% 42.8% 40.3% 
1% MOLD BATCH 3 BATCH 9 
0% SALT 46.8% 42.3% 40.2% 
47.1% 42.3% 40.0% 
1% MOLD BATCH 4 BATCH 10 
1% SALT 46.8% 44.9% 41.3% 
47.0% 44.6% 41.5% 
1% MOLD BATCH 5 BATCH 11 
2% SALT 46.5% 43.1% 40.4% 
46.4% 42.6% 40.4% 
Controlled 
BATCH 6 BATCH 12 
ATM 1% MOLD 
2% SALT 46.7% 42.0% 42.0% 
47.2% 44.5% 40.9% 
__________________________________________________________________________ 
LAMINATED ALUMINUM FOIL 
Prior to Inoculation 
24 hrs. After Inoculation 
and Packaging & Packaging End of Study 
__________________________________________________________________________ 
Controlled BATCH 13 
ATM 1% MOLD 47.4% 45.5% 42.6% 
2% SALT 
__________________________________________________________________________ 
In this study the packages of cheese curds were evaluated for flavor, 
color, texture and appearance. Flavor is a composite of sensations, of 
which taste and odor are important components. 
Scores for flavor and color ranged from 1 (the least acceptable) to 5 (the 
most acceptable). Scoring was done by an experienced cheese judge. The 
closer the cheese curds resembled commercial Blue cheese the higher the 
scores. 
Color and flavor of curds packaged in LDPE 
Tables 3 through 8 present color and flavor scores of cheese curds packaged 
in low-density polyethylene. During initial ripening activity the curds 
began to have a moldy appearance, with yellow curds turning slightly green 
with gray specks. The curds required an average of seven days before blue 
color development was evident. 
Curds which contained 0% salt and 1% mold tasted better and had better 
color than batches with salt. Although salt is added to improve the flavor 
of cheeses it did not have that effect on these particular batches of 
curds. Salt is also added to suppress the growth of microorganisms capable 
of spoiling cheese. 
TABLE 3 
______________________________________ 
Sensory Evaluation of Control Curds Packaged 
in LDPE containing 0% Salt and 0% Mold 
BATCH 1 
DAY COLOR FLAVOR 
______________________________________ 
1 1.0 1.0 
2 1.0 1.0 
3 1.0 1.0 
4 1.0 1.0 
5 1.0 1.0 
6 1.0 1.0 
7 1.0 1.0 
8 1.0 1.0 
9 1.0 1.0 
10 1.0 1.0 
______________________________________ 
TABLE 4 
______________________________________ 
Sensory Evaluation of Curds Packaged 
in LDPE containing 0% Salt and 1/2% Mold 
BATCH 2 
DAY COLOR FLAVOR 
______________________________________ 
1 1.0 1.0 
2 1.0 1.0 
3 1.0 1.0 
4 1.5 2.0 
5 2.0 2.0 
6 2.5 2.5 
7 2.5 3.0 
8 2.5 2.0 
9 2.5 2.0 
10 2.0-2.5 2.5 
11 2.5 3.0 
12 2.5 3.0 
13 2.5 2.5-3.0 
______________________________________ 
TABLE 5 
______________________________________ 
Sensory Evaluation of Curds Packaged 
in LDPE containing 0% Salt and 1% Mold 
BATCH 3 
DAY COLOR FLAVOR 
______________________________________ 
1 1.0 1.0 
2 1.0 1.0 
3 1.0 1.0 
4 1.0-1.5 1.0 
5 1.0-1.5 2.0 
6 2.0 2.0 
7 2.0-2.5 2.5 
8 3.5-4.0 3.0 
9 3.5-4.0 3.0 
10 3.5-4.0 3.0 
11 4.0 3.0 
12 4.0-5.0 3.0 
13 4.0-5.0 2.5-3.0 
14 4.0-5.0 3.0 
______________________________________ 
TABLE 6 
______________________________________ 
Sensory Evaluation of Curds Packaged 
in LDPE containing 1% Salt and 1% Mold 
BATCH 4 
DA COLOR FLAVOR 
______________________________________ 
1 1.0 1.0 
2 1.0 1.0 
3 1.0 1.0 
4 1.0 1.0 
5 1.0 1.0 
6 1.5 1.0 
7 1.5-2.0 1.0-1.5 
8 1.5-2.0 1.0-1.5 
9 3.0 1.5 
10 3.0 1.5 
11 3.0-3.5 1.5-2.0 
12 3.5 1.5-2.0 
