The manufacture of cheese of the cheddar type from pasteurized milk

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Title:
The manufacture of cheese of the cheddar type from pasteurized milk
Series Title:
Bulletin / U.S. Department of Agriculture, Bureau of Animal Industry ;
Physical Description:
95 p., 6 p. of plates : ill. ; 24 cm.
Language:
English
Creator:
Sammis, J. L ( John Langley ), 1873-
Bruhn, A. T ( Aksel Theodor ), 1875-
Publisher:
U.S. Dept. of Agriculture, Bureau of Animal Industry
Place of Publication:
Washington, D.C
Publication Date:

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Subjects / Keywords:
Cheddar cheese   ( lcsh )
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federal government publication   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )

Notes

Bibliography:
Includes bibliographical references.
Statement of Responsibility:
by J.L. Sammis and A.T. Bruhn.
General Note:
"June 30, 1913."

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University of Florida
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All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 029611246
oclc - 22255357
System ID:
AA00018892:00001

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IsnUO(d .nJ ,3). 3 1910'.

U. S. DEPARTMENT OF AGRICULTURE,
BUREAU OF ANIMAL INDUSTRY.-BUI.LETIN 165.
A. D. MELVIN, CHIF- o0, BUREAU.





THE MANUFACTURE OF CHEESE OF

THE CHEDDAR TYPE FROM

PASTEURIZED MILK.





BY

J. L. SAMMIS, PH. D.,
Associate Professor of Daity Husbandry, College of Agriculture,
University of I-'isconsin,


AND
A. T. BRUHN,
Expert Cheese Maker, Dairy Division,
Bureau of Animnal Indusry.


WASHINGTON:
GOVERNMENT PRINTING OFFICE.
1913.





"En
":::::















THE BUREAU OF ANIMAL INDUSTRY.


Chief. A. D. MELVIN.
Assistant Chief: A. M. FARRINGTON.
Chief Clerk: CHARLES C. CARROLL.
Animal Husbandry Division: GEORGE M. ROMMEL, chief.
Biochemic Division: M. DORSET, chief.
Dairy Division: B. H. RAWL, chief.
Field Inspection Division: R. A. RAMSAY, chief.
leat Inspection Division: R. P. STEDDOM, chief.
Pathological Dirision: JOHN R. MOHLER, chief.
Quarantine Division: RICHARD W. HICKMAN, chief.
Zoological Division: B. H. RANSOM, chief.
Experiment Station: E. C. SCHROEDER, superintendent.
Editor: JAMES M. PICKENS.
DAIRY DIVISION.
B. H. RAWL, chief.
I ELMER RABILD, in charge of Dairy Farming Investigations.
S. C. THOMPSON, in charge of Dairy Manufacturing Investigt, lions.
L. A. ROGERS, in charge of Research Laboratories.
ERNEST KELLY, in charge of Market Milk Investigations.
ROBERT MCADA M, in charge of Renovated Butter Intspection.











LETTER OF rIRANSMITTAL.


U. S. DEPARTMENT OF AGRICULTURE,
BUREAU OF ANIMAL INDUSTRY,
Washington, D. C., January 30, 1913.
Sra: I have the honor to transmit for publication as a bulletin of
this bureau the accompanying manuscript entitled "The Manufac-
ture of Cheese of the Cheddar Type from Pasteurized Milk," by Prof.
J. L. Sammis, of the College of Agriculture, University of Wisconsin,
and Mr. A. T. Bruhn, expert cheese maker in the Dairy Division of
this bureau. The work herein described was conducted at Madison,
Wis., in cooperation between the Dairy Division and the Wisconsin
Agricultural Experiment Station.
The Dairy Division has been represented at Madison by L. D.
Bushnell, Alfred Larson, and Miss Alice C. Evans, bacteriologists, in
succession; S. K. Suzuki and E. F. Flint, chemists, and J. W. Moore,
F. W. Laabs, and A. T. Bruhn, expert cheese makers, in succession,
all of whom have assisted at various times in this work. The Wis-
consin Station has been represented by Prof. Sammis, who from the
beginning has had charge of the cooperative experiments in the manu-
facture of the Cheddar type of cheese from pasteurized milk.
The comparison of this cheese with that made from raw milk by the
regular factory method has been systematically and thoroughly
carried out under a variety of conditions by the use of duplicate vats
of milk, one of these being pasteurized in each instance. During
1910 and 1911, especially in the latter year, the new process was per-
fected and a large quantity of the pasteurized cheese was made under
commercial conditions and placed upon the open market. The
results are fully described, also the process of making the cheese,
and it is shown that the use of pasteurized milk is highly satisfactory
and economical. As pathogenic bacteria have been found to survive
for several months in cheese made from raw milk, the pasteurization
of milk in making cheese is also desirable for the protection of the
health of the consumer.
Respectfully, A. D. MELVIN,
Chief of Bureau.
Hon. JAMES WILSON,
Secretary of Agriculture.







''H















CONTENTS.

Page.
Introductory....................................... .............. ........... 9
The need for a new method of cheese making............................. 9
Faults to be corrected in milk for cheese making......................... 10
The necessity for the pasteurization of milk for cheese making ............ 11
Amount of heat necessary to destroy various bacteria................ 12
Previous attempts to make cheese from pasteurized milk................. 13
Difficulties met in making cheese from pasteurized milk ................. 14
Difficulties overcome by acidulation of pasteurized milk .................. 15
The pasteurization process ................................................. 18
Pasteurization in a discontinuous or "held" pasteurizer .................. 18
Continuous and "held pasteurization compared ........................ 18
Selection of best temperature for pasteurization in the continuous machine 20
Objections to higher temperatures than 160-165 F. for pasteurization .... 23
Effect of pasteurization on the properties of cheese curd .................. 25
The different types of continuous pasteurizers used ...................... 28
The acidulation process ..................................................... 28
The standard acidity of milk for cheese making ........................... 28
Comparison of different kinds of acid for cheese making ................... 30
The proportion of hydrochloric acid required daily ....................... 30
Testing milk for acidity ................................................. 31
Preserving the tenth-normal solution .................................... 32
Diluting normal alkali to tenth-normal .................................. 32
Adding acid to milk after pasteurization ................................. 33
Calculating the amount ot acid to be added ............................. 33
Preparation of normal hydrochloric acid in the cheese factory ............ 35
General directions for pasteurizing and acidulating milk ...................... 37
'Making ready to pasteurize ............................................. 38
Starting and stopping the pasteurizer ................................... 39
Starting and stopping the acidulator ..................................... 40
The use of bacterial starter in the new process ............................... 40
The reason for adding starter in making pasteurized-milk cheese ......... 40
A practical sterilizer for the cheese factory .............................. 42
Preparation of the starter ............................................... 43
Method of making cheese by the new process ................................. 45
General arrangement of schedule ........................................ 45
Uniform proportion of color used in 1911, and rennet required ............ 46
Adding starter, color, and rennet to the milk ............................ 47
Cutting, stirring, and heating the curd .................................. 48
Drawing the whey, matting, cutting, and turning the curd ............... 49
Milling, salting, and hooping the curd .................................. 49
Pressing and dressing the cheese ......................................... 50
Drying, paraffining, and curing ......................................... 50
Branding and selling the cheese ......................................... 51
Testing cheese for moisture when dressed in the hoop .................... 52
5







6 CONTENTS.

w.a
Results of two years' trial of the new method ................................ 53
Increased yield of cheese obtained by the new process .................... 53
Apparatuas and methods of study .................................... 53
Search for systematic errors in experiments on yield of cheese......... 56
Shrinkage before paraffining, and yield of paraffined cheese........... .s
Shrinkage and yield of cured cheese................................. 62
The causes of the increased yield from pasteurized milk................. 69
The losses of fat from vat and press ................................. 69
The increased moisture content of pasteurized-milk cheese........... '73
The quality of pasteurized-milk cheese................................ 75
Scores and criticisms of pasteurized and raw milk cheese............. 75
Cheese cured at Madison at normal temperature...................... 75-
Cheese cured in the South.......................................... 79
Cheese cured in warm room at Madison............................... 84
Cheese cured in cold storage........................................ 85
Exceptional differences between the raw and pasteurized milk cheese. 86
Summary of discussion of scores...................................... 87
The demand for pasteurized-milk cheese............................... 88
Opinions of purchasers ............................................. 89
The extra cost of making pasteurized-milk cheese......................... 89
Further trials of the new process in cheese factories.................... 90
Summary ....................... ........................................... 90
Preliminary and comparative work with the old and new methods ........... 90
Some advantages from the use of pasteurized milk and hydrochloric acid.. 92
Outline of the new method............................... .............. 93
























ILLUSTRATIONS.


PLATES.
Page.
Plate I. Outfit used in testing milk for acidity (Manns's acid test) and in testing
strength of hydrochloric acid used in cheese making............... 32
II. The continuous disk pasteurizer, and apparatus used in acidulating
pasteurized milk-.............................................. 32
III. The continuous "flash" pasteurizer, and apparatus used inacidilating
pasteurized milk.............................................. 32
IV. Transferring acid from full to empty carboy by means of siphon....... 36
V. Vat strainer for straining milk into receiving vat.................... 36
VI. A uniform layer of curd, showing use of curd gauge...........-..-- 48
TEXT FIGURES.

Fig. 1. A combined sterilizer, cooler, and incubator for cheese-factory starter.. 43
2. Method of marking cheese.......................................... 52
3. Distribution of total scores of pasteurized and raw milk cheese-........ 78
4. Distribution of flavor scores of pasteurized and raw milk cheese........ 78
5. Distribution of texture scores of pasteurized and raw milk cheese....... 79
6. Distribution of total scores of pasteurized and raw milk cheese ....... 81












































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THE MANUFACTURE OF CHEESE OF THE CHEDDAR
TYPE FROM PASTEURIZED MILK.


INTRODUCTORY.
THE NEED FOR A NEW METHOD OF CHEESE MAKING.
Economy of time and labor and improved quality and uniformity
of the cheese produced make the large cooperative factory more
profitable to farmers than the small factory, provided they retain
the control, if not the complete ownership, of it. There are two
objections sometimes raised against the replacement of four or five
small cheese factories in a neighborhood by one large, better-
equipped, better-manned, and more economical cheese factory, -
namely: First, that by present factory methods cheese makers could
not make as good cheese from milk gathered over a large territory,
because it would be longer on the road to the factory and therefore
would not be so fresh as otherwise; second, farmers object to haul-
ing milk a great distance, even to a good cheese factory.
The only Way to get a large, first-class cheese factory located within
a short distance of a sufficient milk supply is to centralize the latter-
that is, to keep as many of the best cows on every farm as the land
will support. Until this is done there will be many factories which
must draw milk from a large area. Some modification of present
cheese-factory methods is needed by which milk from a large territory
can be successfully handled.
The great amount of inferior cheese on the market and the lack of
uniformity which characterizes the product of the present cheese
factory of average size is due primarily to the variable quality of the
milk supply from different farms, especially as to the presence of dirt
and bacteria, which produce faulty flavors and textures in great
variety, and to the variable ripeness or acidity of the milk received
from day to day, depending upon the care given to it on the farm,
its age, etc.
The immediate effect of these conditions is that cheese makers in
their effort to produce cheese of uniform quality from milk of variable
quality must necessarily use methods which vary from day to day
and from factory to factory. Under this system each vat of milk
must be watched carefully at every stage of its manufacture, and the
9






10 CHEDDAR CHEESE FROM PASTEURIZED MILK.

cheese-making process must be hastened, or delayed, or modified
every day, according to the cheese makers' judgment. The yield of
cheese also varies from day to day, depending upon the quality of the
milk and the method used in handling it.
The ideal conditions for cheese making require an absolutely dean
and perfect milk supply, and this can not be realized until methods
of milk production on the farm are vastly improved. In the mean-
time a process for treating milk daily at the factory so as to bring it
into practically uniform condition for cheese making purposes is
needed. Such a process should include means for stopping the
ripening and the growth of harmful bacteria, etc., in the milk as soon
as it is received at the factory, in order that it may be ripened with a
clean starter, in a uniform manner, daily. The process should be
applicable to milk of any degree of ripeness which can properly be
accepted as fit for cheese making from a sanitary standpoint. When
milk is thus brought by a preliminary treatment into uniform condi-
tion at the factory, both as to acidity and as to bacterial content,
the present variable and irregular methods of making cheese could
probably be replaced by a routine process, operated upon a fixed time
schedule without variation from day to day. As a result, it is to be
expected that the uniformity, quality, and yield of cheese would be
much improved as compared with that obtained by the older methods.
In many other lines of manufacture in recent years preliminary proc-
esses have been devised for bringing raw materials into uniform
condition before they enter the manufacturing process, and improved
products, increased economies, and larger output and profits have
resulted. It is desirable that the same general methods of improve-
ment which have been used with success in other lines be applied also
to the cheese-making industry.

FAULTS TO BE CORRECTED IN MILK FOR CHEESE MAKING.
The defects most commonly met with in milk, which must be cor-
rected by such a preparatory process as that contemplated, are of
bacterial origin. A variable content of lactic-acid bacteria causes
milk when received at the factory to exhibit different degrees of
acidity and also causes the subsequent development of acid in the
milk and curd, while in the vat, to go on at varying rates. On
account of the important influence which acidity has upon the rate
at which whey is expelled from curd, as pointed out in a previous
bulletin,' it may well be said that this is the leading controlling factor
in the manufacture of American Cheddar cheese. Therefore it is of
prime importance to secure milk of uniform acidity with which to
i Sammis, J. L., Suzuki, 8. KL, and Laabs, F. W. Factors controlling the moisture oontemt of ehese
curds. U. 8. Department of Agriculture, Bureau of Animal Industry, Bulletin 122. Washington, 1910.
Beep. 29.






NECESSITY FOR PASTEURIZATION.


S begin cheese making, and also to provide for subsequent acid de-
velopment at a practically fixed rate every day in order to avoid the
present troubles due to irregular acid formation.
Those bacteria which produce gas or tainted, unclean flavors are
all too common in milk, and are the cause of much trouble in the
cheese factory. Bacteria which produce diseases such as tuberculosis,
typhoid fever, diphtheria, dysentery, etc., have often been found in
milk, although it is difficult to prove that any person ever contracted
these diseases from eating cheese. These and other bacterial infec-
tions of raw cream and milk for city trade are usually combated by
pasteurization; this is true, likewise, in butter making, and with skim
milk when used for feeding stock. It seems reasonable, therefore,
that any process, such as pasteurization, which will kill the acid,
taint, gas, and disease-producing organisms in milk would also im-
prove the quality of the cheese produced therefrom.

THE NECESSITY FOR THE PASTEURIZATION OF MILK FOR CHEESE
MAKING.

In view of the possible presence of tubercle bacilli in market
cheese, MohlerI in 1908 recommended the "pasteurization of the
milk in order to make the cheese perfectly safe." Mohler, Washburn,
and Doane2 prepared and studied cheese from milk to which cultures
of bacillus tuberculosis had been added. They inoculated guinea
pigs with such cheese at various periods of time after its manufacture
and found that-
Advancing cases of generalized tuberculosis were developed (in guinea pigs) by
means of inoculation of cheese 220 days old, and that slight tubercular lesions were
caused by the injection of an emulsion of cheese when 261 days old."
They add:
If it is possible to use pasteurized milk in the manufacture of cheese without injuring
the product a simple solution of the problem is offered to the cheese manufacturer in
the process known as pasteurization.
These autl4ors also give a brief r6sum6 of previous work on this
subject in Europe and America.
It is evident that the bacillus of tuberculosis not only retains its
life but also its virulence in cheese for a considerable period of time,
and that cheese made from raw, unpasteurized milk should therefore
be considered as a possible carrier of tubercle bacilli.
There is a strong tendency at the present time to cure American
cheese more rapidly than in the past, so that it commonly reaches
SMohler,John R. Conditions and diseases of the cow injuriously affecting the milk. U.S. Treasury
Department, Public Health and Marine-Hospital Service, Hygienic Laboratory, Bulletin 41. Washing-
ton, 1908. See p. 495.
2 Mohler, John R., Washburn, Henry J., and Doane, C. F. The viability of tubercle bacilli in cheese,
Twenty-sixth Annual Report of the Bureau of Animal Industry, U. S. Department of Agriculture (1909),
pp. 197-191. Washington, 1911.


11







12 CHEDDAR CHEESE FROM PASTEURIZED MILK.

the consumer at a less age than four months. It has also ben
shown' that practically all-95 to 98 per cent-of the baeteta
present in milk are retained in the cheese. These facts serve to
emphasize the desirability of pasteurizing milk for cheese making.
An ordinance passed by the common council of the city of Chicago.
July 13, 1908, contemplated the pasteurization of milk used for
cheese making, although at that date no practical methods for
making American cheese from pasteurized milk had been published.
The ordinance was as follows:
'Chreft Be it ordained by the city council of the city of Chicago, *
SECTION 2. It shall be unlawful to sell any such cheese in the city of Chicago unless
there b-e stamped on the package in plainly legible letters of not less than oae-eighth
i1rh4 type: "Made of milk (or cream) from cows free from tuberculosis as shown by
tuberuliin test," our "made from milk (or cream) pasteurized according to the rules
and regulatiuns of the department of health of the city of Chicago * 0.
SEC. 4. This ordinance shall be in full force and effect from and after January 1,
1909.
AMOUNT OF HEAT NECESSARY TO DESTROY VARIOUS BACTrfJA.
The question as to what temperature of pasteurization will kill
disease-producing bacteria in milk is of interest to the consumer and
all connected with the business.
Tlhe thermal death point of various pathogenic organisms is I
already well known. Rosenau states as a result of his work and that
of others that "milk heated to 60 C. (140 F.) and maintained at
that temperature for two minutes will kill the typhoid bacillus."
The great majority of these organisms are killed by the time the
temperature reaches 1 or 2 degrees below the point named and few
survive to 140 F.
Thle diphtheria bacillus succumbs at comparatively low tempera-
tures. Oftentimes it fails to grow after heating to 55 C. (131 F.).
Some occasionally survive until milk reaches 60 C. (140 F.). The
cholera vibrio is similar to the diphtheria bacillus so far as its thermal
death point is concerned. The dysentery bacillus is somewhat more
resistant to heat than the typhoid bacillus. It sometimes withstands
heating at 60 C. (140 F.) for five minutes. All, however, are
killed when lield at this temperature for ten minutes.2
In 1904 Russell and Hastings 3 found that the tubercle bacillus is
killed by heating at 71 C. (160 F.) for one minute.
From the foregoing it is clear that pasteurization at 71 C. (160 F.)
for one minute, and in most cases for a shorter period, is effective in
1 Sammis, J. L., Suzuki, S. K., and Laabs, F. W. Factors controlling the moisture coatat of ches
curds. U. S Department of Agriculture, Bureau of Animal Industry, Bulletin 122. Washington, 1910.
See p. 29.
0 Robenau. Milton J. The thermal death points of pathogenic microorganisms In mU. U.S. Trary
Department, Public Health and Marine-Hospital Service, Hygienic Laboratory, Bulletin 5b pp. 6-00
N ashingtoD, 1909.
* Russell, H. L., and Hastings, E. 0. Effect of short periods of exposure to heat on tabde bacll I
milk. Wiconsin Agricultural Rxpwmnt Station, Twenty-Orst Annual Report (1904), pp. 175-1i M.d.
o, 190L. See p. 186.







PREVIOUS ATTEMPTS WITH PASTEURIZED MILK.


destroying pathogenic bacteria in milk and preventing their entrance
into cheese.
Babcock and Russell,1 from their experiments upon the thermal
destruction of galactase, state that "heating the enzym solutions for
10 minutes at 76 C. (169 F.) suffices to destroy the digestive fer-
ment galactase, and even at 71 C. (160 F.), for the same exposure,
its action was materially reduced." It seems likely, therefore, that
an exposure to 160 F. for 1 minute or less in the continuous pas-
teurizer would not greatly weaken the action of this enzym in milk
for cheese-making purposes.2
Much less attention has been paid by bacteriologists to the thermal
death point of those bacteria in milk which produce gas and tainted
flavors in cheese. Moore and Ward 3 have described a gas-producing
bacillus isolated from milk and from gassy cheese which "is destroyed
in freshly inoculated small tubes of bouillon when exposed to a tem-
perature of 60 C. (140 F.) for 10 minutes in a closed water bath."
It is to be hoped that in the future investigators will determine
also the minimum temperature required to kill various species of
milk bacteria with an exposure of 1 minute or less as in the continuous
pasteurizer.

PREVIOUS ATTEMPTS TO MAKE CHEESE FROM PASTEURIZED MILK.
The possibility of making American cheese from pasteurized milk
has been studied at several experiment stations and elsewhere. The
two difficulties met with are:
First, the fact, long known, that heated milk coagulates slowly
with rennet, giving a loose, spongy curd which is not suitable for
cheese making because it is too fragile to be handled.
Second, pasteurization causes curd to expel whey more slowly
than otherwise.
In order to restore the coagulability with rennet to pasteurized
milk, Klein and Kirsten4 in 1898 added calcium chlorid and a bac-
terial starter and were able to obtain fairly good limburger and other
soft cheeses. They used for 100 kilograms of skim milk 100 to 125
cubic centimeters of a solution containing in 100 c. c. 40 grams of
calcium chlorid, corresponding to 20 grams calcium oxid.
I Babcock, S. M., Russell, H. L., and Vivian, Alfred. Properties of galactase: A digestive ferment of
milk. Wisconsin Agricultural Experiment Station, Fifteenth Annual Report (1898), pp. 77-86. Madison,
1898. Seep. 82.
2 Kastle, Joseph H., and Roberts, Norman. The chemistry of milk. U. S. Treasury Department,
Public Health and Marine-Hospital Service, Hygienic Laboratory, Bulletin 56, pp. 315-417. Washington,
1909.
3 Moore, V. A., and Ward, A. R. An inquiry concerning the source of gas and taint producing bacteria
in cheese curd. New York (Cornell) Agricultural Experiment Station, Bulletin 158. Ithaca, 1899. See
p. 236.
4 Klein and Kirsten, A. Versuche, betreffend die Wiederherstellung der Verkisumgsfiihigkeit erhitzter
Milch durch Chlorcalciumzusatz. Milch-Zeitung, vol. 27, no. 50, pp. 785-787, Dec. 10; no.51, pp. 803-805,
Dec. 17. Leipsic, 1898. See also Fleischmann, W. Lehrbuch der Milchwirtschaft. 4th edition. Leipsic,
1908. See pp. 304, 305.


13







14 CHEDDAR CHEESE FROM PASTEURIZED MILK.

In Denmark a kind of cheese is made from pasteurized skim milk
to which about 10 per cent of buttermilk is added so as to bring the
acidity up to about 0.21 per cent just before adding rennet.1
In 1907 Dean 2 stated as a result of experiments in the use of cal-
cium chlorid with pasteurized milk for cheese making "the coag-
ulum was of a soft, weak nature and the cheese tended to be soft and
porous." He also added 1i to 3 per cent of bacterial starters to
milk pasteurized at 180 F. and ripened some time before adding
rennet. The rennet coagulated the milk, but the curd was weak in
body. He noted an increased yield of cheese, but the cheese tended
to be open and weak in body and texture. He adds:
On the whole the results are not very satisfactory and we shall require more light
on the subject of making pasteurized milk cheese before we could recommend the
method to Canadian cheese makers.
In 1910 C. A. Publow mentioned briefly some experiments in
making cheese from pasteurized milk, adding to each 100 pounds of
milk 2 cubic centimeters of a 25 per cent solution of calcium chlorid
and 2 or 3 pounds of bacterial starter. The details of the method
and the opinions of cheese judges other than the author respecting
the product are not published. At this station in previous yearn
efforts have been made to obtain good American cheese from pas-
teurized milk with the aid of calcium chlorid, but without success.

DIFFICULTIES MET IN MAKING CHEESE FROM PASTEURIZED MILK.

Pasteurization of milk prevents or greatly delays subsequent
coagulation with rennet. The curd from such milk when finally
cut into cubes expels moisture with much greater difficulty than a
raw-milk curd, probably because of some chemical change produced
in the casein by the heat of pasteurization. Rapid acid formation
by bacterial action which occurs in raw milk and raw-milk curds
does not occur in the pasteurized material. The presence of a mod- -
erate amount of lactic acid in raw-milk curds greatly hastens the
separation of whey from the curd, and the lack of acid development
in pasteunrized-milk curds is another condition favoring the retention
of excessive moisture in the curd and cheese.
The addition of calcium chlorid to milk which has been pasteurized
is known to restore in a measure the coagulability of the milk with
rennet, but we have observed, as Publow' points out, that, although
coagulation begins in about five minutes, "the curd does not become
firm enough for cutting in the usual time and should not be cut
before it is firm." Although the addition of calcium chlorid restores
I Decker, John W. Cheese making. 5th edition. Madison, Wis., 1909. Seep. 194.
I Dean, II. 11. Experiments in cheese making. Ontario Agricultural College, Thirty-third Annal
Report (1907). Toronto, 1908. See p. 120.
* 1'ublow. (Charles A. Fancy cheese in America. Chicago, 1910. See p. 20.
SLoc. cit. See p. 21.







DIFFICULTIES OVERCOME BY ACIDULATION.


the coagulability with rennet, it does not correct the acidity and the
other difficulties mentioned above as being caused by pasteurization.
The lack of acidity in such curd might be supplied by adding starter
to the pasteurized milk and ripening for several hours before starting
the cheese making, but the resulting loss of time would prohibit this
practice in factories. Where both starter and calcium chlorid are
added to milk after pasteurization, as suggested by Publow, and the
cheese-making process is begun at once without waiting for ripening,
the daily variations in natural acidity of the milk used produce cor-
responding variations in the moisture content of the cheese which
affect its quality. (See Table 1.)
What is needed in place of calcium chlorid for addition to pasteur-
ized milk is something which will not only restore the coagulability
with rennet, but which will also bring up the acidity without delay to
a sufficiently high percentage to induce reasonably rapid and com-
plete separation of whey from curd. A uniform acidity is necessary
daily so as to avoid daily variations in moisture content of cheese.
DIFFICULTIES OVERCOME BY ACIDULATION OF PASTEURIZED MILK.
The substance which has been found to meet all of the foregoing
requirements and which appears to be unobjectionable from all stand-
points is hydrochloric acid. While it might appear impracticable
at first glance to acidulate milk in large quantities daily at a factory,
yet upon trial this is found to be entirely practicable; and it has now
been done almost daily for nearly three years, without any trouble
arising from coagulation of the milk with acid at any time.
In Table 1 is shown the moisture content of green cheese obtained
on 12 days from pasteurized milk by the use of calcium chlorid
in the proportions suggested by Publow (see p. 14) and by the
use of hydrochloric acid, using always sufficient acid to raise the
acidity of the milk to 0.25 per cent calculated as lactic acid. The
milk used in the two vats was taken from the same receiving vat
full of milk, after thorough mixing. It was all pasteurized alike
and one-half was then treated with calcium chlorid and, the other
with hydrochloric acid. These were then made up into cheese
separately and were sampled for moisture at the time the cheeses
were dressed, after pressing one hour.1 From the table it can be
seen that whenever the acidity of the milk used was low (0.16 to 0.18
per cent) the moisture content of the cheese made with calcium
chlorid was high (40 to 44.45 per cent), and when the acidity was high
(0.21 to 0.23 per cent) the moisture content was low (38 to 40 per
cent). But in all cases where hydrochloric acid was added instead
of calcium chlorid the moisture content of the card was 37.5 to 40
per cent, whether the natural acidity of the milk was high or low.
SThe correctness of this method of sampling cheese for the moisture test is demonstrated in the latter Fart
of this bulletin.


15





CHEDDAR CHEESE FROM PASTEURIZED MILK.


TABLE 1.--Comparison of moisture cintnte and quality of dcese nude w "m
chlorid and with hydrochloric acid.


Date made.


Acidity
of milk
when
p&-
teur-
ized.


1911. Perct.
Aug. I8... 0.165
Do...... .165
Aug. 22 .... .165
Do....... .165
July 28..... .17
Do...... .17
Aug. 23..... .175
Do ...... .175
Aug.24..... .175
Do...... .175
Aug. 25 ..... .175
Do...... 175
Aug. ..... .15
Do...... .IR5
Sept. 4 ...... .190
Do....... .190
Aug. 17..... .21
Do...... .21
Aug. 36 .21
Do...... .21
Aug. 2. ..... 22
Do....... .22
Aug. 7...... .31
Aug. 10..... .187
Aulg. 21 ..... .215
Average... ......
Do..... .......


How made.


Calcium chloride ...
Hydrochloric acid.
Calcium chlorid...
Hydrochloric acid.
Calcium chlorid...
Hydrochloric acid.
Calcium chlorid...
H ydrochloric acid.
Calcium chlorid...
Hydrochloric acid.
Calcium chlorid...
Hydrochloric acid.
Calcium chlorid...
Hydrochloric acid.
Calcium chlorid...
Hydrochloric acid.
Calcium chlorid...
Hydrochloric acid.
Calcium chlorid...
Hydrochloric acid.
Calcium ehlorid...
Hydrochloric acid.
.... .do...........
..... do.........
..... do.............


Moisture
content of
dressed
cheese.


Score.


Fla-
vor,


Tex-
ture.


Criticism.


I 12


Flavor.


'1 1-4-.? 4


Per cent.
42.25
37.70
42.35
38.80
41.50
37.70
44.27
39.30
44.27
39.62
44.45
39.02
42.90
39.90
41.50
39.95
39.20
39.62
38.70
38.60
40.60
39.95
39.05
37.58
38.67


38
411
40
41
38
414

37
41
411


39
411
41
41
39
411
41
41


26
271
26
271
24
28
2,4
27
25

25
28
25
28
26




27
26j
271


Calcium chlorid... 42.00 39.45 25.73
Hydrochloric acid. 38.96 41.23 27.36


Flat, pungent.....
Clean.............
Flat, lacking......
Clean and O.K...
Lacks acid........
Trifle acid.........
Low, lacking.....
Trifle sharp.......
Sour-milk flavor..
Trifle sharp.......
Clean and O.K...
O. K .............
Bitter, lacks acid..
O.K ..............
Sweet, bitter......
Acid aftertaste....
Tastes salty.......
..... do.........
Vinegar flavor.....
Clean and O.K...
Trifle bitter.......
..... do............

.... ...... ......
S....................


Tstum.


Curdy to m, a.
Tried im.
Weak, sticky.
Trifle weak.
Wet and sticky.
Trifle sticky.
Trifle weak.
Do.

Sticky, loose,sbrt.
Coarse, oow.
Weak, mechanical
hole.
Mechanical holes.
Weak and sticky.
Loose, sticky.
Sweet holes.
Trifle loou.
Short, sticky.
Trifle Short.


