INVESHGATEONS ON THE EFFECTS OF AGE
0? MILK AND ST ARTER, AND AUNT!"
CONTROL OF WHEY N THE

MANUFACTURE OF COTTAGE CHEESE
T319535 {er the Deer” cf M. S.
WCWGAN STATE COLLEGE

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thesis entitled

.1 Investigations on the Effects of Age of Milk
and Starter, and Acidity Control of Whey in
the Manufacture of Cottage Cheese

presented by

 

K. S. Shroff

has been accepted towards fulfillment
of the requirements for

_M’__S_'__ degree in M_ ’

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I ‘ ,//" ; aajor professor

Date W59—

 

 

 

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INVESTIGATIONS ON THE EFFECTS OF AGE OF MIIK AND STARTER,
AND ACIDITY CONTROL OF WHEY IN THE

MANUFACTUPE OF COTTAGE CHEESE

By

KAPILBAI SHLNTILAL SHRDFF
Man.“

A THESIS
Submitted to the School of Graduate Studies of Michigan
State College of Agriculture and Applied Science
in partial fulfilment of the reqqirements
for the degree of
MASTER OF SCIENCE

Department of Dairy

1950

pr“ {Field
.2 . .“

 

THESIS

ABIGJOBIEDGEEITI'S

The author wishes to express his gratitude to Prof.
Jen. Jensen, Department of Dairy, for his valuable guidance
and suggestions in the conduct of this study and to
Dr. Earl'Weaver, Head of Department of Dairy for making

this study possible.

2375751

TABLE OF CONTENTS

 

 

P32. NO.
Introduction . . .l. . . . . . . . . . . . . . 1
Review'of Literature 2
Cottage cheese '
Kinds of cottage cheese . . . . . 2
Flavor and Quality of cottage
cheese. . . 3
Lanufacture of Cottage cheese
Methods of manufacture . . .'. . . h
LongsetmfithOdeeeeeeeee 5
Short set method . . . . . . . . . 6
Rennin in Manufacture . . . . . . 7
Cooking of Cottage Cheese
Wheyexpulsion...o.....o 9
Addition Of Water 0 e o e e e e e 10
Temperatures in cooking . . . . . lO

Determining firmness of curd . . . ll
Draining and Washing e e e e e e e 12

Acidity and Its Role
WheyACidi-tiesc...oo.... 11L
Standardization of acidities . . . 16

Effects of Quality'of Milk and its

‘Ireatment on cottage cheese
Effects of milk solids on cottage
cheese . . . l7
Pasteurization of milk and its
effect c e e e 18

 

Quality;of Starter and Cottage cheese. . 21
Whey disposal problems. . . . . . . . . 22

Table of Contents (continued)

Storage of Cottage cheese
Storing in Brine e e e e o e

Freezing and storage 0 e e e e e e
EffeCt or light 0 e .7. e e e e 0
Effect of chlorine . . . . . . .
Gelatin in cottage cheese . . . .

Origin of the Present Study . . . . . . . 0

Preliminary StUdiSS e e e e e e e e e e e e

Iitratable acidity and pH studies .
Study of whey expulsion properties .

The PrOblem O O O O O O O O O O O O O O O O 0

Scope of Investigation

Experimental Procedure . . ._. °,°-'..' . . .

RBSUItS e e o e e e e e .,. e 0.0 e e e 0.0

Discussion 0 e e e e e e e e e e .,. 0.0 0

Summary and Conclusions . . . .p. ... . . .

Appendix.l e e e
Appendix 2 e e e
Appendix.3 . . .

Bibliography . .

O 0 O O O O O O O O
O O O O O O O O O O
O O O O O O O O O O

Page No.
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IKTRCDUCTION

Cottage cheese is a skim milk product that has become
of commercial importance throughout the United States. Its‘
manufacture has in the past largely been confined to plants
whose main enterxrise consisted of marketing bottled fluid
milk. In several instances in‘michigan.however, the manufacture
of cottage cheese has attained such proportions that its
manufacture has become the major operation of some dairy
plants. Attending the manufacture of cottage cheese there
exists a big waste disposal problem that becomes quite important
in cities where waste treatment in sewage disposal plants is
limited. Approximately 85 percent of the skim.milk used in .
cottage cheese making becomes whey, a product that is usually
too low in food value after normal cheese making practices to
make it useful for animal feeding or for processing by means of
condensing. A.further loss occurs when milk and bacterial
cultures respond abnormally causing sgoiled batches.

The following study was made in order to determine the
effect of quality of milk and starter on batch losses and further
to investigate the possibility of reducing the Volume of Fhey
that would hate to be disposed of without sacrificing cheese

quality.

REVIEW OF LITERATURE

QQITACE CHEESE
1- Kinds of Qottage cheese

Cottage cheese is essentially an unripened skim milk

 

curd. It may be made from.reconstituted skim.milk, dried
skimwmilk or concentrated skim.milk. Cottage cheese consists
of small particles or flakes of curd which have a meaty
consistency (57). The particles may be as small as kernels of
wheat or as large as popped kernels of corn. The large flake
cheese is known as pot cheese in some markets. Pot cheese is
uncreamed. Cottage cheese is sold as cottage cheese curd and
also as creamed cottage cheese. The creamed cottage cheese
contains not less than fodr percent fat.

When cottage cheese is made in large flakes by the use of
rennet, the product is known as low acid, sweet curd, rennet-
type, or flake-type cottage cheese. Baker's cheese is a dpecial
type of cottage cheese.

The rennet-type cottage cheese is very popular in critical
markets and probably is responsible for the rapid increase in
cottage cheese sales and production. According to‘United States
Department of Agriculture, Bureau of Agricultural Economics,

the production of cottage cheese curd for 1948 was 255,606,000

pounds, a rise of eight percent over the 1947 production
figures. The cottage, pot, and baker's cheese production
in skim.milk equivalents in 1948 was 1,598 million pounds
of skim.milk. The production of cottage cheese curd and of
creamed cottage cheese in Michigan during 1948 was 18,350,000
and 23,373,000 pounds respectively. The State of'nichigan
ranked fourth in cottage cheese curd production while it was
third in creamed cottage cheese production.
2- Egavor and Quality of cottage cheese

The flavor of cottage cheese should be clean and very
mildly acid (48). Lucas (22) says a perfect flavor in cottage
cheese somewhat resembles that of fresh butter. According to
Hales (14) a good grade of cottage cheese should have a clean,
sweet, creamy flavor; a meaty smooth body, a uniform appearance
and just enough salt to intensify the natural flavor of the
curd. The common defects in cottage cheese are acid flavor,
bitter flavor, fermented or yeasty flavors, rubbery curd,
crumbly curd, slow setting curd, gaseous curd, and low
yields. (7,14,35,3e,47,4s) Different workers have tried to
evaluate the steps of'manufacturing cheese either in general
or with a view to find out an important step particularly to be
watched. According to'Wilson and Trimble (60), one of the most

important factors that control the flavor of the final product

was proper pasteurization of the skim milk.3 While,according

to Thurston (49), whey acidity at the time of cutting the curd
was the most important single factor concerned in the manufact-
uring of cottage cheese. Reichart and Davis (38), say that the
success of the entire cheese making depends on the use of a
fresh starter with a clean, distinct, pleasant and mildly acid
flavor. Ruehe (44) discusses the method, equipment and cost

in making cottage cheese, while Tretsvem.(55), has tried to
evaluate the steps followed in the manufacture of cottage cheese.
Wilson (59) in 'Quality and.Uniformity of Cottage cheese and

its practical control' says,“ to maintain the characteristic
appearance of cottage cheese it is necessary to develop a curd
that after cutting, cooking, washing, chilling and creaming will
largely retain its original shape and have a very mild acid
flavor. To control the quality and uniformity of cottage cheese
and especially that of the lowuacid rennet-coagulated type,

it is necessary to have proper and adequate equipment that is
kept in a sanitary ccndition, and to use only good quality

skim milk that has been properly pasteurized.“

 

.2- !ethods oflanufacturigg

The methodsof manufacturing cottage cheese are under slow

evolution. There are in general two methods by which

cottage cheese is made. These differ in the time allowed

for curd to form. The long set or overnight coagulation
method required 14-16 hours for curdling while in the short
set method it needed about 4-6 hours for the cure to form.
The long or overnight set method is one of the first methods
of making cottage cheese(8).
Long Set Method

The literature is full of directions on hOW'tO make a
good cottage cheese. Lucas (22) suggested 70°F as the setting
temperature for the over night set. In 1927 Reichart and Davis(38)
suggested two distinct temperatures varying with the season.
They recommended 90: 95°F as the setting temperature during the
winter months, while 70- 75°F for the summer for‘the overnight-
set. ‘Hartin (24) has put down the range of 68°F to 72°F as the
setting temperature for the long set method. According to
Tracy (52) it takes fifteen to twenty hours for complete
coagulation when set at 70°FLwith two to three percent starter
and 0.2 m1 rennet for each ten gallons of milk. When the long
set method for cottage cheese manufactures is used Glover and

Burgwald( 8) employ 72°F as their setting temperature. Hales (1;)

also advises 72°F as the proper setting temperature if the long

set method is employed. Flavor Line Incorporated Public-
ations (8) contains 68-7OOF for the long set.
M

The trend in the past two decades is definitely towards
the short set method. The short set method has three definite
advantages over the long set method. Thurston and Gould (51)
report thatkthe setting temperature of 90°F is preferable to
70°F because the higher setting temperature reduces the time
required for completing the process of manufacture, thus
enabling the worker to complete the whole procedure during
the normal working day. This, in general, results in a closer
control of the whole process, because the worker has the chance
of watching throughout the entire setting period. He can make
occasional acidity tests and thus is sure to cut it at the
right time. Furthermore,they also observed that fermentations
producing undesirable off flavors did not occur often in the
high temperature set. Flavor Line Incorporated‘s publication(8)
also reports similar conclusions. The five hours set is more
desirable as usually it works out in the daily plant operation
and thus can be watched more closely. In the line of checking
undesirable fermentations they have something more to say.