______________________________________ 
TABLE 7 
______________________________________ 
Sensory Evaluation of Curds Packaged 
in LDPE containing 2% Salt and 1% Mold 
BATCH 5 
DAY COLOR FLAVOR 
______________________________________ 
1 1.0 1.0 
2 1.0 1.0 
3 1.0 1.0 
4 1.0 1.0 
5 1.0 1.0 
6 1.0-1.5 1.0-1.5 
7 1.5-2.0 1.5-2.0 
8 2.0 2.0 
9 2.5-3.0 2.0 
10 3.0 2.0-2.5 
11 3.5-4.0 2.5-3.0 
12 3.5-4.0 3.0 
______________________________________ 
TABLE 8 
______________________________________ 
Sensory Evaluation of Curds Packaged 
in LDPE, Under Controlled Atmosphere, 
Containing 2% Salt and 1% Mold 
BATCH 6 
DA COLOR FLAVOR 
______________________________________ 
1 1.0 1.0 
2 1.0 1.0 
3 1.0 1.0 
4 1.5 1.5 
5 1.5 1.5 
6 2.0 2.0 
7 3.5-4.0 4.0 
8 3.5-4.0 3.5 
9 3.5-4.0 3.5-4-0 
10 3.0 3.0-3.5 
11 3.0 3.0-3.5 
12 3.0-3.5 3.5 
13 3.5 3.5-4.0 
14 4.0 3.5-4.0 
______________________________________ 
Curds with 2% salt had no visible signs of growth by spoilage organisms. 
Although some batches (i.e. BATCH 4) received above average color scores, 
the flavor scores were below average. Therefore color and flavor were 
determined to be independent variables. 
Curds packaged in controlled atmosphere showed initial changes in color and 
flavor sooner than the other batches, definite blue color also developed 
sooner. Even though curds became over-grown with mold, and powdery, the 
texture remained firm throughout storage. The 2% salt possibly discouraged 
spoilage organisms from growing. pH values were stable. The higher oxygen 
levels had a definite impact on flavor development and on the rate that 
the cheese curds turned blue. The accelerated conditions encouraged mold 
to sporulate and according to flavor scores, resulted in an acceptable 
tasting "in-package" ripened Blue cheese. 
Color and flavor of curds packaged in EVA 
Tables 9 through 12 present color and flavor scores of cheese curds 
packaged in ethylene vinyl acetate. With initial ripening of these curds 
slight hints of blue or gray hues developed. The texture was fuzzy/hairy 
until curds became powdery. 
Curds which contained 0% salt and 1/2% mold, tasted better than some of the 
other batches that contained salt and 1% mold. This batch also produced 
enough color to be favorably compared to other batches 
TABLE 9 
______________________________________ 
Sensory Evaluation of Control Curds Packaged 
in EVA containing 0% Salt and 0% Mold 
BATCH 7 
DAY COLOR FLAVOR 
______________________________________ 
1 1.0 1.0 
2 1.0 1.0 
3 1.0 1.0 
4 1.0 1.0 
5 1.0 1.0 
6 1.0 1.0 
7 1.0 1.0 
8 1.0 1.0 
9 1.0 1.0 
10 1.0 1.0 
______________________________________ 
TABLE 10 
______________________________________ 
Sensory Evaluation of Curds Packaged 
in EVA containing 0% Salt and 1/2% Mold 
BATCH 8 
DA COLOR FLAVOR 
______________________________________ 
1 1.0 1.0 
2 1.0 1.0 
3 1.0 1.0 
4 1.5 1.5-2.0 
5 3.0 2.5 
6 3.5 2.5 
7 3.0 3.0 
8 3.0 2.0 
9 4.0-5.0 3.0 
10 4.0-5.0 3.5 
11 3.0 3.0 
12 4.0 3.0 
13 4.0 3.5 
______________________________________ 
TABLE 11 
______________________________________ 
Sensory Evaluation of Curds Packaged 
in EVA containing 0% Salt and 1% Mold 
BATCH 9 
DAY COLOR FLAVOR 
______________________________________ 
1 1.0 1.0 
2 1.0 1.0 
3 1.0 1.0 
4 1.0 1.0 
5 1.0-1.5 1.0 
6 2.0-2.5 2.0 
7 3.5 2.0-2.5 
8 3.5 2.0-2.5 
9 3.0-3.5 2.5 
10 3.0-3.5 2.5 
11 4.0-5.0 3.0 
12 4.0-5.0 3.0 
13 4.0-5.0 3.0 
