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IPIMENT sBTATIOFS-PlAI,8 m ,sITTUTE LECTURE NO. 1.
A. C. TRUE, Director.
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R. A. PEARSON, M. S.,
Cornell University, Ithaca, N. Y.
GOVERNMENT PRINTING OFFICE.
PREFATORY NOTE. .. '
This syllabus of a lecture upon The Care of Milk, by R. A. PfemW4
M. S., Professor of Dairy Industry in the School of Agriculture of QO*
nell University, Ithaca, N. Y., is accompanied by 44 lantern .ui a
illustrating the topic. The syllabus and views have been prepared fuq
the purpose of aiding farmers' institute lecturers in their presentaso
of this subject before institute audiences.
The numbers in the margins of the pages of the syllabus refet to
similar numbers on the lantern slides and to their legends as giveH'i
the Appendix. Those in the body of the text refer to corresponding
numbers in the list of authorities and references.
In order that those using the lecture may have opportunity to full
acquaint themselves with the subject, references to its recent litHrataM
are given in the Appendix. Hi
Farmers' Institute Specielist
Recommended for publication.
A. C. TRUE, Director.
JAMES WILSON, Secretary of Agriculture.
WASHINGTON, D. C., October 1, 1904.
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THE CARE OF MILK.
By R. A. PEARSON, M. S.
The value of the milk and milk products produced in the
united States in the last census year, 190, iA in by AVd 1 /?, (/ -~
t4. f1 4 a This is greater than the value of
!t he metallic minerals produced in the same year and including
'ig iron, silve, old, c per, lead, zinc, and other metals. It
is also eWKe total value of nonmetallic minerals i nt
produced in 1 Ol0and including bituminous coal, Pennsylva- j -Vt a.tido -
ifia anthracite, petroleum, natural gas, brick clay, cement, etc. / (j 4/,
K Undoubtedly the most important use of milk is in its natau-
form as a human food or as "market milk" (2-p. 5) and
I.-p. 3). Almost every individual of our population uses 3
-more or less milk and often depends largely upon it for suste-
Mpance. But most of the milk produced is used for making
butter, while a comparatively small amount is used for mak- 3
'6ju.g cheese. It is estimated that the amount of milk teed-es ec W cd
101C6 Uvtrilk" (ansmallmPat Of it APml1d)} 1;1 g na l allt *i/K Lu- arIIt
I- ... 9 ~"Onr&O
1"j^tanakip- g qua- th prnoiictioc of 9,n 111700,05 uuw0 cd "y
: 1..oo-nB mZking" 80,000 uuwt, limkillg a Iuntl of abowjy-
. NIN etywa i"tleli Uled states -
SThe profitable production of milk involves two very differ- //
mnt kinds of problems: First, how can the farmer form a herd
'that will give in the milk pail liberal returns for the cost of 0 r-3
e! ed and care ? and, second, how should the milk be handled 7l,, .e
ato keep it in the best marketable condition? 2 1
I. (a) As is well known, there are great differences in the
i:ailue of cows as milk producers. In the same herd there are jS Z 2C4
Eften found individuals that do not yield enough to pay for c
eir feed, and others that yield enough milk to pay for feed o. 36 #? j.
and care and leave a handsome profit for the owner (4-p. 45).
N! stages between these extremes are represented. The
I~sest way to improve the average of a herd is to get rid of
ioie unprofitable cows, and the two best aids for this are milk
scales and a Babcock tester, with a carefully kept record of
peMh cow and a determination to relentlessly cull all unprom-
ii.ng stock (5-p. 8). Some of the unprofitable cows can be 6
M*'eaning reference book or bulletin No. 1, page 44.
4 : .
found without these aids, but the best judges are liable
make mistakes in picking them out. This is largely beaui
the richness of milk can not be told by its appearance. a
(b) Very many dairy herds would show better returns 'i
they were fed better. Cows giving milk are performing hard
I work and must be well nourished. If the ration is small, but
little of it will be available for making milk after the neceisapryI
requirements of supporting life are satisfied. And care muml,
be taken to have the ration include the proper constituents-i
protein, carbohydrates, and fat-for making milk, repaSirig
tissue wastes, and producing bodily heat (6). It is necess
to carefully study the markets and the possibilities
farm to be able to obtain feed most cheaply.