According to them.by using large quantities of starter, the

bacterial population of desirable bacteria is increased
and thus undesirable bacteria giving out off flavors do
not get an easy chance to take possession. Also the rapid
development of acidity checks the activity of undesirable
fermentation prematurely.
Rennin inguanufacturg

Because of the capacity of giving softer curd and at
lower acidities, rennin is almost always used now in the
manufacture of cottage cheese.h There are other coagulators
also on the market, but Tretsven (56) prefers rennin to
pepsin and other proteolytic enzymes because it only coagulates
and does not break down by hydrolysis the protein in curd.
Thurston and Gould (51) from their experiments on concen~
trations of rennin and their effects on the curd of cottage
cheese conclude that the true function of rennin in this type
of cheese is not related to its coagulating property. According
to them.its coagulating properties are of secondary importance
while its important function is to prevent matting of the curd
flakes. Rennin should be used at the rate such that it will
not produce coagulation very far in the advance of the proper
acidity of cutting, otherwise a large part or all of the

calcium paracaseinate due to the later development of acid

after rennin coagulation thus resulting into a curd that lacks
cohesive properties. According to them, 0.75 to 1.5 ml of
rennin for every 1000 pounds of skim.milk is the useful .
range for rennin} To produce a more desirable curd there
must be a balance obtained between rennin action and acid
development. They advise as much rennin as possibly could
be used should be used in order to reduce matting. An
attempt to obtain this balance is made by Angevine (1) by
adding the rennin extract as late as one and a half hours
after the starter has been stirred in.

The procedure for manufacturing cottage cheese ( 11,12,
13,14,19,22,32,35,38,47,53) give 1.0 m1 of rennin extract
per 1000 pounds of skim.milk as the required amount for good
results. Tracy (51) has suggested the using of rennin at
the rate of 0.2 ml for every ten gallons of milk. Thurston (46)
found that varying the rennet extract from 1.33 to 3.33 ml
per 100 pounds of milk had no effect upon the manufacturing
process or character of the curd produced from the skim.md1k
pasteurized at 185°? for twenty seconds. The dilution of
rennet into a cup of water plus agitation of milk after the
rennet is added will ensure against local action of the enzyme.

It is believed that excess agitation at this time may render

the rennin inactive. Thus it is best to mix the starter and
the skim milk thoroughly, prior to the addition of rennet

and then mix gently the diluted rennet after sometime after

the starter has been added. Parfitt (30) concluded that too
much enzyme may lead to a soft, pasty cottage cheese. Thurston
and Gould (51) and 'Ihurston (49,50) report that use of Calcium
Chloride proved of no value in.hastening coagulation by rennin

or in firming of the curd during cooking.

COOKIfiGgQF COTTAGE cnssgg

Whey expulsion
Sommer (38) writes that as soon as the curd is cut some

 

whey will be excluded but this takes place to a limited extent
only. Janoschek (17) has studied the whey draining from casein
curd. According to him.the wheying off starts when the milk
thickens, rises to a maximum.rate after cutting and then
diminishes. To produce the desired whey separation heating is
necessary. In the process of heating, enough stirring must be
employed to prevent the cohesion of curd particles. Until some
shrinking and firming of the curd particles has taken place, they
are very fragile and to prevent shattering the agitation must

be very gentle. Above 90°F the curds shrink and become more

firm thus facilitating mechanical stirring.

-10..

Addition of water

Sommer (48) further writes that when the vat capacity
and the acidity of batch permits, a convenient method of
providing for early heating with a minimum of agitation is to
add warm water at llO-lZOoF inpamounts up to 50 percent of the
volume of the skim milk. Jensen (19) suggests one inch of
water over the cheese. .Price and Kelley (37) in 1933 said
that the use of water in cooking is very beneficial. Water in
quantities up to 40 percent or more of the weight of milk in
the vat may be added. The temperature of the cooking water
they recommend as 100-105OF. The water according to them causes
the curd to firm more quickly after the heat is applied and
tends to sweeten the flavor of the curd."Tretsven (56)
comments on addition of water by saying that addition of hot
wster reduces friction during agitation, aids in syneresis and
dilutes the acidity to some extent.
Temperatures in cooking

'"EVen if 115°F water is added directly to the vat the

firming process will last an hour to an hour and a half. According
to Sommer (48) three to five minutes should be taken for each

degree rise in temperature. However, the temperature and length

- 11 -

of cooking time depend“ upon the firmness desired, the casein
content of the original skim milk, pasteurizing temperature,
acidity developed during coagulation, salt composition and the
degree of enzyme activity.' Tracy (52) advises 114-116°F as

the final cooking temperature. Lucas (22) has put down the range
for cooking temperature as 100—1200F. According to Jensen (19)
the final cooking temperature should be 125°F. mull, Reid and
Arbuckle (25) in their new short time method suggest 1180F as

the final temperature for cooking and if the curd is not firm

by then they advise holding it at that temperature till firm to
the required extent. Parmelee and Rosenberger (32) take 115°F
to 125°? as the cooking temperatures. A range of 110-140°F for
cooking temperature is indicated by Reichart and Davis (38).
Schock (46) has kept the range for final cooking temperature
between 115 and 1200?. Flavor Line Incorzorations Publication (8)
mentions lO-20°F difference in temperature between the vat and

the Jacket. Jensen, JkM. in a private communication suggested

a 45 to 509 difference in temperature between the whey temperature
and the water temperature, the latter being that much higher.
Qgterminigg_firmness of curd

The ranges of final cooking temperatures suggested by

different writers are thus very great indicating the impossibility

of setting up definite standards of time and temperatures
of cooking for producing good cheese. Consequently, physical
tests must be used-to determine the firmness of the curd.
The most common method of determining the firmness of the
curd is to let drop a flake on the floor from waist high.
The cube should not shatter on contacting the ground if it is
properly cooked and should retain its form. Other method
suggested by Hales (14) is to place the curd particle in cold
water. This will make the curd particle more firm and will
show the characteristics that can be expected in the finished
cheese. The cube should break evenly and should be free of
escaping moisture after being broken open. Also, when a handful
of cubes is squeezed lightly they should be somewhat springy and
tumble apart when released (14). All these methods of testing
curd firmness are empirical, or what may be called as 'Practical
Methods' and Tretsven (56) has expressed a great need for more
accurate methods for determining the firmness of the curd particles.,
‘Qraining and Washing

After'the curd is properly cooked the whey is drained 'off

and the curd washed with water. This washing serves two main

purposes;

-13-

1- It washes the excess acid from the curd.

2- It firms the curd by chilling.
Thurston (50) has suggested the use of cold water for
washing purposes. Menus (23) on the other hand advise!
the slow cooling and chilling of the curd. He advises
first warm water washing because cold water chills the
outside of the curd and thus traps the remaining whey
inside. ”Only cold water (75°F) helps wash the outside of
the cheese flakes but does not remove the acidity from inside
the flakes. So, if warm water is substituted mgr the warm
whey early in the cooking procedure, a more rapid movement
of lactic acid from the interior of the flakes to the warm
water may take place without the excessive firming, thus
producing as a result, a good, softer, sweet tasting curd;
If the water is too cold, says Hales (14) there is a danger
of shattering the curd and making it too tough. This can be
said to be sanething like a cold shock. .Hales (14) suggested
the use of 85°F water for the first wash. Gross and Mutton (B)
ask not to draw off all the warm whey before adding cold wash
water. This will stop matting of warm curd. ‘5 cube form is
retained much better if the curd is not cooled off too rapidly.‘

Both Reuhe (42) and Angevine (1) suggest warm wash water for

 

.p

. .3; \;

vvlLA v

h

H

first washing and then the use of very cold water. The curd
should be carefully yet sufficiently agitated, during washing
with a cheese fork to permit all of the curd to come in contact
with the fresh water. The first wash water should not be

drained for at least five to ten minutes (14). ‘Water at
temperatures at 60°F or lower is preferred for chilling. As

a rule, two washings are sufficient. (Excessive washing may
produce a product that is quite flavorless, especially if the
original acidity was low} and with certain types of water’may’
produce slippery curd due to a solvent action on curd, especially

if the acidity was barely high enough to start with (48).

ACIDIEEES AND THEIR ROLE

Whey acidities

Thurston (49) in 1931 concluded that the acidity of the
whey at the time of cutting the curd is the most important
single factor, concerned in the manufacturing process of cottage
cheeses. Regardless of variations in other factors, a whey
acidity of 0.35 percent or more was found necessary in order
to produce a curd with a desirable body. The upper limit of
acid development was set by him.as 0.68 percent acidity. However,

average acidity at cutting was 0.48 percent. Thurston (50)

reports that acidities higher than 0.48 percent for whey tend

to favor coarse textured curd. As many changes in milk are
associated with changes in pH, rather than titratable acidities
of milk, Price and Kelley (37) took measurements of acidities
by both these types of methods during the process of making
cottage cheese. Their results show that the relation between
the two types of acidity measurements is smooth. There is
a marked difference in titratable acidity between curd at
cutting and whey which drains off. This is not apparent in pH.
Gross and Hutton (12) showed that the whey acidity
humediately after cutting should have an acidity of 0.45 to
0.50 percent. Acidities above 55 percent resulted in a slihhtly
grainy, tough, curd. Thurston and Gould (51) concluded that
curd cut at whey acidities of 0.35 percent or lower behaved
in cooking as a rennet curd, while that cut at acidities
higher than 0.4 percent behaved like acid curd. The average
whey acidity of curds producing desirable results at cutting
was 0.48 percent. The different processes of‘manufacture
suggest a whey acidity at cutting between 0.5 and 0.55 percent.
Angevine (1) uses 0.5 to 0.55 percent while Lucas (22) had

used 0.70 percent as the whey acidity at cutting.