14 4.0-5.0 2.5-3.0 
______________________________________ 
TABLE 12 
______________________________________ 
Sensory Evaluation of Curds Packaged 
in EVA Containing 1% Salt and 1% Mold 
BATCH 10 
DA COLOR FLAVOR 
______________________________________ 
1 1.0 1.0 
2 1.0 1.0 
3 1.0 1.0 
4 1.0 1.0 
5 1.0 1.0 
6 1.0 1.0 
7 1.0 1.0 
8 1.0 1.0 
9 1.0-1.5 1.0-1.5 
10 1.5 1.0-1.5 
11 1.5-2.0 1.5 
12 1.5-2.0 1.5-2.0 
______________________________________ 
that contained 1% mold. The lack of salt did not have a negative influence 
on the taste, in fact, the peppery/sharp taste that makes Blue cheese 
desirable was enhanced. 
Scores for curds with 1% salt and 1% mold remained below average from the 
beginning until the end of storage; none of the scores exceeded 2.0. 
Improper mixing or pre-package spoilage organisms could have been 
responsible for the low scores. This batch was considered unpalatable. 
Batches which contained the least and the most amount of salt were 
considered favorable. Curds with 0% salt allowed flavor to become 
distinct; 2% salt discouraged initial spoilage organisms and produced an 
acceptable tasting curd. 
In this particular case, curds packaged in controlled atmosphere did not 
produce definite blue color as quickly as curds packaged in ambient 
conditions. But as ripening progressed, mold eventually grew and the curds 
became excessively powdery. Accelerated conditions did not significantly 
improve flavor, but curds received above average scores, and would appeal 
to consumers. Near the end of the study, the texture changed from firm to 
soft. The 70% nitrogen used to help control the package's atmosphere did 
not prevent spoilage organisms from occurring. 
End of storage results revealed changes in texture and consistency. The 
curds became soft and mushy; this was the first macroscopic indication of 
spoilage organisms. All curds packaged in EVA became soft or mushy by the 
end of storage. Of the three packaging materials used in this study, EVA 
has the highest water-vapor transmission rate. 
Color and flavor of curds packaged in LAF 
Table 13 presents, color and flavor scores for cheese curds packaged in 
LAF. As early as DAY 4, color scores improved significantly, with slight 
improvements in flavor. Above average color scores were achieved and 
maintained throughout storage, while flavor scores remained average until 
the end of storage. Curds packaged in this controlled atmosphere did not 
become soft or mushy. However, the curds became excessively powdery and 
dry. Even distribution of mold and good blue color could easily account 
for the high scores in color, but it was determined that high color scores 
did not necessarily dictate high flavor scores. Perhaps the curds turned 
blue too rapidly, and the mold did not have the opportunity to properly 
ripen and mellow the curds, therefore flavor did not fully develop. 
TABLE 13 
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Sensory Evaluation of Curds Packaged 
in Aluminum Foil, Under Controlled 
Atmosphere, Containing 2% Salt and 1% Mold 
BATCH 13 
DAY COLOR FLAVOR 
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1 1.0 1.0 
2 1.0 1.0 
3 1.0 1.0 
4 2.5 1.5 
5 2.5-3.0 1.5 
6 3.0-3.5 1.5 
7 4.0 2.0 
8 4.0 2.0 
9 4.0 2.5-3.0 
10 4.0 2.5-3.0 
11 4.0 2.5 
12 4.0 2.5 
13 4.0 2.5 
14 4.0 2.5 
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