(c) Health and comfort of the cow and regularity and kind -:
ness in her care are also prime requisites for the economistl
production of milk (5-pp. 10 and 18).
II. The lossessuffered by dairy farmers because of imptroprI
methods of handling milk amount to a vast sum. Milk iseis
ideal condition when first secreted in the udder of the healthy
well-kept cow, but if it is not properly cared for it will less i-
part or all of its market value soon after it is taken froml ta .
udder. The changes of milk are due to bacteria and, if th.
dairyman understands somewhat the nature and habits o'|
these little creatures, he is greatly aided in protecting hii, e.
against their depredations (7--Chap. I) and (8-Chap. I)
Bacteria are very abundant in nature. They are minute veg
table organisms and many kinds of them are useful,
some are objectionable and even dangerous. Numerous
8 ferent kinds have been found in milk and some of them hAd
been carefully described and illustrated. Souring is them
common bacterial change of milk and is due to the p
and activity of a large number of germs called lacu
germs, that change the sugar of milk into acid (9).
9 times milk undergoes putrefactive changes, or it may
stringy, or bitter, or red, or blue, or it may be affected in
other ways, each different kind of change or ferment
being due to the growth of large numbers of some kind
teria. Besides the bacteria that produce marked chan
milk, forms sometimes get into it that retain their life
t not multiply and produce changes, and others that igro ..
or less rapidly but without producing noticeable e
although they make the milk unwholesome. Unfort
these latter kinds sometimes include germs that cause disease,
and if they once get into a supply of milk they may produce 10
lsiekness and even death to the consumer. The diseases most
ble to be thus carried by milk are typhoid fever, diphtheria,
.-and scarlet fever (8-Chap. V). To be sure, these diseases are
Aiot often transmitted by milk, but they have been carried in
his way often enough to prove that the possibility and the
'uldanger exist. The dairyman, then, should produce and han-
Shis milk in such a way as to exclude all disease-producing
or pathogenic bacteria and as many as possible of the. forms
it:;hat cause milk to sour or otherwise deteriorate in value.
How do bacteria get into milk and how can they be ex-
4q luded? (7--Chap. III), or (8--Chap. II), or (10-p. 13).
If the udder is diseased it may be the source of a large num-
.'.ber of objectionable bacteria. But a small number of bac-
twria %re in the milk in the healthy udder. They enter
: through the orifice of the teat and become permanently estab- 11
Slashed in the teat, milk cistern, and ducts. They are most
abundant in the first few streams drawn, and in dairies where
every possible precaution is taken to exclude bacteria, it is
the rule to discard the first few streams from each teat. Some
recent investigations seem to indicate that the contamination
Iof milk from this source is not as serious as once supposed.
The chief source of bacteria in milk is foreign matter which
Finds its way into milk in greater or less quantities according
Sto the care taken to exclude such contamination. Small par-
Iticles of soil or manure, hairs, dust, old milk, impure water,
Setc.-all are carriers of bacteria.
(a) The cows should be kept clean. This can be managed
easily if the barnyard and stable are kept reasonably clean. 12
IThe stable air should be as free as possible from dust; the 13
Room should have a tight ceiling, no hay nor straw should be 14
stored in it, no dry feed should be given at or just before milk- 15
ing time, and everything which tends to produce dust should
Sbe avoided as much as possible.
: (b) Stables should be well lighted and ventilated both for
cleanlinesss and the health of the animals. The mistake is 16
: often made of constructing cow stables with too few windows
lor none and without provision for ventilation. The newest
idea is to admit an abundance of light and to have ventilating 17
i. shafts to conduct away the most impure air which is nearest 18
Sthe floor and others to admit fresh air near the ceiling (11-
ti~*dk'rik *d**i -'i. .,s .