-16-

Standardization of Acidities

Acidity, as we have seen, has an important function.
For some time it has been.thought that the true dairy
products flavor of cottage cheese and cultured buttermilk
is submerged by the ordinary concentration of lactic acid
present. It is believed that standardization of acidity
at some step of manufacturing cottage cheese, when a.high
quality starter is used, should produce a full flavored,
c1ean.milk product (26). ‘Associatesof Rogers (2) state that
somewhat unsatisfactory results were obtained when alkalies
accompanied by pasteurization, were used to standardise high
acid milk previous to its use in cheese-making. ‘Phillip (33)
has noted that acidity standardizers are sometimes added to
the last wash water in the cottage cheese production.k He ’
also says that two or more washings of the curd are required
to produce a milH.flavored cottage cheese. mull, Reid and
Arbuckle (26) have studied the effects upon the physical and
chemical properties of cottage cheese in which variable amounts
of standardizing agent 'MINSOL' were added to skim milk, to
the wash water, to the storage water, and to the cream used

for creaming the curd. An improved flavor of the cottage cheese

.‘ 'H’N“:

 

 

 

1‘!

el

ltd

-17-

resulted from the use of moderate amounts of standardizer

in the skim milk and in the wash water. Excess amounts how-
ever produced unnatural flavor and impaired keeping quality.
The use of standardizing agent at more than one step was not
recomended. If cottage cheese is stored for too long a time,
usually six days in alkaline water, unnatural flavors are
developed and there is a tendency towards matting.

EF__‘F:ECTS OF QUALITY OF MILK ANQQS TREATMENT 0N COEAGE cm

Effects of milk solids on cottage cheese
Good quality milk is required to produce good quality

on . -

cottage cheese. Composition of skim milk is an influential

 

factor on the quality of the cottage cheese. Olson (27)

found that cottage cheese made from high solids skim milk

were superior in quality to the cheese made from low solids
content. has high solids skim milk produced a firmer coagulum.
Skim milk with higher solids also developed acid more rapidly,
the cooking of the curd was accomplished in a shorter time and
the losses in handling the curd were less than in low solid

milk. Higher percentage of solids in skim milk help in giving

a uniform body and firmer texture, which means that the individual
particles retained their shape better than in the case of the

cheese made from the low solid milk. The total solids content

 

 

 

 

 

 

*18-

of 102 samples of commercial cottage cheese manufactured in
the North Eastern section of the United States as reported in
1943 hy Garrtt (9) varied from 1h.89 to 28.71 percent. He

also showed the mean calcium.content of cottage cheese to be

0.80 percent and the mean phosphorus content to be 0.23 percent.
Pasteurization of milk and its effect on cottage cheese

Nowadays skim.milk is usually pasteurized before being
used in manufacturing cottage cheese. It is a law in most of the

States that skim.milk be pasteurized. Higher temperature is
found to have some sort of a stabilizing effect on the protein

(#8). When rennin is being used as a coagulator, soluble

calcium salts are necessany. But pasteurization changes the
concentration of soluble calcium.salts creating improper

coagulation. This is especially true in the case of low solids
skim milk necessitating addition of 0.06 to 0.08 percent
calcium. chloride, (Ll). Reid and Brock (39) report work

done on the disturbance in the natural oxidation reduction
equilibrium.of milk with special reference to the using of

dehydrated milks in the manufacturing of cottage cheese.
According to them, normal pasteurization does not alter

the character of the oxidation reduction potential (Eh) of

. o
raw fluid whole milk appreciably but temperatures exceeding 1h? F

-19-

or holding periods exceeding thirty minutes do affect the
character of the Eh in relation to excess time or temperature
applied. E1 to them seems to be related to the physical and
chemical properties of milk and cheese. Cottage cheese, having
an altered Eh when dry milk is used in its mufacture, appears
to be more sensitive to oxygen, light, lactose, lactic acid,

and electrolytes, with a corresponding change in its physical
and chemical properties. The same opinion that higher temperatures
of pasteurization are not favorable to cottage cheese has also
been voiced from manufacturing experience. According to Wilson
and Trimble (60) one of the most important factors in the control
of flavor in the finished cheese was pasteurization. Holding
method (145°! for 30 minutes) or even flash pasteurization
(MO-165°]? for 15 seconds) was satisfactory if properly
controlled. Parfitt E.H. (30) reports that a soft, pasty,
cottage cheese may result from too high a temperature of
pasteurization. Higher temperatures, say Glover and Burgwald (11)
are detrimental to the texture of the resulting curd. Holding
milk in H.T.S.'I‘. for twenty three seconds, according to Reuhe(43)
will have a slightly greater effect upon the calcium salts in
the skim milk than holding for sixteen seconds. This may

necessitate addition of slightly higher amounts of calcium

- 20 -

chloride to skim milk for the manufacture of cottage cheese.
Kloser (20) thinks that the whole process of cottage cheese
making would be benefited very much by the accurately

controlled operation in the H.T.S.T. Different manufactur-

ing processes suggest 142-1450F for temperature and twenty

to thirty minutes for'holding during pasteurization of milk

that is to be used for the production of cottage cheese.

Reichart and Davis (38) suggest 142-145°r for thirty minutes,
while Goss and Mutton (13) suggest l42—l43°r for thirty minutes.
Lucas (22) prefers 145°F for twenty minutes instead of thirty
minutes for'holding to obtain proper firmness and texture in

the resulting curd. Martin(24) advised 145°r for thirty minutes;
so also are 'Ihurston and Gould (51). On experimentation they (51)
found that temperatures of 165°? and l85°F caused reduction

in firming process and necessitated higher cooking temperatures.
Also, curd from higher temperatures loses its cohesive property
resulting in shattering of flakes. Jensen (19) puts 144% for
thirty'minutes as the pasteurization temperature. A.temperature
of l43§°F for thirty minutes has been put as required temperature
for pasteurization by Angevine (l). Goss and Hutton (12),

Tracy and Reuhe (53) and Schock (47) all suggest 143°F for thirty
minutes for proper pasteurization of skimrmilk to be used in

cottage cheese manufacture.

-21..

WW 0F STARTER AND COle‘LAGE 01mg
Van Slyke and Price (57) say that it is essential to

use a lactic culture of high quality in commercial manufacture
of cottage cheese. Starter made from skim milk is desirable
to use in manufacture of cottage cheese because, when starter
made from whole milk is used, it is ligater in density than
skim milk in the vet. Also the slight caramel color of curd
containing the whole milk starter is sometimes objectionable.
Somer (51) states that a good commercial culture contains
5. lactis, S.citrovorous, and S.paracitrovorous. The presence
of all three of these is necessary in a starter for a higl
flavor and aroma. According to Reichart and. Davis ((38) the.
success of the entire cheesemaking process depends on the use
of a proper starter. It should have a clean, distinct, pleasant,
mildly acid flavor and be fresh to insure the viability of its
bacteria. Rapid curdling produces a cleaner flavored curd for .
cottage cheese than slow curdling. 'Ihe acidity of a good starter,
calculated as lactic acid, should vary between 0.6 to 0.8 percent.

The amount of starter used depends upon the method
employed. . From 0.5 to 3.0 percent of starter is suggested for
the long set method, while five to ten percent is the usual

recomended amount for the short set method. Reichart and Davis (38)

- 22 -

recommend 0.5 to 3.0 percent for long set and ten percent for
short set. Hales (14) has asked to use five percent starter
for short set and one percent for long set. Jensen J.M. (19)
has recommended ten percent starter for short set method and one
percent for overnight.
WHEY DISPOSAL PROBLEQS

The cottage cheese industry utilizes only a portion of the
milk solids for the production of cottage cheese. The rest of
the unused solids remain in the whey, which is a waste to a”
cottage cheese manufacturer. Quite a number of ways have been
suggested and applied industrially for the utilizing of whey.
According to U.S.D.A. statistics about one and one quarter,
billion pounds of whey are produced by cottage cheese and related
types (Bakers cheese, pot cheese etc.) annually. Thus, unused
whey is a liability to the factory and it must be hauled away
from the factory or vented into the sewage system. Either*method
is expensive. According to Sanders (46) what is needed for a
small plant is a simple and economical method of processing
whey in order to compete with similar products from other sources.
ZBackmeyer (3) has discussed the effect of whey upon the operating
of an activated sludge plant. The continuous daily dumping of
whey into the sewage system and the 'batch' dosbs create difficult

operational problems at an activated sludge plant. Backmeyer(4)

discusses a cheese whey disposal process by digestion. The
report of the Task Committee on Dairy waste Disposal of the
Dairy Industry Committee (64) outlines a system of waste
prevention that can be adopted with little or no expenditure
of money by any plant dperator.
ETORAGE 0F COTTAGE CHElgg
Storing in Brine

As soon as the curd is drained after washing it is ready
for creaming andsalting. The salt may be added to the cream
and then the cream added to the curd ‘19). The amount of the ;
cream will vary according to the butter fat content of the cream.