From the above table it is evident that when milk is acidulated with
hydrochloric acid after pasteurization, as in the new method, the
moisture contentof the green cheese is not affected by the ripeness of the
milk before pasteurization and is quite constant between 37.5 and 40
per cent. This advantage does not attend the use of calcium chlorid.
The daily variations of moisture content shown in column 4, which
are between 37.5 and 40 per cent, are doubtless due to causes other
than acidity, and did not noticeably affect the quality of the cheese.
The scores and criticisms show that the cheese made with calcium
chlorid was neither as uniform nor as good in quality as that made
with hydrochloric acid.
The addition of hydrochloric or lactic acid to cream to raise its
acidity without delay, preparatory to churning, was attempted by
Babcock in 1888.1 The addition of a commercial acid to raw milk
to raise its acidity without waiting for bacterial action was suggested
to the writer in 1905 by Dr. S. M. Babcock, chief chemist of the
Wisconsin Experiment Station, and during tho years 1905-6 the
effort was made, following the suggestion of Dr. Babcock, to avoid
the necessity for ripening milk for cheese making at the factory and

1 Babock. S M. Churning ltts. Wisconsin Agricultural Experiment Station, Fifth Annual Report,
I19 p. 111-121. Madison, ISw. See p. 118. See also patent granted to MUIller, Milch-aeitung, vol. 23, u.
19, p. 301, Bremen, May 12, 1894; also notes on thLi subject in same volume, pp. 425,464, 701,750.


16


!1







DIFFICULTIES OVERCOME. BY ACIDULATION.


to substitute for such ripening the addition of a commercial acid to
the milk as soon as it was received. Immediately after acidulating
the milk it was heated to 86 and rennet was added and the process
completed in the usual manner. The.e exl)eriments sh'Iwed conclu-
sively that a commercial acid such as hydro( hloric a( i(d can be added to
milk without in any way damaging the quality of the cheese obtained.
However, the quality of cheese obtained from overripe or tainted
milk was not improved by the use of the acid, and it was concluded
that acidulation alone does not offer sufficient advantages to warrant
its recommendation to cheese makers. The addition of acids to
pasteurized milk for cheese making was begun by the writer in 1907.
Pasteurization and acidulation of milk appear to be complementary
processes, each supplying what the other lacks and together forming
the basis of an improved method of cheese making.
Since the use of calcium chlorid in pasteurized-milk cheese will not
be referred to again in this paper, two other points will be mentioned
here in which the use of hydrochloric acid is more advantageous.
These are: First, that the hydrochloric acid curds always begin to
thicken 61 to 7 minutes after rennet is added, while with calcium
chlorid the first visible coagulation occurs earlier if the milk used is
very ripe and later if the milk is sweet, thus varying from d(lay to day,
as shown in Table 2. Second, the percentage of fat lost in the whey is
on the average about 0.14 per cent greater in the method using cal-
cium chlorid than when hydrochloric acid is used, as also shown in
Table 2. This is probably because calcium chlorid curds are always
more mushy and easier to break utp in stirring than curds made with
hydrochloric acid. The latter are really superior in this respect to
curds obtained by the regular factory methods.

TABLE 2.-Comparison of calcium chlorid with hydrochloric acid as to their effects on checae
made with pasteurized milk.

Time required for Per cent of fat in
E Hwhey at tim of ,
visible coagula- whey at time of
tion after adding and ma L Li n gAc
rennet, curd. t Acidity
Date. of milk
used.
Calcium Hydro- Calcium Hydro-
chlorid. chloric chlorid. chloric
acid. acid.

1911. Minutes. Minutes. Percent. Percent. Percent.
July 28 14 7 0.23 0.13 0.17
Aug. 11 15 7 .35 .14 .185
16 6 7 .16 .12 .21
17 4 7 .21 14 .21
18 14 7 .32 19 .165
22 142 7 .32 18 .165
23 18 7 .39 20 .175
24 18 7 .42 20 .175
25 16 7 .38 16 .175
28 61 7 .17 13 .22
Average.. .................. .. 295 .159
79994. -Bu 165-13.2
799940--Bu11. 165--13---2


17







18 CHEDDAR CHEESE FROM PASTEURIZED MILK. I

THE PASTEURIZATION PROCESS.

PASTEURIZATION IN A DISCONTINUOUS OR "HELD" PASTEURIZER.

In May, 1907, one day's milk supply was divided in two portions,
one of which was made up by the regular method and the other was-
pasteurized for Is minutes at 160 F. and acidulated with hydro-
cldliric acid. The pasteurized vat gave the best-flavored cheese after
curing, though it was inferior in texture to the other. On March 12
1Id 127, 1908, milk pasteurized at 140 for 20 minutes and then acidu-
latedi gave such good cheese that a systematic study of the combined
process of pasteurization and acidulation was begun in July, 1908.
('wese was made from milk pasteurized at 140 F. for 20 minutes,
either in a Potts pasteurizer or in the cheese vat, by running first
steam and then cold water into the jacket. At the same time part of
tine milk supply after mixing anti dividing was used for making cheese
by the regular methods. The scores given to the two lots of cheese
thus obtained are shown below:

TABLE 3.-Comparison of flavor and texture of cheese made from raw milk and from mUlk
pasteurized at 140 F. for 20 minutes.

Pasteurized cheese. Regular make.
Date ____________
made.
Flavor. Texture. Flavor. Texture.

1908.
July 16 38.3 26.2 36.2 27.8
17 40.0 27.0 38.5 26.25
18 41.7 27.5 39.25 27.0
20 40.8 26.3 37.3 26.75
21 41.2 26.0 41.2 26.2
22 41.3 2ti.8 38.0 26.75
23 40.8 26.7 39.5 26.5
24 41.0 27.25 38.3 26.25
31 40.25 26.25 36.5 26.5
Average.. 40.59 27.00 38.30 26.66


The scoring was done by J. W. Moore and F. W. Laabs. In every
case but one the pasteurized cheese had better flavor and there was
little difference in texture between the two lots.

CONTINL'OUS AND 'HELD" PASTEURIZATION COMPARED.

On account of tlihe large volume of milk which must be handled
daily in a cheese factory, and the greater expense involved in providing
arrangements of sufficient capacity for heating and cooling 5,000 to
7,000 pounds of milk at one time as compared with the small cost of
a continuous )asteurizer, most of the later work was done with
continuous )pasteurizers. These can be used for handling any
required volume of milk, a larger quantity simply necessitating a








COMPARISON OF CONTINUOUS AND HELD PASTEURIZATION. 19

longer time for running. At the present time they are believed
preferable for cheese-factory use over any form of intermittent pas-
teurizer yet devised. Good results had been obtained by pasteuri-
zation at 140 for 20 minutes, but since continuous pasteurization
seemed the more practical factory method, it was determined to use
both methods in comparison on the same milk for several (lays. On
eight days, between July 16 and 24, 1908, half of the milk was pas-
teurized at 140 for 20 minutes and the other half at either 150, 160,
or 170 in the continuous machine. The effectiveness of the two
methods of pasteurization was judged from the increase in acidity
observed in the whey within the time from cutting curd to drawing
whey specified in each case.

TABLE 4.-Increase of acidity after pasteurization by continuous and by held processes.

Milk held at 140* Miik pasteurized Milk pasteurized Milk pasteurized
for 20 minutes. at 150. Instan- at 160". Instan- at 1700. Instan-
for 20 minutes, taneous. taneous. taneous.
Date.___________ ___________ ___________ _____
In- Time. In- Time. In- Time. In- Time.
crease. crease. crease. crease.

1908. Per ct. H. m. Per ct. H. m. Per ct. H. mn. Per ct. H. m.
July 16 0.11 2 57 ................... 0.055 3 0 ....................
17 .068 2 17 .................... .03 2 59 ....................
18 .055 2 17 .................... .03 2 46 ....................
20 .01 2 31 ............... ....... ... ............ 0.01 3 30
21 .02 2 19 ..................................... .01 3 30
22 .03 2 21 ...................................... 035 3 20
23 .078 2 10 .................... .................... .053 3 8
24 .018 2 30 0.01 2 40 ........ ............ ........ ............


From the above it can be seen that where milk is highly inocuIated
when raw, as on July 16, 17, 18, and 23, the acidity of the whey rose
0.05, 0.06, 0.07, and 0.11 per cent in about 21 hours after pasteur-
izing at 140 for 20 minutes, while it rose only about half as high in
3 hours after pasteurizing at 160 or 170 in the continuous machine.
A further substantial difference between curds from milk pasteur-
ized on the one hand at 140 for 20 minutes and on the other at 160
in the continuous machine is that the former curds often become mel-
low and greased on the surface and leak white whey after milling, in
this respect resembling some raw-milk curds. It was supposed at
first, from analogy to ordinary factory methods, that the curd which
became mellow and somewhat greased on the surface and which leaked
more or less white whey was more likely to turn out well than the
other, which was supposed to be lacking in acid or acid-forming
bacteria. The observation was made that a curd from milk pasteur-
ized at 170 and afterwards treated with 5 per cent starter did not
become mellow in the least, while curds from the same day's milk
pasteurized at 140 for 20 minutes and then treated with three-







20 CHEDDAR CHEESE FROM PASTEURIZED MILK.

fourths per cent starter, became very mellow and abundantly greased
before milling. It was judged unnecessary, thereafter, to wait for
mfll,,owiless or any other evidence of bacterial action or acid develop-
nment ii a 1)astturized-milk curd. If a sufficient proportion of starter
lhas Iben added after pasteurization, it is perfectly certain that the
bilact.ri-a ar, present in the curd, and will take part id the curing on the
sluilf. From tiLs point of view the mellowness which the 140 curds
occasiLMIIaIllV exhlibit is to be regarded as objectionable and as evidence
of lack of uinformityv between different days' make, and since this
never occurs with milk pasteurized at 160 in the continuous machine
the hitter appears preferable.
T"l('e cause for thle greater increase of acidity in whey after cutting
cirdI from milk pasteurized at 140 for 20 minutes, as shown above,
is li) dloulbt tlhe fact that the milk thus pasteurizedl contained more
living, active bacteria than that pasteurized in the continuous
mach1line. Samples were taken for bacteriological count in every
case imlnmeliately after pasteurizing, and then three-fourths per
cent of starter was added to each vat, followed immediately by
rennet as soon as the vat could be heated. Bacterial counts were
made on these samples by Mr. L. D. Bushnell, bacteriologist, as
follows:

TABLE. 5.-Number of bacteria per cubic centimeter in raw and pasteurized milk.

Pasteurized milk.
Date. Raw milk.
At 1400 for 20 In continuous machine.
minutes.

1908. Numberperc.c. Numberper c. c. Numberperc.c. "F.
July 17 102,000,000 2,206,000 652,000 160
18 72,000,000 2,620,000 1,960.000 160
20 119,000,000 262,000 200,000 170
21 30,000,000 33,000 9,200 170
22 173,000,000 320,000 38,000 170
23 360,000,000 15,320,000 1,300,000 170
24 65,000,000 62,000 1,100,000 150


SELECTION OF BEST TEMPERATURE FOR PASTEURIZATION IN THE
CONTINUOUS MACHINE.

Tlhe teml.erature selected should Le high enough to insure that
the rii:ening of the milk shall be uniformly checked daily, regardless
of the bacterial content of tlhe milk used, and it should not be so
highli as to injure the quality of the cheese. Tests were made as
follows: On several days the milk supply after mixing was divided
into four lots, one of which was made up by regular methods, the
others were pasteurized at 140, 150, and 160 and made up in
separate vats. The cheese after curing was examined by several







BEST TEMPERATURE FOR PASTEURIZATION.


expert cheese judges,
H. J. Noyes, F. W.
given in Table 6:


including Messrs. U. S. Baer, Robert McAdam,
Laabs, and Gottlieb Marty, whose scores are


TABLE 6.-Quality of cheese made from raw milk and from milk pasteurized at different
temperatures in the continuous-disk machine.


In nearly


every case


the 160


pasteurized-milk


cheeses were


cleaner in flavor and scored higher than the check, and in every
case they scored higher than the cheeses pasteurized at 140 and 150.
The different judges scored the cheese at different ages, which will
account for the wide variation of some scores. Bacterial counts
made by Mr. W. H. Wright' show that pasteurization at 160 is
more effective than at loNer temperatures. This is well illustrated
in Table 7.

Unpublished work by W. H. Wright, instructor in agricultural bacteriology, University of Wisconsin.


21


Pasteurized at-
Regular make.
Date. 140 F. 150 F. 1600 F.

Flavor.] Tex- Flavor. Tex- Flavor. Tex- Flavor. Tex-
ture. ture. ture. ture.

1908.
July 14 ................. 40.0 28.5 41.5 28.5 43.0 28.5
15 40.0 28.5 40.5 28.5 41.0 29.0 41.0 29.0
16 36.0 27.0 38.0 28.0 40.0 29.0 41.0 29.0
17 36.0 28.0 38.0 28.5 41.0 29.0 42.0 29.0
20 38.0 28.5 40.0 28.5 41.0 28.5 42.0 29.0
21 39.0 29.0 41.0 28.5 41.0 28.5 41.5 29.0
22 35.0 28.0 37.0 28.0 38.0 28.0 39.0 27.5
15 38.0 27.0 ........ ....... ............... 41.0 27.5
40.0 26.0 ........ ........ ........ ....... 44.0 28.0
40.0 26.0 ... ..... .. .. ............. 42.0 28.0
16 38.0 21.0 ....... .. .. ...... ......... 40.0 27.0
38.0 24.0 ............................... 44.0 28.0
36.0 27.0 ........................ ........ 41.5 28.5
17 37.0 26.0.0........ ...................... 3s.0 23.0
40.0 26.0 .................................. 44.5 29.5
35.0 2G.5 ....... ........ ........ ........ 43.0 29.0
20 37.0 20.o ................................ 40.5 28.0
42.0 27.0 .......... ..................... 44. 0 29.0
33.0 28.0 ................ ................ 41.0 28.0
21 36.0 28.0 ................................ 40.0 28.0
37.0 25.0 ...... ........................ 40.0 27.0
39.0 26.0 .......................... ........ 44.0 29.0
36.0 28.0 ........ ........................ 37.0 29.5
22 42.0 2S. 0 ................................ 40.0 25.0
370 7.0 27 ....... ....................... 35.0 25.5
23 44.0 26.0 ................................ 43.0 27.0
36.0 27.0 ................................ 40.0 28.0
24 43.0 28.0 .................. ...............4.3.5 28.5
32.0 28.0 ............................... 36.0 26.0







22 CHEDDAR CHEESE FROM PASTEURIZED MILK.

TABLE 7.-Bacterial content of milk pasteurized at different temperature in thecosttuwn.
disk machine.


I Bacteria per cubic centimeter.


Raw milk.


4423,6x6,(Wo
11,600,000


Milk pasteurized at-


140* F. 150" F.


6,080,000 600,000
5,800,000 600,000
1,540,000 139,000


That the use of 160 for pasteurization is high enough to kil most
of the bacteria in milk, so as to meet requirements such as those of
the Chicago ordinance previously referred to on page 12, is shown in
Table 8 by the following bacterial counts made by Mr. Alfred Larson
in 1909:


TAzLE 8.-Bacterial content


of milk before and after pasteurization in the wnfinuous-
disk machine at 160 F.


Date.




1909.
July 22
23
24


160 F.


50,000
60,000
23,000


Bacteria per cubic centimeter.

Date. Decrease.
Raw m Pasteurized
Raw milk. milk.


1909. Pter cnf.
Aug. 17 161,600,000 223,350 99.8
18 43,300,000 1,275,000 97.0
19 57,600,000 211,000 99.6
20 16,560,000 252,160 98.5
21 20,938,000 40.960 99.8
22 15,548,000 420.250 97.0
24 89,750,000 544.260 99.0
26 44,075,000 86,120 99.8
27 76,000,000 30,450 99.9
28 78,825,000 166,400 99.8
31 148,200,000 77,560 99.9
Sept. 1 25,836,000 9.670 99.9
2 51,650,000 52,125 99.9
14 27,150,000 29,250 99.9
16 77,650,000 341,600 99.6
17 38.900,000 136.350 99.6
18 124.700,000 159,80 99.8
19 60,280,000 287,500 99.5
21 185,000.000 477,600 99.6
22 63,500,000 263,200 99.7
23 45,525,000 142,300 99.7
28 18,376,000 202,600 98.8
29 13,660,000 31.000 99.7
30 980,000 14,580 98.5
1910.
July 11 6,500,000 27,000 92.6
12 1,600,000 25,000 98.5
13 5,250.000 17.200 99.7
14 4,700,000 36.000 99.3
15 10,000,000 28,700 99.7
20 5,350,000 21,000 99.6
Sept. 19 2,525,000 30,000 98.8


Milk pasteurized st--








OBJECTIONS TO HIGH TEMPERATURES FOR PASTEURIZATION.


Raw milk.


23


Similar determinations were made by Miss A. C. Evans upon milk
pasteurized in the continuous "flash" machine in 1910. They are
shown in Table 9:

TABLE 9.-Bacterial content of milk before and after pasteurization in the continuous
"'flash'' machine at 160 F.


Number of bacteria per cubic
centimeter.


Killed by
pasteuriza-
tion.



Per cent.
99.95
99.65
98.45
99.68
99.83
98.47
98.75
99.99
99.87
99.86
99.93
99.96
99.97
99.44
99.53
99.29
99.80
99.73
99.13
99. 97
99. S3
99.35
99.67
99.75


7,950,000
4,250,000
9,750,000
1,500,000
6,450,000
2,850,000
1,017,500
38,000,000
4,500,000
3,750,000
18,150,000
14,000,000
47,300,000
2,150,000
5,650,000
8,800,000
2,800,000
10,200,000
2,120,000
18,000,000
2,52,5,000
1,700,000
9,000,000
11,200,000


Pasteurized
milk.


4,700
15,300
142,000
4,850
11,250
43,600
12,725
700
6,000
5,500
13,800
6,500
16,200
12,000
27,000
63,000
5,500
21,200
18,500
5,700
4,300
11,000
30,000
28,000


OBJECTIONS


TO HIGHER


TEMPERATURES THAN
PASTEURIZATION.


160-165 F. FOR


Cheese made by the new process from milk pasteurized at 160 has
always a clean, mild flavor which suits practically all markets, and
will please any consumer who likes a mild-flavored cheese. Those
who are accustomed to and prefer very old high-flavored cheese
would not be suited, but estimates by leading cheese dealers indicate
that the proportion of consumers preferring the high-flavored cheese
is very small. Most of the cheese sold to-day is only a few weeks
old, because the dealers generally avoid long storage, preferring quick
sales and immediate profits. This makes it practically impossible
for most consumers to develop a taste for any but the new mild
cheese sold in most markets. The steady sales of pasteurized-milk
cheese during the past two years indicate that the flavor of the 160
pasteurized product is satisfactory for filling regular orders. Indeed,
it is an open question whether most of the "high snappy" flavor
often observed in old cheese is not due to the long-continued, slow
development of those same taints and off flavors from unclean milk
which we recognize as objectionable when they develop rapidly.


Date.



1910.
Aug. 3
4
5
9
11
15
16
17
18
19
24
25
30
Sept. 1
7
8
9
12
13
16
19
21
23
26







24 CHEDDAR CHEESE FROM PASTEURIZED MILK,

T'hie use of hluglier temperatures than 160 for pasteurization wa
tried on several days, with the result that the flavor production in
the cheese w.-as practically prevented and the texture was inferior.
I'li scores given to these cheeses are tabulated below:

TAL.LE 10. Quality of cheese from milk pasteurized at different temperatures tLin
continuous-disk machine.

PaJsterized at Paste-rized at Pasteurized at
160I F. 1700 F. 180 F.

Flavor. 1Texture. Flavor. Text.re.[ Flavor. Texture.

Oft. 12 40 29 3s 27 35 15
13: 40 29 39 28 35 15
14 40 2I 1 38 27 35 15

The scoring was done by Mr. F. W. Laabs. The 180 cheeses have
no Ch'leddar flavor, but taste like first-class cottage cheese. They
are so crumbly and short that it is impossible to draw a solid plug.
Tley keep) well, and it is possible that a good trade might be built
by tlie sale of this p1)roduct under some such name as "pressed cottage
CIeecst." In all cases thlie use of 160 for pasteurizing milk gave better
cheese than higher temperatures.
Three reasons have been suggested why the milk pasteurized at
180 gi 'es flavorless cheese:
First. If bacteria are the essential cause of flavor production, it
would appear likely that the necessary kinds of milk bacteria are
d(cstrovyed by the high temperature of pasteurization.
Second. If milk enzyms such as galactase are the essential cause
of flavor production, these enzyms are perhaps destroyed by the use
of 1 So0.
Third. It may be that the casein or other native milk constituent
which in normal cheese umidergoCs cleavatre, forming the flavor-giving
substances plrs.'nt in ripened cheese, is changed chemically either in
COiilJ)osition or as to constitution by tlhe heating to 180, so that upon
cleavage by by bacteria, enzy.ns, acids, or other agencies it yields differ-
('eit cleavage products, lacking the flavor, etc., which characterize
.(,rinal cl(eese.
III atte.mJpting to test the first, of these possible explanations a
variety of substances have been added( as starters to milk after pas-
teurizinlg at ISO0 or other high temperatures in order if possible to
supply the bacteria or enzynm needed for normal curing and flavor
prolductionl. Among tlhe special starters so used were pure cultures
of vtirioiis bacteria; raw iilk up to 20 per cent of the vat contents;
cultures of bacteria isolated from milk and cheese capable of develop-






EFFECT OF PASTEURIZATION ON CHEESE CURD.


ing 1.6 per cent or more lactic acid in milk (described by Hastings');
cheese of various ages rubbed to creamy consistency with milk and
added in different proportions through a hair sieve to the pasteurized
milk in the vat; cultures made by adding cheese in this manner to
milk and incubating overnight before adding to the cheese vat. All
of thcse materials were added to milk which had been pasteurized at
high temperatures up to 180, and cheese was made therefrom; but
in no case was it possible to get a normal flavor development in the
resulting cheese.
The lack of flavor production under these circumstances, where
many kinds of bacteria and starters were added to the pasteurized
milk, seems to indicate that the casein, etc., in milk thus treated is
incapable of cleavage into the flavor-giving substances; in other
words, that the casein, etc., is changed chemically by the heat of pas-
teurization. There is additional evidence that such a change occurs.

EFFECT OF PASTEURIZATION ON THE PROPERTIES OF CHEESE CURD.

A series of cheese curds made from milk pasteurized at 160, 170,
180, or higher temperatures show a regular gradation of certain char-
acteristics. The higher the temperature of pasteurization the more
tenaciously the curd retains moisture and the more difficult it is to
expel the whey by ordinary means. This is shown in the following
experiment: Thle milk in the receiving vat each morning was thor-
oughly mixed and then divided into three portions which were run
through the pasteurizer at different temperatures and made up into
cheese in different vats. Three-fourths per cent of starter was added
to each vat and the milk and curds were handled in all respects as
nearly alike as possible, the only difference being in the temperature
of pasteurization. The curds in separate hoops were pressed in the
same press, and the next morning moisture tests were made on each.
This entire work was repeated on several days. The results are
shown in Table 11.

TABLE 11.-Moisture content of green cheese made from milk pasteurized at different tem-
peratures in the continuous-disk pasteurizer.

Milk pasteurized at-
Date. _________
160 F. 170 F. 180 F.

1909. Per cent. Per cent. Per cent.
Oct. 12 38.4 42.2 46.6
13 37.0 39.9 43.5
14 39.0 40.7 45.5
I Hastings, E. G., Hammer, B. W., and Hoffman, C. Studies on the bacterial and leucocyte content ol
milk. Wisconsin Agricultural Experiment Station, Research Bulletin 6. Madison, June, 1909.


25






26 CHEDDAR CHEESE FROM PASTEURIZED MILK.

Each per cent given is the average of two closely agreeing dupli- m
cates. It is seen that in every case the higher temperatures of pas-
teurization cause higher moisture content in the green cheese. These
curds were all cut with a three-eighths-inch knife and heated to 104
in the whey.
Even when a 180 curd was cut with one-fourth inch curd knives
and a 160 curd with three-eighths inch knives, the moisture content
in the former remained higher, as is shown in the following experiment:

TABLE 12.- Moisture content of curds made from milk pasteurized at different tempaUe
in the continuous-disk pasteurizer and cut with knives of different Ams.


Each per cent in the table is the average of two closely agreeing
moisture determinations.
It is unquestionably true that pasteurized-milk curds retain mois-
ture more tenaciously than raw-milk curds, and this effect is more
marked the higher the temperature used in the pasteurization. It
therefore follows that the higher the temperature used in the pasteur-
izer the greater will be the weight of cheese obtained from pasteurized
milk. The yield per hundred pounds of milk weighed before pasteur-
ization in each vat on three days is given in Table 13.

TABLE 13.- Yield of cheese per hundred pounds of milk pasteurized at different tempera.
tures.


It will be shown later that the yield of cheese obtained by pasteur-
izing at 160 is slightly greater than that obtained from raw milk, so
that in this respect the effect of pasteurization is distinctly noticeable
even when the lower temperature is used in the pasteurizer. Again,


Milk pasteurized at 160* F. Milk pasteurized at
1800 F.

Time ter Cttin ut into Cut into Cut into
Time afer cutting f-inch f-inch j-inch
curd. cubes, cubes. cubes.

H. m. Per cent. Per cent. Per cent.
1 0 .............. 67.6 70.0 66.5
2 0 Drew whey... 60.1 63.9 61.0
2 30 .............. 47.2 52.4 50.6
3 30 Milled curd... 43.3 47.2 46.0
4 30 Salted curd... 42.2 45.9 44.6
4 50 Hooped curd. 41.4 45.1 43.9


Temperature of pasteurization.
Date made. -
160 F. 170" F. 1800 F.

1909. Pounds. Pounds. Pounds.
Oct. 12 12.28 13.42 15.42
13 12.10 12.97 14.53
14 11.93 12.70 14.44






EFFECT OF PASTEURIZATION ON CHEESE CURD.


among the peculiarities of pasteurized-milk curds is their decreased
power to coalesce or mat when on the rack or in the press. This
effect is not noticeable with milk pasteurized at 160 to 165, but is
perceptible at 170 and is very marked when the milk was pasteurized
at 180 or higher. The 180 curd cubes when piled on the rack pack
together like raisins or figs in a box but do not coalesce or unite, and
by rubbing the finger over the mass at any time the pieces can be
pulled apart. The same effect is noticed when the curd is pressed in
the hoop. The pieces pack together tightly but do not unite; and
at any time during the curing a plug drawn with a trier will either
come out in fragments or will break into pieces instantly when han-
dled. Instead of milling such a curd, it is merely stirred or shaken
apart with the hands.
These two peculiarities of pasteurized-milk curds, which can not
be remedied or avoided by any other means than reducing the tem-
perature of the pasteurization, considered together with the impos-
sibility of developing Cheddar flavor after pasteurization at high
temperatures, appear to indicate that the pasteurization produces
some deep-seated change in the chemical constitution of casein.
Another peculiarity of pasteurized milk, that of coagulating with
rennet only with great difficulty, need only be mentioned in this
connection, because in the process of cheese making here described
the addition of hydrochloric acid to the pasteurized milk entirely
-restores the coagulability with rennet, producing a curd in many
respects superior to and easier to handle than the curd commonly
obtained in the regular way from raw milk.
From what has been said it will be seen that the use of 160 to 165
for pasteurization offers many practical advantages. It is sufficiently
high to check effectually the further ripening of the milk during the
next few hours, while the use of 150 is not high enough for this pur-
pose. Furthermore, 160 gives cheese of cleaner flavor than 140 or
150 (no doubt by more effectual destruction of taint-producing
bacteria) or than raw milk, as shown in Table 6. It may be mentioned
also that over 99 per cent of the total bacterial content of the milk is
destroyed by use of 160, as shown in Tables 8 and 9. The 160 is
preferred to 170 or 180 because the cheese obtained by the use of
160 is more nearly like the best American cheese in moisture content
(see Table 11) and in texture and flavor. (See Table 10.)
So far as it is possible to say at the present time, the use of 160 is
sufficient to kill most probably 99 per cent of the gas and taint-
forming bacteria in milk. It can not be claimed that they are all
killed, because it is true that when very unclean milk is handled by
this process the cheese sometimes shows slight traces of unclean
flavors, though not enough to affect the market value. While gas
and pin holes have often been seen during the seasons of 1909, 1910,


27






CHEDDAR CHEESE FROM PASTEURIZED MILK.


aind 1911 in cheese juade by regular n:ethods at this factory, no gas
whatever was seen in any curd or cheese made during 1909 or 1911,
and tlie gassy cheese obtained, nine days in succession, in 1910 was
demonstrated to be tduie to the use by n istakeof a gassy starter which
was added to the ii ilk after pasteurization. The fault arosa at that
tij.e, fro. ii tlie inefficient n ('ans then att hard for preparing and heat-
irig Milk for propJa.ation of tlhe starter. An improved steam sterilizer
WaL' at once, set up for this purpose, which prevented all further diffi-
culty of this sort during tihe past two years.
Tlie templlwrattnur finally selected as ni-ost completely securing the
advantages and avoiding thle disadvantages of pasteurization for
(]j(,,seI( liakinig is (i(0 to 165 F. In practice the pasteurizer is set
ruuniiiig at 103 a.nd lld there as closely as possible.

TIrlE I)IFFIRENT TYPES OF CONTINUOUS PASTEURIZERS USED.

Two (i'erent pasteurizers were used in this work with entire
succUss, being apparently equally (ftective in producing the desired
r pjr J our capacity anrd a "flashj" n machine of 1,200 pounds capacity
per hour. (See PIs. II and 111.) The choice between these two types
of patstcurizing n achimus for use in this process appears to depend
uponi their relative cost and ease of operation and cleaning, rather
tlhan upon any diffT rence in efctctivencss. They were used alternately
on successive (days for several weeks, and on three days, September 1,
12. and 19, 1910, the milk was divided, one-half being run through
Coach. Tlhe cli c(se was first class in each case and showed no differ-
ences that could be traced to thlie use of different machines.
THE ACIDULATION PROCESS.
TIlE STANDARD ACIDITY OF MILK FOR CHEESE MAKING.