p. 354). But this system will not work where there
19 ings through which the air can pass outward or inoai di i
out control. It is a serious mistake to think that their pfrs.i
o tions necessary in the stable for the production of pus
require the construction of a costly building (12-p. il .'ii):4
(c) Before milking, the cow should be cleaned, e sapj C
S1 those parts from which dirt might fall into the milkpa:l.ii:,i
22 Petri plate (7-p. 41) exposed under a cow whose :ddS,:l
surrounding parts are being more or less shaken by tthe:i, l
of milking, indicates the large number of bacteria dio i t
23 at this time. It does not require much time to brua~ h esit`
cows and to wipe the udder and flanks with a damp lo t
24 before milking. Fraser reports (13-p. 593) that 22 .timll .
much dirt will fall from an udder slightly soiled. as frem : n
that has been washed, and when the udder is muddy .ti
quantity is 90 times as great. Between the cleaning and
milking a cow can be kept standing by a simple device :cnn'
sisting of a chain attached to one side of the stanchion, with
a hook on the end, to be fastened to the other side of thq
stanchion under the cow's neck.
(d) But with all the care that can be exercised some di*
and bacteria will be constantly falling where milking is
26 progress. The common milking pail has a wide open top
catch a large amount of this falling material. The am
falling into the milk pail can be greatly reduced by the us!
a pail with a small top (14-p. 5). If the diameter is redu
to one-half, then the opening will be reduced to one-fourth Un
usual size. This can be easily done by using as the milk
an ordinary 10-quart serving pail having an opening abouii
inches in diameter. The opening can be still further red
by the use of a special form of serving pail, one having a
attached at one side of the opening and projecting over a
of it. When the pail is in use the visor is on the upper'
away from the cow, and the more the pail is tipped
the cow the more the opening is protected from falling
If the visor is high the opportunity for dirt to enter w~ahle,
pail is in use is reduced to almost nothing. This kin
sanitary milking pail seems to have some advantages:
those in which cloth strainers are used. Experience
that milkers can soon become accustomed to this at *
pail, and the difficulty of milking into a small opening ai.j
as serious as at first supposed. A simple experiment ...
28 show that milk can be easily drawn into a small opening.
(e) So far as possible sharp angles should be avoided in 29
p' inilk utensils because of the difficulty in cleaning such places.
i.: (f) Persons who milk cows and handle milk should be in
o:od health and under no circumstances come in contact with
person suffering from a contagious disease. A special gar- 30
Spent should be worn when milking or handling milk, and
IIands should be carefully cleaned and kept dry. In dairies
I*here every precaution is taken to keep the milk pure it is
q:!rftomary for attendants to wear white overall suits that are
c:l'eaned and sterilized daily. This would be impracticable in
|iShe average dairy, but a special garment could be used for
AllWl k work and cleaned at frequent intervals without a notice-
a~ increase in the operating expenses. If milkers are ex-
pected to keep their hands clean, provision for this should be 31
i7;aade in or near the stable.
(g) Immediately after milk is drawn it should be cooled to
i below 500 F. to prevent the multiplication of the bacteria
: that have found their way into it (7-p. 47), or (8-p. 100). 32
tThis can be done by pouring the milk over a cooler or by stir-
riiing it in cans set in cold water. If the milk has been taken
inl a cleanly manner and there is no bad flavor on account of
grweeds or other flavor producers in the cow's ration, then aera-
iiion is not necessary. A good glass floating thermometer 33
btould always be at hand. With the aid of Petri plates the
e-!ffect of different temperatures upon the rapidity of bacterial
AiFcrease in milk is clearly shown. They increase very slowly 34
below 500 F.
'-' (A) Milk should not be handled or stored in the stable (13--
i'p. 606). A separate milk house can be' built at small cost, or
if this is impracticable, a room can be partitioned off in the
Corner of the stable most distant from the barnyard. It is
Swell to have but one entrance to this room, and place it so
that a person entering from the stable will have to first pass
!u::t of doors.
k Inside the milk room there should be smooth walls and no 36
,~ unnecessary shelves, nooks, and corners for catching dust. 37
If milk is to be bottled, this can be done quickly and easily 38
,II by harid if a small amount, or with a special bottling machine. 39
S(i) The proper cleaning and sterilization'*of utensils is a
,, matter of great importance (7-p. 27). When there is much
of this to be done, special equipment is necessary, but thor- 40
41 ough work oan be performed by hand and with the ump i
equipment. It is a great help to have a boiler and steam for
sterilizing, but even without this as good results can be
obtained by the use of boiling water. Before sterilizing, a:
utensils should be cleaned by rinsing in warm water, tholrou
washing in hot water, and rinsing in clean warm or cold watr.