Federal law has put four percent butterfat as the minimum

requirements of cottage cheese.~ It is usually desirable to store
cheese uncreamed. Jensen 0. (10) has recommended storage of
uncreamed cottage cheese in three to four percent brine at 45°F.
The cottage cheese thus stored will keep its flavor for two weeks;
but if a weaker solution of salt is used, or stored in water, or-
Just dry, it will deteriorate rapidly. Willard (58) has suggested
that curd to be stored frozen should be cooked less and should
be salted at the rate of one half‘of one, to one percent.
Cottage cheese can also be held in storage in brine solution.

.Angevine (1) also advises storage in salt water. Jensen J.M. (19)

 

‘ u‘.‘... -.

-a-

recommends storage of cottage cheese in a cold room after it is
creamed and salted.
Freezing and Storage

Possibilities of making cottage cheese when the skim.milk
is plentiful and then storing it for the slack time of the year
have been long explored. Ellenherger (6,7) in 1919 had
suggested the possibility of storing cottage cheese in a frozen
condition for six.to seven months. According to him.cheese
held in storage for seven and a half months, from early August
and until April develOped a decidedly disagreeable flavor.
On the whole the texture of the cheese was but slightly changed.
Even though higher acidity was not detectable, the flavor
criticism on the stored cheese was mostly high acid. The
average loss in weight in storage of this cheese was 2.62 percent.

Lucas (22) stated that cottage cheese keeps indefinitely

at freezing temperatures. Parfitt (29) says that cottage cheese
curd can be kept very satisfactorily for a period of six months
if frozen hard in an ice cream storage room.and kept frozen
Instil ready for use. According to Willard (58) crumbly body
is produced on thawing a frozen cottage cheese curd. He also

refers to a patented process of freezing cottage cheese curd.

- 25 -

In this process, cottage cheese is prepared by cutting
enzyme coagulated curd at a whey acidity of between 0.25 and
0.45 percent, cooking to obtain a rubbery tough body, freezing
the curd to break down the rubbery body, and thawing to produce
a firm body and smooth textured product, devoid of a chalky,
crumbly, mealy texture.
Effgct 9f Light

Light also has an effect on cottage cheese flavor as
shown by Phillip (34). He conducted an experiment on the effects
of sunlight on.creamsd and.uncreamed cottage cheese stored in
clear glass containers exposed to sunlight. Exposures of one
half of one to two hours developed flavor defects. Creamed
cottage cheese exposed to the sunlight for one half of one hour
developed a tallowy odor and flavor. ‘Uncreamed cottage cheese
when given identical treatment, also developed characteristic
and objectionable flavor defects. Tracy and Rgflhe (53) also
state that a disagreeable burnt flavor develops on exposure of
cottage cheese in glass or open containers in either direct or
indirect sunlith.
Effe of Chlorine

Reid and Painter (40) as reported by Mull, Reid and Arbuck1e(26

found that the keeping qualities of uncreamed cottage cheese were

-26-

improved 80 percent by rinsing in a chlorine rinse. Their
work indicated that cottage cheese treated with chlorinated
water and subsequently creamed showed deterioration on the four-
teenth day, as compared with the control sample which began to
deteriorate on the seventh day. ‘The storage is usually done in
parchment lined butter tubs (l4).
Gelatin in Cottage Cheesg

”Addition of gelatin in fractions of one percent improves
the quality of the product”, Parker (31). It does not affect
preparation of the curd, and is added with the cream. Gelatin
eliminates the watery appearance or wheying off by preventing
separation of moisture from.the curd. Gelatin also imparts an
impression as if cream of much higher butterfat has been used in
creaming it. If ten percent cream is used in combination with_
gelatin, it will show off as if twenty percent cream.were used.
According to him the exact amount of gelatin used varies from
one fourth to three fourths percent, depending upon the fat content.
In.using gelatin.in.ccttage cheese curd its greatest value is
where the curd is made in the spring, frozen and held till summer
or'fall. The gelatin enables the thawed curd to hold its shape,

so, each individual curd retains its identity. Parfitt (28)

-27..

writes that gelatin is helpful in storage and in giving
appearance. It could be added either in ten percent solution
or directly to the cream. It supplies muscle building amino
acid lysin also.

 

 

 

-28..

ORIGIN OF THE PRESENT STUDY

A.review of the methods of manufacturing cottage cheese
show that in a number of the processes, addition of a certain
amount of water at the time of cooking is recommended. In
some processes where addition of water is not mentioned it is
not definitely said to omit it. The addition of this water has
been followed in order to heat the whey initially and thus help
in speeding up the cooking. But there are other effects of this
water addition. It is apparent that it dilutes the acid of the
whey and also supplies a large volume of liquid for the curd to
float in (55, 56), but no experimental work is done on the
diluting of the acid or extent of dilution.

There is another feature that comes in the picture as the
quantity of cottage cheese manufactured goes on increasing.

That is of sewage disposal. 'mis fundamental problem of the
dairy industry is also increasing. As it is, the whey given off
from curd is voluminous enougl to create serious sewage problems.
By the addition of water at the time of cooking, the quantity

of whey to be disposed is increased. Thus, it adds to the
sewage disposal problem if dumped and to the cost of processing

if evaporated. In instances where they must be hauled away for

. 5|. . u; y

- 29 -

disposal it adds to thecost of transportation. The origin
of the present study lies in attempts to solve the problems
mentioned.
Wu

The literature on cottage cheese even though it is quite
vast, is directed mostly towards setting up directions for
manufacturing cottage cheese, while a surprisingly small number
deals with definite experimental work.

Some insight into the effect of rennet on acid development
has been shown by Thurston and Gould (51). They have shown a
rise of titratable acidity with time when different amounts of
starters ranging from one to ten percent were used. The amounts
of rennet used by them were from 0.75 to 3.3 ml per 1000 lbs of
skimLmilk.
. In order to obtain some preliminary information regarding
curd properties of skim milk, studies were made of lots of’milk
to which various amounts of rennet were added.
Titggtable Acidity_and_pH studies

In order to determine the coagulation point of milk set
at 32-33% (90°F) and 25-25% (70°F) with :17. percent starter

and using varying concentrations of rennet extract from

- 3O -

0.0 ml to 1.0 ml of rennet per 1000 pounds of skim.mi1k, the
following procedure was used. This is the short set method.
ggperimentalz Six beakers of 1 litre capacity each were filled
with a measured quantity (1 litre) of skim milk pasteurized
at 143°F for thirty minutes and five percent starter was
stirred in each. After the starter was thoroughly mixed by
stirring, the rennet of properly diluted strengths was added

according to the following scheme:

L2§_E2. Ml. rennet added per 1000 lbs skim.milk
1 0.0
2 0.2
3 0.4
4 0.5
5 0.8
6 1.0

This scheme is used throughout this investigation.

After the rennin was mixed with the milk, the prepared
milk was transferred to small bottles and two sets of such
bottles were obtained. There were thus six bottles in each set.
It was necessary to use the large beakers to facilitate the
rennet addition and to avoid large errors. The bottles were-

placed in a constant temperature bath, thermostatically controlled

at 32-33°c (90°F).

From.one set of the bottles changes in pH and titratable
acidity were noted every hour till coagulated; while the second
set was allowed to rest quietly till coagulated. Curd strength
from.the second set of curds was measured by a curd tensiometer.

This was done approximately thirty minutes after complete
coagulation.

A second series of experiments was done Just as above
but with the setting temperature at 25-26°C (70°F). The

titratable Acidity (T.A.) is expressed as percent lactic acid.

-32...

 

 

 

 

 

 

 

 

 

 

 

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In order to determine the whey acidities the curdled

milk was broken up and the whey given off was collected after

about fifteen minutes, and was centrifuged in small tubes for

clarification.

ation of the T.A. and pH of whey.

This clarified whey was used for the determin-

Table 3. mg, and pH 9f whey from milk set at 32-35°C (90°i)

 

and 25-26°C (70°F) going five percent starter,

 

 

 

 

 

 

3

3
3 3 time 3 Beaker number ___3
3SEI'I‘ING3req'd to 3 3 3 3 3 3 3
3 temp. 3coagulate3w l fiL a 3 3 3 4 3 5 a _§___~_3
3 3 3 3 g 3 3 3 3 3 3 3 3 3 3
3_ 3 3 H T 3 T 3 H 3T 3 3T 3 3T. 3 8' 3
3 3 3 3 3 3 3 3 3 3 3 3 3 3 3
332.500 3 ~ 3 3 3 3 3 3 3 3 3 3‘ 3 3 3
3(900F) 3 4-6 hrs.34.6 3.515 34.6 3.49 34.593.51 34.6 3.50534.593.51534.63. 52 3
3 3 3 3 3 3 3 3 3 3 3 3 3 3 3
326.506 3 3 3 3 3 3 3 3 3 3 3 3 3 3
3(7oor) 3 5-7 hrs.34.813.690 34.77:.71 34.783.7 34.763.71 34.803.70 34.83.7053
8 3 3 3 3 3 3 3 3 3 3 3 3 3 3
3 1 4 1 1 3 3 3 3 3 3 3 3 3_ 3

 

n3. curd strength was measured from the second set of the bottles

by means of the curdtensiometer. The results obtained are shown in

Table 4.‘ ‘Ihe readings were quite variable but the results slnwn are an

average of three to five experiments which were in the same vicinity.

-35-

Table 4- Curd tensigns for milk set at 32-33°C containing

fivg pgrcent starter and different amountg 9f rennet.