Milk as it flows from the pasteurizer varies daily in acidity and is
lacking in bacteria of tlhe lactic-acid type, needed to aid in cheese
curing. By the addition of sufficient hydrochloric acid to raise the
acidity of the milk to 0.25 per cent (as lactic acid) after pasteurizing,
and of three-fourths per cent of a first-class starter, the pasteurized
ziilk is brought daily into standard condition both as to acidity and
bacterial content for cheese-making purposes. The reasons for
adding acid and starter as specified will now be given in detail.
Tlhit stna:dlard acidity is 0.25 per cent, and the acidity of pasteur-
izeVd milk is raised to this figure ratliher than to 0.20 or 0.30 per cent
for the following reasons:
First. In regular cheese making the acidity of whey when drawn
is, on the average, about 0.17 per cent, corresponding to an acidity


28







STANDARD ACIDITY OF MILK.


of milk of about 0.25 per cent. Anyone can test the correctness of
this statement by transferring a pint of milk from a cheese vat, just
before adding rennet, to a small tin pail, keeping thle milk sample at
the same temperature as the vat and titrating the milk in the pail as
well as whey from the vat at intervals. When the whey reaches 0.17
per cent the milk reaches nearly 0.25 per cent.
The control of acidity at the instant tihe whey is drawn is commonly
regarded as most important in regular cheese making. \\With milk
pasteurized at 160 there is little or no increase of acidity (usually
about 0.01 per cent) in whey, before the whey is drawn. The acidity
of milk is adjusted to 0.25 per cent in this process after pasteurizing
in order to parallel ordinary working conditions at the time of drawing
the whey.
Second. Mixed milk in the factory cheese vat is commonly at 0.16
to 0.18 per cent acidity when received, although often at 0.19 to 0.21
per cent. It should never be over 0.23 per cent acidity. It is found
that an addition of hydrochloric acid equal to at least 0.02 per cent
of lactic acid is required to restore the coagulability with rennet to
such milk after pasteurization, but the daily addition of owly 0.02
per cent of acid would leave the milk of varying acidity, which is
objectionable. If 0.20 per cent were adopted as the standard acidity,
after adding 0.02 per cent in the form of hydrochloric acid, this rule
would exclude from use all milk having a higher acidity than 0.18
per cent when received, which it is not desirable to do. Only rarely
is a vat full of milk at 0.23 per cent acidity received at any factory,
but even such milk can be handled in the routine manner at tlhe sta'd-
ard acidity of 0.25 per cent by adding the required 0.02 per cent of
hydrochloric acid after pasteurization.
It might be stated as a matter of record, not as a precedent for
factory practice, that vats of milk of 0.24 to 0.28 per cent acidity
when received have been successfully made up into good cheese with-
out varying the process in any particular, excepting that only enough
acid is added after pasteurization to raise the acidity 0.01 per cent,
which is sufficient to restore the rennet coagulation to such ripe milk.
The only apparent lim-it of acidity for milk to be handled by this
process is that the milk should not, of course, be sour enough to
curdle in the pasteurizer, and this limit is reached at or about 0.30
per cent.
However, it should be recognized by everyone that milk that has
reached 0.30 per cent or even 0.25 per cent acidity before it gets to
the cheese factory must have received very poor care and attention
on the farm and must be entirely unfit for cheese making from a sani-
tary point of view.


29







30 CHEDDAR CHEESE FROM PASTEURIZED MILK.

COMPARISON OF DIFFERENT KINDS OF ACIDS FOR USE IN CHEESE
MAKING.
Of the more common acids-sulphuric, hydrochloric, and phos-
Jphoric --the first is the least convenient to handle, especially in a
ch(wese factory, because of the great amount of heat liberated when it
is diluted, and the impossibility of diluting it in the carboy in which
it is received.l Ilydro hloric acid is much better in this respect
ILaS it can |be readily diluted with an equal volume of water by pouring
tic' water into the acid with no danger and very little heat evolution.
Thus dilutedd it fumes very little, if at all, and can be readily and accu-
rately standardized by titration with normal caustic soda and phenol-
phlthalein indicator. Phosphoric acid can be purchased in carboys
of about 50 per cent strength, requires no dilution in the carboy, and
liberates little or no heat when diluted.
Tihe choice between hydrochloric acid and acid made from phos-
phorus is greatly in favor of the former because of the high cost of
the latter. Recently, however, phosphoric acid made from bone ash
or bone black has been put on the market in this country, containing
about 45 per cent free phosphoric acid and less than 1 per cent each
of hydrochloric acid, sulphuric acid, and phosphates of iron and
alumnina, this product being offered at 6 cents a pound in paraffined
barrels. The price of this acid is very nearly the same as that of chem-
ically pure hydrochloric acid for equal neutralizing power.
('hemnically pure hydrochloric acid is and has been foryears a stand-
ard article of manufacture, whose purity is tested daily by use in
hundreds of laboratories. On the other hand, the manufacture of
phosphoric acid from bone ash in a form free from objectionable
impurities has been accomplished only very recently.
A number of cheeses were made with phosphoric acid, but these
showed no advantage over those made with hydrochloric acid; indeed
theyseemed to have a slight peculiarity of flavor, as a rule, after curing.
Most of the cheeses made from pasteurized milk have so far been made
with hydrochloric acid, and the use of this acid is described and recom-
metnded in the present bulletin.
The selection of hydrochloric acid was made because it is cheap
andl n.ore easily obtained than any other chemically pure acid, and
being a natural (onstituent of gastric juice in the human stomach, no
objection could be raised on sanitary or other grounds against its use
in this process.
THlE PROPORTION OF HYDROCHLORIC ACID REQUIRED DAILY.
It is necessary to determine first what the acidity of each vat of
the mixed milk is, in order after pasteurizing to add the requisite
quantity of hydrochloric acid to bring the acidity up to 0.25 per cent.
Where only one vat of milk is to be pasteurized and only one workman







TESTING MILK FOR ACIDITY.


is employed it is probably better to weigh in all the milk then stir the
vat well and take out a half cupful of milk for the acid test.
Where two men are employed and([ it is desired to start the
pasteurizer running as early as possible (before the receiving vat is
full), the intake man should take from each weigh can of milk a
sampling tube full, mixing these samples in a pint jar. The acidity of
this mixed sample will then be the same as the average acidity of all
the milk run into the vat. As soon as one vat full of milk (say 5,000
pounds) has been run from the weigh can into the receiving vat, the
pint jar containing the sample for the acid test is handed from the
intake to the man running the pasteurizer, together with the total
weight of milk run into that vat. The pasteurizer was started when
perhaps only half of this milk had been received, but the receiving
vat is still about half full, and after making the acid test on the sample
the operator can tell exactly how much more hydrochloric acid must
be added, while pasteurizing the remaining milk in order to bring the
acidity of the whole vat up to the right point, or 0.25 per cent.
TESTING MILK FOR ACIDITY.

In determining the acidity of milk, measure a 17.6 cubic centimeter
pipette full of milk sample into a white china cup, which should be
shallow and wide rather than narrow and deep. Add two drops of
phenolphthalein indicator and while shaking or stirring the milk in
the cup run in tenth-normal alkali (Manns's solution) from a burette,
rapidly at first, and later by single drops, until the faint pink color pro-
duced by the last drop does not disappear on tborough.mixing. The
volume of tenth-normal alkali used is read from the burette, and this
volume divided by 20, which can be done mentally, gives the exact
acidity of the milk in per cent of lactic acid by weight. For example,
if the volume of alkali solution used was 3.2 cubic centimeters the
acidity is 3.2 divided by 20, which equals 0.16 per cent. Subtracting
the acidity of the raw milk from 0.25 per cent shows how much the
acidity of the milk is to be raised with hydrochloric acid after pas-
teurizing. For example subtracting 0.16 per cent from 0.25 per cent
leaves 0.09 per cent, which shows that the acidity is to be increased
0.09 per cent with hydrochloric acid.
The outfit needed for testing milk is shown in Plate I. It consists of:
1. A burette with rubber tip and pinchcock; capacity 25 c. c., with
110 c. c. graduations.
2. A 17.6 c. c. pipette as used for the Babcock test.
3. A white china teacup, which is best if shallow and wide and with
flat bottom.
4. A support for the burette, which may be an iron stand and clamp,
or a wooden strip with a hole in it, fastened to a window casing, as
shown at the left in Plate I.


31






3 2 CHEDDAR CHEESE FROM PASTEURIZED MILL '

5. A nrubber-sto)ppered bottle of Manns's solution (tenth-iormal
alkidi) which may be purchased at $1 per gallon of dealers in dairy
supplies, or may be made by diluting the normal alkali solution,
which must be purchased as it is required in this process as described
on page 36. '.. .,!|
6. A 2-ounce or 4-ounce bottle of phenolphthalein indicator sofu.
thin.
7. The additional outfit required for use in this process of cheese
making is also shown hi the figure. It consists of 1 gallon of normal
alkali (ten times as strong as Manns's neutralizer), a 50 cubic e0t.
meter measuring flask, a 500 cubic centimeter measuring cylinder, mad
a 2 cubic centimeter pipette, which should be accurately made. A
galdlon of normal caustic alkali contains about 5 ounces of caustic
sida, worth about 15 cents, andi should cv st the cheese makerno more
than a gallon of tenth-normal s-luti.mn-that is, about $1.

PRESERVING THE TENTH-NORMAL SOLUTION.

Instead of using the large bottle of tenth-normal solution to fill the
burette with, it is much better t3 get a smaller battle, holding 6 or
S ounces, alsj pr.)viIedl with a rubber stopper, and to fill this
smaller b1) ttle occasionally frjm the larger bottle, which is then put
away, tightly stoppered, in a safe place. The small bottle is kept-
near the burette and used daily in filling it, and the large bottl is
thus protected from unnecessary exposure, loss cf strength, and from
(IaT!ger of spilling. The use cf tw. battles in this manner has proven
in. st satisfactory in this laboratory and dairy school during the past
four years. It is recommended' as a means of avoiding loss of
strength through exposure to the air, which has heretofore been the
greatest difficulty to overcome in the i se of Manns's test in the cheese
factory.
DILUTING NORMAL ALKALI TO TENTH-NORMAL.

One may prepare tenth-normal alkali by diluting the normal alkali
as follows: Pour into a 500 cubic centimeter graduated cylinder
exactly 50 cubic centimeters of the normal solution measured in the
50 cubic centimeter flask. Add at once 450 cubic centimeters of pure
water, either rain water or condensed steam. Pour the-mixture into
a clean glass bottle, mnix by shaking, and keep stoppered with a
runb)lber stopper to avoid loss of strength by exposure to air. If the
mixture is muddy or turbid, the water used in diluting was not pure.
A slight turbidlity may be neglected.
Sammniis. J. L. The preservation of Mann's alkaline solution inches fhctorim. Ho rd's Dfyumi=
vol. Vl. No. 41, p. 1200. Fort Atkinson, WIs., Nov. 12, 1901.






.. !I
':!|









































OUTFIT USED FOR TESTING MILK FOR ACIDITY (MANN'S ACID TEST) AND IN TESTING STRENGTH OF HYDROCHLORIC
ACID USED IN CHEESE MAKING.















i. 165 B-'rFAu o, A,vaW. I'%Du'TRV, U. S. DEPT. or AGICULTURtJE.


PLATE II.










































THE CONTINUOUS FLASH" PASTEURIZER AND APPARATUS USED IN ACIDULATING PASTEURIZED MILK.









ADDITION OF ACID TO MILK.


ADDING ACID TO MILK AFTER PASTEURIZATION.

For this purpose the acid of normal strength is placed in an acid-
proof container on a shelf near the outlet of the cooler. A glass bottle
or a paraffined wooden cask can be used, as shown in Plate III. The
container has a small opening on one side near the bottom, through
which the acid is drawn by a rubber tube of one-eighth or one-quarter
inch internal diameter closed by a screw pinchcock. On the outside
wall of the container, beginning at the top, a scale is engraved or
otherwise permanently attached, with graduations showing pounds,
halves, and quarters of acid delivered. If the container is opaque, a
glass level-tube placed outside near the scale shows the acid level
within at any time. The capacity of the acid container should be
about 10 gallons for use with a 7,000-pound vat of milk. In addition,
a two-quart tin pan is connected by means of a short piece of con-
ductor to the cooler outlet. The milk from the cooler and acid from
the container are thoroughly mixed in the conductor and mixing
pan, from which the acidulated milk overflows and runs into the
cheese vat.
In order to avoid coagulation of milk with acid, the acid is added
from a jet so as to strike the cooled milk while the latter in a thin
stream is moving rapidly down the short, steeply inclined piece of
open-conductor pipe. The mixture then enters the mixing pan and
its direction is abruptly changed twice, thus securing thorough
mixing of milk and acid before it flows over the edge of the pan into
the cheese vat.
In using this acidulator there is never any danger of coagulation if
the operator remembers always to shut off the acid before the milk
flow stops. It has been repeatedly shown that 2 pounds of acid,
or twice as much as commonly required, can be safely added in this
manner to 100 pounds of milk at 60 to 80 F. without causing coagula-
tion. If any small particles of curd are formed, they rise to the
surface of the milk when quiet in the vat and can be plainly seen.
They can then be taken up with a hair sieve and rubbed through the
sieve into the milk without causing loss of yield. In practice,, the
acidity of the vat of milk, when all in and stirred, always comes
between 0.24 and 0.26 when attempting to make it 0.25 per cent,
and this degree of accuracy is entirely satisfactory.

CALCULATING THE AMOUNT OF ACID TO BE ADDED.

To calculate how many pounds of normal hydrochloric acid are
required by any vat of milk after pasteurizing, it should be remem-
btered that 1 pound of the acid added to 100 pounds of milk will raise
its acidity just nine hundredths (0.09) per cent, From this it is easy
799940-Bull. 165-13--3


33







CIIHEDDAR CHEESE FROM PASTEURIZED MILK.


t4) see that for 2,500 pounds of milk, of 0.16 percent acidity, just 2
poiunis of normal strength acid will be required, and for 3,050 pounds
,f milk 30.5 pounds of acid will be needed, etc. If the milk showed
an aridity (if 0.21 per cent when raw, then subtract 0.21 from 0.25i
which leaves 0.04 per cent. In this case, since the milk is riper td
start with, less acid will need to be added; only four-ninths of a pound
(if acid for each 100 pounds of milk will be necessary to bring the acid.
ity up from 0.21 to 0.25 per cent. In any case the weight in pounds
f acid require is equal 0.25- acidity of raw milk weight of milk,
.9f acid required is equal to 100

or 0.25- acidity of raw milk weight of milks Stated in words the
9.0
rule is, divide the weight of milk by 9 and multiply by 0.25 minus
the acidlity of the raw milk.
The following table shows the amount, in pounds, of normal acid
required to be added for each 100 pounds of milk when the acidity
of the latter before pasteurizing is 0.15, and for each one-hundredth
increase up to 0.27:

TABLE 14.- Weight of normal aid required to be added for each 100 pounds of milk.

Weight of
Acidity of normal Acidity of
milk when acid added milk after
pasteur- to 100 the addi-
ized. pounds of tion of acid.
milk.

Per cent. Pounds. Per cent.
0.15 1.11 0.25
.16 1.00 .25
.17 .88 .25
.18 .77 .25
.19 .66 .25
.20 .55 .25
.21 .44 .25
.22 .33 .25
.23 .22 .25
.24 .11 .25
.25 .11 .26
.26 .11 .27
.27 .11 .28


Where milk appears to be of, say, 0.175 per cent acidity when
received, it is treated as if it were at 0.17 per cent, dropping the 0.005
out of the calculation.
The following table, conveniently posted, may aid in calculating
the weight of acid required for any weight of milk at any acidity:


34







PREPARATION OF NORMAL IYDIROCIILOHIC ACID.


35


TABLE 15.--Weight of normal hydrochloric acid required for stated quantities of milk at
stated acidities.

Hydrochloric acid required when acidity is -
Weight __________-----___
of milk.
0.27 to 0.23. 0.22. 0.21. 0.20. 0.19. 0.18. 0.17. 0.16. 0.15. 0.14.
01.24.

Mbs. Lbs. Lbs. Lbs. Lbs. Lbs. Lbs. Lbs. Lbs. Lbs. Lbs. Lbs.
10,000 11.1 22.2 33.3 44.4 55.5 66.6 77.7 88.S 100.0 111.1 j 122.0
9,000 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100.0 110.0
8,000 8.9 17.8 26.7 35.6 44.4 53.3 62.2 71.1 80.0 SS. 9 97.8
7,000 7.8 15.5 23.3 31.1 38.9 46.7 54.4 62.2 70.0 77.8 S5.6
6,000 6.7 13.3 20.0 26.7 33.3 40.0 46.7 53.3 60.0 66.7 73.3
5,000 5.6 11.1 16.7 22.2 27.8 33.3 38.9 44.4 50.0 55.5 61.1
4,000 4.4 8.9 13.3 17.8 22.2 26.7 31.1 35.5 40.0 44.4 48.9
3,000 3.3 6.7 10.0 13.3 16.7 20.0 23.3 26.6 30.0 33.3 36.7
2,000 2.2 4.4 6.7 8.9 11.0 13.3 15.6 17.8 20.0 22.2 24.4
1,000 1.1 2.2 3.3 4.4 5.5 6.7 7.8 8.9 10.0 11.1 12.2
900 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0
800 .9 1.8 2.7 3.6 4.4 5.3 6.2 7.1 8.0 8.9 9.8
700 .8 1.6 2.3 3.1 3.9 4.7 5.4 6.2 7.0 7.8 8.6
600 .7 1.3 2.0 2.7 3.3 4.0 4.7 5.3 6.0 6.7 7.3
500 .6 1.1 1.7 2.2 2.8 3.3 3.9 4.4 5.0 5.6 6.1
400 .5 .9 1.3 1.8 2.2 2.7 3.1 3.6 4.0 4.4 4.9
300 .4 .7 1.0 1.3 1.7 2.0 2.3 2.7 3.0 3.3 3.7
200 .2 .4 .7 .9 1.1 1.3 1.6 1.8 2.0 2.2 2.4
100' .1 .2 .3 .4 .6 .7 .8 .9 1.0 1.1 1.2
75 .08 .17 .25 .34 .42 .50 .60 .67 .75 .83 .92
50 .06 .11 .17 .22 .2S .33 .39 .44 .50 .56 .61
25 .03 .06 .09 .11 .14 .16 .19 .22 .25 .28 .31


To find how much normal hydrochloric acid will be needed to
raise 6,754 pounds, for example, of milk of 0.17 per cent acidity to
0.25 per cent acidity, take from the table the figure given under 0.17,
opposite 6,000, which is 53.3; add to this the figure opposite 700,
which is 6.2; then add the figure opposite 50, which is 0.44; the total
gives the number of pounds of acid required, namely, 59.9 pounds.

PREPARATION OF NORMAL HYDROCHLORIC ACID IN THE CHEESE
FACTORY.

Chemically pure hydrochloric-acid solution, as purchased in carboys
containing about 120 pounds each, contains about 40 per cent by
weight of hydrochloric acid and 60 per cent of water, and costs about
7 cents a pound. Its strength varies somewhat, and it must be
diluted with water before it can be added to milk in this process.
The preparation of normal-strength acid used in cheesemaking is
carried on at the cheese factory in twvo steps, as follows:
First step.-Remove the wooden cap from the top of a fresh carboy
of acid and loosen the glass plug in the neck by tapping it on different
sides very gently with a piece of wood (not metal) until it can be
drawn out readily with the hand. Set an empty carboy alongside the
newly opened carboy. Fill both limbs of a glass siphon with water,
removing all air bubbles, and insert the two limbs into the carboys at
once, as shown in Plate IV. When the siphon is in place, as shown in
the lower figure, the acid will flow from the full carboy into the other
until in about half an hour each is practically half full. Now fill up






36 CHEDDAR CHEESE FROM PASTEURIZED MILK.

each carboy nearly to the neck with water, leaving space enough
beneath the neck to l)ermit mixing the contents readily by shaking.
Tip each carboy up on one edge and rock vigorously for about five
minutes with the stopper out to induce thorough mixing. The liquid
gets slightly warmer on mixing, and it is stoppered and left to stand
,overnight to cool and is then called "dilute" acid. i
To determine how much further each carboy of dilute acid requires
to lW dliluted with water to make it exactly "normal" in strength, set
ul) theim burette used in Manns's test, but fill it with normal alkali solu-
(ion, which is 10 times as strong as that used in testing milk. Using
a 2 cubic centimeter pipette, transfer exactly 2 cubic centimeters of
tle dilute' acidl from the carboy to the porcelain cup containing a little
pure water, letting the pipette drain into the cup half a minute by the
watch and blowing out the last drop of acid from the tip into the cup.
Now add one or two drops of indicator and after reading the level of
alkali in the burette, draw out the alkali from the burette, precisely as
in testing milk, rapidly at first, later by single drops while shaking
the cup in a circle until the last drop added produces a distinctly pink
color which remains throughout the entire liquid after thorough mix-
ing. Read and record the volume of alkali solution used. Rinse out
tlie cuP), till up the burette, shake up the acid in the carboy for a
minute and test another 2 cubic centimeters of the acid for the sake
of accuracy.
If the contents of the carboy were thoroughly mixed at first, the
two titrations will agree closely, not differing by more than 0.20 cubic
centimeter. If they do not agree, the carboy contents were probably
not well mixed at first, and should be given another very thorough
shaking for five minutes, after which the titrations are repeated.
Once thoroughly mixed the acid and water remain mixed, and never
need to be shaken again.
Suppose that in the two tests the 2 cubic centimeters of acid
required 11 and 11.2 cubic centimeters of normal alkali to produce
tie pink color, the average being 11.1 cubic centimeters. Divide the
volume of alkali by 2-the volume of acid used-which gives in this
11.1
case -- -5.55. This means that the acid is 5.55 times as strong
as it should be for normal acid, and that it must be diluted to 5.55
times its volume with water to make it exactly normal in strength.
Tlie work described above is performed once on each carboy of
dilIuti, a(cid before using it for cheesemaking, and the object is to get
tie figure .5.55 in this case) which shows how much too strong the .
.iiu is, 111( ll low Nmuch it must be diluted to make it normal in '
Sm r'gt Ii.
Sf r'ml .stp.-lThe second step consists in diluting up, each day, as
much uf the acid as will be needed for the milk on that day. This








BUL. 165, BUREAU OF ANIMAL INDUSTRY, U. S. DEPT. OF AGRICULTURE.


FULL CARBOY OF EMPTY GARBOY
HYDROCHLORIC ACID

TRANSFERRING ACID FROM FULL TO EMPTY CARBOY BY MEANS OF SIPHON.


PLATE IV.














































VAT STRAINER FOR STRAINING MILK INTO RECEIVING VAT.







DIRECTIONS FOR PASTEURIZING AND ACIDULATING MILK.


! is performed as follows: Having determined that the dilute acid is
5.55 times stronger than normal, the acid is further diluted for use
Each day, adding 1 volume of acid to 4.55 volumes of water, thus
i making the total volume 5.55 times as great as the acid used.
To do this, measure out any convenient volume (say 500 cubic
centimeters for about 2,500 pounds of milk) of the acid in a glass
cylinder and add it to 4.55 times its volume of water (in this case
500X4.55=2,275 cubic centimeters water). The acid should always
, be measured, but if more convenient the water can be weighed in
pounds if it is remembered that 453 cubic centimeters of water weigh
2,275
1 pound. In this case 453 =5.02 pounds of water needed.
453
The acid and water can be mixed in the acidulator or in a wooden
pail, or in a bright tin pail, if the water is put in first and the acid
added later. After the proper amounts of acid and water have been
poured into the acidulator, they should be thoroughly mixed at once
by stirring with a wooden paddle, and once thoroughly mixed the
normal acid is always ready for use. Of course the acid should not
be handled in galvanized iron or aluminum vessels, as it will rust
them. The undiluted acid will also discolor tinware and should be
measured in the glass cylinder, as directed. The "dilute" acid is
drawn from the carboy into a gallon glass bottle through a glass
siphon, which is first filled with water. The water used in the siphon
is so small in volume-about 1 per cent of a gallon-that it does not
noticeably affect the strength of the acid.
There is nothing difficult about the preparation of normal-strength
hydrochloric acid for use in cheese making, and anyone who knows
how to titrate milk for acidity can learn to do this also. To test the cor-
rectness of the work when completed, transfer two cubic centimeters
of the acid with a pipette from the acidulator to the porcelain cup,
and titrate it with the normal alkali in the burette. The volume of
alkali required should be between 1.9 cubic centimeters and 2.1 cubic
centimeters, or, better, exactly equal to the volume of acid used.
The degree of accuracy required in this whole process is very easily
attained, as quite satisfactory results will be obtained in acidulating
milk if the normal acid used is anywhere between 0.95 and 1.05 normal.

GENERAL DIRECTIONS FOR PASTEURIZING AND ACIDULATING
MILK.
The method described is well adapted for use in a large factory.
At a factory handling two to three large vats of milk daily two men
should be employed. The inspection and weighing of milk at the
intake is performed by one man while the other makes the determi-
tions of acidity and runs the pasteurizer. After the milk is all in
and pasteurized the two men work together, heating up the vats,


37




*iI

38 CHEDDAR CHEESE FROM PASTEURIZED MILK.

ad(lding the starter, color, and rennet to the vats at least 10 or 15 min-
utes apart. lThey cut the curtis in the same order, each 25 minutes
after tlie rennet hlas been added, and start the agitators in each curd
as soon as cut. The vats are heated up and the whey is drawn from
tlhe, vats in the same order, Loth men working together in putting
the ctirds on the rack, finishing each vat of curd in time to handle
tlie next.
If more than three vats are handled in one factory, additional help
will Ie net(eded, especially for bandaging hoops, turning cheese, and
other labor.
Where only one vat of milk is handled daily, the milk is run first
into tlhe receiving vat, from which it flows into the pasteurizer,
tlhroutgh the cooler, and into the cheese vat. If two vats of milk are
hanldled( daily, the first milk received may be run into one cheese vat,
from which it is pasteurized into the other cheese vat, while the milk
received later is run into the steel receiving vat, from which it is
pasteurized into the second cheese vat.
If three or more vats of milk are handled daily, the receiving vat
and the first cheese vat are filled alternately with milk from the in-
take, and alternately emptied through the pasteurizer into the other
cheese vats. It is only necessary to see to it that the last vat filled
from the intake shall be the receiving vat in order that this last milk
may be run into one of the cheese vats after pasteurization. One re-
ceiving vat is needed in addition to the necessary cheese vats wherever
this process is used.

MAKING READY TO PASTEURIZE.

Since pasteurization is essentially a cleaning process, care should
le taken to keep the make room, the vats, machinery, etc.. and every-
thing with which the pasteurized milk comes in contact as clean as
possible.
Although milk flows intermittently from the weigh cans, it is de-
sirable that the pasteurizer, once started, shall run continuously, with
a steady milk supply, and for this purpose a receiving vat is pro-
vided. The milk should be run into the receiving vat through a
strainer which will remove all flies, straw, etc., and which can not
by accident fail to work properly. Such a strainer is shown in Plate
V. It is set up ay slipping a piece of seamless cheese bandage over
the wooden frame of the vat strainer and placing the metal part on
to)p. The metal part collects all large pieces of dirt and prevents the
nidk from sj)lashinig over the side. The two thicknesses of cheese-
chitlh effectually remove finer particles of dirt. This arrangement
has been used in this series of experiments for about two years and is
hIart il- recommended. Of course the cloth should be scalded daily.






OPERATION OF THE PASTEURIZER.


The weigh can, conductors, receiving vat, and pasteurizer should
be washed daily, immediately after use, and again rinsed with clear
hot water before use, if necessary. The pasteurizer and cooler and the
connecting pipes should be washed thoroughly daily. Just before
starting the pasteurizer each morning the operator should rinse out
the cheese vat and steam it by running steam into the jacket. The
pasteurizer and delivery pipes, especially those parts which are in
contact with the cooled pasteurized milk, should be also scalded or
steamed. This can be done by running a couple of pails of hot water
into the heating compartment, heating it there to 180 or higher,
and running it over the cooler without having any cold water inside
the cooler.
Where only one vat of milk is being pasteurized, the acidulator may
be set on the edge of the vat, but to avoid moving it, when several
vats of milk are handled daily, the acidulator should be set near the
pasteurizer and the acidulated milk run into the different vats
through a movable conductor, as shown in Plate III.

STARTING AND STOPPING THE PASTEURIZER.

When milk enough has been received to insure a continuous supply
for the pasteurizer, the latter may be started.
First, see that everything is in place and that the pump supplying
water for cooling is running. Set the pasteurizer in motion, turn on
a little steam, and run enough milk into the beating compartment
nearly to fill it so as to register its temperature on the naked glass
bulb of the thermometer placed near the exit to the cooler. Do not
allow any milk at all to run into the cooler. If any does by accident,
draw it out and scald the cooler with a pail of hot water.
Open the steam valve to the full running capacity. When the
thermometer in the milk registers about 155 start the milk supply
again and adjust so that the thermometer stands at 162 at the exit
From the heater. Use care to see that no milk at all is allowed to runn
to the cooler at a temperature below 160. If any irregularity occurs in
Starting, it is much better that the first milk should be heated higher
than 160, even up to 180, rather than that any portion should pass
over into the cheese vat without reaching 160. It will do no harm at
all if for a few minutes at first milk at 170 or 180 passes over into the
cooler, because this milk will at least be thoroughly pasteurized, but if
Smilk at 140, or any temperature below 160, passes over it may carry
over harmful bacteria which may injure the entire vat of cheese. A
file mark on the steam-valve handle is a great help in quickly adjust-
ing the steam supply to the right point.
Once adjusted, and with steady milk and steam supply, the pasteur-
izing temperature remains nearly constant and requires only momen-


39






CHEDDAR CHEESE PROM PASTEURIZED MILK.


tairy inspection every few minutes. No doubt an automatic tempera-
lure-il' troltdling device could be used to advantage here.
AltillugIl tdie thermometer now supplied with some forms of
pasteulrizers is metal jacketed to prevent breakage, yet in all the
expewrimnents here rep irted this metal-cased thermometer was found
to register mInre slowly'than a naked glass-bulbed thermometer, set in
a rlubbelr stopper. Tle latter kind hlias been in use two years without
breaking and is therefore preferred.
In stopping thile pasteurizer for any reason, the operator should
renimenber to stip the acidulator first, then the milk supply, and last
of all tlle steam. If thle stoppage is for long, as at the end of the
d(ay's run, tile lhot milk in the heating compartment is drawn out in a
pail (its temperature should be 160 or above) and added to the vat.
The minilk in thie cooler is also drained and rinsed, if desired, into the
vat.
Thle water supply for cooling must be ample so that a thermometer
placed in thle milk flowing from the cooler is not above 85 at any
fime, and preferably at 80 or lower, since the milk in the vat can
easily be heated to 85-86 for setting with rennet, but can not so
well be set, or easily cooled, if above 86.

STARTING AND STOPPING THE ACIDULATOR.

As soon as the pasteurizer has been started and regulated the
pinchlcock at the acidulator is opened, allowing one or more small
streams of lihydrochloric acid to run into the milk. The height of the
liquid in tile acidulator sliould be marked on the glass scale with a
pencil or string, when starting, and another mark placed lower down
onl tle scale. to show how much acid is to be drawn out for that vat
of milk. By tilts means the operator can see from any part of the
roomn when tile acidulator is ready to be stopped. Always stop the
acidulattor before stopping the milk.

THE USE OF BACTERIAL STARTER IN THE NEW PROCESS.
TIlE REASON FOR ADDING STARTER IN MAKING PASTEURIZED-MILK
CHEESE.
Thle addition of tlhe required amount of hydrochloric acid to milk
raises its acidity at once to 0.25 per cent, but does not cause any fur-
tiher ii'Cre'ase of acidity at any time. Of the acid thus added, only
abiii it ,zie-fort ietli remains in thle curd, the rest escaping in the whey.
No lii.,iic.al method lhas l)bct n found for increasing the acidity of a curd
(o, 1, raick. so that if acid plays any important part in the cheese-
.riii,, lpr..ss, ii will le necessary to add bacteria to the milk in order
t. d'evel, i tlie necessiiry acid in tlhe cur:d and cheese. A number of


40








THE USE OF BACTERIAL STARTER. 41


experiments were performed in which the milk supply was divided
and made up in different vats, using different proportions of starter.
The cheese was finally scored by Mr. J. WV. Moore with the following
results:


TABLE 16.-Quality of cheese made from pasteurized milk
added.


I "e" in thi column indicates raw-milk cheese.