42 (j) Milk hauled to the station or factory in hot weath
should be covered to protect it from heat (10-p. 35).. E
43 some places wooden casks are used for carrying milk, but
metal or glass is much better because easier cleaned.
Dairy literature is chiefly in the form of a small number E
44 books and bulletins issued during the last few years, besides
some periodicals that give all or a part of their space today
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The distribution of milch cows in the United States.
From U. S. Dept. Agr., Bureau of Animal Industry Bul. 55, PI. I.
The most important use of milk is as a human food.
Most of the milk produced is used for making butter and cheese.
Table showing the annual production and creamery value of the milk of each cow
tested through one period of lactation.
From Wisconsin Sta. Bul. 75, p. 23.
Milk scales and the Babcock milk tester.
Diagram showing composition of milk.
From Wisconsin Sta. -Bul. 61, fig. 2.
Table giving the average digestible nutrients in American feeding stuffs.
A variety of bacteria liable to be found in milk.
1 and 2, typhoid bacillus (Pfeiffer); 3, pus and pus cocci; 4, B. dysenteriw (Shigar); 5, Proteus
vlgaria; 6, Clostridium butyricua; 7, 9, 10, 11, types of common lactic bacteria (Conn); 8, a
coccus without influence on milk (Conn); 12, 13. 14, three bacilli producing slimy milk (fig. 12,
Marshall; figs. 13 and 14, Conn); 15, 16, 17, 18, 19, types of liquefying and putrefying bacteria
which digest the casein (Conn).
From H. W. Conn's "Bacteria in Milk and Its Products," fig. 16.
From New York Cornell Sta. Bul. 195, fig. 5.
Graphic representation of a milk epidemic of scarlet fever.
A, B, and C are milk producers. 1 and 2 are milk distributers. The circles represent house-
holds, the inclosed dots cases of scarlet fever. Upon farm A there was a case of scarlet fever.
The diagram shows that milk from farm A gave rise to scarlet fever even when mixed with
From H. W. Conn's "Bacteria in Milk and Its Products," fig. 23.
The interior of the cow's udder.
From New York Cornell Sta. Bul. 158, PI. III.
A badly kept barnyard.
From Illinois Sta. Bul. 84, fig. 7.
A well kept barnyard means much for the cleanliness of the milk.
From Illinois Sta. Bul. 84, fig. 8.
The air in a stable such as this is constantly filled with dust.
From Illinois Sta. Bul. 84, fig. 18.
Tight ceiling and cement floor, sanitary throughout.
From S. L. Stewart's Brookside Dairy, Newburgh, N. Y.
16. Cow stable and dairy house improperly located and constructed and linorly Se
Frbm U. S. Dept. Agr., Farmers' Bul. 63, fig. 2..
17. A well lighted, modern, sanitary stable.
From Walker-Gordon Laboratory Co., Boston, Maus.
18. The ventilating shaft removes the impure air which is nearest the foor.
From Illinois Sta. Bul. 84, fig. 21.
19. Uncontrolled ventilation.:
20. The barn of a small farmer who made certified milk.
From S. D. Belcher's "Clean Milk."
21. The flanks as well as the udder should be clean.
22. Fig. l.-Petri plate exposed two minutes out of doors. Contains 6 coloams.
Fig. 2.-Petri plate exposed two minutes in barn. Contains 111 oloanime
Fig. 3.-Petri plate exposed two minutes under cow being milked. Coatais 1J -
Figs. 1, 2, and 3 show the extent of the contamination to which milk is exposed from thedmnt
of the barn and the droppings from the belly and udder of the cow.
From "Medical Record," March 28, 1896.
23. Cows should be kept clean.
From U. S. Dept. Agr., 17th An. Rpt. Bureau of Animal Industry, PL XXXV. 4:
24. The amount of dirt caught under muddy and slightly soiled udders, before and after
From Illinois Sta. Bul. 84, fig. 11.