 

 

 

 

 

 

 

3 3 3
3 Curd strength in 3 Beakgr number #3
3 3 3 3 3 3 3 3
3 gms for milk set 3 1 3 2 3 3 3 4 3 5 3 6 ‘3
3 3 3 3 3 3 3 3
3 at 32.500. average37 gms 3 5 3 2.5 3 2 3 2 3 2.5 3
3 3 3 3 _3_ 3 3 3
3 3 3 3 3 3 3 3
3 curd strength in 3 3 3 3 3 3 3
8 8 3 8 8 8 8 3
3 gms for milk set 3 4 : 3 3 5.5 3 2.5 3 3.5 3 5.5 3
3 ' ' 3 3 3 3 3 3 3
3 at 25.5°C. average: 3 3 3 3 3 3
3 3 3 3 3 3 3
Discussigg 91 Reggltg;_These results show that there is little

difference in the final pH and titratable acidity of milks of
the same series containing varying amounts of rennet. However,
the milk with the highest amount of rennet (Beaker No.6)
which contained 1 ml per 1000 pounds of skimxmilk, shows a
slightly higher acid development than the rest of the milks
except the first. This may be due to the softer curd affording
more freedom.to the bacteria to act. '

There is a slightly higher increase in titratable acidity

and lowering in pH of the final curds in the series which was
set at 25.5°C than in the series that was set at 32.50c, This

is attributable to the longer time required for coagulation at

the lower temperature which gave more time for acid production.

- 36 -

The final acidities of the curd and of the whey show
that there is about 0.2 percent acidity retained in the curd.
There is no difference in the final pH of the curd and the pH
of the whey. This agrees with the findings of Price and
Kelley (37).
STUDY OF WHEY EXPULSION PROPERTIES

In order to study the amount of whey given off by curd
containing 0.03 0.2; 0.4; 0.6; 0.8; and 1.0 ml of rennet
extract per 1000 pounds of skim milk in a definite time.
the following experiments was devised.
Experimental- For the purpose of this experiment small amounts
of milk were required, but, in order to facilitate the measurements
of rennet extract,lOOO m1 of skim.milk in six beakers were prepared
as under titratable acidity and pH measurements.

One hundred ml of this prepared milk was measured out from
each beaker into small beakers (150 ml capacity). Thus six
samples were obtained. These small beakers were incubated in
the constant temperature bath kept at 32-33% and allowed to
coagulate without disturbing.

Six.measuring cylinders and six funnels of the same

size were taken. Six equal pieces of cheese cloth were cut

-37-

and folded ‘(three folds) to fit into the funnels. The size
of each piece was three square inches after folding. The
cheese cloth pieces were moistened with water before placing
into the funnels. The curd from all the 100 ml milks was first
broken up by stirring in the beakers and then immediately
poured one by one on the cheese cloth in the centre of the funnel
and the time was noted. The curd was levelled out in the funnels
by means of a stirring rod if necessary. As much time was not
lost during the operation,the wheying-off could be taken to have
been of curd at 90°F at least for the first fifteen minutes.
The readings were taken every few minutes as shown in Table 5’
and the amount of whey collected at the time elapsed were noted
for each. I

The cheese cloth was moistened to avoid absorption of the
whey by the cloth; but care was taken to see that it was not
dripping with water. The amount of whey collected after fifty-
five minutes was so insignificant that the amount of whey collected
at the end of the fifty-five minutes has been taken for the
purpose of this experiment as the total available whey. The

results are an average of three trials.

-38-

 

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These results clearly show that the curd with the maximum
amount of rennet gives off the maximum amount of whey in the
shortest time. However, the amount of whey given off will always
depend upon the characteristics of the milk used. Within the
first two minutes the one containing no rennet has given off
twenty m1 of whey while the one containing 1.0 ml rennet has
given of thirty four ml of whey. At the end of five minutes
almost seventy five percent of the total whey collected was
available from 1.0 ml rennet curd. On the basis of the assumption
that the total available whey is collected at the end of fifty
five minutes; at the end of five minutes the whey yield is
approximately 49 percent, 52 percent, 56 percent, 67.0 percent and
75 percent of the total collected whey for curds containing 0.0;
0.2; 0.4; 0.63 0.8; and 1.0 m1 rennet per 1000 pounds of skim
milk respectively. At the end of ten minutes the percentages
are approximately 66 percent, 68 percent, 72 percent, 82 percent,
85 percent-and 87 percent respectively.

Thus it is quite apparent that by the end of the first ten
minutes the cylinder numbers four and five containing whey from
the curd having rennet at the rate of 0.6 and 0.8 ml per 1000

pounds of skim milk are close to the 1.0 m1 rennet containing

milk's wheying off speed. There is a clear distinction noticeable
between curd numbers one to three and four to six; the first
being slow, tending toward the properties of curd containing
0.0 ml rennet, while the other group tends towards the
wheying off characteristics of curd containing extract at the
rate of 1.0 ml per thousand pounds of skim milk.
anclusions

All these preliminary experiments show that curd
containing rennet extract at the rate of 0.6 ml per 1606 lbs
of skim milk has quite suitable properties. It generates enough
acidity, the time required for setting is comparable to higher
rennet content milk studied here, has a nice soft, compact
curd and gives off enough whey within ten minutes. It was
decided that in all the subsequent experiments rennet at the
rate of 0.6 ml per 1000 pounds of skim milk should be used,

unless otherwise required.

-41..

THE PROBLEM

The literature survey revealed that little attention
has been paid to the standardization of acidity in the manufacture
of cottage cheese. The only work of importance in this direction
has been done by Mull, Reid and Arbuckle (26). This work
was concerned with standardizing the acidities of skim.milk,
washwater, cream.and storage water used in production and
storage of cottage cheese. No attention has been paid to
standardizing the acidities of the whey itself.

Primary attempts at cooking cottage cheese batches by the
short set method as suggested by Jensen (19) , but cooked in
absence of water was either not satisfactory or failed completely.
The difficulty encountered involved the production of crumbly
curd with a pronounced tendency to mat together. According to
Thurston and Gould (51) this may be due to high acidity at
cutting, or insufficent rennet content, or there was too rapid
expulsion of whey from some of the curd, probably due to high
temperature differences between the vat and the jacket.

The short set method was selected because of its advantages
of’completing the work faster, as well as the ease of control of
conditions like temperature and arrest cf’unfavorable

fermentaticns. But, with this, the short set method also brings

some problems of its own to be faced, especially of quality of
milk and starter.
Scope of Iglestifiation
The present study was designed to determine:
(l)- The effects of standardizing the whey acidity on the
manufacture of cottage cheese.
(2)- The effect of controlling the ages of milk and the starter
on the curd and final product.
(3)- The effect of rate of cooking on cheese making properties.
(h)- Final cooking temperatures of cheese with standardizing
acidity. i
(5)- Differences in body, texture, and flavor of fi nal product
when neutralized with caustic soda and lime.
(6)- Possibility of manufacturing a uniform product.
EXPERDIENTAL PROCEDURE
About thirty successful batches of cottage cheese are
reported in this work. In order to have as far as possible near
commercial conditions, fifty gallons of skim milk were used for
every batch in a hundred gallon vat.
The short time, five hour method of manufacture was employed.
M different methods of cooking were followed according as to

V1.“ ther the batch was to be neutralized (standardized) or was

to be cooked in presence of water by the standard method (19).
METHOD 1

Fifty gallons of skim milk pasteurized at 143°? for thirty
minutes were processed into popcorn type cottage cheese in a
hundred gallon stainless steel vat. The milk washeated to
90°F and ten percent starter was added to it. After the starter
was thoroughly mixed with the milk the temperature was adjusted
to 90°F. The water in the Jacket was kept at 92-930F. Fifteen
minutes after the starter was added, rennet extract was added
at the rate of 0.6 ml per 1000 pounds of skim milk. The
concentrated rennet extract was diluted to; approadmately a
litre with water before adding to the milk. Thus. prepared milk,
was allowed to coagulate. Since coagulation occured in advance
of the acidity that was desired for cutting the coagulum, a
cavity was made in the curd where whey was collected and drawn
off for acid testing. When the titratable acidity reached the
desired value, the curd was out first hprizontally and then
vertically with half inch cheese harps. After the curd was
cut, the temperature in the water jacket was raised to 10001?
in order to bring the temperature of the curd to 90°F. A fall

of approximately 10°! occured during the five to six hours

required for coagulating. After the cheese was cut it was allowed
to stand for fifteen.minutes in order to expel the whey and fins
up to some extent. Thurston and Gould (51) also give this period
of time to accomplish the freshly cut surfaces to what they call
' heal up" . After the whey was expelled, the titratable acidity
was again tested. At this step a neutralizem~or an acidifier
or both were added if, and as, necessary.. The acidity desirable
for best results appeared to be O.h5 to 0.h8 percent. The
sodium.hydroxide flakes or the calcium.hydroxide or concentrated
hydrochloric acid used for these purposes, were mixed with
one gallon of cold water and then sprinkled on the cheese as
evenly as possible. The neutralizer was allowed to act for
twenty to twenty five minutes during which time the curd was
stirred very very gently twice or thrice. At the end of the time
allowed for the action of the neutralizer the acidity was again
checked. As soon as the desirable acidity was obtained the
cooking was started.

The Jacket was heated slowly throughout the cocking period.
.A temperature difference of 20—25OF was kept between the jacket
and the vat during cooking. The curd was stirred very carefully
and slowly after each increase of two degrees was obtained in

the cheese.In order to insure a reasonably standard procedure

- 45 -

of cooking for all batches, the temperature in the jacket was
npt raised till temperatures in all parts of the vat were almost
equal and constant. There was always a difference of a degree
or two between the sides and the centre, the sides being hotter.
The jacket temperature was then raised and held there till the
cheese temperature was steady again. This process of heating
was continued tillthe cheese was properly cooked. It was
necessary to be very cautious in stirring till the temperature
of the cheese reached 1100?, otherwise the curd particles broke
and uneven cheese resulted. The curd was in most cases

cooked at 116-117OF. The cheese was allowed to eta;r at this
temperature for fifteen minutes. As soon as the cheese
temperature was reached the maximum the water jacket was drained
off in order to amid raising the vat temperature beyond this
point. The extent pf cooking was determined by the firmness
test as suggested by Hales (1L). Individual cheese cubes were
allowed to drop on the floor from waist heigh, and as soon as
they did not smashupon striking the floor, the cheese was taken
as properly cooked. It took about one and a half to two hours
to cook the cheese.