These scores may be summarized as follows:

TABLE 17.-Situnn.mmary of scores in Table 16.


with varying amounts of starter


Propor- Tempera- Score.
Date. Cheese tion o ture of ______
made. No. strr. pasteuri-
starer nation. Flavor. Texture.


1908. Percent. F.
Au-. 17 1076c .................... 40.50 27.00
1079 0.25 157 40.50 27.25
1081 .50 157 41.25 27.25
1083 .75 157 42.50 28.00
18 1085C .......... .......... 41.00 27.25
1087 .25 157 41.75 27.75
1889 .50 157 41.00) 27.25
1091 .75 157 40.25 27.00
19 1093c .................... 40.50 27.00
1095 .25 157 41.25 27.00
1097 .50 157 42.50 27.75
1099 .75 157 42.75 28.00
20 IOlc .......... .......... 41.25 27.00
1103 .25 157 42.50 28.25
1105 .75 157 42.25 27.75
21 110 .......... .......... 40.75 27.00
1111 .75 157 42.25 27.25
1113 1.00 157 42.50 27.25
1115 1.25 157 42.50 27.75
22 117C .................... 39.50 27.25
1119 .75 157 42.25 27.00
1121 1.00 157 41.75 27.25
1123 1.25 157 42.25 27.00
31 1157c .................... 41.00 27.00
1159 None. 162 41.00 27.00
1161 .3 162 42.50 2.00
1163 .6 162 42.50 28.00
Sept 1 1165c .......... .......... 39.00 2<.50
1167 None. 162 40.50 26.00
1169 .3 162 42.00 27.50
1170 .6 162 42.50 28.00
2 1173c .................. .. 40.00 27.00
1175 None. 162 41.00 26.00
1177 .3 162 41.00 27.00
1179 .6 162 41.50) 27.00
1021 3.0 .......... Sour. Color-cut.
1026 5.0 .......... Sour. IColor-cut.


Ntmer Average scores.
Nt mr her
Amount of starter, ofcheies -------
scored. Flavor. Texture. Combined.


Per cent.
0 3 40.S3 26.33 67. 1
0.225 to 0.30 7 41.64 27.53 C9.18
.5 to .6 6 41.AS 27.54 6t9.42
.75 6 42.04 27..50 6)9.54
1.0 2 42.12 27.25 69.37
1.25 2 42.37 27.37 69.75




..... ..


42 CHEDDAR CHEESE FROM PASTEURIZED MILK.

'these scores indicated that the cheese obtained by three-fourths,
Ime, or one and a quarter per cent starter are about equally good,
considering both flavor and texture, and the use of three-fourths per
cent starter has been continued since August, 1908, to the present
time, with good results. The starter used should be first class in
quality, just beginning to thicken, containing the maximum number
of lactic acid bacteria in active condition, and free from all objection-
able germs or flavors.
Only a starter above criticism, such as every good cheese maker
should know how to prepare, can be used with pasteurized milk. If
tlhe starter is at all tainted it is sure to damage the flavor of the cheese
to some extent. With raw, badly tainted milk, especially in warm
weather, a starter of only fair quality will often greatly improve the
quality of a vat of cheese, l)ut pasteurized milk is freed from practi-
cally all taints by the pasteurization, and to such milk only the best
starter can safely be added.
Thle importance of a good starter was made apparent when, begin-
ning June 9, 1910, nine days' make of pasteurized-milk cheese proved
to be gassy and off flavor, and bacteriological examination of the
starter as well as of the cheese demonstrated the presence of the same
gas-forming organism in both. It was clear that the organisms in
question did not pass through the pasteurizer, since their thermal
death-point was found to be lower than the pasteurization tempera-
ture (160) employed in the process. Therefore there could be no
doubt that the improper preparation of milk for propagating
"startoline" was the cause of the trouble in this case.

A PRACTICAL STERILIZER FOR THE CHEESE FACTORY.

The essential equipment for propagating a starter is some sort of a
sterilizer, ani incubator, and a supply of a dozen pint cream bottles
which are best provided with fairly tight tin covers about 2 inches
deep. Various different sterilizers have been recommended, the sim-
plest being an inverted tin pail covering the bottles of milk on the
steam table. For use as an incubator, a small covered shotgun can
may be steamed out daily, and after placing the bottles therein and
adjusting thle cover it may be carried to the ice box, the cellar, a hay
cooker, or any room of suitable temperature. Where bottles of
starter must be handled and carried about there is always some
danger of their becoming infected, and this can only be prevented by
intelligent work on the part of the operator. On account of its small
size a culture propagated in a bottle is often called a "startoline,"
meaning a little starter. A combined sterilizer, cooler, and incubator
made of galvanized iron has been devised, and used in our work
during thle past year with entire satisfaction. Its use saves time in






PREPARATION OF TIHE STARTER.


handling and reduces the danger of contamniatiw to a nliiillimum.
It is shown in figure 1.
The apparatus consists of a galvanized-iron container with cover,
a movable false bottom, and with steam, water, and (drain connections.
Where pint bottles are used, the perforated shelf is raised and se(t on
lugs as shown. If quart bottles are used, the perforated bottom is
lowered, so that the top of the bottle always stands It tlhe to) Of the
sterilizer.

VIVVA\


U .OVER 01

aafi BOTLE \/

0 00 W
FALsE BOTTOM cPROUND Cc)C


WATER FIE= 0E
hi





R"--I -




AP FOR AP FOR .
MILK BOTTLE WATER BOTTLE NOTCHE,5.w,1 "
FIG. 1.-Combined sterilizer, cooler, and incubator for cheese-factory starter.
PREPARATION OF THE STARTER.
The bottles having been cleaned and filled nearly ful with the
best whole milk obtainable are each covered with a tin cap and set in
the sterilizer, together with one bottle of water carrying the ther-
mometer. The lid is put on and the steam turned on very slowly at
first, by turning handle a. After the thermometer projecting through
the small hole in the lid shows that the contents of the bottles are
heated to 200 or above, the steam is left running for three quarters
of an hour, and then turned off. To cool the bottles of sterilized milk
open valve b and slowly run in cold water, which escapes at the
overflow c. If the water is turned on by mistake faster than the


43






44 CHEDDAR CHEESE FlOM PASTEURIZED MILK.

overflow can carry it off, the tin caps will keep it from entering the
bottles of milk. When the thermometer shows that the bottle con-
teiits are cooled to about 70 the water may be turned nearly or
entirely off. The bottle of "startoline" from the previous dayu,
which has not yet been opened, is now brought in and a portion,.
about a tablespoonful by guess, is poured into each bottle of newly
sterilized milk in the apparatus, lifting the tin caps for an instant for
tils purpose. The room should be free from drafts, floating dust,
or other source of contamination, and the transfer should be made as
(quickly a0nd carefully as possible. The cap is then replaced and the
cover put on. The temperature of the water can be kept between
600 and 70 for a few hours, and in the evening, in summer, if the
weather is very warm, a piece of ice can be added to the water.
This daily process of propagating the "startoline" was performed
in the clwheese factory during the year 1911 by Mr. A. T. Bruhn, with
enlitire success, carrying along the same culture of bacteria throughout
the year. Each day after inoculating the fresh bottles of milk, the
remainder is examined by pouring out a little in a teaspoon or cup,
to be tasted and smelled to see that it is in good condition;' and if so,
the remainder in the jar is used in making up starter for the next
day's cheese vat in the following manner:
To prepare starter from this "startoline," place in a shotgun can
about eight or nine pounds of milk for each thousand received daily,
cover up), and heat in a tub or deep pail of water by passing steam
until the water is boiling and a thermometer in the milk reads at least
10S. Keepl) it at this temperature for three-quarters of an hour and
then cool by tilling the tub with cold water. A dash stirrer whose
handle is slipped through the smallest possible hole cut in the cover
is a convenience and saves opening the can for stirring. When thor-
oughly cool-about 70'-add to the contents of the can the remain-
ing contents of the "startoline" jar, as stated above. Stir this well
and leave for live or six hours at this temperature, after which it
may be put in a cooler place to stand overnight.
Tr e general principle on which the temperature of starters,
etc., is regulated is that the starter should ripen only fast enough so
as to be barely thick, or just getting thick, when required for use
next day. If the acidity increases too rapidly at first, the bacteria
are kept too long before use in a highly acid medium, not favorable
to their growth, and in general this is to be avoided. The thickening
of thie milk at about 60 or 70 may be taken as an indication that
tle( acitlity is in the neighborhood of six-tenths per cent, which is
about as lihi as it ought to go for this purpose.
To control thle temperature for ripening is not so likely to be
troill.somvie as to avoid getting dirt and foreign bacteria into the
"startolil('" or starter after it has been once thoroughly sterilized.
F 'T' *i,.t tirlirr tie qua:lil tii the stunrler. a bottle of the thkickened milk, unshaken and unopened, may
Ic w-i taw) in a u arzii IuIac fur a day or i o. to see if gas bubbles or tmunpleasant flavors develop.







TIME SCHEDULE FOR MAKING CHEESE.


Strictly speaking it is impossible to sterilize milk so perfectly as to
kill all spores by one such heating, and on this account attention
should be given to selecting the best possible milk for starter making.
At the beginning of the season a small bottle of bacterial starter
can be obtained from dealers or from a college of agriculture.
It is well to begin propagating the starter several days before
cheese making is to begin, and also to carry along two or more starters
from different sources, separately, in order that if one is lost or found
unsuitable another may be at hand.
METHOD OF MAKING CHEESE BY THE NEW PROCESS.
GENERAL ARRANGEMENT OF SCHEDULE.
In making cheese by the new method the cheese maker is relieved
of a great deal of the uncertainty which attends cheese making by
the ordinary methods. Having inspected the milk at the intake and
rejected any that is curdled or otherwise unfit for use, he determines
by means of Manns's acid test the acidity of the entire vatful of
mixed milk. This may be anywhere from 0.14 to 0.25 per cent, or
even a little higher, but if much above 0.28 per cent the milk is likely
to curdle and clog the pasteurizer. He then runs the milk through
the pasteurizer and adds to the cold milk as it flows into the cheese
vat enough dilute hydrochloric acid to raise the acidity of the whole
vat to just 0.25 per cent (calculated as lactic acid). Three-quarters
per cent of a first-class starter is added, and after heating to 85 the
color and rennet are stirred in immediately.
The rest of the process is conducted according to a fixed time
schedule, which is never varied. The time from adding rennet to
hooping the curd is always exactly five hours and fifteen minutes,
and the intermediate process is as shown in Table 18. This is carried
on0 every day in the season without exception.
While it may be found desirable or convenient at some factories
to modify somewhat this routine, described below, yet it appears
practically certain that whatever routine of operations is adopted
at any factory, it can be followed without modification throughout
the season.
TABLE 18.-Time schedule for making cheese by the new method.

Time inter- Total time
Operation, val between after add-
operations. ing rennet.

H.7m. H. m.
Adding rennet.................................................................. 0 0 0 0
Cutting the curd................................................................ 0 25 0 25
Beginning to heat............................................................... 0 15 0 40
Turning off steam ............................................................... 0 20 0 60
Placing rack after drawing whey................................................ 1 25 2 25
Milling the curd................................................................. 1 30 3 55
Salting the curd................................................................. 1 00 4 55
Hooping the curd............................................................... 0 20 5 15


45







46 CHEFDDAR CHEESE FROM PASTEURIZED MILK.

For example, if the rennet were added to the milk at exactly 9
o'clock tihe curd would be ready to put in the hoops five hours and fif-
teen minutes later, i.e., at2.15in theafternoon. As soon as therennet
is alidded it is best to have a written schedule showing the time when
c(ti0 operation should be performed. Having once learned how to
perform each operation in this method of cheese making it is only
necessary to (do everything in as uniform manner as possible in order
to get satisfactory results daily throughout the season. There is
never many need to hurry the process if the milk was overripe at the
beginning, because the lactic-acid bacteria are practically all killed
lby the pasteurization. The same is also true of the gas-forming
bacteria, so there is no time lost in working gas out of the curd.
There is no reason for waiting to ripen the milk at the beginning of
the process before adding rennet.

UNIFORM PROPORTION OF COLOR USED IN 1911, AND RENNET REQUIRED.

('Color.--Tlhroughout the season of 1911 two-thirds of an ounce of a
standard make of cheese color per thousand pounds of milk was used,
giving the clieese a medium shade of color. These cheeses were
shipped into a number of different cities and appeared satisfactory
to dealers in all parts of the country, except in Philadelphia, Pa.,
and Boston, Mass., where some dealers asked for white and others
for highly colored cheese, as is shown by the following extracts from
letters. Where more than one extract appears from the same city
they are from different dealers.
Boston, Mass ............ Our market uses white cheese exclusively.
Boston. Mass............ Use both white and colored.
Boston, Mass............ A very light color would not do for this market.
C'hicago, 11.............. No comment on color.
Fond du Lac, Wis........A little too light color.
Geneva, N. Y.---------.......... No comment on color.
Marshfield, Wis .......... No comment on color.
Minneapolis, M inn mi....... No comment on color.
New York, N. Y ........ Color is exactly right.
New Yoirk, N. Y ........ Should be a trifle higher color.
Philadelphia, Pa........ Have to have white cheese for Philadelphia.
Plymouth, Wis. ........- No comment on color.
Sheboygan, Wis......... A good commercial color, but might stand a trifle more color.
Sheboyg-an, Wis ......... No comment on color.
St. Louis, Mo ........... No comment on color.
Vashington, I). C. ...... .Most of our customers want it colored.
Waterl o, Wis........... No comment on color.
Renne t.-The same proportion of rennet is always used in this
process, because the milk is always in the same condition as to acidity
at thle time of a(d(Iing rennet, and always ripens equally fast afterwards.
Therefore, having once selected the most suitable proportion of
rennet, there is no reason for changing it. The use of 2 ounces of




IIi






ADDING STARTER, COLOR, AND RENNET.


Hansen's or Marschall's rennet per thousand pounds of milk is adopted
as the best practice, since this quantity produces visible coagulation
in 7 minutes, as shown in Table 2, and the curd is in prime condition
for cutting in 25 minutes after adding rennet. If the rennet extract
is weaker than it should be, such amounts should be used as will
cause coagulation in the time stated.
If a larger proportion of rennet than 2 ounces per thousand
pounds were used, there would hardly be time for the milk to become
quiet before visible thickening began, and the curd might be damaged
and broken through thickening while still in motion. On the other
hand, over two years' experience with the method has shown that
there is no need for using a smaller proportion of rennet than 2
ounces. Good cheese can be made with 1 ounce of rennet per
thousand pounds of milk, but the coagulation of the milk is unnec-
essarily slow.
As in regular cheese making, great care must be taken not to
measure or dilute rennet extract in any container in which there is
present the least trace of cheese color, because the cheese color is
strongly alkaline, and rennet loses its coagulating power almost
instantly when in contact with alkalies.
ADDING STARTER, COLOR, AND RENNET TO THE MILK.

The temperature of all the mixed milk after pasteurizing is never
above 85 and commonly only 70 to 80. The acidity may be
tested, if desired, and should be just 0.25 per cent, or between 0.24
and 0.26 per cent. Three-quarters of a pound of starter per hun-
dredweight of milk in the vat is added immediately through a hair
sieve, stirring the milk. The rake is then put in and the vat stirred,
while heating up to 85. The desired amount of color is stirred in,
and always, without exception, the rennet is stirred in last of all.
The rennet extract measured out for 5,000 pounds of milk should be
diluted in a pailful of water. In adding rennet, first stir the milk
across the vat the short way, going rapidly from one end of the vat to
the other. With the largest-sized vats, two men with rakes may
begin at the middle and walk toward the ends while stirring. Then
walk back along the vat, adding the diluted rennet from a pail to the
milk which is still in vigorous motion, noting on the clock the instant
when the rennet first enters the milk. Set down the pail and again
stir the milk across the vat the short way, with the rake or rakes, for
exactly one minute, in which time the operator should be able to
walk up and down the vat three or four times. In this way the
smallest as well as the largest vats of milk should be set. Take out
the rakes promptly one minute after the rennet entered. Cover the
vat at once, and leave undisturbed. No top stirring is necessary or
permissible, as the milk begins to thicken almost exactly seven mim-


47




.. . ...


48 CHEDDAR CHEESE FROM PASTEURIZED MILK.

utes after adding rennet, before there is any visible cream rising.
Follow exactly the directions as to temperature, acidity, and propor-
tion of rennet every day in the season.
CUTTING, STIRRING, AND HEATING THE CURD.

Tile curd formed in this process is always ready to cut exactly 25
minutes after thle rennet entered the milk. Therefore as soon as the
rennet has been added it is best for the operator to write the entie
time schedule, as shown in Table 18, for the rest of the day's weak
on a paper, or, better, on a blackboard, which can be seen across the
room. Some operators may suppose that possibly the curd might
be cut a little earlier or later, but experience has shown that the cur;,
is always in a thoroughly satisfactory condition for cutting juit 25:
minutes after adding rennet. There is therefore no need for repeated
testing of the curd with the finger; it is only necessary to keep a
eye on the clock, and follow the time schedule.
In cutting, begin with the horizontal knife and cut lengthwise of
the vat; then use the vertical knife across the vat, cutting alternately
toward and away from the operator. Finally cut lengthwise, with
the vertical knife. Do not cut the vat more than once in each direc-
tion, and try to do the cutting in exactly the same manner every day.
The different cuts should not lap, nor should portions of the curd
wider than three-eighths of an inch be left uncut between the knives,
except in the following case: In cutting next to the sides of the vat,
as in the first and last cuts in each direction, hold the knife as close
to the metal sides of the vat as possible. If the knife does not appear
wide enough to cut the remaining curd at the last stroke, cut close to
the tin and leave a narrow strip of uncut curd, not at the edge of the
vat, but between the last cut and the next to the last. This strip
will be cut more thoroughly by the knives moving in other directions
than if it had been left next the tin. Knives with blades three-eighths
of an inch apart are required for this method.
Immediately after cutting put the agitator blades in place and
start them in motion. The curd obtained in this process is so firm
and solid that this can always be done safely. Go around thet*at
with the hand some time during the next 15 minutes, loosening the
curd from the sides, bottom, and corners of the vat. A form of agi-
tator which is very satisfactory has one pair of revolving blades
which also move up and down the vat, somewhat resembling the
motion of the rake.
Exactly 15 minutes after cutting turn steam into the jacket of the
vat, and raise the temperature gradually during the next 20 minutes-
just 19 to 1040-which temperature is maintained until the whey
is drawn.





..... '. :... '











































































A UNIFORM LAYER OF CURD, SHOWING USE OF CURD GAUGE.


- - ---- ----------- ------- --------- -- .. ..... ... ...... ", ", ,










MISCELLANEOUS OPERATIONS IN CHEESE MAKING.


DRAWING THE WHEY, MATTING, CUTTING, AND TURNING TIlE CURD.
SThe agitator is left running until about two minutes before the whey
is to be drawn, when it is removed, and the curd, after settling a few sec-
onds, is pushed slowly away from the gate with one or two rakes. The
whey strainer is placed inside the vat and the hair sieve below the gate
in the conductor, the gate being opened at such a time as will permit
the whey to be out and the first rack to be put in place at the time
given in the schedule. When the whey is nearly all out, the gate end
of the vat is lowered gradually, and a few seconds later the curd is
pushed down toward the gate, leaving-the upper third or half of the
vat bottom bare and free from whey. In this process the curd is
always sufficiently firmed in the whey so as not to need any stirring
in the whey or on the rack. With reasonably brisk work the curd
can be transferred to the curd cloth on the rack with a curd pail or
scoop before it has time to become lumpy on the bottom of the vat.
Each pail of-curd as it strikes the rack should fall apart loosely and
not show the presence of great lumps of curd matted together. Any
such lumps should be lightly broken up with the hand, and if many
lumps appear it indicates lack of skill and quickness.
The curd is piled evenly on the rack about 4 or 5 inches thick,
and the top is leveled off with the hand in the usual manner and cov-
ered with a curd cloth. More racks if necessary are put in place and
the vat is finally covered, leaving the curd to drain. The little curd
gauge, made of wood, devised during the course of these experiments
is a help in getting the layer of curd of the right thickness and also
gives a good square end to the curd, which makes it easier to cut into
blocks of uniform shape. (See P1. VI.)
Just 15 minutes after the time scheduled for putting in the rack
the curd gauge is removed and the cutting of the matted curd into
blocks 8 inches square, or 6 by 12 inches, is begun.
The blocks are turned over immediately after cutting, and again
turned 15 minutes later. They are then turned once in 10 minutes,
and one hour after drawing the whey are piled two deep, and replied
every 10 minutes until milled. In turning and piling, care is always
used to turn the outer cooler surfaces toward the inside, in order that
the entire mass of curd may remain at practically uniform temperature
throughout, as in ordinary practice.
MILLING, SALTING, AND HOOPING TITE CURD.
Exactly one and a half hours after the whey is drawn the curd is
milled. The milled curd is piled along the sides of the vat, so as to
drain toward the middle. It is stirred up with the hands from the
bottom, turning the pile over about once every 10 minutes after
milling, so as to cool it somewhat, prevent matting, and allow free
S79994-Bull. 165-13----4


49







50 CHEDDAR CHEESE FROM PASTEURIZED MILK.

drainage. Little or no white whey ever escapes from the curd after
milling or salting when made up by this process, although some clear
whey or brine does drain away.
One hour after milling salt is thoroughly mixed with the curd at
the rate of 2 pounds of salt per hundred of curd, which amounts
practically to 2 pounds per thousand of milk in the spring and early
summer, and 21 pounds per thousand of milk in the fall, when the
yield of cheese per hundredweight of milk is somewhat greater. The
curd is stirred over several times during the next 20 minutes, by
which time the salt is all dissolved, and the curd, at a temperature of
S2 to 86, is ready to be hooped. Each hoopful of curd is covered
with a cloth and follower as soon as filled, in order to prevent the sur-
face of the curd from cooling so far that it might fail to close well in
the press.
It is of the utmost importance that every cheese should be well
closed and develop a perfect rind, free from cracks or other openings.
Where openings occur mold is sure to enter during the curing process,
and the flavor especially is apt to suffer as a result.

PRESSING AND DRESSING THE CHEESE.

Throughout the present set of experiments the cheese has been
pressed for about an hour, applying pressure with the hand lever
only, and at first only sufficient pressure is used to keep the drippings
running from the hoops. After an hour the cheese is dressed and
returned to the press, when continuous pressure is put on and it is
left for the night.
In bandaging the hoops, the usual starched circles are used under
the heavy muslin or duck cap cloths, or if it is found that the circles
are hard to remove for paraffining they may be left out and the cap
cloths left on the cheese until paraffined. The cap cloths, being of
heavy cloth, can be stripped off rapidly without tearing and washed;
in this way they may be used many times. The next morning it is
customary, as in cheese factories generally, to look over the cheese,
straighten any bandages which may be faulty, and turn any crooked
cheese over in the press, leaving them until noon to straighten.

DRYING, PARAFFINING, AND CURING.

The cheeses when taken from the press are stenciled with the brand
and date of making or a reference number, and placed on shelves in a
well-ventilated room to dry on the surface. This room may be as
high as 70. HIere they are turned over once a day.
The cheese should be paraffined when 5 to 10 days old, or pos-
sibly earlier. The paraffin should be at 220 F., at least, and better at







MISCELLANEOUS OPERATIONS IN CHEESE MAKING.


230 to 250 F. The thinnest possible coat of paraffin is the best,
and the cheese should be held in the paraffin about 5 seconds and
then drawn out and left to drain over the vat, on a rack, until it can
be handled. A thin coating of parallin is flexible and less likely to
crack than a thick coating.
It is possible to cure this cheese at any temperature between 34
and 75. When it is desirable to cure the cheese as fast as possible,
a temperature of 75 may be used without injury to the quality.
. However, at this temperature there is considerable shrinkage, and it
is necessary to wipe the cheeses occasionally and( turn them over to
prevent them from getting moldy and sticking to the shelves.
At 45 to 55 the cheese cures well, with little shrinkage and a
minimum amount of labor. It also cures well when stored at 34
at the age of 1 week and develops little or no mold on the surface,
but owing to the extra cost this temperature should only be employed
where it is necessary to hold the cheese for a considerable length of
time.
BRANDING AND SELLING THE CHEESE.

In order that customers may be sure that they are getting genuine
pasteurized-milk cheese when called for, every cheese should be
marked with the words "Pasteurized cheese" running all round the
edge of the cheese. All persons making cheese according to the process
here described should use such a brand, in order to distinguish this
product from the ordinary Cheddar cheese. A large number can
be rapidly marked with a rubber stamp or by rolling the cheese over
rubber type, set in a board, as shown in figure 2. Narrow strips of
wood on each side of the board prevent the cheese from rolling side-
wise off the type.
In a new style of product uniformity is a quality which consumers
and dealers require. It is recommended that the maker of this style
of cheese keep back one cheese from each day's make, when shipping,
until the consignment has been accepted and paid for by the buyer.
The sample cheese can then be sent along with the next shipment
without plugging. If necessary, the cheese can be plugged with a
trier, and by this means the maker will be able to study any faults
which may be observed by the buyer and avoid them in the future.
Names of leading cheese dealers who have already received sample
shipments of this make of cheese and found it suitable for their
trade may be obtained from the authors.
SWhere a maker doubts whether the buyer is giving him fair treat-
ment, it is recommended that parts of each day's make be sent to
two different dealers, whose criticisms, if any are received, can be
compared by the maker at the factory.







52 (CHIIEIDAR CHEESE FROM PASTEURIZED MILK.

TESTING CHEESE FOR MOISTURE WHEN DRESSED IN THE HOOP.

In making cheese by this process, the green cheese was found to
IiftIer vern little im moisture content from day to (lay, as is shown in
Talle 19. Excepting the first day the cheese was made each day in
two vazts, alnd each vat of curd was tested for moisture separately.
Thi'e deterinilation of moisture in cheese is not recommended as a
part of the daily work in a factory. It is of great value, however,
in experimental work, where it is desired to study the effect on their
moisture content of different methods of handling curds, or the effect
of different moisture content on the market value or keeping quality
(Of climese.


....... ... ~ ...: : :: :. .... .... :.:." :.
1 '9

N .. .... ..:















FIG. 2.-Method of marking cheee.
.Moisture tests are easily made. It is objectionable, however, to
pluti a new cheese every (lay for a moisture test because of the dan-
I"ger of admhiittingr molds, et-c., beneath the rind, anti it has been found
that plufrmingr the green cheese can be entirely avoided by sampling
it lit tile timle it is dressed in the. hoop, about one hour after putting it
to press. The. trier hole made at this time by turning down the
bandagre and linserting the trier at the side will close entirely over
nilrha in the. press, leaving the rind perfect. Samples of cheese thus
tnkrii fromn tie. dressed curd and. tested for moisture agreed closely
ill mo1isture content, with samples taken With a trier from the same
crieses tile. next, day, after pressing about twenty hours, as may be
s11411 fromn Table 19.
The moisture tests were till made, by heathig 10-gr~am portions of
the <-iirl for at least threc hours ill the Wisconsin high-pressure
4...:p .. ... ...



.., ..... i
l :... ..."i....* .. ............. .,. ...

... ; .... ..'. ..S

I E .






Flo. 2.--Method of marking cheese.
Moisture tests are easily made. It is objectionable, however, to
p~lug a new cheese every (lay for a moisture test because of the dan-
ger of admitting mohlds, etc., beneath the rind, anti it has been found
that plugging the gr,,een cheese can be entirely avoided by samplin
it at the time it is dressedl inl the hoop), about one hour after putting it
to) press. The trier hole made at this time by turning down the
lIaiulage antl inserting the trier at the side will close entirely over :
night in the press, leaving the rind perfect. Samples of cheese thus
iikcn from the dressed curd and tested for moisture agreed closely
iii moisture c'onten t with samples taken with a trier from the same
c.li(,. te the next (Izay, after pressing about twenty hours, as may be
.t't'ii from Table 19.
"li']t hl~istUre tests were all made by heating 10-grain portions of
the, cu rd for at least three hours in the Wisconsin high-pressure







INCREASED YIELD OF CITEESE OBTAINED. 53

steam oven.' After three or four hours there is practically no further
loss of weight from samples of fresh curd in 24 hours' heating. Sait-
pies of cured cheese continue to lose weight with continued heating
much more noticeably than samples of fresh curd or green cheese.

TABLE 19.-Comparison of moisture determinations made on samples taken when cheese
was dressed, three-quarters to one hour qfter pressing, and on samples taken fromn rent
cheese, next day, when remoredfromn press.

Moisture content when cheese Moiture content, next day,
was dressed, when removed from press. DiTffer-
Date. er-
L ----- ene.
First. Second. Average. First. Second. Average.

1911. Per cent. Per cent. Per cent. Per cent. Per cent. Per cent. Per cent.
Aug. 15 37.6J 37.41) 37.5j 37.95 37.25 37 6) +0. t10
I 16 38.50 38.70 38.6) 3.S.50 39. 0) 34. 7.i + .15
16 38.50 38.90 38.70 3S.0 38.5.) 3S. 27 43
17 39.60 39. 10 39.35 3S. 50 3S. 6i) 3i. 55 .SJ
17 38.90 39.00 38.95 39.40 39.41) 3.1.4 J + 4
18 37.80 37.75 37. 77 37.75 37.95 37. Si + OS
18 42.25 42.25 42.25 41.25 41.40 4."L32 .93
23 38.80 38. S) 3S. 835 8. 05 3,. 45 3,. 2 55
23 42.25 42.45 42.35 42.20 42.10 42.15 20
24 39.35 39.05 39.20 39.70 40.3) 4 1. 0.) + .S)
24 44.25 44.30 441.27 43.15 43.3) 43.2 22 -1. 15
25 39.55 39.70 39.62 39.30 39.65 39.46 .16
25 44.10 44.45 44.27 44.25 4-1.95 44.6) + .33
26 38.95 39.10 39.02 38.8) 39. 03 38. 90 .12
26 44.30 44.60 44.45 42.80 43.00 42.9J -1.5.53


RESULTS OF TWO YEARS' TRIAL OF THE METHOD.

INCREASED YIELD OF CHEESE OBTAINED BY THE NEW PROCESS.

APPARATUS AND METHODS OF STUDY.

In the season 1909-1910 it was found that an increased weight of
cheese is regularly obtained after pasteurization as compared with
the weight obtained by the regular factory methods. For the pur-
pose of accurately studying the yield of cheese in 1911 two scales
were used, one of 5,000 pounds' capacity graduated on the beam to
one-half pound and one of 300 pounds' capacity graduated on the
beam to one-tenth pound. The larger scale was set up permanently
in one corner of the make room, and a wooden frame carrying a 300-
gallon steel receiving vat was placed upon it. The outlet of the vat
is of sanitary metal piping, suspended by wire to the vat in such a
way that the pipe and contents are weighed each time with the vat.
The frame, vat, and pipe weighed 487- pounds when empty. The
separate weights and the scale on the beam were carefully tested by
use of test weights. The entire set of weights agreed among them-
Sselves so closely that no difference could be detected in the equilibrium
of the beam when oAe weight was substituted for another in weighing
a load. The error in a single weighing is not over one-quarter of a
'Farrington, E. H. A creamery method for the determination of water in butter. Wisconsin Agri-
cultural Experiment Station, Bulletin 154. Madison, Sept., 1907.