25. A chain under the neck of the cow will keep her from lying down after being eleaise
and before being milked.
26. The wide-top pail catches too many falling particles of dirt and dust.
27. The common milking pail; one with smaller top; and the Freeman pail. i
28. Milk can be drawn into a small opening.
29. The wrong and the right kind of a milk pail. .:
A,.the ordinary type of pail showing sharp angle between sides and bottom; B, the ialnlh"!
properly flushed with solder so as to facilitate thorough cleaning. The lower figare s, ni:!|(
ajomt as ordinarily made in tinware. The depression affords a place of refuge for bo tes
which they are not readily dislodged. This open joint should be filled completely with
From H. L. Russell's "Dairy Bacteriology."
30. A special garment for milking.
31. A place where the milker can wash his hands.
32. Cooling the milk.
From Tennessee Sta. Bul., Vol. XV, No. 4, frontispiece.
33. Glass floating thermometer.
34. Showing the effect of temperature upon bacteria growth.
a, A single bacterium; b, Its progeny in twenty-four hours in milk kept at WrP F., 5
r, its progeny in twenty-four hours in milk kept at 70 F., 750 bacteria. Figures ta5bffalt
an actual experiment.
From H. W. Conn's "Bacteria in Milk and Its Products," fig. 20. :
35. A separate milk house.
From Illinois Sta. Bul. 84, fig. 37.
36. 'Smooth walls in the milk room.
S37. Dust traps in the milk room should not be permitted.
38. A cheap and clean way of bottling milk.
i From Illinois Sta. Bul. 84, fig. 42.
39. Students receiving instruction in milk-bottling in a dairy school.
40. A pressure sterilizer.
From S. L. Stewart's Brookside Dairy, Newburgh, N. Y.
S41. Washing and sterilizing milk cans.
S From Illinois Sta. Bul. 84, fig. 28.
42. Farmers delivering milk to the shipping station.
From S. D. Belcher's "Clean Milk."
S43. From the mountains-carrying milk to the cheese factory in Switzerland.
From U. S. Dept. Agr., 17th An. Rpt. Bureau of Animal Industry, P1. XLVI,
44. Some recent books and bulletins upon milk production.
1. Statistics of the Dairy. U. S. Dept. Agr., Bureau of Animal Industry Bul. 55.
2. Facts about Milk. U. S. Dept. Agr., Farmers' Bul. 42.
; 3. Milk as Food. U. S. Dept. Agr., Farmers' Bul. 74.
S 4. Studies in Milk Production. Wisconsin Sta. Bul. 102.
5. The Dairy Herd: Its Formation and Management. U. S. Dept. Agr., Farmers'Bul. 55.
6. The Feeding of Farm Animals. U. S. Dept. Agr., Farmers' Bul. 22.
7. Dairy Bacteriology. By H. L. Russell. The Author, Madison, Wis.
; 8. Bacteria in Milk and Its Products. By H. W. Conn. P. Blackiston's Son & Co.,
9. Souring of Milk. U. S. Dept. Agr., Farmers' Bul. 29.
10. The care of Milk on the Farm. U. S. Dept. Agr., Farmers' Bul. 63.
11. Physics of Agriculture. By F. H. King. The Author, Madison, Wis.
12. Clean Milk. By S. D. Belcher. The Hardy Publishing Co., New York.
* 13. Dairy Conditions and Suggestions for Their Improvement. Illinois Sta. Bul. 84.
14. The Covered Pail a Factor in Sanitary Milk Production. Connecticut Storrs Sta.
^ Some other books and bulletins upon milk production.
Milk and Its Products. By H. H. Wing. The Macmillan Co., New York.
Testing Milk and Its Products. By E. H. Farrington and F. W. Woll. Mendota Book
C:o., Madison, Wis.
The Principles of Modern Dairy Practice. By Gosta Grotenfelt; translated by F. W. Woll.
..John Wiley & Sons, New York.
': Ebments of Dairying. By John W. Decker. The Author, Columbus, Ohio.
Tii he Chemistry of Dairying. By Harry Snyder. The Chemical Publishing Co., Easton, Pa.
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UNIVERSITY OF FL
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