After the final fifteen minutes holding period was over,

 

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-46-

the whey was drained off through a gate strainer till sufficient
whey remained to cover the cheese on the bottom of the vat.
This has two effects:
(l)- it avoids mushing up of the hot curd particles
under their own weight.
(2)- It helps to warm up the first wash water, as ‘
suggested by'Gross and Hutton (13) and Menus (23).

The gate valve was closed and cold water allowed to enter.
the vat in.the quantity equal to the original quantity of milk.
The curd was stirred slowly to wash, then drained completely.

At this time the jacket was filled with cold water. Cold water
was once more run into the vat, this time filling it completely.
The curd was stirred to wash and then kept under cold water for
ten.minutes to ensure proper chilling of the curd particles. The
‘water was drained off and the cheese drainage time was allowed
for twenty five mdnutes.

After the cheese was drained it was either creamed and salted
or stored dry. When the cheese was creamed and salted in the vat,
the salt was mixed with cream.before adding it to the cheese in

order to facilitate salting.

at

as

- g7 -

METHOD 2

All the steps were done just as in Method 1 except that
at the time of cooking water in quantity equal to thirty two
gallons ( LO percent of the original volume of milk) was added
in place of the neutralizer. Here the temperature difference
between the jacket and the vat was kept at about 50-550F
otherwise the rate of heating was too slow. The stirring could
be done with less fear of the coagulum.breaking. The final
cooking temperature was 1200?. The cocking for each batch was

generally completed after two hours of heating.

~A8-

RESULTS

Acidities required at Cutting

In order to effectively standardize whey acidity it was
necessary to determine first the acidity at cutting that would
give best results. Both Methods 1 and 2 were used in obtaining
the results shown in Table 6. In order to secure curd formation
at lower acidities it was necessary to use 1.0 ml of rennet per
1000 pounds of skim.milk instead of at the rate of 0.6 ml which
was used for acidities higher than O.h7 percent.

Table 6 also shows the final acidities of whey, i.e.
acidities of whey at the end of cooking and just before draining.
The curd was cut at the acidities of whey shown in the Table and
the cocking started. The body, texture, and flavor of final
product were noted and they were the guides in selecting the
proper whey acidities. Final temperatures of cooking have also
been noted. '

These results tend to show that the best whey acidities at
cutting time, for cheese made from nonmal milk that is to be
cooked with water is in the vicinity of 0.50 to 0.54 percent.
These results are in line with recommendations advised by different

‘writers. The addition of water reduced the acidity of whey. The

acidities here obtained did not exceed 0.2 percent at the end of

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-49-

cooking. These acidities were well in the range of those
where rubbery curds are frequently formed.
men the cheese was cooked without water, the results

show that the coagulum was cut best at whey acidities ranging
from 0.47 to 0.50 percent. Cheese cooked from a coagulum cut
at theseacidities had smooth and creamy texture and the flavor
was good. The final whey acidities at the end of cooking were
0.50 1:00.53 percent. At the higher acidities of cutting
(0.52-0.55) the curd was crumbly and hard. Thus in further
experiments of neutralization acidities of 0.47 to 0.50 percent

were used.

figges 9n Rate gf Cgoking

During the process of manufacturing cottage cheese in
absence of water it was noted in the beginning that the cheese
had a tendency to mat together and stick to the bottom, forming
big chunks. This could be avoided if stirred continuously and
vigorously, but that meant shattering the curd particles.

The temperature of the jacket was kept 45-50°F higher than
the vet when the same procedure was used for cooking cheese in

presence of water. The matting was very well avoided here by

- 50 -

the much more free stirring permitted by the large volume
of water. It was necessary to determine the rate of cooking
i..e the difference in temperature between the vet and the

jacket.

- 51 -

Table 7 Egperiment oggthe effect of temperature difference
between the vat:gnd the jacket on cookingrgnd the

characteristics of the curd

 

3 a 3
:Temperature 3 ngking with water 3 Cooking without water
3 Difference 3 Rate of 3 Nature of 3 Rate of 3Nature of

 

 

3

t

3
3 °F 3 cooking 3 curd 3 cooking 3 curd 3
3 x 3 s_ 1 8
3 3 3 x 3 3
a 10 3Almcst nil 3soft,easi1y3 very slow 3 soft 3
3 3 3crushed 3 3 3
3 3 3 3 3 3
3 20 3very slow 3soft and 3 good 3soft and 3
3 3 3separate 3 3 separate 3
3 3 3 3 3 3
3 30 3 slow' 3 ' 3 rapid 3separate,but 3
3 3 3 3 3tendency 3
3 3 3 3 3toward mat- 3
3 3 3 3 3ting. 3
3 40 3 good 3 ' 3 ' 3sticks to the:
3 3 s : 3bottomlcf vat:
3 3 3 3 3and forms a 3
3 3 3 3 3sticky made, 3
3 50 3 rapid 3tendency 3 very rapid3tco much 3
3 3 3toward 3 3sticking to 3
3 3 3sticking to3 3the bottoms :
g: 3 athe bgttgm 3 3 :

 

 

anditions of experiment;
For cooking with water and without water3

 

Ten percent starter. 0.6 ml rennin per 1000 pounds of

skim milk. Temperature of setting 90°F.

 

 

-52-

These results show that when cooking cottage cheese with
water the temperature difference should be 40 to 50 degrees
F. while for cooking without water the optimum.difference in
temperature between the jacket and the inside of the vat should
be 20-30%.

Natggg 9f cprg as cooking progresses

None of the literature studied presented observations
in regard to the nature of the curd at different stages of
cooking either without water or with water; the process most

used. Here, the 'normal curd' has been taken as the curd

obtained from.the regularly pasteurized fresh skim.milk and
froth starter. The curd was cut at the acidities suggested
by Table 7 for both the methods No. 1 and 2 respectively.

The results are reported in Table 8.

- 53 -

Table 8 Effect 9f time and temperature on the natuge of
thg pgrmal curd cogged with and without water.

 

 

8 Temp. 3Length of‘ 3

 

 

 

 

°F. 3timn held. 3 cooked with water 3 cooked without water3Remarks
3 3 Rate of 3Nature of 3Rate of 3Nature of: ‘—_
1, ' 3 cooking ;_onrd gogokigg :rcurd A. 3
95 3till the 3Progressivef soft gProgressivei soft 3
xtemp. in the: 3 : , ,
3different 3 3 3 3 3
3parts of the3 ! ‘ g '
3vat were ' ° ’ g ,
3almost coast: ' : 3
100 3 w 8 w ‘ w ' : w 8
105 3 ~ ' " :tendency § 3slightly 3
’ ‘ 3toward ‘ § hard 3
' ’ 3mashing 3 , 3
’3 : 3together , 3
110 3 ' 3 " 3 " 3 3cooking 3
‘ ' ' : 3hardness ,
’ ' ' : 3enough to,
3 3 ' 3permdt 3
‘ ' ‘ ‘ 3faster ,
' ‘ ' ' 3stirring. ,
‘ ‘ 3 ' 3forms
3 3 3 3 3
' 3clumps. :
' ‘ 3 3 3whioh can:
: : : : {easily be8
' 3peparated.,
115 ‘ " ’ " 3started :cooking
‘ ‘ 3hardening3 3 3almost
3 3 3 3
3comp1eted3
117 3 " ‘ " 3half 3 ‘ 3cooking 3cookid
'“ ‘ 3 3cooked 3 yoompleted;curd was
‘ ' ‘ ‘ 3held here
i z z : : 3for 15
120 , ' 3 " 3cooking 3 3 3 ' ‘ 3minutos
3 3 3comp1eted 3 3 3 fl

‘-

i54-

Table 8 (continued)

Conditions ofefixperiment

Ten percent starter. 0.6 ml rennin per 1000 pounds of skim
milk. Setting temperature 90°F. Number of trials reported;

four per each method.

The results here give a good directive as regards the
nature of the curd at different temperatures. Under a particular
set of conditions; with the sources of milk reasonably constant
and the starter prepared by the same process daily the results
as obtained above should not vary much for a particular plant.
Thus as soon as a particular temperature is reached any worker
should be reasonably sure of the nature of the curd at that
particular time. Two temperatures were obvious with cooking
in the whey;

(1)- 110°F after which faster stirring and thus rapid

cooking were facilitated.
(2)- 117°r when the cooking should be completed. _

120°F was the cooking temperature for cheese cooked with

water dilution.

_S_t__udi_es on Stemdardiiation of 'Hhey Acidities
lhe previous experiments have shown that when cheese
is to be cooked in its own whey;
l- The best whey acidity to start cooking cheese is
0.47- 0.50 percent.
2- ‘I‘he vat temperature should be 20-30°F lower than the
Jacket temperature.
3- The final (cooking temperature would be in the vicinity
of 117%.

In order to study the effects of standardizing the whey,

three series of experiments have been conducted here.

1- Coagulum cut at a low acidity and increased in acidity
to the optimm of 0.47- 0.50 percent by addition of
hydrochloric acid. In order to secure coagulation
at low acidity 1.00 ml of rennet per 1000 pounds of
skim milk was used.

2- Cutting at higher acidity and reduced downward to the
optimum by:
2.1 sodium hydroxide
2.2 calcium hydroxide

3- Cutting at higher acidity and bringing down to a much

lower acidity by Sodium hydroxide and then bringing up

-56-

with hydrochloric acid.