11~~~~~~~


54 CHEDDAR CHEESE FROM PASTEURIZED MILK.

pound with large or small loads. Except when weighing the lever :
is kept up, thus relieving the knife edges from load and wear.I
Tit n metlihlod of using this apparatus is as follows: The vat being
empllty with the pilps in place and stopcocks closed, the supply of
milk is run into the vat through a conductor and cloth strainer. The
strailier aIndl conductor are then removed, the lever is lowered, and
thei weight of vat and contents determined. It is our habit to balance
tilt scales exactly, giving neither "up" nor "down" weight. The
lever is then raised, and the operator climbs up the ladder on the
frame to the ruinl)board along the side of the vat. With a dipper he
stirs the milk continuously and vigorously for 5 or 10 minutes, and
contitnueis stirring while a portion of the milk is being drawn out for
uise in one of the experimental cheese vats. The vat and the remain-
ing milk are then weighed with the same precautions as before, after
wvi'ch another portion of the milk may be drawn off for use in another
vat in the same manner.
'The p precautionss mentioned above seemed sufficient to insure that
the milk used in the two vats-one for ordinary and one for pas-
teurizedl cheese-was thoroughly mixed at the time it was drawn
from the receiving vat, and that each lot was weighed accurately
with a total possible error of not over one-half a pound in a vat of 200
to 2,000 pounds of milk-an error of one-fortieth to one-fourth of
I per cent, at most.
The other new scale mentioned above is a counter scale graduated
onil tihe beam to one-tenth of a pound and sensitive to one-twentieth of a
)pound* with any load up to 200 pounds. This was used for weighing
the cheese throughout the work here described. The set of weights
used with this scale agreed among themselves and with the test
weights mentioned above in the description of the other scale.
Witli tlie smaller scale, 20 to 200 pounds of cheese could readily be
weighed with an error of not over 0.05 of a pound, or 0.25 per cent,
at most. On 68 days during the season of 1911 the receiving vat of
milk was divided into two accurately weighed portions for this exper-
iment. One of these was pasteurized and made up into cheese by
itil, lew, method, the other portion was made up into cheese by regular
factory methods. The cheese was 134 inches in diameter by 4 inches
hligil, tihe "daisy" size. The green cheese was always weighed as
quickly as possible after being removed from the hoops. The daily
record of weights of milk used and of cheese obtained, and the per
ce.it of increased yield which resulted from pasteurization, are shown
in 'abl e 20.








55


INCREASED YIELD OF CHEESE OBTAINED.


TABLE 20.-Increased yield of green


cheese obtained by the new method front pI uter-
ized milk.


Date made.


1911.
Feb. 23
24
27
28
Mar. 1
2
3
7
8
9
10
13
14
15
16
17
20
21
22
Apr. 5
7
11
13
17
18
24
27
28
May 2
3
8
10
15
17
22
25
29
June 1
2
7
9
13
15
16
19
21
26
27
28
July 3
6
8
10
11
12
24
26
Aug. 29
30
Sept. 1
5
6
7
8
20
22
25
Oct. 2
3


Pasteurized milk.


Milk
used.


Green
cheese.


Pounds. Pounds.


538.0
504.5
1,026.5
800.0
350.0
389.5
340.0
855.0
590.0
418.0
442.0
1,166.0
956.0
570.5
531.5
395.0
1,344.0
570.0
362.5
585.0
508.0
549.0
364.0
800.0
720.0
1,254.0
570.0
420.0
636.0
558.0
1,693.0
798.0
1,587.0
1,088.5
1,223.0
851.0
1,315.0
798.0
799.5
790.5
800.0
1,090.0
795.0
800.0
810.0
798.5
770.0
801.0
801.5
1,234.0
995.0
1,068.0
1,064.5
914.0
873.0
1,195.0
1,099.0
294.5
344.0
322.0
291.5
276.0
286.5
292.0
263.0
265.0
748.0.
700.5
251.0


Average. .......


53.20
51.00
106.20
82.20
35.40
39.00
35.00
88.20
60.70
42.80
44.70
122.00
103.40
58.10
56.90
41.20
136.00
56.40
36.00
60.80
51.15
55.00
35.70
80.25
71.15
122.80
55.30
40.85
65.05
54.30
158.15
77.60
161.60
109.00
129.40
87.00
138.60
83.50
82.85
79.65
82.30
119.70
85.50
83.45
87.60
81.75
80.65
83.50
85.90
122.75
102.45
108.50
107.30
93.50
93.15
125.10
118.32
31.58
35.82
34.10
31.00
28.95
31.03
31.50
29.15
29.20
83.90
79.25
27. 75


Yield of
cheese
per hun-
dred-
weight
of milk.


Pounds.
9.89
10.11
10.35
10.27
10.11
10.01
10.29
10.32
10.29
10.24
10.11
10.46
10.81
10.18
10.71
10.43
10.12
9.89
9.93
10.39
10.07
10.02
9.81
10.03
9.88
9.79
9.70
9.73
10.23
9.73
9.34
9.72
10.18
10.01
10.58
10.22
10.54
10.46
10.36
10.07
10.29
10.98
10.75
10.43
10.81
10.24
10.47
10.42
10. 73
9.95
10.30
10.16
10.08
10.23
10.67
10.47
10.77
10.72
10.41
10.59
10.63
10.49
10.83
10.79
11.08
11.02
11.22
11.31
11.05


Raw milk.


Milk
used.


Pounds.
380.0
380.0
600.0
400.0
510.0
628.0
522.0
380.0
388.5
417.5
700.0
275.0
260.0
380.0
359.0
396.0
384.0
378.0
542.0
390.0
339.5
549.0
364.0
600.0
540.0
660.0
380.0
420.0
424.0
372.0
800.0
798. 0
800.0
800.0
800.0
800.0
800.0
800.0
800.0
800.0
800.0
800.0
800.0
800.0
800.0
800.0
770.0
800.0
800.0
800.0
660.0
660.0
800.0
660.0
800.0
600.0
190.0
290.0
340.0
320.0
292.0
275.0
286.5
292.0
263.0
266.5
250.0
420.0
250.0


10. 7.......


Green
cheese.


Pounds.
35.40
36.60
57.80
38.30
50.20
59.70
52.30
38.40
39.30
41.00
66.40
25.70
25.80
37.50
37.40
39.80
36.60
35.30
51.80
37.70
32.50
52.60
34.55
55.50
49.80
61.90
35.70
40.05
42.00
35.55
70.95
73.70
76.90
76.60
78.20
78.80
80.20
83.10
79.50
76.60
78.15
80.20
80.70
78.95
79.65
77.70
75.45
79.00
82.00
72.35
66.10
62.80
74.35
63.65
78.20
58.20
19.32
30.50
34.05
32.60
29.65
27. 20
29. 48
30.25
27.80
28.05
26.40
45.10
26.25


Yield of
cheese
per hun-
dred-
weight
of milk.


Pounds.
9.31
9.63
9.63
9.57
9.84
9.51
10.02
10.11
10.12
9.82
9.49
9.34
9.92
9.87
10.42
10.05
9.53
9.34
9.56
9.67
9.57
9.58
9.49
9.25
9.22
9.38
9.39
9.54
9.91
9.56
8.87
9.24
9.61
9.57
9.77
9.85
10.02
10.39
9.94
9.57
9.77
10.02
10.09
9.87
9.96
9.71
9.80
9.88
10.25
9.04
10.02
9.52
9.29
9.64
9.77
9.70
0.17
10.52
10.01
10.19
10.15
9.89
10.29
10.36
10.57
10.52
10.56
10.74
10.50

9.815


Gain by
pasteur-
ized
milk.




Per cent.
6.23
4.98
7.48
7.31
2.75
6.61
2.79
2.08
1.68
4.27
6.53
12,00
8.97
3.14
2.78
3.78
6.19
5.89
3.87
7.45
5.22
4.59
3.37
8.43
7.16
4.37
3.30
1.99
3.23
1.81
5.30
5.19
5.93
4.60
8.29
3.76
5.29
.67
4.23
5.22
5.32
9.58
.6.54
5.67
8.54
5.46
6.84
5.46
4.68
10.07
2.79
6.72
8.50
6.12
9.21
7.94
5.90
1.90
4.00
3.92
4.73
6.46
5.24
4.14
4.82
4.75
6.25
5.31
5.24

5.374


Proportion of
starter used.


Pas-
teur-
ized.



Per ct.
0.75
75
75
75
75
75
.75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
75
.75
.75
.75
.75
.75
.75
.75
.75
.75
.75
.75
.75
.75
.75
.75
.75

.75
75
75
.75
75
75
75
75
75


Raw.




Per ct.
0.00
.00
.00
.75
1.50
75
1.50
2.00
1.50
1.00
.00
.00
.75
.75
2.00
2.50
.00
.00
1.67
S75
.75
.75
.75
.00
.00
.75
.75
.75
75
.75
.715
.75

.75
a,

.73
75

.75
.75
75

.775
75
.75
.00
.75O
.75
.00
AO
.75
.00
.75

.00
.75
.00
75
.00
.00
00
.75
75
.00
.75
.75
.75
.75
.75
.75
.75
.75
.75
.75
.75
.75






CIIEDDAR CHEESE FROM PASTEURIZED MILK.


It w;1! be noted that every (lay in the season there was a greater
yield of cheese from the pasteurized milk. From 250 to 1,700 pounds
of milk were handled in each vat. The average yield of green cheese
from raw milk was 9.815 pounds and from pasteurized milk 10.337
pouitlds per hundred pounds of milk.
The daily increase in yield ranged from 0.6 per cent to 12 per cent,
and in 50 cases (72 per cent) lay between 3 and 8 per cent, while the
average increase in yield by the new process on 69 days was 5.37 per
cent. (iOn 45 days the same proportion of skim milk starter-three-
fourths per cent-was used in both the raw and the pasteurized
milk. In the raw milk none was used on 16 days, and on 8 days
1 to 2; per cent (on the average 1.71 per cent) was used, while in
every case the pasteurized milk received three-fourths per cent
starter. If the use of starter affects the yield of cheese, the average
yield from the pasteurized milk on 16 clays was raised about three-
fourths per cent, while the average yield from raw milk was raised
on S days about 1.71 per cent. These two effects offset each other
in the table, giving a slight advantage to the yield from the raw milk,
so that the final average figure-5.37 per cent-representing the aver-
age gain in yield of green cheese by the new process, is no higher and
possibly a trifle lower than it would have been if equal proportions of
starter had been used in all cases.
Among the 17 cases in Table 20 in which no starter was used in the
raw-milk vat, the average gain in the pasteirized-milk vat, using
three-fourths per cent starter, was 7.48 per cent; and in 8 cases where
more than three-fourths per cent starter was used in the raw milk, the
average gain in yield in the pasteurized-milk vat was 3 per cent.
From this it would appear that the proportion of starter used does
notably affect the yield of cheese, contrary to some recent statements.'

SEARCH FOR SYSTEMATIC ERRORS IN EXPERIMENTS ON YIELD OF CHEESE.

The presence of systematic errors was carefully guarded against in
the daily work on the yield of cheese. Before dividing the milk from
the receiving vat for use in the two make vats, the milk was first
thoroughlly stirred for 4 to 10 minutes, as already stated, and the stir-
ring was continued while the milk was running out. The portion of
milk drawn out first was commonly used for making the raw-milk
cheese, but sometimes, as on March 8, 9, 10, 17, 21, 22, and April 7,
11, 17, IS, and May 10, the portion drawn first was used for making
the past urized-milk cheese. The average gain in yield through pas-
Slioth the median and the mode lie between 5 and 6 percent. The mode is the class which occurs with
the greale-t! fre S Stai ist i .! Methods," by C. B. Davenport, New York, 199, or h Principles of Breeding," by E. Daven.
txrl, t Boston, 107, p. tGS4.
Van Slyke. l uius L.., and Pulilow. Charles A. The science and practice of cheese making. New York,
lJ9y. .Set. -.4f.


56






INCREASED YIELD OF CHEESE OBTAINED.


teurization on these 11 days was 5.15 per cent, so nearly equal to the
general average of 5.37 per cent (see Table 20) as to indicate that the
gain in yield is not idue to any difference in composition of the milk
when divided into two lots. Carefully tested thermometers and the
same pair of curd knives were used( in every vat.
S Usually the vat of pasteurized milk was set first with rennet, and
the vat of raw milk 5 minutes later. The two vats were placed near
each other, and conditions were such that one operator could stir
them both at once, if desired. On 11 days, April 18, 24, 27, May S,
10, 15, 17, August 29, 30, September 1, and October 2, the rennet was
K added to the raw milk first, and to the pasteurized milk 5 minutes
later. The average gain in yield on the 11 days was 4.63 per cent,
indicating that the order of setting the vats had nothing to (do with
the gain in yield.
In order to ascertain what per cent of unavoidable error enters into
the measurement of yield of cheese, a special experiment was performed
on 34 days. Each day, with all of the usual precautions, two lots
of milk drawn from the receiving vat were run through the pasteurizer.
one after the other, and made up into cheese in separate vats marked
(C) and (D) standing near each other, and handled by the same oper-
ator (Mr. Bruhn). The vats were heated and set exactly 5 minutes
apart by the watch, and the time schedule for each vat was strictly
followed in every detail. The same curd knives and thermometer
were used in both vats.
The pasteurizer and cooler are always rinsed with hot water at the
beginning of the first run, but are wet with adhering milk at the close
of the run just before beginning the second run. Thus the actual
weight of milk in the first vat might be slightly less than it should be.
To avoid this source of error, the pasteurizer and cooler were allowed
to drain each time into the vat for several minutes (until the stream
of milk broke into single drops), and then the metal surfaces were
carefully rinsed with two measured portions of clean water. Thus
the surfaces of the pasteurizer and cooler were wet with water at the
beginning of the second run as well as the first. The milk content
of the rinsings (see Table 21) was found to be very small and uniform,
amounting to about 0.8 of a pound of milk each time, which if it were
all lost from one vat but not the other would cause a difference of
yield of cheese from a 500-pound lot of milk (as in Table 22) of
about 0.16 per cent. In order to avoid this source of error entirely,
the rinsings from both runs were either thrown away, as on the first
15 days listed in Table 22, or the rinsings after each run were added
to the respective vats, as on the last 19 days.


57








58


The yield of cheese obtained in duplicate vats thus handled was
never exactly equal and varied on the average for 33 days by 0.585

per cent of the weight of the cheese, as shown in Table 22. The milk
in Vat C was drawn first from the receiving vat, and was pasteur-

ized and set first in all cases except where otherwise noted.

TABLE 22.- 'ariation in yield of cheese from duplicate vats of pasteurized milk.


Date.


1911
Mar. 23
24
27
2
29
30
31
Apr. 4
6
10
12
14
19
20
21
25
2,;
May 4
5
9
11
12
lI
Is
19
2:1
24
:li
:31


14
17
*Al


Vat C.


Weight
of milk
used.


Pounds.
430. 0
390.0
375.0
350.0
585.0
495.0
540.0
5%5.0
534.0
1. 0O(). 0
555.0
3SU0.0
400.0
370.0
380.0
420.0
370.0
420.0
M 1. 0
40S. 0
410.0
795.0
.SO. 0
tiO. 0
60. 0
t6(Ki. 0
ti12.'25
60tl. 0
600. 0
.S.M. 0
ti(w). 0
(0). 0
5.9. 5
fCMb. O


A ~eragt~. ~ 22


Weight
of green
cheese.



Pounds.
42.50
38.,0
36.10
36. 60
59.10
50.10
54.20
60.50
54.15
106.30
55.70
38.10
40.30
36.75
37.00
41.U0
36. 20
42. 10
51.40
40.65
41.50
7S.25
80.30
63. S0
62.20
64.00
64.35
61.30
62. 10
59.15
61.55
62. 28
62.71
60.30


Cheese
per cwt.
of milk.



Pounds.
9.884
9.949
9.627
10.457
10.102
10.121
10.038
10.342
10.140
9.842
10.036
10.026
10.075
9.932
9.737
9.762
9.7. 4
10. 024
9. W.
9. 963
10. 122
9.943
10.0L37
10.633
10.367
10.667
10.510
10.217
10.350
10.146
10. 25A
10. 3S0
10. 460
10.050


Ratio of
milk
weights.



Vat I1at
C. D.
1 1
1 1
1 3
1 2j
11 1
11 1
11 1
14 1
qi 1
3 1
11 1


I*
1 1

1l
1 1
1 4t
1 1
1 Ift
1 1

ii I

1 1
1 1
1 1

11!
11!
1 1
1 1
1 1
1 1
1 1


.......... 10. l O I..........


1 Th: r,,silI fur Apir. Li omitted in computing the average because of abnormal conditions.

Animing tlhe :34 days' results obtained during the season, as shown
in Table 22', tlie d iflierence in yield between duplicate vats exceeded

1.75 per 'ent inll oinly one case. On this day there was unusual
difficulty inl tihe work because of unexpected failure of the supply of


CHEDDAR CHEESE FROM PASTEURIZED MILK.


TABL.E 21.- Milk contest of rinsing of pasteurier and cooler.


Weight Fat content. Estimated Estimated
Datofrin-- weightof wightof
ches in "in
ns Percent. Weight, rinsins. rinsing.


1911. Pounds. Poand. Pound.. Pounds.
Apr. 25 (Vat C)....... 2.25 1.25 0.028 0.08 0.8
25 Vat 1))- ..... 2.25 1.25 .028 .08 .8
2i(Vatl'C)-------...... 2.25 1.20 .027 .08 .8
2t(Vat D)..... 2.25 1.20 .027 .08 .8


Vat D.


Weight
of milk
used.



Pounds.
430.0
390.0
1,125.0
875.0
390.0
330.0
360.0
390.0
356.0
360.0
370.0
380.0
4no. 0
55 0
570 0
420.0
555.0
420. 0
354.0
612.0
410.0
795.0
800.0
600.0
600.0
600.0
612.25
600.0
600.0
577.75
600.0
600.0
599.5
600.0

536.37


Weight
of green
cheese.



Pounds.
42.55
39.10
109.20
92.20
39.45
33.50
36. 15
40.55
37.35
35.65
37.60
38.40
40.60
55.40
55.45
40.90
54.35
42.50
34.35
60.80
41.80
79.50
80.65
62.70
61.95
63.75
65.15
60. 75
62.12
59.15
61.85
62.15
63.11
60.90


Differ-

=ield of
two
vata


Per sWt.
0.11
.77
.83
.76
.13
.30
.04
.53
13.46
.62
1. 25
.79
.74
.50
.43
.Oil
.25
.00
.95
.24
.28
.72
1.59
.44
1.75
.41
.39
1.24
.91
.03
.91
.49
.21
.64
9.
1.585


Cheese
per cwt.
of milk.



Pounds.
9.89M5
10.026
9.707
10.537
10.-115
10.151
10.042
10.397
10.491
9.903
10.162
10-0.105
10.150
9.728
9.728
9.738
9.7B3
10.119
9.703
9.935
10. 195
10. 000
10.081
10.450
10.325
10.625
10.641
10L 125
10.353
10.239
10.308
10.358
10.527
10.150

10. 149


..i;






DISCUSSION OF VARIATION IN YIELD.


water for cooling, and, although the direct, cause of the exceptionally
high figure (3.46 per cent) can not be directly traced, it seems likely
That some gross error occurred, which was avoided on the other d(lays.
STherefore this figure (for April 6) is omitted from the general average.
On 28 days (82 per cent of all cases) the variation in yield between
duplicate vats lay below 1 per cent and on 33 days (omitting April 6) it
averaged 0.584 per cent. For present purposes, therefore, it may be
considered that the figure 5.37 per cent, from Table 20, representing the
average increased yield of green cheese obtained through pasteuriza-
tion, is correct within 0.58 per cent, or about one-ninth of its value.
The yield of cheese from pasteurized milk is thus capable of meas-
urement with an average difference between duplicate determina-
tions of 0.6 per cent of the amount determined. This degree of
accuracy in manipulation is comparable with that attained in many
analytical chemical processes, in which a limit of 1 per cent of the
amount determined is commonly set as the maximum allowable
difference between duplicates.
The principal cause for the difference of 0.60 per cent in the yield in
making duplicate vats of cheese does not lie in the weighing of the
milk or cheese, because with the scales employed both the milk used
and the cheese obtained therefrom could be weighed with an error
of not over 0.10 per cent. The per cent of difference in yield was not
reduced when the weight of milk handled was increased. It appears
likely, therefore, that there are small unavoidable differences caused
by the size of the cubes or in the manipulation of the milk and curd
which cause an average difference in yield of from 0.50 to 0.60 per
cent between duplicate vats.
An effort was made so far as time permitted to determine whether
any one of several causes was regularly or chiefly responsible for this
average difference in the yield. The stirring of the vats was done
by hand in all cases where the weight of milk in a vat was less than
400 pounds. For experiments with 400 to 800 pounds of milk in a
vat a pair of vats of 800 pounds capacity was used. These were
stirred with a pair of wooden rakes, exactly alike in shape and size.
Larger quantities of milk than 800 pounds were always handled in a
vat of 2,400 pounds capacity in which a two-bladed rotating and
oscillating agitator was used instead of the rake. The difference
in yield between duplicate vats could not be traced to the methods
of stirring. Thus, on March 27, the agitator-stirred vat (D) gave
- 0.83 per cent greater yield than the hand-stirred vat (C), but on
April 10 the hand-stirred vat (D) gave 0.62 per cent greater yield
than the agitator-stirred vat (C). The average difference on 12
days in yield between duplicate rake-stirred vats was 0.70 per cent,
and the average difference in yield between duplicate hand-stirred
vats on 19 days was 0.52 per cent. The differences varied slightly
whatever method of stirring was employed.


59








CH EDDAR CHEESE FROM PASTEURIZED MILK.


Again, handling different amounts of milk did not appear to affect
the yield in duplicate vats. On 12 days, using one and one-half to
three times as much milk in one vat as in the other, the average differ-
ince in yield was 0.40 per cent, which is a little smaller than. the

average (if the other days, showing that the quantity of milk handled
by tills method does not affect the yield. Since the same results are
obtained in a small vat with 375 pounds of milk as in a large one
with 1,125 pounds dif milk, it is believed that the general result of
tills investigation are applicable to the largest sized vats of milk used

in factories.

SIHINKA.EK BEFORE PARAFFINING, AND YIELD OF PARAFFINED CHEESE.

Since there is always some loss in weight of cheese previous to

paraillinig, it is of interest to compare the shrinkage of ordinary
cheese with that of new-process cheese, and to determine whether

tire is an increased yield of pasteurized-milk cheese when paraffined

coIrreVp()onding to the increased yield observed in the same cheese
whelcn green. This can be d(lone readily from Table 23, which shows

the average results for the season and also the range of daily variation.

TABLE 23.-Comparison of old and new process cheese as to shrinkage before paraffining
and yield of paraffined cheese.


Age
when
yar-
-rtn-If-I


amleu. Pasteur-
ized.

Days. Pounds.
19 5.92
18 5.98
15 5.32
14 5.23
13 5.36
12 5.26
15 5.71
11 5.21
10 4.45
9 5.49
8 3.58
12 5.08
11 5.13
10 3.,6
9 4.22
8 3.Ks
12 5.37
11 4.42
10 4.72
10 4.31i
8 4.10
10 5. 09
8 4. (2
12 5.11
11 4.85
12 5.05
9 3.98
N 2.X2
I1 4 36
10 4. :33
13 4.52
11 4.19
12 4.114
III 4.57
12 4.71
11 4.71
13 4.72


Shrinkage per 100
pounds of green
cheese before
paraffining.


Gain in
yield
by new
process.


Per cent.
5.32
3.94
6.64
6.56
2.24
4.40
2.43
1.24
1.86
3.53
6.32
10.95
8.00
2.95
2.09
3.19
5.16
5.23
2.94
6.65
4.60
4.05
2. (3
7.45
6.70
3.15
2.98
1.712
2.84
1.53
5.32
4.83
5.65
3.26
7.57
2.96
4.69


Yield y
pounds


Pasteur-
ized.

Pounds.
9.30
9.50
9.79
9.74
9.57
9.49
9.71
9.78
9.83
9.(S
9.75
9.93
10.-2t;
9. 78
10.25
10.03
9.58
9.46
9.46
9.94
9. l>6
9.51
9.35
9.52
9.40
9.30
9.32
9.45
9.79
9.31
N.91
9.32
9.71
9.49
1(. OS
9.74
10.04


per 100
of milk.


Raw.


Pounds.
8.83
9.14
9.18
9.14
9.36
9.09
9.48
9.66
9. 65
9.35
9.17
8.95
9.50
9.50
10.04
9.72
9.11
8.99
9.19
9.32
9.20
9.14
9.11
8.86
8.81
8.99
9.05
9.299
9.52
9.17
8. 46
S.89
9.19
9.19
9.37
9.46
9. 59


Raw.


Pounds.
5.23
5.05
4.67
4.57
4.8z
4.35
5.35
4.43
4.58
4.82
3.35
4.28
4.26'
3.73
:3. hi
3.27
4.37
3.68
3.86
3.58
3.85
4.56
4.051
4.23
4.42
4.11
3.64
2. >2
3.93
4. 08
4. IW5
3. 73
4.3t;
3.q98
4.19
3.93
4.37


O60


Date
made.



1911.
Febl. 23
24
27
28
Mar. 1
2
3
7
8
9
10
13
14
15
IIt
17
20
21

Apr. .5
7
11
13
17
I.
24
-27
28
May 2
1;(
15
17

.5
1'9









COMPARISON OF SHRINKAGE BY OLD AND NEW PROCESSES.


61


TABLE 23.-Comparison of old and new process cheese as to shrinkage before parajfining
and yield of parajfined cheese-Conli iued.


Shrinkage per 1(0
pounds of green
cheese before
paraffining.


Date
made.




1911.
June 1
2
7
9
13
15
16
19
21
26
27
28
July 3
6
8
10
11
12
Aug. 29
30
Sept. 1
5
6
7
8
20
22
25

Average..


Age
when
paraf-
ned.



Days.
10
9
7
8
10
8
7
12
10
12
11
10
14
J1
9
10
11
10
11
10
8
13
12
11
10
10
8
16
.... o......


Yield per 100
pounds of milk.


Pasteur-
ized.


Pounds.
1.0.05
9.93
9. uiii
9.90
10.40
10. 18
9.97
10.29
9.78
10.00
9.99
10.30
9.49
9.86
9.79
9.60
9.77
10.19
10. 18
9.97
10. 15
10.17
10.09
10.45
10.45
10. 66
10. 64
10.49

9.833


Raw.


Pou nds
111 III
9. :.t,
9.22
9.42
9.t.5
9.701)
9.51
9.53
9.31
9.40
9.50
9.90
8.(19
9.61
9.19
8.86
9. 26
9.42
9.88
9. i61
9.77
9.74
9.54
9.98
10.07
10.21
10. 19
9.94

9. 383


In practically every case in Table 23 the

showed a greater shrinkage than the raw-milk

before paraffining, which was 7 to 19 days.

of raw-milk cheese before paraffining, for


pasteurized-milk cheese

cheese during the period
The average shrinkage

all 65 cases, was 4.08


pounds per hundred of green cheese, and for the pasteurized-milk

cheese it was 4.55 pounds per hundred, nearly one-eighth greater

than the raw. This excess shrinkage is observed whether the cheese
was paraffined at 7 or 14 days, as is shown in the following table,

which is a summary of Table 23.

'TABLE 24.-Shrinkage of cheese when paraffined at different ages (summary of Table 23).


Pasteur-
ized.


Pounds.
3.92
4.22
4.21
3.80
5.26
4.49
4.43
4.85
4.46
4.53
4.19
4.02
4.56
4.20
3.64
4.80
4.46
4.54
4.99
4.22
4.14
4.35
3.82
3.49
3.17
3.80
3.43
6.49

4.546


Raw.


Pounds.
3. t-7
3.92
3.66
3.58
4.74
3.82
3.64
4.27
4.18
4. 17
3.80
3.41
3.91
4.01
3.42
4.64
4.01
3. C5
6.07
4.05
4. 14
4.05
3.49
2.99
2.81
3.41
3.21
5.87

4.078


;ain In
yield
Ihy now
process.



Per cent.
0. 40
3.98
4.77
5.09
S.90
4.95
4.84
7.97
5.05
6.3S
5. 16
4.04
9.21
2. tO
(. 53
8.35
5.51
8.17
3. 14
3.75
3.89
4.42
5.65
4.71
3.77
4.41
4.42
5.53

4.7651


Average shrinkage in
weight per 100
_pounds green cheese.
Age when Cases av- pounds green cheese Excess in pasteurized.
paraffined. eraged. Exe n paste .
Pasteur- Raw.
ized.


Per cent of
Days. Number. Pounds. Pounds. Pounds. raw.
7to 8 11 3.95 3.56 0.39 11
9 5 4.31 3.88 .43 11
10 16 4.35 3.83 .52 13
11 12 4.52 4.10 .42 11
12 10 4.84 4.17 .67 16
13 to 19 11 5.29 4.78 .51 11







62 CHEDDAR CHEESE FROM PASTEURIZED MILK.

On account of this excess shrinkage before paraffining, amounting
t, abixut one-half pound per hundred pounds of cheese, the average
increased yield of 5.37 pounds per hundred of milk observed in the
pasteuIrized cheese when green (Table 20) was reduced to 4.76 pounds
(see Table 23) by the time the cheese was paraffined.

SHRINKAGE AND YIELD OP CURED CHEESE.

The further shrinkage and yield of cheese after paraffining was
studied: (1) With cheese cured at Madison, Wis., at a temperature
of (10o to 75; (2) with cheese cured at New Orleans, La., and weighed
both at New OrleansI and Madison; (3) with cheese cured at New
Orleans or at Columbus, Ga., and weighed both at Chicago and at
.Madison; (4) with cheese cured in a warm room at Madison; and (5)
witli cheese put in cold storage at 340 F. at Waterloo, Wis..t at differ-
ent ages after paraffining. So far as possible duplicate cheeses from
the samein days' make were cured in the different ways stated.
These different methods of curing were chosen for study as repre-
senting (1) curing conditions at Wisconsin factories; (2), (3), and (4)
conditions to which annually large amounts of cheese are subjected
when shipped south for sale; and (5) when cured in cold storage as
commonly practiced by dealers.
The shipments to New Orleans were sent on four dates between
April 29 and July 24, 1911. Each shipment consisted of 9 to 25
pasteurized-milk cheeses, and an equal number of raw-milk cheeses
for comparison. In order that the cheese stored might be as repre-
sentative as possible, each pair represented a different day's make.
For each lot of cheese shipped away from Madison for storage, a
dutiplicate lot from the same days' make was kept at Madison. The
method of designating these different lots of cheese is shown in
Table 25:

TABL.E 25.-Reference numbers to different lots of cheese stored in 1911.

Cured at
Date made. Cheese Cured at Cured at New Or- Cured in Cured at
Date made. s. Madison. New Or- leans and warm room Waterloo,
Nos. Madi. leans. Columbus. at Madison. Wis.
Ga.