Method No. 1 of Manufacture was used here.

 

 

Table 9
f set I stander zin the whe acidit yari us
i act 8 use 1‘ acid edu ants and nor c acids
3 3 3 3 3 3 3 3 3
3No. of whey aciditymhey aeidity3Agent 3Body a: 3Flavor 3Final 3F‘ihal 3
3trials 3st cutting 3brought to 3 used 3texture3 3cooking3whey 3
mused; 3 L 3 3 3temp_ °F3 acidity
3 3 3 3 3 3 3 3 3
3 2 30.4 -.42 3 .47-.48 3 301 3sticky 3slightly3llS-1203 3
3 3 3 3 3rubbery3 flat 3 3 3
3 3 3 * ' 3 3 3 3 3‘ ’ 3
3 8 3 .52 -.55 3 .46-.49 3 Neon 3smooth 3Excellent116-ll73.51-.53:
3 3 3 3 3creamy 3 3 3 3
3 3 ' 3 3 3 3 3 3 3
3 3 3 .52 -.55 3 .46—.49 3Ca(0H)23 " 3 " 3 " 3 " 3
3 3 ' 3 ' 3 3 3 3 3 ' 3
3 l 3 .52 -.55 30.4 -.42 3 NeDH 3rubbery3 Acidic 3115-1203.43-.453
3 3 ' 3 ' 3 3 3 3 3 3
3 3 3 .52 -.55 3 .46-.49 3119.08 0: 3smooth 3Excellent116-ll73.51-.533
3 3 3 3 HCl 3creamy 3 3 3 3
3 3 3 L 3 L L .8 3

 

gonditions 9f Eggpegimeny
Ten percent Starter. 0.6 ml rennet extract. Setting

temperature 90°F.

 

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V ' D O D
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I
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o 0 e o 0
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. l _ i
e O. h a. I. ‘. I ll ‘4 u
v a P
_ _ _
r n a
. N O

 

, urn}. Jewish-Iii \

w

 

- 57 -

When the coagulum.was cut at a low acidity of
0.4 - 0.42 percent and the whey acidity was brought up to the
optimum.of 0.47 - 0.50 percent by the addition of’hydrochloric
acid, the resulting cheese was rubbery. The whey acidity therefore
does not affect the physical properties of the coagulated milk.
The low acidity of the cubed coagulum was unaffected by the
acid surrounding them and the heat that was applied caused the
typical rubbery mass that accompanies that condition.

When the whey acidity at cutting was 0.52 - 0.55 percent
and it was brought down to the lower limits of 0.4 - 0.42
percent with acid reductants, it was noted that such curd when cooked
was also rubbery. Here the cheese acidity was considerably
above the limit for rubbery texture, yet, as the whey was
brought within the rubbery texture limit by over-neutralization,
the resulting effect was to form a rubbery cheese.

In a third experiment a combination of acidity reduction
and acidity increase was used. The curd was cut at high acidity
( 0.52 - 0.55) the whey brought within lower limits (0.4-- 0.42)
by over neutralizing and then was brought up to the optimum
acidity (0.46 - 0.49) by the addition of hydrochloric acid,

and cooked. The result was a fine, creamy textured cheese with

3' M3

 

- 58 -

excellent flavor. These experiments clearly show the
importance of keeping both whey acidities as well as the
acidities of curd particles above 0.42 percent (best within
0.45 - 0.5) if a rubbery curd is to be avoided. The results
in Table 6 have shown the effects of higxer acidities of
0.52 to 0.56.

A further series of experiments were conducted using
various acid reductants. The curd was cut at higher acidity,
0.52 to 0.55 percent and then neutralized to the optimum
acidities. Both sodium hydroxide and calcium hydroxide were
used. By bringing down the acidity to the optimum 0.46 to 0.49
percent a fine product was obtained from both. .No difference in
the body, texture and flavor of the cheese obtained with caustic
soda and lime as acid reducing agents was noticed. The caustic
soda would thus be preferable to use because of its easy
solubility necessitating less stirring, which means a more
uniform product. Besides, as most of the salts from neutralizing
are to be washed away caustic soda would be preferable because

of higher solubility of sodium compounds than of Calcium compounds.

- 59 -

The results of these experiments are thus quite
significant. If the curd has been cut at a sufficiently
high acidity it can be brought to the optimwm acidity of
0.45 to 0.49 percent by any of the neutralizing methods used
here without adverse effects on the resulting cheese.
Effects of ége gf milk:§nd age of starter

It is not always possible to get a fresh supply of milk
and a fresh supply of starter, which are ideal for’making a
good quality cottage cheese. It was thus thought advisable to
note the effect of ages of milk and starter on the curd, and the
cheese obtained from it. These observations were made as a
part of the other experiments that have been reported here.

The results are summarized in Table 10.

I

 

- 60 -

Table 10 Effect of age of milk and age of starter on
curdling time. nature of the curd. and the nature

of the cheese

 

 

3 3 3 3 3 3
3N0. of 3Age of 3Age of 3 Curdling 3Nature of the3Body and

3 trials 3 milk 3starter 3 time 3 curd 3texture of
3reported3 3 3 3 3 cheese

3 A3 3 3 3 3

3 3 3 3 3 3

3 12 3 fresh 3 fresh 3 4-6 hrs 3smooth, 3Excellent
3 3 . 3 3 3 compact 3

3 3 3 3 ‘ 3 3

3 5 3one deyx fresh 3 5—6 hrs 3very slight 3 Irregular
3 3 3 3 3 gassy 3

3 5 3 fresh 3one day 3 5-7 hrs 3 ' 3very '

3 3 3 3 3 3

3 5 3one daytone day 3 6-8 hrs 3gaesy open 3 ' ”

3 3 3 3 3 3

3 2 3 fresh 3two deys3 6-9 hrs 3 ” 3 ” "

3 3 3 3 3 3

3 l 3two day3two days: 7-10 hrs 3very gassy 3breaks down
3 3 3 3 3and open 3to fine

3 3 3 3 3 3particles
3 3 3 3 3 3

 

 

anditigns of experime§t3
Ten percent starter. 0.6 ml rennin per 1000 pounds of

milk. Setting temperature 90°F. Cooked without addition

of water.

eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

The few batches studied here have shown that excellent
results were obtained when fresh milk and fresh starter
combination was used in preparing the cottage cheese. As long
as one of them.was fresh and the other a day old satisfactory
results were obtained, but as the ages went beyond that,
adverse effects on the cottage cheese production were apparent.

A.two day old milk with a.two day old starter was impossible

to cock into an acceptable pop-corn type cottage cheese.

- 52 -
DISCUSSION

Cottage cheese of good quality could be produced with
cooking in the whey only. It is customary to cook cheese
with addition of water because of the initial heating that
could be obtained by addition of hot water and also the free stirring
provided by the largevolume of liquid.media available for the
curd to float in. The water also dilutes the whey acidity.

According to Table 6 the acidity of whey at the end of
cooking did not go above 0.2 percent when 40.0 percent water
was used for cooking. The final whey acidity for cheese cooked
in its own whey was 0.57 percent (maximum) under the conditions
of the experiment. The proper whey acidities for cutting a
coagulum.in order to obtain a cottage cheese with smooth creamy
texture and good flavor, cooked with and without water were
found to be 0.52 percent to 0.54 percent and 0.47 to 0.50
percent respectively. If a coagulum.was cut at acidities of
0.40 to 0.42 percent the resulting curd after cooking was rubbery.
In the case of cottage choose that was made by cutting at higher
acidities of 0.52 to 0.54 percent and by cooking in absence of
water, the curd was crumbly and hard and.had quite an acidic

flavor. The final temperature obtained during cooking increases

's.s--.z_.

r7~ .
I u.

~63-
as the whey acidity at cutting is increased. Thus for a

cottage cheese to be cooked without resorting to water dilution
the coagulum.should be cut when the whey acidities reach
0.h7 to 0.50 percent.

Heating the coagulum.after cooking is resorted to fine
the curd particles by facilitating rapid whey expulsion. In
order to avoid over heating of coagulum.and as a result too

rapid whey expulsion from a few curd particles in contact with

the sides of the jacket, it is necessary to stir the whole mass;
otherwise they would form.a.matted mass and have a tendency to

stick to the bottom of the vat. The stirring also helps in

transferring heat to the rest of the bulk and thus increase the
rate of temperature rise. But the stirring has to be done very
carefully as the coagulum at the beginning (till temperature
reaches llOPF ) is very soft and is liable to be crushed. Thus
when curd is cooked in presence of added water; higher rate of
cooking could be used because the large liquid.medium.would

permit stronger and faster stirring. The same rate of heating
could not be used when cocking cheese in its own whey because

of the large.mass of coagulum floating in a small quantity of the

whey. Any'attempt at stirring faster here meant breaking down

' 4 .3? if. :Jfiigifl‘fifi IKEJVd'o 11‘ C L .o‘

pr

-54..

the 'popcorn' curd particles. Table 8 shows the nature of

the curd at different temperatures between water in the Jacket
and the whey in the vat. While a difference of 40 - 50°F

was suitable for cooking in presence of added water, only

20- 30°F difference was found suitable for cooking in absence
of water. At this rate of heating quite an even cottage cheese
was obtained.

As the cooking progresses the cubes become firmer and firmer

 

and when the temperature reaches approximately 1124115°F,when .
cooking with waterjand 110°? When cooking in the whey only, the
curd particles have hardened enough to permit faster and more
frequent stirrings without the fear of shattering the cubes
completely.
Acidity of the whey at the time of cutting plays an
important part in determining the quality of final product to
be obtained. From.the experiment (Table 6) it was observed
that for the cheese to be cooked in absence of added water,
the desirable whey acidities at cutting time were 0.46-0.49

percent. This acidity could be attained either by keeping

 

-55..

a close track of the acid development in the coagulum.or by
standardization after cutting a firm coagulum at any acidity.