Feb. 23 to Apr. 16.... 171 to 207 1A B ... B ..... ............ ........................
Apr. 24 to Mav 17. .. 211 0to 227 2A...... 2......... ............ ............ ....
MaV 22 to( June 16 ... 230 to 246 3A..... ....311 ...... ..3C ....... 3 ........... ... ......
June I'II t Jully 12.... 24.4 to 2(i63 4AX....... 411 ........ 4C.........4D ..
July 13 to Aug. 21 .... 24 to 2.3 5A ..................................I ........ :: ..

In addition to weighing each cheese separately they were also
weigliti in lots of five, and the close agreement of the weight of a lot
I The ui'lrilk of the work at New Orleans connected with the storage, weighing, and shipping of the
chew, usedil In this test were handled by Mr. W. J. Bleecker, Junior dairyman of the Dairy Division,
i ureau of Aniial Indlustry. Thanks are due to Mr. Bleecker for his very careful attention to this work.









CURING VARIOUS LENGTHS OF TIME.


63


of five with the sum of the five separate weights proved the accuracy
of the weighing. This general method of double weighing was
followed in obtaining all the weights of cliheese in the 14 lots.
The tabulated results show the shrinkage of the different lots and
the yield of green, paraffined, and cured cheese per hundred pounds
of milk. In addition to the average results for each lot of cheese,
the individual variations in shrinkage and yield of the single cheeses
are shown, from which the extent of daily variations from the general
average figures can be studied by anyone interested.
Cheese cured at Madison (lots 1A to 5A).-Fifty-two pairs of cheese
cured at 60 to 70 were weighed one or more times (92 times in all) at
different ages, from 21 to 117 days after paraffining. In every case
there was a gain in yield of pasteurized cheese over raw cheese. The
gain averaged 4.59 per cent among 10 pairs of cheese cured 20 to 30

days, 4.58 per cent among 37 pairs of cheese cured 30 to 60 days,
4.38 per cent among 28 pairs of cheese cured 60 to 90 days, and 3.58
per cent among 17 pairs of cheese cured 90 to 117 days. On the
average of all cases the gain in yield of pasteurized over raw was
4.22 per cent of the weight of the cheese.


TABLE 26.-Comparison of yield of raw and pasteurized-milk cheese
various lengths of time at Madison, His.


Weight of cured
cheese per 100
pounds ol milk.


Pastetur-
ized.


Pounds.
9.27
9.52
9.40
9.37
9.47
9.87
10.02
9.68
10.03
9.72
9.53
9.57
9.61
9.55
9.62
9.30
9.13
9.43
9.15
9.86
9.70
9.64
9.12
9.26
9.51
9.49
9.57
9.21
9.29
9.06
8.95
9.19
9.41


Raw.


Pounds.
8.96
9.06
8.94
9.12
8.99
9.63
9.96
9.38
9.34
8.80
9.36
9.49
9.51
9.29
9.09
8.73
8.64
8.89
8.85
8.94
9.30
9.04
8.63
8.93
9.00
8.99
9.08
8.94
8.98
8.86
8.51
8.79
8.58


after curing for


Date
made.




1911.
Apr. 24
Mar. 20
21
22
20
17
16
15
14
13
2
7
8
9
10
Apr. 17
18
May 15
17
June 13
15
16
Feb. 23
24
27
28
Mar. 1
2
Apr. 11
13
May 10
June 7
9


Time
cured
after
paraffin-
ing.


Days.
21
26
26
26
33
32
32
32
32
32
42
42
42
42
42
42
42
44
44
44
44
44
45
45
45
45
45
45
50
50
50
50
50


Gain by pasteur-
ization.




Pounds. Per cent.
0.31 3.46
.46 5.08
.46 5.15
.25 2.74
.48 5.34
24 2.49
.06 .60
.30 3.20
.69 7.338
.92 10.46
.17 1.81
08 .84
.10 1.05
.26 2.80
.53 5.83
.57 6.54
.49 5.67
.54 6.07
.30 3.39
.92 10.29
.40 4.30
.60 6.64
.49 5.67
.33 3.69
.51 5.67
.50 5.56
.49 5.39
.27 3.02
.31 3.45
.20 2.26
.44 5.17
.40 4.55
.83 9.67


I


o









64 CHEDDAR CHEESE FROM PASTEURIZED MILK.


TABLE 26.-Comparison of yield of raw and pasteurized-milk rheese after curing for
various kengts of lime at Madison, IVis.-Conuinued.


Date
made.



1911.
July 3
6
June 1
2
May 29
Apr. 25
May 2
3
Apr. 7
May 25
22
26
27
21
19
21
Apr. 2.S
27
24
Mar. 10
21
20
Apr. 17
18
Mar. 17
16
15
14
14
Apr. 13
11
7
5
Mar. 9
8
7
3
2
1
Feb. 2s
27
24
Mar. 20
21
22
17
16
15
14
13
9
S
7
3
2
1
Feb. 2,
27
24

Average..


Weight of cured
vhtve ijr In A 00
pounds of milk.


Pasteur-
Ized.


Time
cured
after
pura llin-
lug.


Days.
51
51
55
55
55
56
58
58
56
62
62
fi61
61
61
66
66
65
65
65
69
6X
68
72
72
74
74
74
74
74
8O
SO
86
96
84
84
84
84
87
S7
S7
87
87
98
98
98
104
104
104
104
104
114
114
114
114
117
117
117
117
117


..........j 9.2 j


Raw.


I j


Cu74rse stlrd? at Nfw Orleans (lots 1B to 4B).-Fifty-four days'
mnnke re'prresCnte(I by 54 raw and 54 pasteurized-milk cheeses were
siiipped to New Orleans in four lots at different times during the


S('llSOI.


These cheeses showed an increased yield for the new-process


cl,',s(, as compared with the old, in every case.

Iiglires for each lot are given in Table 27.


The average


Pounds.
9.05
9.35
9.59
9 33
9.52
9. R2
9.32
8..%2
9. 36
9.19
9.40
9.16
9 3
9.67
9.66
9.16
R.97
8.78
9.01
9.10
9.15
9.15
9.03
8.81
9.43
9.72
9.34
9.62
9.37
8.76
8.9g
9.09
9.33
9.24
9.40
9.39
9.24
8.93
8.97
9.25
9.2.S
S.9A
8.94
8.95
8.91
9.20
9.51
9 12
9.41
9.14
9.02
9.14
9.14
9.06
8. O)
8. Ai
9.12
9.15
8.79


Pounds.
8.38
9.21
9.49
8.95
9.05
9.07
9.06
8.66
8.89
9. h9
8. X6
8.74
8.,S0
S.95
9.35
8.90
8. 72
8.82
8.10
8.68
8. 5
X.67
8.74
s.47
S 34
9.28
9.55
9.06
8.99
X.53
8.58
8.74
8.68
8.8S
8.94
9.09
9.13
9.02
8.64
8.S5
S. SO'
8.71
8.78
8.72
8.62
8.44
S.69
9.08
9.35
8.92
8. 43
S.4*t
S.72

8.93
8.5.
K.51
S.75
%. fM"
S.63
S. fi2

8.907


Gain by pasteur.
ization.




Pounds. Per cent.
0.b7 s. U
.14 1.52
.10 1.05
.3 4.24
.47 5.19
.55 6.06
.26 2.87
.16 1.84
.47 5.28
.33 3.72
.66 7.55
.36 4.09
.47 5.25
.32 3.42
.76 8.54
.44 5.05
.15 1.70
.68 8.40
.33 3.80
25 2.S2
.49 5.53
.41 4.69
.56 6.61
.47 5.63
.15 1.62
.17 1.78
.28 3.09
.63 7.01
.84 9.84
.18 2.09
.24 2.74
.41 4.72
.45 5.07
.30 3.35
.31 3.41
.26 2.85
.22 2.44
.29 3.35
.12 1.35
.54 6.20
.5)0 5.69
.26 2.98
.32 3.71
.51 6.04
.22 2.53
.12 1.32
.16 1.71
.20 2.24
.5S 6.57
6 R. 03
.30 :3.44
.26 2.93
.21 2.35
.21 2.37
.29 3.41
.11 1.25
.49 5.11fi7
.46 5.29
.17 1.97

.38 4.22








CURING VARIOUS LENGTHS OF TIME.


TABLE 27.-Average yield per


o00 pounds of milk rf raw
cured at New Orleans.


and pasteurized-m ilk cheese


Lot
No.


Method.


Numn-
ber of
dmtvs'
mnke.


YiCli of rheCse per 100 pounds of milk.


Green.


-I I


1-4B


Pasteurized.................
Raw........................
Gain, pounds.............
Gain, per cent............
Pasteurized...................
Raw ..........................
Gain, pounds.............
Gain, per cent............
Pasteurized...................
Raw........... ...............
Gain, pounds.............
Gain, per cent............
Pasteurized...................
Raw..........................
Gain, pounds.............
Gain, per cent-...........
Pasteurized...................
Raw..........................
Gain, pounds.............
Gain, per cent............


FPound.q.
25 10. 19
23 1.67
25 iL.OT
....... 52
........ 5.37
9 9. 3
9 9.4.5
........ 38
........ 4 02
10 10.47
10 9.93
........ ..54
........ 5.44
10 10.38
10 9.69
........ 69
........ 7.12
54 10. 22
54 9. iUS
....... .. 54
........ 5.5S


P:a r.f-
Iilledl.



Pou nds.


Shlip-
pedl
to New
4ir-
leans.

Pou ni d.


9. (,9 9.55
9.26 9.16
. 43 .39
4.64 4 23
9.40 9. ,7
9. 0.O 9 .05
.32 .2',
3.52 3.54
9.99 9.92
9.54 9.47
.45 .45
4.72 4.75
9.92 9.83
9.31 9.24
.61 .59
6.55 6 3.8
9.74 9.64
9.29 9.21
.4.5 .43
4.84 4.67


Re- SrRe-
ceived Stored Stored ceivedr
at New one i two at
SIr- month. monthlis. Madi-
leans. son.


Pou nd., Pou nds.'Poundrls. Pounds.
9.32 1 .S, 1 S.;, 8.31
9.14 8.36 7.. 3 7.78
.2. .49 .53 .53
4. t16 5..St6 6.75 6.81
9. 2 ; S. 4 ....... 40
S. 7 I ,. 12 ........ 8.01
.29 ........ .39
; :';3 414 ......... 4.87

9.77 9.29 I........ 9.17
9.34 '.L J ........ 8.55
43 ."0O ........ 62
4.60 6.9)0 ........ 7.25
9.7 S.94 ......... 8.71
9.19 S.28 I........ 8.14
.59 .66 ........ .57
6.42 7.97 ........ 7.00
9.57 8.s,9 ........ S.556
16 8.37 ........ S. 03
.41 .52 ...... 53
4.47 6.21 ........ 6.60


Among the four lots in Table 27, and in the summary at the
bottom of the table, it will be seen that the percentage of gain in
yield of pasteurized cheese over raw fell off slowly as the green
cheeses were paraffined and shipped, on the average from 5.58 to 4.47
per cent. After these cheeses had been in storage at New Orleans
for one month, the raw-milk cheeses were found to have shrunk
more than the pasteurized in the majority of cases, raising the per-
centage of gain in average yield of pasteurized cheese to 6.21 per
cent. This was also observed in lot 1B after the second month of
storage, and is confirmed both by the weights taken in New Orleans
by Mr. Bleecker and by the weights taken at Madison. It was
expected that the pasteurized-milk cheese, containing slightly more
moisture than the raw-milk cheese, would lose more in weight than
the latter when stored at high temperatures. It was surprising to
find that the reverse is true in most cases.
The mean daily temperature at New Orleans, as reported by the
'United States Weather Bureau, varied from 71, the average for April,
to 83, the average for June. It is likely that the temperature of the
Cheese in the warehouse was somewhat higher than the average
Figures given above, because the warehouse, although well ventilated,

S 799940-Bull. 165-13-5


65


I
i






CHEDDAR CHEESE FROM PASTEURIZED MILK.


was necessarily open more or less during the hot days and dosed
during the cool nights.
Cieese cured at New Orleans and at Columbus, Ga. (lots S0 and
40).-Forty cheeses, including 20 pasteurized and 20 raw, were
slhipl)pe(d ill two shilpmients for storage in the South through a firm'
(if cheese dealers in Chicago, who weighed the cheese, both before and
after storage for one month.I
In tlhe first siipmenl, t 1 cheese, No. 243-3, was lost in transit,
and in tile second shipment, 2 cheeses, Nos. 254-1 and 254C1,
Vwere damaged so that their weights are not included in the following
sum1nar". Inl thle first shipment, according Lo the Chicago weights,
s? pasteurized-niilk cliheeses weiglied 172 ;pounds before storage
and 162- pounds afterwards. Thle loss, 101 pounds, is 5.94 per cent
of the original weight. In the same shipment 10 raw-nuilk cheeses
weighed 1S9j pounds before shipment and 175 pounds afterwards.
Thle loss liere, 14 1)ounds, is 7.53 per cent of thle original weight.
In tlie seOCnd shipment nine )pasteurized -milk cheeses weighed
176 pounds before and 159- pounds after storage. The loss, 16
p)ouiIds, is 9.49 p)er cent of thle original weight of tlhe cheese. In the
s11n0 shiJplWitent ninei raw-iilk c leese(,s weilghcd fil 61 pounds before and
144" ]pollulds after storage. The loss in this case, 161 pounds, is
10. (i jper cent of tlie original weight. In bitli shipments the raw-
milk cl(.vcs h lst aa greater per (cent of their weiglht tltan the pasteurized-
liilk citeese. ()n cop;,ring tlhe' individual cliteeses in pairs, it was
found( that in most cases thle pasteurized-milk cheese lost less than
tlhe raw-iiilk cheese, aIlthough in a few cases thle reverse was true.
rPlI(. weighlts taken at Mad(liston on the same lots of cheese gave the
firures shown in Table 28, agreeing substantially with the results
(obitlaiLed at Chica"l":

TA 1. 2 .- A t t g r7et' !/1'/ per 1undriL pr nl (if i. ,'(k 'M Ill: fi a ii ,nsteuzri'd milk cities .
curcl in tihe 'J mI /fh.
I I
\\'I,,'0!i ol (O*:L'0%V [0?H 1ixI pounds of milk.
1.ur ~N mInl'i''r ---------------- ----_____
Meo.od of .1 1 iilel Ie ie
,' Method.* o[,I --' I P.,r:,.,- shipped Received
;m ir n.*i I fruiom at
Nl i M .son. Madison.
i
i l',,,< ii ,/ l' ,, , l '" 'ri- 1 niin s. P o u n d s.
Sl uri ... . . ... .................. ... ( lI ;"11 47 44 9.92 9. 24
kI'. .. .............. . . . . . . I,, .0 9.. 9.I.",-* 9.4 g.t .68
I; ii, ti A r : ......................................I 4 4.72 4. 6.44
4i Jil,'J:"t::r ....................... ............... .. .. 7..44 4.72 4'.%,: .44
W ,; .. % 92 9. S. S3
4 1" i ,.LI ... .: ............. ... ................ ......... .. 9.,60 ..5924
I .i:it, [p..' .,n ........................................ 7.1. t 5. 6.49 7.16

N Vt art. i ,iltb l o Mt .i- 'r.S. e'ru.siy & Mr... r, :ur hilicir kin i t-oop1rati3D In this work.


66







CHEESE CUBED IN WARM ROOM. 67

Cheese cured in a warm room (lots SD and 4D).-To further test
the effect of storage at high temperature 40 cheeses, lots 3D and 4D,
were put for 47 days into a warm curing room at Madison where the
temperature was held at 75 to S5.
TABLE 29.-Average yield per hundre'l pounds of mill: oJf raw and pasteurized milk cheese
cured in warm foont.

\Veiliht of cheese per 100 pounds or milk.
.Ni:mher
Lot Method. o; ." pt in Taken
j No.III ,k. P r r P- out of
G, r. fin. warm warm
room. m
room.

P'j,-nd-h. Pou''J7 I Poundq. Pound.e.
Pasteurized .................................. 1 ]: 47 '.9 'Y 9.91 9.37
Raw ....................................... 91 .9 34 9.4,6 S..S.
3D---------------
S Gain, pound ...... ..................... .........I . .4 I .45 .49
Gain, per ce-i .......................... ...... 4. 4 4. 72 4.75 5.52
Pasteurized................................... .., '11. 9 :. 9. :
Raw ...................... ........ ...... .9. li 9 '.: j..1 9.2.3 8.73
4D
Gain, ponl ,. ..................................... '' .... ,'2 h0
Gain, pe xt 2nt .................. ........ ........ 7.12 G. .j G. 72 6.S7
ii
From these result; with eil'it l- t of lie,-e- lB, '2B, 3B, 4B, 3'C,
4C', 3D, and 4D-it can be -tntted wi ii Ve1n ainttv that ~a-.teiirizetl-milk

cheese does not lose more in weight th:lii raw-milk chliee-e when stored
in warm rooms or in the South, after parallining. On tlhe contrary,
the pasteurized-milk cheese lost on the average a smaller percentage
of weight in warm storage than the raw-milk cheese. At first this
fact seemed inexplicable, but the rea-son i)ecame clearly apparent from
inspection of the cheese kept in the warm curing room at Madison.
Within a few days after going into the w.arm room the raw-milk
cheese became very greasy on the surface, antl the grea-ze running on
to the .-helves and the floor market 'l the sp-t where e.ich' cliee-e stood.
The pasteurized-milk cheese, standing alungsi Ile of them on the same
shelves, did not exude grease, or only very slightly in a few cases, and
the difference between the greasv raw-milk clheese andl tlhe dry surface
of the pasteurize.d-milk cheese was s.) marked that there was no
dilliculty in picking out each kind Iby the ;sev-e of touch alone.
To demonstrate further the difference in till-; respect, each cheese
of the last lot when put into the warm room w-as placed on a piece
of wire gauze in a shallow tin pan, so that the grease runiing from each
cheese could be collected. A very little of the paralir was scraped
from the surface of each cheese by contact with the wire gauze in the
bottom of the pan. The total weight of material, practicaLly all
paraffin, collected from the 10 pasteurized-milk cheeses weighed 0.13 of
a pound, while the material, m .stly fat, with a little parafli and mold,
collected from the raw-milk cheeses, weighed 1.92 pounds, which is
1.2 per cent of the'weight of the raw cheese when placed in the store-
room.








CHEDDAR CHEESE FROM PASTEURIZED MILK.


At present we are unable to explain with certainty why the pasteur-
izel-milk chees-,e should lose fat less readily when stored at 70 to 80
flthan the raw-milk cheese. Further study will be made of this phe-
fmenllom. The p purposee of beginning these studies of losses of weight
in warm rooms was to determine whether the increased yield obtained
Iv pasteutirizatioIn would be ofset by increased losses in weight when

Paisteuriz.(I,-milk cheese are shipped to the South, and it is now fully
tleinoMsttritetl that the pasteurized-milk cheese stored in the South

mauitain their advantage as to increased yield.
C'hitese tha c d( in cold storage at Waterloo, Wis. (lot SE).-The losses
of weight observed in 35 pasteurized-milk cheeses put into cold
storage at 34 at different ages are shown in Table 30. The cheese
represent seven days' make (luring July and August, 1911.

TABLE 30.-Shrinkage rif pasteurized-milk cheese in cold storage.


hen When put
fined into cold
med, storage.

Weight. Age. Weight.


Pounds. !Days.
19.60 i (1)
20.70 1
19.21 7
20.05 14
18.90 28
19.44 41
21.60 (2)
17.58 1
19.35 7
17.98 14
18.8s 28
1.40 I 28
18.86 40
19.86 (1 )
19.95 1
19. 11 7
20.58 14
19.25 29
21.31 43
17.80 (2)
19.45 1
19.01 7
19.92 14
17.91 27
19. -22 41
20.65 (2)
19.30 1
18. 55 7
20.55 14
20.57 29
20.50 46
18.63 (1)
19.98 1
19.50 7
1&.W66 15
18.45 28
.. .. .. .. C')
19.50 1
IS.A! 8
17. 9) 15
IS. K4 29
17.662 42


Pounds.
(3)
20.70
19.21
20.04
18.70
18.95
(3)
17.58
19.35
17.92
18.42
18.13
18.36
(1)
19. 95
19.11
20.58
18.98
20.t62
(3)
19.45
19.01
19.92
17.60
18.61
(2)
19.30
18.55
20.55
20.26
19.75
(3)
19.98
19.50
18.63
18.21
(')
19.50
18. S1
17.70
18.S.62
(2)


When taken
out of cold
storage.


Age.

Dayi.
100)

100
100
100
100
99
99
99
99
99
99
99
95
95
95
95
95
95
93
93
93
93
93
93
89
89
89
89
89
89
81
81
81
81
81
67
67
67
67
67
67


Weight.

Pounds.
18.15
20.38
19.15
19.85
1%.28
1.%.65
20.10
17.45
19.25
17.75
18.05
17.68
18.10
IS. 50
19.80
I1.g90
20.38
IS. 58
20.25
16.45
19.20
18.95
19.55
17.22
18.25
19.00
19.05
18. 22
20.25
19.90
19.50
17.20
19.6C0
19.30
I8. 40
17.75
18.10
19.38
18.75
17.40
18.45
16.80


Total shrinkage.


Pounds.
2.45
.73
.95
1.22
1.61
1.80
2.39
.53
.96
1.11
1.53
1.57
1.65
2.32
.49
1.07
1.17
1.65
1.95
2.25
.68
.90
1.32
1.58
1.97
2.91
.73
1.18
1.57
1.90
2.25
2.70
.82
1.14
1.50
1.95
2.00
.52
.93
1.40
1.39
1.85


Per cent.
11.89
3.45
4.72
5.79
8.09
8.80
10.62
2.94
4.75
5.89
7.81
8.16
8.35
11.14
2.41
5.35
5.43
8.15
8.78
12.03
3.42
4.53
6.32
8.40
9.74
13.28
3.69
6.08
7.19
8.71
10.34
13.56
4.01
5.57
7.53
9.89
9.95
2.61
4.72
7.44
7.00
9.92


SUM MARY.


No. of chee- ................ 7 7 7 7 6 7
.\W when 'tured .............i 1 day. 1 week. 2 weeks. 4 weeks. 6 weeks. In cellar.
.\A per4ge tutal shrinkage,
per rent.................... 3.22 5.10 6.51 8.29 9.29 11.78


I In warehouse at Waterloo, Wis., by courtesy of the Roach & Seeber Co.


68


w
para


Age.

Days.
9
1
7
9
9
9
8
1
7
8
8
S
8
S
11
1
7
11
11
11
9
1
7
9
9
9
11
I
7
11
11
11
11
1
7
11
11


Date.
mjde.



1911.
July 19
19
19
19
19
19
21
21
21
21
21
21
21
25
25
25
2.5
25
25
27
27
27
27
27
27
Aug. 1

I
I
1
I
8
8
8
S
22
I.)*
2
2"2
b2
22


ChNo.
No.


264-1
264-2
264-3
264-4
264-5
264-6
2t65-1
265-2
265-3
265-4
265-5
263 6
265-7
267-1
267-2
267-3
267-4
267-5
267--
269-1
269-2
2i9-3
269-4
26;9-5
2119-6

272-1
272-2
272-3
272-4
272-5
272-6
276-1
276-2
276-3
27(6-4
276-5
*2.3-1
L" *2.3- 3
2-:2 -4
276,1 5
2k 6t


Weight,
green.



Pounds.
20. 60
21.11
20.10
21.07
19.S9
20.45
22. 49
17.9S
20. L21
I.U. s
19.5S
19 25
19.75
20. 82
20.29
19.97
21.55
20.23
22.20
IS. 70
19.S1
19.85
20.87
IS. so
20. 22
21.91
19. 7s
19.40
21.,2
21. SO
21.75
19.90
20.42
20. 44
19.90
19.70
20. 10
19. 90
19. i8
Is. N,)
19. %4
IS. IJ


I Cured in cella.






CAUSES OF INCREASED YIELD.


Although the seven cheeses put into storage at thle age of 1 day
showed an average of only 3.22 per cent shrinkage after three niitlis,
yet they were not well broken down and required further curing at
60 to 70 to get rid of their curdy, lumpy texture. The cheese
paraffined and stored when 1 week old showed an average total
shrinkage of 5.10 per cent, and these were found to be thoroughly
broken down when taken out of cold storage. This series appears
to indicate that the quality of pasteurized-milk cheese is not damaged
by placing in cold storage at the age of 1 week, while the shrinkage
(5.10 per cent) is about half that of the duplicate cheese, cured in
the cellar at Madison (11.78 per cent), as shown at the bottom of
the table.

THE CAUSES OF THE INCREASED YIELD FROM PASTEURIZED MILK.
THE LOSSES OF FAT FROM VAT AND PRESS.
The increased yield of green cheese from pasteurized milk, amount-
ing to over 5 per cent (Table 20), is due partly to the fact that about
half of the fat lost in the whey and drippings by the old process is
retained in the cheese by the new process of making. Also it is
found that a little more moisture can safely be incorporated in the
new-process cheese without danger of spoiling it, but on the contrary
giving it a moist, fat appearance which consumers generally like.
The loss of fat in the whey is caused partly by the passage of the
curd knives through the curd in cutting, at which time a considerable
proportion of fat is brushed away from the surface of the curd cubes.
During the stirring and heating some further fat globules are lost
from the curd cubes, and still further losses occur after milling and
during pressing. In the new process of making cheese from pasteur-
ized milk the. curd is so firm and elastic (not brittle) at the time of
cutting that the loss of fat in the whey averages only about one-half
that observed in cheese making by the ordinary process.
The average fat content of whey from good clean milk is stated to
be 0.30 per cent and from average cheese factory milk 0.36 per cent.1
On a great many days during the past two and one-half years the
milk supply in the receiving vat has been divided and one half made
up by the regular methods and the other half by the new method.
The quality and composition of the milk was thus the same in both
vats. On the 24 days listed in Table 31 the average fat content of
the whey from the regular vats was 0.25 per cent and from the
pasteurized-milk vats was 0.159 per cent.
I Van Slyke and Publow, loc. cit., pp. 189,190.


69








70 CHEDDAR CHEESE FROM PASTEURIZED MILK.

TABLZ 31.-Comparison of the percentage of fat in whey by new method and by regular
method of cheese making.


In these cases the small amount


of milk handled in each vat per-


mitted hand stirring, and neither the rake nor the agitator was used.
lyv tils means the whey fat of the regular-process vats was kept at a
lower tigurc, perhaps, than could have been done with large vats,
.s handled in a commercial factory using the regular process.
On 22 days, using 1.200 to 2,000 pounds of pasteurized milk in
each vat, the percentage of fat in the whey at the time of drawing
the whey averaged 0.17 per ('cent, as shown in the following table.
In these cases the vats were stirred with an agitator.

TABLE 32.- Fat con tent of whey from pst'curizcd-m ilk cheen.


Date.



1io10.
May 25
26
2-
June !
6
7
S
9
10


Fat in Weicht
whey two of milk
hur-;ufler handled.
cutting.

Per cTrif. Pounds.Iu.
(0. 14 1. 2:14
16 1.322
,s 1,1: 7
.17 1.517S
12 2.11 M;6
.1 1.427
14 1.4,41
.1 1.336i'1
.17 1.44A1


New method. Regular method.

Date. F iFat in
Dat Mil. k. Weight Fat Weight Fat in
or nilk whey of milk whey
o ilkd when when
tbed, drawn. used. drawn.


1911. Per ct. Pounds. Per cent. Pounds. Per cent.
Aug. 29 4.1 2941 0.14 2"M) 0.17
30 3.6 344-1 .14 344 .26
Septt. 1 ........ 322 .15 32o .20
5 4.1 29'Ji .17 "-2 .28
6 3.6 276 .19 7.6 .32
7 4.1 2S61 .18 ..wT .32
8 ........ 292 .16 795 .26
1909.
July 21 4.0n 2w) .15 2(0 .21
22 3 9 14) .12 200 .20
23 4.0) .15 21 ) .19
24 4.0 121X) .12 2)xj .22
Aug. 12 3.7 20) .16 2X) .26
190R.
July 1.S 4.1 210 .12 20(] .22
Oct. 1 4.7 2.1K) .-2'1 2' .30
2 4 5 1 2X) .18 2(,p .29
7 4.4 2'IX1 .14 2Ji .19
8 4.(i 2,X .15 724k1 .25
Sept. 1 4.3 2W) .17 2'1 .32
2 4.2 21,I .IS 2PM) .31)
14 4.2 :.hh 1S 2_A. l .24
16 4.0 2' il .13 21mJ .27
17 4.4 2,1 2)'1 ) .29
IS 4.4 2"' 18 21, .25
19 4.2 2,-J .17 2'10 .23
Avera':e.................... .159. .......... 25


Weight
of cheese.


Pounds.
139
153
144
166
226
159
158
147
162









CAUSES OF INCREASED YIELD. 71

TABLE 32.-Fat content of whey from pasteurized-milk cheese-Continued.

Fat in Weight eight
Date. whey two of imilkght
Dhur. after handled. of cheese.
tufting.

1910. Per cent. Pounds. Pounds.
June 14 0.20 1,3u8 148
16 .20 1,165 126
17 .20 1,320 152
20 .20 1, Sm 171)
21 .23 1,292 144
22 .14 1. 347 144
23 .16 1,329 139
24 .18 1. 337 13i.
28 .24 1,277 13)
29 .14 1, 210 13o
30 .17 1,243 131
July 5 .1P 1,242 125
6 .14 1, 229 134
Average.. .17 ............ .....:......


Most of the loss of fat from curd occurs at, thle moment of cutting,
as shown by the figures in Table 33. On 23 days samples of whey
were taken daily from the vat as soon after cutting as it was possible
to obtain any clear whey-that is, in four to six minutes. The fat
content of this whey, sampled five minutes after cutting, tested 0.47
per cent on the average of 23 (lays, while the average test of samples
taken from the same vats two hours after cutting was 0.16 per cent.
The average weight of milk handled (laily in tihe vat was 1,110
pounds, and the average fat test of the milk was 4 per cent.

TABLE 33.-Fat content of v'hey at time of cuttinq curdaind 2 hours later.


Time alter c'l tlu
curd. IWe ih
Date. of milk \ heese.
4 to 6 2 harnile'. fceese.
minutes, hours.

19101. c; fat. fat. Pounds. Pounds.
Apr. 8 u. 45 0. 16 1.1)11 102
12 .46 .1') 1,011 104
13 .40 .15 9067 98
14 .41) .14 1,045 10-S
15 .50 .12 1,0)11 1U0
IS .35 .13 91: 3 103
19 .55 .22 906 97
22 .4( .16 755 77
25 .42 .19 1,.065 117
26 .52 .17 9401 103
27 .52 .16 1.0,4 109
28 .57 .15 972 102
29 .45 .14 796 102
May 3 .65 .16 1,041 122
4 .67 .16 1,055 118
5 .52 .17 1,119 129
6 .50 .20 917 97
10 .52 .16 1,2S8 141
11 .50 .15 1,285 138
18 .35 .15 1,239 137
19 .40 .14 1.186 130
23 .25 .12 2,477 268
24 .45 .19 1,454 154
Average.. .47 .16 1,110 119.8








CHEDDAR CHEESE FROM PASTEURIZED MILK.


Tlie reason for tlhe decrease in percentage of fat in whey at two
ioirs after cuttitig is that there was little fat lost from the curd
dtiuring the time thle whey was being expelled, so that the fat lost
from the curd cubes at tlie moment of cutting was diluted about 0.47
divided by 0.16=3 times by the water expelled from the curd during

thl two-hour period.

Losses of fal after drawing the whey.-On several days the whey
drij)plings from tlte p)asteurized-muilk curd, from the time the curd

was all on tihe rack up to the time when it was taken from the press,
were collected, weighed, and tested for fat. From this could be cal-
culatedi tlhe wCiglt of fat lost in the drippings, as shown in Tables 34,

35, anti 36:

TABLE 34.-Loss of fat in. drippings in 2 hours and 50 minutes-From dipping fo
hoopIP g-Pasteurized-m inilk curd.


Fat in drippings.



Percent. Pound.
0.27 0.07A
.27 I .075
.30 M (I"
25 o',2
.2) ( .(42
.10 .026
.15 11311
.IS I .A45
.12 .U25


Total
weight of
drippings
collected.


Pounds.
29
28
31
"M
21
26
20
25
21


Weight
of cheese
made.


P pounds.

9-S
104
RA1)
103
97
91i
951
77


.5048 117
. 544 991


25S ..........
I. .. .. .


TABLE 35.--Losses of fat in drippings before pressing pasteurized-milk curds.


Dale.




Apr. 27
2s
94
May 3
4
5
,0
1 1
13
DI
19
:'3
24
Total.......
S('L I i u -
lated fur
III1s. of
rheese...


Drippings in 14 hours--dip-
ping to milling.


Weight.


Pou ids.
35
24
24
25
25
29
26
24
25
24
25
2'26

3541


2.01


Drippings in I hours-mill-
ing to hooping.


Fat content. Weight.


Per cent.
0.02
.05
.02
.08
.05
.07
.07
.07
.16
.06
.05
.04
.14


Pound.
0.007
.012
050
.020
.012

.017
.040
.014
(12
.015
.036

.273


.00157


Pounds.
5.0
5.0
3.0
2.5
1.5
3.0
4.0
3.0
3.0
4.5
5,0
9.0
5.0

53.5


.3078


Fat content.


Pe r cent.
I.x
1.8
1.8
1.8
.6
1.7
1.2
1.6
2.0
2.0
1.4
1.5
2.0


Pound.
0 0




IWOl
.090
.07154
.1045
I0WE





.R90

.07012
1490


.00512


"2


Date.



1910.
Apr. 12
13
14
15
18
19
20
21
22
25
Total.....


Weight
of cheese.


Pounds.
109
Win
102
94
1221
118
129
141
1371
103
137
125
26%
162

1.738


I


i







CAUSES OF INCREASED YIELD. 73

TABLE 36.-Loss of fat in drippings from pasteurized-milk cheese in pre.

Total Total
Date. oehtee %- weight of Fat in drilppings.
of celIesele dipns
pressed. drippings.

o191. Pounds. Pounds. Per cent. Pound..
Mar 16-20 sOs 24 3.sN5 0. 42
23-27 S73: 32 3.2 1.02
Total....... 1,6S1 56 ............ .... 1.94
C a .I c [I -
latel for
]lllbs. of
cheese .............. .. 33 ............ .0115


Summary of losses of fat by the new method of cheese making.-The
total loss of fat from cheese in the new process is about 1.6 per cent
of the weight of the cheese, as shown in the following summary of
the preceding tables:

TABLE 37.-Total losses offat in making 10 pounds of cheesefrom pasteurized milk.

Totl Loss of
Period.Toal. Fat content, fat from
weight. cheese.

Pounds. Per cent. Pound. Per cen:.
W hey when drawn............................................S. 7.4 0.16 t 0. 1400 1. 401
Drippings from curd before milling............................. 2.01 .OS .0016 .011'
Drippings from curd in vat after millng........................ .31 1.66 .0051 .051
Drippings from press........................................... .33 3.46 .115 .1IU
Total..................................................... 90.035 .......... 1583 1.583


The average total loss of fat from 100 pounds of milk handled by
the new process of cheese making is seen to be on the average 0.158
pounds of fat, or a little less than 4 per cent of the total fat content
of milk containing 4 per cent fat. The loss of fat from 100 pounds
of milk in ordinary cheese making under average factory conditions
has been found to amount to 0.33 of a pound of fat, or 0.36 per cent
of fat in the whey, or 9 per cent of the total fat content of the milk.1
It will be seen from these figures that the loss of fat is reduced to
less than one-half by the new process of cheese making. It might
be expected from this statement that each day's make of pasteurized-
milk cheese tested by the Babcock test would show a higher percentage
of fat than the same day's raw-milk cheese. In Table 38, however,
it is seen that in 15 cases out of 21 the pasteurized-milk cheese tested
lower in fat (0.65 per cent lower on the average) than the raw-milk
cheese.
THE INCREASED MOISTURE CONTENT OF PASTEURIZED-MILK CHEESE.
This is due to the fact that there is an increased content of moisture
as well as of fat in the new-process cheese, and in most cases the in-
crease of moisture is greater than the increase of fat. On this

'Van Slyke and Publow, loc. cit., p. 189.








174 CHIIEDDAR CHEESE FROM PASTEURIZED MILK.


aicount the moisture content of pasteurized cheese listed in the
table below is greater than that of the raw-milk cheese in 29 cases

(olit, of 33, and the average percentage was 1.68 greater.
'Flie cheeses listed in the table were the same as those in Table 26,
and the testing for fat and n moisture was done immediately after the
last weights had been taken for the determination of yield and

shlirinkage. The samples of cheese weighed into the Babcock test
bottles were rapidly dissolved in a mixture of hot water and sul-
plihuric acid, aits suggested by one of us in a previous paper.1

T'A.IL: 3S.-ECuinjirison of the f/;t (in -inoisture content of raw and pasteurized milk
cheese cared at ifvidison.


Moisture content of cfhece.


''s l c"r lRaw.
-I


Per crt.
:I I. ,Ill0

:3 2. 52
32. 5.
3 1. ()5
31.05
3 1. w0
:32. 17
:32. 77
32. 415
3:3. 15
33.51
3 I. ,2
33. 41)
34. 15
32. 72
32. 90
34. ()10
34. 101
34. ,52
:12. 1m
:;I. 7.s
3:3. 47
33.55
32. 2
31. MJl
3:4. 17
:32. t.3

:; I. l."
: 1 ,7
i ". 17
:3 7


Prr cl.
3:i. 15
30. 15
30. (i5
31. 2.3-
3:). 75
.l1.47
2'". 75
30 17
3 1. 32
31. 47
30.00
3L. 95
3(:i. tl
3(11s7
3 ii. ]



31. 17
32.1'S
3-2. 7O
i32 22
;:il. ~'s-
31.0
301. 17

3-2. i.S
312 70
"33. "12
3'1. .':)
*, 1i. "15-

:<-. '2A


I 32. I
-\ \'erati'.. 32.9 (A 3L. "


Fat content of cheese.


1)itkerence. l'ws'eur.
Direne.ized. R I aw. Difference.


+Perfl. -Perct. Perct. Prrct. -Pertd. +Pet7cd.
0 3: .......... 3S. i ; 39.10 0.24
3 411 .......... .......... .......... ..........
21.471
2.47 30 ................... ............ ......... ..........
.......... .......... . '.. .
. %. ..... ... ... ...... .......... .. .......... .. .. .....
................................4.2
2. 15 .. ...... 37.44 :3.1, .72 I .... .....
2. 2 ....... . . 9 : i 17 i. . .....
1.435 .......... A 6l 38. U04 .......... 0. 57
3.15
1. "511
1. =00 ........ .. ....... .. .......... .o. . =.. ... 1
3. 17.1 ...... ........ . .. .. . .. .........
.7 .. . . . 4 3%k. f 08
2.5:; .......... :1',.,1 '",. .3 I ..........- .22.
J3 ..L........ 3I.01 37.97 .04

..:.......... . ... ... ..... .
1 .......... .......... .......... .. .........

N 1 .1..'.9 3 37. j It; i .........
. ......... . ... 37... .. .-1 IS ..........
3.,l ilkY,
"I .. I .. :..... ..... ..................
. .... . 3 ... '" :3 .,2 1. i73 ... .. ...
-- .. 4 ,1.. I ~ . 3



.. . ..' .910 ^%.e4 3.I.dit .02 |. ...
,I .......... .. I,. i 3: ,4 1. 1 3 .........
,'4 .......... 3... .1.. S 1.713 .........
. 1,. ... ... IS 41. 4i3.1 .. ... .......
1........ ......3s,.1. 4 .0. Ili .02
".45 .............;7.9.2j2 .12IS1.15
.... ... ,: 4 i' s 1. .. ... .. .


1... .............8 41.743..n ......
1. . .... .. .. 37. 7 3',. lii 1.0 .... ...
1 -.Y) ... ...... 39. '2s A9. 27 I. ... ... .01
1. "_, . ......... -. #7 3"% ., ;,. i9 . .......
.... .... .71 I 10 37. 7 .......... .43
l.i1 3 .1 %.21 3S.59 o .,26


The cmtlbilie',d (11 'fe't1 upon tlhe percentage compositions of cheese
caused b(lv iinrcasiig bothli the fat aml moisture content is shown in
tilt follo)win., exa'nple:

T'ii ipiids (if raw-milk]( chlist of the same average percentage
('o11p)(1siti,,n as in Talel :S, as shown at I, below, would contain the

weights o(f fuit, moisture, adi(i casil., etc., shown at II. If by pas-
tetiri';iztiii the fat content off the cheese is increased about 4 per cent
of itself, a1ndt, ilie moisture content is increased about 12j per cent of

itself, there will Ie obtainiied 10.54 pounds of pasteurized-milk cheese

'- .1'liln,. J. I,. ltw .letermiLnation tof fat in .lieese 1 b the Babcock test. Journal of Industrial and
i.-ngiuerrwig t'heinistry, vol. 1, ino. 8, p. 11.. Etistiu 1'la., Aug., 1909.


)ale. '


1911.
Feb. 24
27

Mar. 1
2
3
7
S

10
9

13
14
15)
I1;
17
20
21
.3.3
.A pr. 3
7
11
3.1
17
2'4
'-a
.s
May~ 2



1,
17


I


I


>






75


QUALITY OF PASTEURIZED-MILK CHEESE.


as shown at III instead of 10 pounds of raw-milk cheese, a theoretical
gain of 5.4 per cent in the yield of cheese. (The actual gain shown
in Table 20 was 5.37 per cent.) The percentage composition of this
pasteurized cheese will be as shown at IV, which agrees closely with
the average composition of the pasteurized-milk cheese shown at the
bottom of Table 38.
I. II. III. IV.
Fat...... 38.59 per cent. 3.859 pounds+0.154 pounds=4.013 pounds. 38.07 per cent.
Moisture.. 31.28 per cent. 3.128 pounds+0.391 pounds=3.519 pounds. 33.37 per cent.
Casein,etc. 30.13 per cent. 3.013 pounds+ .... pounds=3.013 pounds. 28.57 per cent.
100.00 per cent. 10.000 pounds. 10.545 pounds. 100.00 per cent.
The increased moisture content of pasteurized-milk cheese made
by this process is due to the effect of pasteurization on the prol)perties
of curd, as stated on page 25.
THE QUALITY OF PASTEURIZED-MILK CHEESE.
SCORES AND CRITICISMS OF PASTEURIZED AND RAW MILK CHEESE.
The milk supply used at Madison is no better than the average
cheese-factory milk. Sunday's milk is delivered on Monday through-
out the year and is therefore inferior to that of the other days. Cheese
from every day's make during the season was scored by two judges.
Mr. U. S. Baer, assistant dairy and food commissioner of the State of
Wisconsin, and Mr. A. T. Bruhn, junior dairyman'l, United States
Department of Agriculture, who during the past year have scored the
cheese sent to the monthly scoring exhibition, conducted by the
Wisconsin Experiment Station. The judges worked inde1)ep(lently
and pinned their scoresheets to each cheese without. knowing even the
numbers of the cheese, which were turned toward the wall. Their
scores show close agreement with each other in most cases and leave
no doubt as to the relative quality of the cheese scored. After
finishing about 20 of the cheeses, they turned them around andl added
the cheese numbers to the sheets. In general, a score of 92 or above
indicates that the cheese is of good quality and salable at full market
price. A cheese scored below 92 is likely to be cut in price in a dull
market. Tables 39 to 46 show the scores of both judges as well as
the average scores, which latter are used in the discussion. R aw-milk
cheese is in all cases indicated by the letter C attached to the serial
number.
CHEESE CURED AT MADISON AT NORMAL TEMPERATURE.
Lots IA, 2A, 3A, and 4A.-These lots include 53 pairs of cheese
cured in the cellar at Madison. The temperature of the curing room
showed daily about 3 to 5 difference between maximum and mini-
mum and ranged from 60 to 73 from February to July, 1911. By
opening the windows at night only, it was kept at 60 to 70 from
July to October.








76 CHEDDAR CHEESE FROM PASTEURIZED MILK.


The scores of the 53 pairs of cheese are as shown in Table 3

The average score of all the pasteurized-milk cheese is 92.75 and

the raw-milk cheese 89.09.

TABILE 39.- -Scores of 53 pairs of raw and pasteurized cheese (lots 1A, L2A, A, and 4
cured at Madison.
LOTS IA AND 2A. SCORED JULY 17, 1911.


IS&ored by U. S. Baer.


Fla- Tex- Toa.
vor. ture.


Tern-
pera-
I tire(of
coiriztc
rooin
S a. m.


*F.








.
I.....

















62





62
I.... ....














G4



















62
.... .
... ....* **








""60'
i" l2
'" '63

'"i2 'i6

5'6'














.... .
"".1.3.

"(V.

.. ...


Dale
made.




1911.
Feb. 24
24
27
27
28
28
Mar. 1
1
2
2
3
3
7
7
8
8
9
9
10
10
13
13
14
14
15
15
16
16
17
17
20
20
21
21
22
22
Apr. 5
5
7
7
11
11
13
13
17
17
IS
19
24
24
27
27

28
May 2
2
3
3
S
8
in
In
15
1.5
17
17


172
172C
173
173C
174
174C
175
175C
176
17(;C
177
177C
17S
17SC
179
179C
I80
1: 0("
14
1S1C
1S2

1 3
I -C
1 N 3C
1 S4
1F4C
I S
1V5

ISti
167

1S7C
187C
1 SSC
issr

1S9C
1 q9c
198
19sC
200
20or
202
202C
204
204C
206
20(C
207
207C
211
211C
214
214C
215
21 5C
236
21fC
217
217C
220
22flc

222C
225
22.iC
227
227C


Scored by A. T. Bruhn.


Flavor.


I- i -


41.0
37.0
43.0
3S.0
41.0
39.0
41.0
40.0
40.0
37.0
40.0
38.0
40.0
3S.0
40.0
35.0
41.0
39.0
41.0
3.O.0
40.0
41.0
40.0
40.0
40.0
40.0
40.0
35.0
42.0
41.0
43.0
35.0
43.0
3,.0
43.0
39.0
43.0
41.0
42.0
35.0
42.0
39.0
41.0
39.0
41.0
40.0
43.0
42.0
43.0
39.0
40.0
37.0
42.0
37.0
41.0
37.0
42.0
37.0
41.0
34.0
40.0
37.0
40.0
38.0
41.0
35.0


Cheese
No.'


Total.


Average.


1------


Flavor.


26.0
27.0
28.5
27.0
27.0
26.0
27.0
26.0
28.0
27.0
27.0
26.0
26.0
27.0
27.0-
26.0
26.0
26.0
26.0
27.0
27.0
26.0
26.0
27.0
26.0
27.0
26.0
26.0
28.0
28.0
27.0
25.0
2. 0
26.0
27.0
27.0
27.0
27.0
27.0
25.0
26.0
26.0
27.0
26.0
27.0
25.0
26.0
25;. 0
25.0
25.0
24.0
27.0
25.0
26. 0
25.0
yo
2.5. n
27.0
2. 0
2.1.0
2.;. n
21;. 0
2,t. 0
26.0
24.0


Tex-
ture.


Total.


.1 1- -


92.0
9. 0
96.5
9ti. 5
90.0
93.0
90.0
93.0
91.0
93.0
89.0
92.0
89.0
91.0
90.0
92.0
86.0
92.0
90.0
92.0
90.0
92.0
92.0
91.0
92.0
91.0
92.0
91.0
86.0
95.0
94.0
95.0
85.0
96.0
89.0
95.0
91.0
95.0
93.0
94.0
85.0
93.0
90.0
93.0
90.0
93.0
90.0
94.0
92.0
94.0
Q9.0
90 0
St;.. 0
94.0
R7.0
92.0
87.0
95.0
87.0
93.0
14.0
90.0
57.0
91.0
R9.0
92.0
94.0


"C" In this column indicates raw.milk cheese.


Tex-
tlure.



26.5
27.0
28.0
27.0
27.5
26.5
26.0
26.5
27.0
27.0
26.5
26.0
27.0
27.0
27.5
26.0
27.0
26.5
27.0
26.5
27.0
27.0
26.5
26.5
27.0
27.0
27.0
27.0
26.5
27.0
26.0
26.5
27.0
27.0
28.0
27.0

21. 0
27.0
2R.0

27.0
27.0

28.0n
27.0
28.0
27.0
27.0
25.0
27.0
27.0
27.0
27.0
27.0
26.0

27.0
26.0
26.0
26.0
27.0
26.0
27.0
25.0
27.0
26. 0
2A.0
27.0
27.0
25.0


40.0
38.0
42.5
40.0
41.0
39.0
40.0
40.0
41.0
39.0
40.0
38.0
40.0
39.0
41.0
38.0
41.0
40.5
42.0
39.0
41.0
40.0
40.0
40.0
41.0
41.5
41.5
41.0
41.0
41.0
41.0
39.0
41.0
40.0
42.0
40.0
42.0
41.5
42.0
40.0
42.5
40.0
42.0
40.0
41.0
3.o 0
41.5
40.0
42.0
39.0
42.5
37.0
42.0
3q. 0
40.5
3. 0
41.5
40.0
42.0
39.0
40.0
40.0
42.0
39.0
41.0
37.0


91.5
90.0
95.5
92.0
93.5
90.5
91.0
91.5
93.0
91.0
91.5
89.0
92.0
91.0
93.5
89.0
93.0
92.0
94.0
90.5
93.0
92.0
91.5
91.5
93.0
93.5
93.5
93.0
92.5
93.0
92.0
90.5
93.0
92.0
95.0
92.0
95.0
94.5
94.0
91. 0
P4.5
92.0
95.0
92.0
93.0
S7.0
93.5
90.0
94.0
91.0
94.5
8.. 0
94.0
59.0
91.5
.9.0
93.5
91.0
94.0
89.0
92.0
91.0
95.0
91.0
93.0
87.0


40.50
37.50
42.75
39.00
41.00
39.00
40.50
40.00
40.50
38.00
40.00
38.00
40.00
38.50
40.50
36.50
41.00
39.75
41.50
38.50
40.50
40.50
40.00
40.00
40.50
40.75
40.75
38.00
41.50
41.00
42.00
37.00
42.00
39.00
42.50
39.50
42.50
41.25
42.00
37.50
42.25
39.50
41.50
39.50
41.00
39.00
42.25
41.00
42.50
39.00
41.25
37.00
42.00
37.50
40.75
37.50
41.75
3S.50
41.50
36.50
40.00
38.50
41.00
38.50
41.00
36.00


26.25
27.00
28.25
27.00
27.25
2.25
26.50
26.2
27.50
27.00
26.75
26.00
26.50
27.00
27.25
26.00
26.50
26.25
26.50
26.75
27.00
26.50
26.25
26.75
26.50
27.00
26.50
26.50
27.25
27.50
26.50
25.75
27.50
26.50
27.50
27.00
27.50
27.50
27.00
25.50
26.50
2(.50
27.50
26.5n
27.00
25. 00
26.50
25.00
S26.50
26.00
26.00
25.00
27.00
25.50
26.00
25.50
27. 50
25.50
27.00
25.00
26.00
25.50
27.00
26.50
26.50
24.50


91.75
89.50
96.00
91.00
93.25
90.25
92.00
91.25
93.00
90.00
91.75
89.00
91.50
90.50
92.75
87.50
92.50
91.00
93.00
90.25
92.50
92.00
91.25
91.75
92.00
92.75
92.25
89.50
93.75
93.50
93.50
87.75
94.50
90.50
95.00
91.50
95.00
93.75
94.00
88.00
93.75
91.00
94.00
91.00
93.00
88.50
93.75
91.00
94.00
90.00
92.25
87.00
94.00
88.00
91.75
88.00
94.25
e9.00
93.50
8t.50
91.00
89.00
93.00
90.00
92.50
R5.50









QUALITY OF PASTEURIZED-MILK CHEESE.


77


TABLE 39.-Scores of 53 pairs of raw and pasteurized cheese (lots 1A, 2A, 1 .1, awl 4A1)
cured at Madison-Continued.

LOT 3A. SCORED AUGU9T 14, 1911.


Scored by U. S. Bacr.


Fla- Tex Total.


vor.


Tem-
pera-
ture of
curing
room
8a. m.

OF.
67







66
""66'




""68'

""66'
66


Lure.


27.0
26.0
25.0
25.0
27.0
25.0
27.0
25.0
26.0
26.0
27.0
25.0
27.0
26.0
27.0
25.0
27.0
26.0
27.0
26.0


95.0
91.0
91.0
SS. 0
94.0
89.0
94.0
85.0
91.0
88.0
92.0
83.0
91.0
90.0
92.0
88.0
93.0
S8.0
92.0
91.0


Scored by A. T. Bruihn.


Flavor.


41.5
37.0
41.0
3T. 0
42.0
37.0
41.0
38.0
41.0
37.0
41.0
37.0
41.5
38.0
41.0
39.0
41.5
40.0
40.0
39.0


ture.-
ture.


2i. 5
25.0
2i. 0)
25. 0
27.0
25.0
2,>.5
2.0
26. 0
2o. 5
25.5


26. 0
21.0
2i|.0

2. 0
*2 .0
27. 0
2l;. 0
26. 0
27.0


TOuall


93 0
S7.0
92.0
-S" 0
94.0
N7.0
92.5
,s9.0
92.5
X7.5
",2.0
!2. 0
92.5
89. 0
92.0
S.. 0
93.5
91.0
91.0
91.0


Average.


I ________________


Flavor


42. 25
3S. 5i0
41. )0
37.0I
42. 00
3M. 00
41.5
36l. 51i
40.50
37.00
40.50
35.00)
40.25
38.50
40.50
38.00
41.25
23.50
40.00
39.50


Te x-
t ure. Total.



26. 75 94.00
25.50 ,89.00
'25.50 (11.50


Date
made.



1911.
May 22
22
25
25
29
29
June 1
1
2
2
7
7
9
9
13
13
15
15
16
16


.7. U0O
94.00
"s. 00
93.25
S7.00
91.75
87.75
92.00
85.50
91.75
s9.50
92.00
8q 00
93.25
S9.50
91.50
91.00


LOT 4A, SCORED SEPTEMBER IS, 1911.


68 June 19 24. 42.0 27.0 94.0 42.0 27.0 94.0 42.00 27.00 94.00
........ 19 248C 40.5 26.0 91.5 40.0 2(6.5 91.5 40.25 26;. 25 91.50
68 21 250 40.0 236.0 91.0 41.0 21i.5 92.5 40.50 2t6.25 91.75
........ 21 250C 37.0 25.0 87.0 3S.O 25.0 8S.0 37.50 25.300 .i87.50
70 26 253 37.0 25.0 87.0 39.0 25.0 S9.0 33S. 00 25.00 S. 00O
....... 26 253C 35.0 25.0 8S5.0 35.0 26.0 86.0 35.00 25.5. I K5.50
70 27 254 41.0 27.0 93.0 41.0 27.0 93.0 41.00 27.00 93.100
........ 27 254C 3,.0 26.0 8S.0 37.0 26.0 S.S.0 37.00 26.(0 0 .00
70 28 255 41.0 27.0 93.0 41.0 27.0 93.0 41.00 27.00 93.00
........ 28 255C 35.0 25.0 85.0 37.0 25.5 S7.5 36.00 25.25 862.5
72 July 3 258 40.0 27.0 92.0 40.5 26.5 92.0 40.25 26.75 92.00
........ 3 258C 35.0 25.0 85.0 35.0 25.0 85.0 35.00 25.00 x5.600
72 8 260 41.0 27.0 93.0 41.0 26.5 92.5 41.00 26. 75 92.75
........ 8 260C 37.0 25.0 S7.0 36.0 25.0 86.0 36.50 25.00 S6.50
73 10 261 40.0 25.0 90.0 39.5 26. 0 90.5 39.75 25.50 90.25
........ 10 2C1.(I 3Rl.0 27.0 90.0 3S.0 27.0 90.0 3S.0nO 27.00 90. 00
73 11 2.2 41.0 27.0 93.0 41.0 26.5 92.5 41.00 261.75 92.75
....... 11 22C 37.0 26.0 S,. 0 37.0 25.5 S7.5 37.(0 25.75 .S7.75
72 12 21:1 40.0 26.0 91.0 40.0 2G.0 91.0 40.00 2l,.00 I 1.OO
....... 12 263C 35.0 26.0 86.0 35.0 26.0 8o. 0 35.00 26t. 00 8. 00

"C" in this column indicates raw-milk cheese.


In 51 cases out of the 53 in the table the pasteurized-milk cheese

received a higher average total score than the raw-milk cheese;


but in two cases the raw-milk


cheese scored one-fourth to one-


half a point higher (Nos. 183 and 184). In the 51 cases just
mentioned the differences in total score between pasteurized and
raw milk cheese ranged from one-fourth of a point to 7 points and

averaged 3.82 points. In four-fifths of these cases the difference in
-the score was over 2 points. In 49 of the 53 raw-milk cheeses the

average score was below 92, while 39 of the 53 pasteurized-milk

cheeses scored 92 or above. The distribution of the scores in each

case is most clearly shown in figure 3.


43.0
40.0
41.0
3S.0O
42.0
39.0
42.0
35.0
40.0
37.0
40.0
33.0
39.0
39.0
40.0
38.0
41.0
37.0
40.0
40.0


25 110
27.1.100
2325.00
26.75
25. n00
2, 25
25.75
21i.5n
25.50
2;. 50
2'.. 00
2l;. !l
2.,. ')-1
27. 00
2', 00
26.50
26.50


Cheese
No.'


230
230C
233
233C
234
234C
237
237C
238
238C
240
240C
242
242C
243
243C
245
245C
246
246C


i






CHEDDAR CHEESE FROM PASTEURIZED MILK.


It can readily be seen from figure 3 that 94 per cent (50 out of 53)
of the pasteurized cheese scores lie between 91 and 95, a range of 4
points, wlUile the same proportion (94 per cent) of the raw-milk cheese
scores are quite uniformly distributed between 85 and 92, a range of
7 points.
The variation in quality of product from dlay to (lay is thus reduced
____________________________ nearly one-half by
MSrTEUR/ZCO-M/i K' ZICC''E the new process. In
:.i iiI: scoring all of these
__* 3> | *$ cheeses the color and
RAW-M.LK WECH SC make-up were al-
l ways marked per-
_ ___ a I __ Io._ _______ feet, and the cheeses
S S 87 a 0s 89 X./ M 93 9W aR were marked off
MrrWt 51MWE'S.
FIG. 3.-Distribution of total scores of pasteurized and raw milk cheese. Onl" on flavor and
texture. It is of in-
terest therefore to consider the flavor and texture scores separately,
in addition to thle (discussion of total scores given above.
The average flavor score for all of the pasteurized cheese is 41.05
and for the raw-nilk cheese 38.13. In 50 cases out of 53 the pas-
teurized-milk cheese has a higher average flavor score than the
raw, in 2 cases the scores are equal, and in 1 case the pasteurized
cheese is one-fourth point less than the raw.
Iii the 50 cases
just mentioned the PASrEU4/ZEo-M/L/c CHMES
(liil'erenceC in the fl&a-
v,,, score between :5
the two makes of i *
(hee(,se ranged from a 8 *
0.50 to 5.50 points, *:00:0SS
averaging 3.1 points. RAW-/LK GCH ,E E
Thle difference was
(eili;il to (,r greater 8 S 2
tlhan 1.25 points il S 0 0 0 S S
47 o(ut of the 50 :: : : o 0 8 0*0
(.1s's, showing that 36 37 36 39 40 4/ 1 42 3
I FLAVO SORE,.
the ilpl o111Ve ellnt, ill
Il'aur thil(>ol] 1l J)S- Fi(;. 4.-ID)i1ribution ,f [iavor scores of pasteurized and raw milk
t ws lit cheese.
tfi-rin:xadon wois Iot
(iiiiv l11(itiesti lOlflle, hIut also consistent.. In 51 out of the 53 cases
tile, lUst e' rized-milk cl('ese(' scored 40 or above for flavor, while 45
wit of tlie 53: raw-milk cheese, scored( below 40 for flavor.
ig -1 4 shows th1-it 04 per cent (50 out of 53) of the pasteurized
clic,,,si flv\-(ir scores lie between 40 and 421, a range of 2j points;
while tlie raw-nilk cheese flavor scores are quite evenly distributed


78






CHEESE CURED IN THI SOUTH.


over a range of 5 points (from 35 to 40 or 41). Th` range of varia-
tion is thus twice as great in the raw as it is in the pasteurlizedl, slhow-
ing that the daily variation of flavor is reduced abouIt one-half by
the new process.
The average texture scores show also some advantage for the new-
process cheese. The average texture score on all of the past(eurized-
milk cheese was 26.70, and on the raw-milk (cheese 25.96.
In 40 cases out of 53 the pasteulrize(l cheese scor(,(ed lighr than the
Iraw, in five cases the scores were equal, and in 8 (cases the p)astelrized
'cheese scored 0.25 to 1.5 points (average 0.59 (point) lower than the
raw. Among the 40 cases just mentioned, the (difcre(I(ces ill texture
score between the two _____________
makes ranged from PASTE/R/ZEO-M/rKCO/EE5Ef
0.25 to 2 points, and \
averaged 1.09 points. I
Figure 5 shows that : ; \ \.
90 per cent (48 out of S ; ; ;
53) of the pasteurized- RAW-M/ZL :.
milk cheese texture GHEESC 1 2
scores lie between 26 i. :: :
and 27.50. a range of 2- 2s 26 2 8zo
1.50 points; while 94 -r------A-- 5CO,1q-T.
per cent (50 out of 53) FIG. .l.-Diqtrilutinn if t('xture s nrei of pa' ,tetrizcd onid raw milk
of the raw-milk cheese
scores are quite evenly distributed between 25 and 27, a range of 2
points, a distinct advantage in favofr.of the new process, both as to
quality and uniformity of texture.
CHEESE CURED IN THE SOUTH.
Lot IB.-Four lots of cheese, lots 1B, 2B, 3B, and 4B, were shipped
to New Orleans for storage, the first lot for two months and the other
three for one month.
Lot 1B consisted of 25 pairs of cheese which were made on 25 dlavs
between February 23 and April 18, at Madison, and shipped to New
Orleans April 29, arriving May 9. They were stored there until July
3, and then shipped back to Madison where they were scored sepa-
rately on July 17, 1911, by Messrs. U. S. Baer and A. T. Bruhn. The
temperatures at New Orleans given below are taken from the Inited
-States Weather Bureau montlily met eorological summaries. The
average daily mean for May was 75.8, with temperature oi different
'bays varying from 60 to 96. For June the average daily mean was
83.2, with temperature on different days varying from 70 to 98.
,The quality of both the raw and pasteurized cheese after returning
from New Orleans was very poor, as shown by the scores of the judges
,and by letters from dealers to whom they were afterwards sold at a
t


79








80 CHEDDAR CHEESE FROM PASTEURIZED MILK.


reduced price. The average score of the 25 pasteurized-milk cheeses
was 85.10 and of the 25 raw-milk cheeses 83.34, a difference of 1.76

points. In 17 cases out of 25 the pasteurized-milk cheese scored
higher, in 3 cases equal to, and in 5 cases less than the raw-milk
cheese. (See Table 40.) The highest average score given to any

cheese in the lot was 90.5 and the lowest 78.50. The scores are

shown in Table 40.