Table 9 shows that if the coagulum is cut at 0.h - 0.42 percent
acidities and then the whey brought up to the optimum acidity of
O.h6 - 0.49 percent the resulting cheese curd is rubbery.

The acidification of whey while changing acidity of the surrounding
curd, is not capable of changing the nature of the curd which
remains more of a rennet curd. If the coagulum.is cut at higher
acidities of 0.52 - 0.55 percent and.then brought down by
neutralization to 0.46 - 0.49 a very good final product was
obtained. But if the whey was over-neutralized to 0.h - 0.h2 percent
acidity a rubbery curd resulted on cocking. Now when the over—
neutralized whey was acidified and brought to the optimum acidity
of 0.46 - 0.49 and then cooked a very good cottage cheese

resulted. These results tend to indicate that first a rennet

type coagulwm i5 fonmed which converts into acid type as the
acidity is allowed to increase without cutting the coagulum.

A rennet type coagulum.could not be brought to acid type after
cutting simply by acidifying the whey; but a coagulum advanced

in acidity could be brought down to rennet type curd by

neutralizing the whey. If an over-neutralized whey is acidified

 

.J’flf‘

-66-

the original curd is got back. The optimum acidity of
0.45 to 0.49 can be said to Show a balance point between
rennet type curd and acid type curd. No difference in the
action of lime and caustic soda was noticeable.

These results show that with this method of whey
standardization and of cooking employed, a product reasonably
standard in body, texture and flavor was obtained with different
skimumilks. Thus successful production of comparable quality
cottage cheese by cooking in absence of added water would help
the dairy industry by not complicating the already existing

sewage disposal problem.

(1)-

(2)-

(3)-

(4)-

(5)-

(6)-

(7)-

(8)-

-67-
summnngilwn CONCLUSIONS

Rennet at the rate of 0.6 ml per 1000 pounds of skim
milk was found to be the suitable amount of rennin to
use for the short set method employed.

For the cheese to be cooked without water, the optimum
whey acidity at cutting was 0.47 to 0.50 percent.

For the cheese to be cooked with water, the acidities of
whey at cutting were found to be 0.50 to 0.54 percent.
'me difference in temperature between the vat and the
Jacket fer cheese to be cooked without water should be
20 - 30°F for a reasonably rapid rate of cooking without
harming the body and texture of the curd.

The final cooking temperature attained for cheese to

be cooked in its own whey was 116-1180F.

There was no difference noticed in the action of caustic
soda or lime neutralizer. -

‘A fine cheese couldbe obtained by cutting at whey acidity
of 0.52 - 0.55 percent and then neutralizing to 0.47-0.49
percent of whey acidity.

‘A rubbery cheese is obtained if out at whey acidity of
O.4--O.42 percent and then the whey acidity brought to

the optimum by the addition of hydrochloric acid.

(.54.)? - - ‘

 

 

~68-

(9)- A rubbery curd also resulted if the curd was cut
at 0.52— 0.55 percent whey acidity and then the whey
acidity over neutralized to 0.4 percent or less.

(10)- A.good quality cottage cheese resulted if cut at high
acidity, overneutralized, and then reacidified with HCl
to optimum acidity.

(11)- Whey acidity as well as the acidity of whey at cutting
were noticed to be important.

(12)- Fresh milk and fresh starter gave the best results.

(13)- When either the milk or starter was one day old and the
other fresh, good cottage cheese was produced.

(l4)- Two day old milk and two day old starter gave a highly
gassy curd which was impossible to cock into cottage cheese

of the type that was attempted to manufacture here.

Appendix 1
METHOD FOR MANUFACTURING COTTAGE CHEESE BY SHORT- SET METHOD,

UTILIZING STANDARDIZATION OF WHEY ACIDITY AND COOKING IN ITS

OWN WHEY

(1)- Take fresh skim milk pasteurized at. 143°F for thirty
minutes, heat it up to 90°F and add ten percent fresh
starter to it. ‘Mix.the starter thoroughly with it.

(2)- After fifteen minutes after adding starter add rennet
at the rate of 0.6 ml per 1000 pounds of skim milk,
diluted with a quart of water. Mix.the rennet with slow
stirring and long enough to ensure proper dispersion
of the enzyme. .

(3)- Bring the temperature to 90°F if lowered and let stand
till coagulated.

(4)- Cut the curd (see appendix 3 for directions) first
horizontally and then vertically when the whey acidity as
tested is between 0.5 and 0.54 percent.

(5)- As soon as the curd is cut, heat the jacket to 100°F,

this will bring the temperature of the curd slowly to 90°F.

 

-70..

(6)- Dissolve Caustic Soda (About 30 grams for 50 gallons of
skim milk used) in a gallon of waterand add sufficient
to bring the whey acidity to 0.h5~ 0.1.8 percent. If the
acidity is still more add till tests to the requirement;
if less than the required, acidify with hydrochloric acid
to the right extent. Mix by slow stirring. Let stand
for twenty minutes with occasional stirring.

(7)- Start cooking. Keep the difference in twperature between

 

the vat and jacket at 20- 30°F. Stir occasionally and
slowly.

(8)- When the temperature has reached 110°F the cheese would
have hardened enough to permit faster stirring.

(9).- At 115°F start testing the extent of firming by dropping
a flake on the ground.

(10)- Heat till 11701? is reached. Then drain off the jacket and
let stand the whey at 117°F for fifteen minutes.

(ll)- Drain off the whey till just enough remains to cover all
the cheese and the bottom.

(12)- Add cold water in amounts approximately equal to the amount

of original skim milk. Let stand for five minutes with occasional
stirring. Drain off. Start running cold water through

the Jacket.

(13)-

(14)-

(15)-

- 71 -

Add cold water to the cheese— as cold as possible.
Fill up the vat. Let stand for ten minutes with
stirring to wash all cheese thoroughly as well as
chill them. Drain off the water.

Let the curd drain.

Cream and salt if to be used immediately or the next
day. Otherwise, store dry in parchment lined tins in
a cold storage, if to be used within two or three days.

Cream.and salt at the time of using.

"if:

 

I: L... N3..f‘-Ul "‘

- 72 -

Appendix 2

A SUGGESTED COTTAGE CHEESE DATA SHEET

Pasteurization e e e e e e e e e 0 Age Of Milk 0 e e e e e e e
GallonSOfNilkoOOOOOOOOePoundSOfllilkooooeoo

Setting
Pounds of Starter. . . . . . . . . Age of Starter . .

e e e e 0

Setting Temperature 0 o o O 0 O O 0 Amount Of rennet . Q o o o o

Acidity at setting . . . . e e e . Percent of Starter . . . . .

Time when set a e e e o e e e e e o Gallons Of Starter e e e o 0
Cutting

Time When cut 0 o o o o o o o o o . Anidity at cutting o 0 e o 0

Temperature when out . . e . . e e 0 Hours to set . . . . . . . .

Acidity after neutralization . . . . Neutralizer used . . . . . .

Qggking

Cooking Started . e e e o'. 0 etc . Cooking Completed . . . . . .
Final whey acidity e g e 0.. o O o 0 Hours to 000k 0 o o o e o o o
HighOSt COOking tempo 0 e e e e e O

washing
Times washed . e". e .'. .'. . . . Total gallons of water used
Drainage time o e e e e e e e e e for washing 0 e e e e e e 00

Final temp. of cheese . . ..

Creamin and saltin

Pounds of cheese used . . . . . e 0 Test of cream . . . . . . ..
Pounds Of salt 0 e 0 e e e e e at... Percent Of salt. 0 0 0'0 0 0
Actual pounds of cottage cheese . . Flavor, body, texture . . ..
Percent yield . . e . . e . . . . . Percent butterfat in

creamed cheese . . . e e . .

92st

Cost Of‘milk e e e ... e e e .7. e o COSt Of Starter e e e e e a
Value of cheese 0 e e e e e e 0 Cost of cream.. . . . . . ..
PaCkaging data 0 e e e e e e e 0 Gross gain 0 e o e e e e e u

-73-

Appendix 3

MLTHOD OF CUTTING COTTAGE CHEESE AS SUGGESTED BY HALES (14)

”First, the horizontal knife is used to cut the curd
lengthwise of the vat. The top of the knife is held on the end
of the vat, while the other end is swung down through the curd
and brought to rest in an upright position against the well of
the vat. In an upright position, the knife is drawn the full length
of the vet. It is then rotated on its cutting edge and lined
up so that it is in the proper position for making another out
directly beside the preceding one. Again the knife is drawn the
full length of the vat and the operation described above is
continued until lengthwise cutting of the curd is completed.

.The vertical knife is new used for the remaining cutting of the
curd. Standing at one side of the vat, the cheese-maker places
the cutting and of the knife just above the curd on the opposite
side. He then pushes the knife downward with the cutting and
sliding down the side of the vat until it strikes the bottom.
During this operation the knife is held at about a 35 degree
angle in respect to the side of the vat opposite the one from which
the cheese-maker is standing. After the knife has been pushed
downward, it is straightened up against the side of the vat

and in this position drawn across and removed from.the curd.

‘(V‘E’t'zrt

 

-74-

This operation is repeated as many times as required.
Following this operation curd is cut lengthwise with the

same knife and in the same manner as it was cut crosswise.“

(1)

(2)

(3)

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(6)

(7)

(8)

(9)

- 75 -
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r C
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to
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