TABLE 40.-Scores of 25 pairs of raw and pasteurized cheeses (lot IB) cured for two
months at New Orleans.


Date ma-le.



1911.
Feb. 23
213
24
24
27
27
28
28
MIar. 1
1
2
2
3
3
7
7
8
8
9
9
10
10
13
13
14
14
15
15
16
16
17
17
20
20
21
21
22
22
AIr. 5
5
7
7
11
11
13
13
17
17
18
18


Tot-il
Cheese scLre
No. (U. S.
Baer).



171 82
171C S7
172 S3
172 173 b7
174IC 85
174 90
174C 83
175 86
175C M63
176 86
17tiC S3
177 Ss
177C 88
178 86
178C S6
179 91
179C S5
ISO 861
1NIC 55
11M 90
181C 65
1S2 60
1I2(2 80
IS13 7s
1 iC b7
184 85
184C S-i5
185 ".5
I oC 85
183 SO
186C 80
1S7 79
187C 79
1SS 77
1lS_ L' b0
ISO 986
189(' 80
I18S 92
1t' 89
20()) S';

"112 .S
2021' S-3
204 19
204C .4

20,C S3
207 5
2070 S3


I' C": in this column indicates raw-milk cheese.


Total
score
(A. T.
iruhn).



80
('7
79
61
U0
b"7
S.j
86
.s5
S7
84

84

86
85
90
8S3

is
Si
So
SO
79
S4
S4
82
?,9
53
Sn
SO
so
so
so
so
$.1
so
S9
S7
S5
ss
84
S7
84
Sl)
$1i
84
84


Average
total
score.


81
87
81
83
88.5
S5.5
87.5
84
si. 5
K3.65
87
83.5
Si
Sri. 5
$j
86.5
86
65.5
90.5
84
S7
S5
89
-5
8O)
so
79
85.5
84.5
&J1.5
S7
So
SO
80
79.5
79.5
78.5

S4.5
SO. 5
NIM
90.5
N5

S7. 5
8.5
8.5
94
17.5
S2
S-5.5
93.5






CHEESE CURED IN THE SOUTH.


It can be seen that storage for so long a period as two months in
New Orleans, at such temperatures, can not be practiced with either
raw or pasteurized cheese without great loss of quality; and that of
the two lots, the pasteurized was somewhat the better when taken
out of storage. On account of the unmarketable quality of both lots
of cheese when scored it appears unnecessary to give the detailed
score and criticisms as to flavor and texture.
Lots 2B, 3SB, and 4B.-These lots were stored at New Orleans for one
month each during parts of June, July, August, and September, 1911.
The mean daily temperature during this period averaged 83.2 for
June, 80.2 for July, 81.8 for August, and 82.6 for September. In
lot 2B the 9 pasteurized-milk cheeses received an average total score
of 90.44, and the raw-milk cheese of 85.56. The pasteurized was
better in every case, and on the average 4.88 points better.

7 7STEURSZED-,M8-ILK9 CHEESE S/
* .; : *_ __ : ; 322. : : : : ... ..
R4 w itr cHEES5E 8 2
@0*
IIs II, Is.
8* US **



In lot 3B the 10 pasteurized-milk cheeses scored the highest in
every case, the average being 7.7 points higher. The average score of
the pasteurized was 90.30, and of the raw 82.60.
In lot 4B the 10 pasteurized-milk cheeses scored the highest in
every case but one, and averaged 85.62, while the 10 raw-milk
cheeses averaged 82.10, a difference of 3.52 points.
From the results shown in Tables 40 and 41 and in figure 6, it is
clear that after storage in the South the pasteurized-milk cheese
came out better in quality than the raw-milk cheese made from the
same milk. It is not intended to suggest that cheese could be shipped
to the Southern States with the express intention of storing it for one
month before it is sold, but it is clear that during the few days or
Weeks necessarily elapsing after market cheese reaches its destination
in the South and before it is eaten, the pasteurized-milk cheese is
less likely to undergo serious deterioration than the raw-milk cheese.
79994-'Bull. 165--13--6


81









82 CHEDDAR CHEESE FROM PASTEURIZED MILK.


TADLE 42.-Scores of 29 pairs of raw andr pateurized cheeses (lots 2B, SB, and 4B) cmd
for one month at New Orleans.

LOT 2B, SCORED JULY 17, 1911, AT MADISON.


tMean Total Total Averaag
tempera- Cheese swore scre
Date made. ture at No.' (U. S. (A. T. total
New Baer) B ) score.
Orleans. E r). Bruhn).


1911. F.
Apr. 24 46 211 90 88 89
24 .......... 211C 85 86 85.5
27 CO 214 92 90 91
27 .......... 214C 85 85 85.5
28 55 215 93 90 91.5
28 .......... 215C 85 14 84.5
May 2 1% 216 90 88 89
2 .......... 216C 85 86 85.5
3 1:I 217 91 89 90.0
3 .......... 217C 85 85 85
S 71 220 90 87 88.5
S .......... 220C 85 58 85
I) T73 222 92 94 93
10 .......... 222C 88 87 87.5
15 76 225 89 91 90
15 .......... 225C 87 85 86
17 76 227 92 92 92
17 ........... 227C 86 85 85.5


LOT 3B, SCORED AUG. 14, 1911,


May 22
22
2.5
25
29
29
June 1
J
2
2
7
7
9
9
13
13
15
15
Ih
16


78

82
84


Si

Si
" Si
"S.
88
8)
S7



. .. . ...


LOT 4B. SCORED


June 19
19
21
21
26
26
27
27
2S
2S
July 3
3
S
8
10
In

11
12
12


76
74


82

80

82
...... .. .
79
.. .. . .. .


82
82

79


no
230
230C,
233
233C
234
234C
237
237C
238
238C
240
240C
242
242C
243
243C
245
245C
246
246C.


SEPT. IS,


248
248C
250
250(C
253
253C
254
254C
255
255C
258
258C
2fi0
2f60C
261
261C
2t62
2620
263
263C


AT MADISON.


84
R4
RO
82
Sn
90
82
90
81
90
82
89
79
92.5
81
90. 5
R5
91
85
g89
82


88.5
83.5
89
79.5
90.5
82.5
90.5
80.5
90.5
83.5
90.5
79.5
92.75
81.5
91.25
85.5
90.5
86
89
84


1911. AT MADISON.


SR.5
81
81
85
87
87
89
76
so80
78
85
82
KSS
Si
62
79
90
85
87
80


97
85
82
85
88
85
89
78
80
77
R'i
87
89
S."
SS
SO
78
84
85
86
80


87.75
84
81.5
85
87.5
8i
89
77
80
77.5
85.5
fri. 5
831.5
88
84.5
81
78.5
89.5
85
86.5
80


I "C" indicates raw-milk cheese.








CHEESE CURED IN THE SOUTH.


83


Lots SC and 4C.-These two additional lots were stored for one
month in the South and subsequently scored at Madison. In lot
3C the 10 pasteurized cheeses averaged 91 and the 10 raw-milk
cheeses 84.85, as shown in Table 42. In every case the pasteurized
cheese scored higher than the raw. In Lot 4C, the 10 pasteurized
averaged 87.82 in total score, and the 10 raw-milk cheeses, 85.07, and
in every case but one the pasteurized scored higher than the raw.
All but two of these 40 cheeses scored below 92 and most of them were
unsalable at full price, after storage as described. The temperature
inside of the storage warehouse was not recorded.

TABLE 42.-Scores of 20 pairs of raw and pasteurized milk cheese (lots 3C and 4C) stored
one month in the South and scored at Madison.

LOT 3C, STORED ONE MONTH AT COLUMBUS, GA., AND SCORED AT MADISON, AUG. 14, 1911.


LOT 4C, STORED


ONE MONTH AT NEW ORLEANS, AND SCORED AT


MADISON, SEPT. 18, 1911.


1911.
June 19 248 90 894 89.75
19 248C 85 86 85.5
21 250 88 88 88
21 250C 85 85 85
26 253 86 87 86.5
26 253C 86 8 5 8,5. 75
27 254 90 891 89.75
27 254C 80 83 81.5
28 255 89j 891 89.5
28 255C 83 85 84
July 3 258 87 88 87.5
3 258C 86 86 86
8 260 89 90 89.5
8 260C 87 86 86.5
10 261 83 84 83.5
10 261C 87 86 86.5
11 262 85 85 85
11 262C 85 85 85
12 263 90 88j 89.25
12 263C 85 85 85

"c'- indicates raw-milk cheese.


Date Cheese Total score Total score
Date Cheese (.S. A.T A average.
made. No.' (U. S. (A. T. Aeae
Bmade.aer). Bruhn). total score.


1911.
Apr. 22 230 90 90 90
22 230C 87 86 86.5
25 233 90 891 89.75
25 233C 85 84 84.5
29 234 94 94 94
29 2340 91 87 89
June 1 237 92 89 90.5
1 237C 85 83 84
2 238 90 91 90.5
2 238C 84 85 84.5
7 240 92 91 91.5
7 240C 78 79 78.5
9 242 91 93 92
9 242C 85 87 86
13 243 Lost. Lost. Lost.
13 243C 85 82 83.5
15 245 91 90 90.5
15 245C 89 84 86.5
16 246 90 904 90.25
16 246C 88 83 85.5







84 CHEDDAR CHEESE FROM PASTEURIZED MILK. :

CHEESE CURED IN WARM ROOM AT MADISON.

Lots 3D and 4D.-These lots of cheese were stored in a warm room
at Madison where the temperature ranged from 70 to 80, occasion-
ally going up to 85, during the months of July, August, and Septem-
ber, 1911. In lot 3D the pasteurized cheese scored higher than the
raw-milk cheese in every case, averaging 90.55 to total score, while
the raw-milk cheese averaged 83.75. In lot 4D the pasteurized cheese
scored higher than the raw in every case but one, averaging 90.52,
while the raw-milk cheese averaged 86.15, as shown in Table 43.


TABLE 43.-Scores of 20 pairs


of raw and pasteurized milk cheese (lots 3D and 4D) stored
in warm room at Madison.


LOT 3D. SCORED AUG. 14, 1911.


Date Cheese Total score Total score Aerage
made. No.' (eU. S. (A.AT. verage
Bmade. No. aer). Bruhn).


1911.
May 22 230 87 87 87
22 2300 85 86 85.50
25 233 90 894 89.75
25 233C 81 80 80. 50
29 234 93 94 93.50
29 234C 85 85 85
June 1 237 94 94 94
1 237C 80 80 80
2 238 90 91 90.5
2 2390C 85 P6 85.5
7 240 94 94 94
7 240C 79 79 79
9 242 92 921 92.25
9 242C, 85 85 S5
13 243 90 89 89.5
13 243C 85 86 85.5
1.5 245 87 88 87.5
15 245f 85 86 85.50
16 ?46 88 87 87.5
16 246C 87 85 86


LOT 4D, SCORED SEPT. 18, 1911.

June 19 248 91 911 91.75
19 248C 85 85 85
21 250 86 86 86
21 2500 86 85 85.50
26 253 88 88 88
26 253C 85 86 85.5
27 254 91 92 91.5
27 2541' 80 82 81
28 2S5 92 921 92.25
28 255(" 89 891 89.5
July 3 258 92 92 92
3 258AC 87 86 86.5
8 260 91 92 91.5
8 260VF 86 i 86.25
10 261 85 85 85
10 261V 89 87 88
11 262 94 94 94
11 22(' 86 88 87
12 263 93 93 93
12 263C 86 89 87.5

a "C" indicates raw-milk cheeamas.









CHEESE CURED IN COLD STORAGE.


85


CHEESE CURED IN COLD STORAGE.

Lot 4E.-Since much of the cheese made by the ordinary process

is put into cold storage at about 34, and most cheese dealers have

cold-storage warehouses, a study was begun of tlhe effect of cold

storage on pasteurized-milk cheese. The milk supply was so short

at the time that raw-milk cheese could be made on only a few days.

Six or seven pasteurized-milk cheeses were made in one vat each day

and placed in the curing room at Madison, and single cheeses were

shipped to a cold-storage warehouse at Waterloo, Wis., at different

ages. After about three months the cheese was all shipped back to

Madison in one consignment and examined by the judges. One

cheese from each day's make was kept at Madison during the entire
period.

TABLE 44.-Scores of pasteurized and raw milk cheese (lot 4E) put into cold storage at
different ages and scored Oct. 30, 1911.


Scored by U. S.
Baer.


Flavor.


42.00
41.00
40.00
41.00
41.00
41.00
41.00
40.00
42.00
40.00
40.00
40.00
41.00
41.00
40.00
41.50
40.00
41.00
42.00
36.00
38.00
38. 00
40.00
40.00
40.00
41.00
41.00
42.50
34.00
35. 00
36.00
37.00
38.00
35.00
37.00
37.00
40.00
40.00
40.00
40.00
41.00
40.00
42.00
40.50
42.00
42.00


Tex-
ture.



28.00
26.50
26.00
28.00
28.00
28.00
27.00
27.00
28.00
27.00
27.00
27.00
28.00
28.00
26.00
27.00
27.00
27.00
27.00
26.00
27.00
27.00
27.00
27.00
27.00
27.00
27.00
28.00
23.00
23.00
25.00
25.00
25.00
25. 00
24.50
25.00
26.00
25.00
24.00
27.00
27.00
26.00
27.00
27. 00
27.00
27.00


Total.


95.00
92.50
91.00
94.00
94.00
94.00
93.00
92.00
95.00
92.00
92.00
92.00
94. 00
94.00
91.00
93.00
92.00
93.00
94. 00
87.00
90.00
90.00
92.00
92.00
92.00
93. 00
93.00
95. 50
82.00
83.00
86. 00
87.00
88.00
85. 00
86.50
87. 00
91.00
90.00
89.00
92.00
93. 00
91.00
94.00
92. 50
94.00
94.00


Scored by A. T.
Bruhn.


Flavor.


42.50
40.50
43. 50
41.00
42.00
42.00
41.00
41.00
42.00
40.00
40.00
41.00
42.00
42.00
40.00
41.50
41.00
40. 50
42.00
36.00
39.00
38.50
41.00
40.50
40.50
40.00
42.00
42.50
32.00
36.00
36.00
39.00
38.00
36.00
38.00
39.00
40.00
39.50
39.00
39.50
41.50
40.50
41.00
41.00
41.50
42.00


Tex-
ture.



27.00
27.00
27.00
27. 50
28.00
27.50
26. 50
26. 50
28.00
27.00
27.00
27.00
27.00
27.00
26.00
27.50
27.00
27.00
27.50
26. 50
27.00
27.00
26.50
26.50
26.50
26.50
27.00
27.50
25.00
25.00
25.00
24.00
25.00
24.00
25.00
26.00
26.00
25. 50
25.00
26.50
26.50
26.00
27.00
26.50
27.00
26.50


Total.


94.50
92.50
92.50
93.50
95.00
94.50
92.50
92.50
95. 00
92.00
92.00
93.00
94.00
94.00
91.00
94.00
93.00
92.50
94.50
87.50
91.00
90.50
92.50
92.00
92.00
91.50
94.00
95.00
82.00
86.00
86.00
88.00
88.00
85.00
88.00
90.00
91. 00
90.00
89.00
91.00
93.00
91.50
93.00
92.50
93.50
93.50


Average score.


Flavor.


42.25
40.75
40.25
41.00
41.50
41.50
41. (0
40.50
42. 00
40.00
40.00
40.50
41.50
41.50
40.00
41.50
40.50
40.75
42.00
36. 00
3. 50
38. 25
40.50
40.25
40.25
40.50
41.50
42.50
33. 00
35.50
36.00
38.00
38.00
35.50
37.50
38.00
40.00
39.75
39.50
39. 75
41.25
40.25
41.50
40.75
41.75
42.00


Tex-
t ure.



27.50
26.75
26.50
27. 75



275
28. 00
27.75
26.75
26.75
28. O0
27.00
27.00
27.00
27. 50
27.50
26. 00
27.25
27.00
27.00
27. 25
26.25
27. 00
27.00
26.75
26.75
26. 75
26.75
27.00
27.75
24.00
24.00
25.00
24.50
25. 00
24.50
24.75
25.50
26.00
25.25
24.50
26.75
26.75
26.00
27.00
26.75
27.00
26.75


Total.



94.75
92.50
91.75
93.75
94.50
94.25
92.75
92.25
95. 00
92. 00
92. 00O
92.50
94.00
94.00
91.00
93.75
92.50
92.75
94.25
87.25
90.50
90.25
92.25
92. XO)
92.00
92.25
93.50
95.25
82.00
84.50
86.00
87.50
88.00
85.00
87.25
88.50
91.00
90.00
89.00
91.50
93.00
91.25
93.50
92.00
93.50
93.75


i "C" in this column indicates raw-milk cheese.


Date
made.




1911.
July 20
20
20
20
20
20
20
21
21
21
21
21
25
25
25
25
25
25
25
25
25
25
27
27
27
27
27
27
27
Aug. 1
1
1
1
1
1
8
8
8
8
8
22
22
22
22
22
22


Cheese
No.'


264.1
264.2
264.3
264.4
264.5
264.6
265.1
265.2
265.3
265.4
265.5
265.6
265.7
267.1
267.2
267.3
267.4
267.5
267. 6
267C1
267C2
267(3
269.1
269.2
269.3
269.4
269.5
269.6
269C1
272.1
272.2
272.3
272.4
272.5
272. 6
276.1
276.2
276.3
276.4
276.5
283.1
283.2
283.3
283.4
283.5
283.6


Age
when
stored.


1 day....
1 week..
2 weeks.
4 weeks.
6 weeks.

1 day....
1 week..
2 weeks.
4 weeks.
4 weeks.
6 weeks.

1 day....
1 week..
2 weeks.
4 weeks.
6 weeks.

1 day....
2 weeks.

I day ....
1 week..
2 weeks.
4 weeks.
6 weeks.
2 weeks.

1 day....
1 week..
2 weeks.
4 weeks.
6 weeks.

1 day....
1 week..
2 weeks.
4 weeks.

1 day....
1 week..
2 weeks.
4 weeks.







86 CHEDDAR CHEESE FROM PASTEURIZED MILK.

In every case the pasteurized-milk oheese put into cold storage at
the age of one day was criticized by the judges as being flat, low, and
not developed in flavor, and the texture was described as curdy, new,
not broken down, not cured, etc. They received an average sore
of 90.84, as shown in Table 44.
The cheeses put into cold storage at the age of one week received
an average score of 91.93. They were found to be well cured, and
they had less mold on the surface (practically none), both when put
into storage and when taken out, than any of the later lots. The
cheeses put into storage at two weeks, four weeks, and six weeks of
age were given average scores of 91.36, 91.82, and 91.46, respectively,
while those kept at Madison for the entire period scored 91.39.
So far as this short series indicates, there is no objection to putting
pasteurized-milk cheese into storage at 34, at the age of one week,
immediately after parafflining. It was planned, however, to make a
more extensive trial of the use of cold storage for pasteurized-milk
cheese during the season of 1912.

EXCEPTIONAL DIFFERENCES BETWEEN THE RAW AND PASTEURIZED MILK CHBain.

It is of interest to collect in one police all of the cases recorded in
the tables where the pasteurized-milk cheese was scored lower than
the raw, in order if possible to locate the cause for such difference.

TABLE 45.-Summary of cases in which raw-milk cheese scored higher than pateuriad.

Lots IA,2A,3A,4A. Lots 1B,2B,3B,4B. Lots3C, 4C. Lot 3D, 4D.

Cheese Total Cheese Total Cheese Total Cheese Total
No.' Score. No.' Score. No.' Score. No.1 Score.

.......... .......... 171 81.00 ......................................
.......... .......... 171C 87.00 ............................ ..........
172 91.75 172 81.00 ......................................
172(' 89.50 172C 83.00 ......................................
177 91.75 177 86.00 .......... ....................
177(C 89.00 177C 86.50 .................... ........ ..........
183 91.25 183 79.00 ................... -.. ........
S183C 91.75 183C 85.50 ......... .................. ....
184 92.00 184 84.50 .......................................
'184C 92.75 184C 83.50 ........................................
188 94.50 188 78.50 ........................................
188C 90.50 '188C 80.00 .......... .......... .......... ..........
250 91.75 250 81.50 250 880. 0 250 8L6.0
250C 87.50 '250C 85.00 250C 85.00 250C 85.50
261 90.25 261 81.00 261 83.50 261 85.00
261C 90.00 261C 78.50 '261C 86.50 '261C 88.00
i "C" indicates raw-milk cheese.
SThese are the cases in which the raw-milk cheese scored higher than the pasteurized. The other moeM
of duplicate cheese in the other lots are given for comparison.

The fact that pasteurized and raw cheese from the same milk may
occasionally score exactly alike or nearly alike would appear to indi-
cate that where the milk supply is excellent the quality of cheese pro-
ducd is not improved by the new process. With so small a differ-
ence in score as half a point, occurring in No. 184 in lot A and No.



j"l






DISCUSSION OF CHEESE SCORES. 87

177 in lot B, it is doubtful whether there was any difference between
the two cheeses which could be ascribed with certainty to the effect
of the pasteurization process.
The most adverse criticism on the process that can be based upon
the 10 cases tabulated above is the following: It is entirely possible
that some harmful bacteria or their enzyms which are occasionally
present in dirty milk may not be destroyed by the pasteurization
process and that such infections damage the quality of pasteurized-
milk cheese as well as raw-milk cheese. In this year's work it has
been noticed that on a few occasions when the raw milk was very ripe
the quality of cheese produced, even after pasteurization, was not so
good as from milk of fairly good quality. For example: The poorest
pssteurized-milk cheese in Table 45 is No. 261, and the milk used for
making this was of 0.28 per cent acidity before pasteurization. In
Table 44, showing the scores of cheese shipped to cold storage, Nos.
272 and 276 are the poorest in quality and these were made from milk
which titrated 0.275 and 0.31 per cent acidity, respectively, before
pasteurization. Of course such milk should not be accepted at any
cheese factory.
No claim is made that the pasteurization process is a cure for all
the troubles of the cheese factory, or that it reduces the responsibility
resting on factory patrons to improve the sanitary quality of their
milk. It would, in fact, be most unfortunate if any process could
be used for making cheese, or any other article of food, which would
relieve the milk producer or the factory man of the necessity for
cleanliness.
SUMMARY OF DISCUSSION OF SCORES.
The scores of lots 1B, 2B, 3B, and 4B, 3C and 4C, and 3D and 4D
all show that cheese, either raw or pasteurized, stored for one or two
months at about 80 are often seriously injured, so as to be unsalable
at the ruling market price. The pasteurized cheese came out of
such storage better in quality than the raw-milk cheese in about 90
per cent of all the cases observed. It is clear that pasteurized-milk
cheese is better suited to stand exposure to high temperature than
raw-milk cheese. This fact may find useful application in two ways:
While it is never advisable to store market cheese for any great
length of time in the South, yet several days or weeks may often
elapse before cheese shipped South is finally sold to the consumer,
and it appears that pasteurized-milk cheese should stand this ex-
posure with less damage in quality than raw-milk cheese. It is
likely, too, that pasteurized-milk cheese can be cured at ordinary
curing-room temperatures below 70 in Wisconsin without the use
of ice or mechanical refrigeration, thus avoiding part of the expense
for cold storage. The quality of the 53 raw-milk cheeses in lots 1A,
2A, 3A, and 4A, cured at 60 to 73 at Madison, is represented by the




p.-


88 CHEDDAR CHEESE FOMt PASTh.tZED MILK.

average total score of 89.09, and would no doubt have been greatly
improved if the cheese had been cured in cold storage. In 51 cases
out of 53 the pasteurized-milk cheese in. these lots scored higher
than the raw, on the average 3.8' points higher, the average total
score of the pasteurized being 92.75 points, which indicates that cold
storage for the pasteurized cheese was not necessary.
In a short series of cheese placed in cold storage at 34 F. at dif-
ferent ages, it was found that those stored at the age of one day were
curdy and uncured at the age of three months, while those placed in
storage at the age of one week were free from this fault and scored
as high, even a little higher, and showed less mold on the surface
than those put in storage when older than one week. From this it
appears that pasteurized-milk cheese can be safely put in cold storage
at the age of one week immediately after paraffining. It was planned
to try cold storage with both raw and pasteurized-milk cheese
during 1912.
THE DEMAND FOR PASTEURIZED-MILK CHEESE.

One of the objects of the work during 1909, 1910, and 1911 was to
sell the cheese to consumers as widely as possible, and learn whether
it would meet with favor and continued demand. It was felt neces-
sary thus to establish its suitability for the market before recom-
mending cheese makers to take up the new process.
The amount of pasteurized-milk cheese sold each year was limited
by the output of the factory, it being impossible to secure a larger
supply of milk. Much more cheese could have been sold to the
same purchases, and doubtless to others, if we had had the cheese
to sell. In nearly all cases the cheese was sold at the current price
ruling on the Plymouth cheese board, f. o. b. Madison without
discount. During 1910, 4,8151 pounds of pasteurized-milk cheese
valued at $711.16 were sold to 19 representative grocery stores,
hotels, restaurants, and delicatessen stores in Madison, Wis. The
total number of such sales was 137 during the season. Nearly
every purchaser reordered it several times, and three of the leading
retailers reordered it 15, 20, and 49 times, respectively, during the
season. The average price paid for all of this cheese was 14f cents
per pound. During 1909, 1910, and 1911, 41 shipments of pasteur-
ized-milk cheese weighing 10,126 pounds in all and valued at $1,382.93
were sent to 27 leading cheese dealers, including a few retail stores,
at New York, Boston, Philadelphia, Chicago, St. Louis, Minneapolis,
and San Francisco, and at various Wisconsin points outside of
Madison, including Plymouth, Sheboygan, Fond du Lac, Marshfield,
Richland Center, Waterloo, and Milwaukee. Samples of the cheese
were also shipped to experiment station workers in the leading dairy
States for an examination.






EXTRA COST OF PASTEURIZED-MILK CHEESE.


OPINIONS OF PURCHASERS.
No written opinions were asked from dealers in Madison handling
the pasteurized-milk cheese, neither were they urged to purchase a
second time. The university delivery wagon making two trips
daily among retail stores took such orders as were given. The fact
that a dealer bought this make of cheese only once may be due to a
variety of causes, such, for example, as business relations with other
wholesale cheese dealers in the city. The fact that several of the
leading grocers sold this cheese continuously for several months and
repurchased it every week or oftener, and always without reporting
any complaint from consumers, is taken to indicate that it was
satisfactory to the retail trade of this city.
An effort was made to obtain a written opinion from every firm
outside of Madison to whom the cheese were sold. It was usually
impossible to send many shipments to a single purchaser, because
it was desired to distribute the available supply of cheese as widely
as possible.
S The letters received from dealers outside of Madison show that all
Except a very few found the cheese to be entirely satisfactory, and
Salable at the full market price. Here again the occasional disap-
,proval of a cheese may be due to an oversupply in the buyer's ware-
Shouse, or other causes than the quality of the cheese iteslf. It is
interesting to note that pasteurized-milk cheese shipped to two firms
Swho apparently disliked it was the same day's make as others shipped
on the same date to three other firms who praised their quality and
pronounced them satisfactory. In every case dealers were informed
that the cheese "was made by special process, which we are trying
at Madison, by which it is hoped that cheese of cleaner flavor and
greater uniformity can be obtained." In no case were dealers in-
Sformed as to the nature of the process or that the milk was pasteur-
ized. The purpose was to excite the dealers' interest and secure
careful examination of the cheese, unqualified by any prejudice for
or against pasteurization.
The very general expression of approval of the product in the let-
ters from dealers and experiment stations appears to warrant fur-
ther trial of the method on a larger scale than heretofore.
THE EXTRA COST OF MAKING PASTEURIZED-MILK CHEESE.
While it has been shown that an increased yield of cheese is ob-
Stained there are also additional costs, which must be charged against
the cheese made by this method. Such costs will include the interest
on investment, and depreciation, of a pasteurizer, cooler, and receiv-
ing vat, a charge for the hydrochloric acid used and for the expense
of steam heat and power for pumping water for cooling the pasteur-
ized milk, and for running the pisteurizer.


89






CHEDDAR CHEESE FROM PASTEURIZED MILK.


Preliminary estimates, based upon available data, seem to indicate
that the extra cost of making pasteurized-milk cheese is less than the
additional value of the cheese, leaving a net profit from the use of the
process, as compared with the regular factory process. Since the
steam and water supplies used in the work at Madison were drawn
from the general service pipes of the Wisconsin. Agricultural Experi-
ment Station it was impossible to determine these items of cost with
exactness.
In order to ascertain precisely what the charges for steam heat,
power, etc., are at an average cheese factory in Wisconsin, a com-
plete outfit for making pasteurized-milk cheese will be set up at a
country cheese factory, easily accessible from Madison, and operated
by an experienced and successful cheese maker. Cheese will be made
there by both the regular factory method and by the new method in
order to ascertain more fully the cost of making, the increased yield,
and the market value of pasteurized-milk cheese.

FURTHER TRIALS OF THE NEW PROCESS IN CHEESE FACTORIES.

The results described in this bulletin appear to indicate that the
new method of cheese making is an improvement over the regular
process now commonly used. Working with the milk supply avail-
able at Madison, the new method is unquestionably an improvement
over the old. It is a fact well known to cheese makers, however, that
the milk supplies found at different factories do not always behave
alike in the cheese vat, so that the old process must frequently be
modified to suit the conditions encountered in different localities. It
remains, therefore, to test the new method at several factories in dif-
ferent cheese-making districts before it can be recommended for use
generally. Cheese makers are advised to await the publication of
results of further trials before undertaking to use the new method on
a commercial scale.
It is hoped that the new method will receive careful attention and
criticism by such cheese experts at experiment stations in different
parts of the country as may be able to give it a trial. The authors
will be glad to correspond with any one interested and to aid in such
trials so far as circumstances permit.

SUMMARY.
PRELIMINARY AND COMPARATIVE WORK WITH THE OLD AND NEW
METHODS.

The continued improvement of the cheese-making industry calls for
more economical factory management. Large, well-equipped facto-
ries should replace many of the small, poorly supported factories of
the present time.


90