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CORNELL UNIVERSITY.

THE
Roswell P. Flower Libravit” |
THE GIFT OF fa ae
ROSWELL P. FLOWER = |
FOR THE USE OF oa *

&

THE N. Y. STATE VETERINARY COLLEGE Re

1897

Peers

8394-1

Corneil University Library
SF 255.J54e

Essentials of milk

il HTT

Cornell University

The original of this book is in
the Cornell University Library.

There are no known copyright restrictions in
the United States on the use of the text.

http://www.archive.org/details/cu31924001177116

ESSENTIALS OF

MILK HYGIENE

A PRACTICAL TREATISE ON DAIRY AND MILK

INSPECTION AND ON THE HYGIENIC PRODUC-

TION AND HANDLING OF MILK, FOR STUDENTS
OF DAIRYING AND SANITARIANS

BY
C. O. JENSEN

Professor in the Royal Veterinary and Agricultural College of Copenhagen, Denmark.

TRANSLATED AND AMPLIFIED
BY

LEONARD PEARSON

Dean of the Vetermary Faculty of the University of Pennsylvania, State Veterinarian
of Pennsylvanin, Member of the Advisory Board of the State Department
of Health, and Member of the Board of Health of Philadelphia.

ILLUSTRATED

PHILADELPHIA AND LONDON
J. Bs LIPPINCOTT COMPANY

COPYRIGHT, 1907
BY
J. B. LIppIncoTt COMPANY

Published June, 1907

Electrotyped and printed by J. B. Lippincott Company
The Washington Square Press, Philadelphia, U. S. A.

CONTENTS.

AUTHOR’S PREFACE (TO THE ENGLISH EDITION).........-.020-. = -V

TRANSLATOR’S PREFACE ............... Mice deiirarauee & ce doh eat, SV
INTRODUCTION ......... cee es aig slants ps Rates sae Sues 9
MILK AND ITS COMPOSITION ............. Sgie ead ss ee re 12
HARMFUL PROPERTIES .............. i saies Boas ate Te 8 RLe Ree se 60
PASTEURIZATION AND STERILIZATION ......... Straits na aie eek 125
THE USE OF MILK FOR INFANTS .........0 000 cc ccc ee ec ee cence 147

PuBLic CONTROL OF THE PRODUCTION AND HaNnpLiINnG or MILK.... 157
AppeNDIxX I.) Tins Mitk SuppLy OF COPENTIAGEN............. 239

APPENDIX II. GeRMAN INSTRUCTIONS FOR PRODUCING NURSERY

ETS tec iio.2. 1b Sashes wot a actus idee ons anaes ieee cela i ee ee 249
APPENDIX III. Tue MILK COMMISSION OF PHILADELPHIA...... 25)
Appenpix IV. A Score Carp ror Dairy FARMS.............. OF

APPENDIX V. THE MILK CoMMISSION OF Essex (o., NEW
JERSEY se cies eo Sains Seca ini gains & itis ee eth ition Actas etl aes aes 259

APPENDIX VI. Report oF THE ROYAL COMMISSION ON TUBER-
CULOSIS: | agate gas on ewes Dale Ale raanererees eSegsdeee Renesas ene oon 269

INDEX: cae o0034; Feb ain Sake ame eae ha Ee ee Tee eel

AUTHOR’S PREFACE.

(TO THE ENGLISH EDITION.)

In the hygienic movement of the times the control of
the production and handling of milk has not been given
a prominent place. But the significance of this subject
is now plain and everywhere efforts are being made to
institute such a control or to improve it. The efforts of
cities to secure a wholesome supply of milk must of
course differ and be adapted to local conditions, but
they must all be governed by the same principles and
rest on exact knowledge of the composition of milk and
of the dangers that are to be avoided.

In the preparation of this book it has been my hope
that it would not only be of use to my Danish col-
leagues, but that my colleagues in other countries would
find it to be of service to them. lor this reason I pub-
lished a Danish and a German edition simultaneously
and for the same reason I have been very glad to grant
Prof. Pearson’s request for permission to prepare an
English edition.

C. O. JENSEN.

TRANSLATOR’S PREFACE.

Tue production of market milk is a rapidly growing
industry. The demand for milk in cities is continually
increasing and there is reason to believe that the rate
of increase will advance.

The milch cow transmutes the pasturage and forage
of the farm into edible protein, lactose and fat—into
units of nutriment for man—at less than one-half the
cost of similar units in beef produced by the steer.
Milk is not only the most economical but, when pure and
undefiled, it is among the most wholesome and it is
the most easily digestible of all foods of animal origin.
These are the strongest possible reasons for its extended
use.

Qn the other hand, there is no other food that, under
ordinary conditions, is so exposed to contamination,
that is so easily contaminated or that so fosters contami-
nation as milk. Hence the necessity for the study of
milk hygiene.

The subject is a broad one. Milk hygiene involves
some knowledge of the physiology of cows, especially
with relation to breeding, lactation and nutrition; of
comparative pathology, particularly the various dis-
eases of the udder of the cow, the abnormal conditions
that affeet milk secretion, and the infectious diseases
of cattle and of man that may be transmitted by milk;
of bacteriology, in regard to the pathogenic organisms
and the saprophytes that oeeur in milk, their effects,
their behavior under various conditions and especially
at different temperatures; of the chemistry of milk and

ity adulterations and, besides these, there must be added
vii

TRANSLATOR’S PREFACE

certain, important chapters from animal husbandry,
dairy husbandry and dairy industry.

Until quite recently, milk inspection in the United
States has been carried on by untrained men who have
had little, if any, knowledge of the sources or nature of
the contaminations of milk or of the means by which
they must be avoided; their whole technical equipment
has consisted in a few rule-of-thumb tests to detect
gross adulterations. A large number of milk inspection
services are still organized on this basis. In several
cities, however, attention has been paid to microscopic
and bacteriologic examinations of milk, and it has been
shown that a very large proportion of the supply fails to
meet even a moderate standard for cleanliness, thus re-
vealing the need for measures at the seat of production
and during transit to prevent injurious contaminations.

It is becoming increasingly manifest to sanitarians
that more must be done to protect consumers from the
unwholesome conditions and the diseases propagated
and transmitted by milk and the broader men in dairy
industry realize that milk must be made safe and be pro-
tected if it is to find and retain its proper place in the
dietary of the people.

This makes a demand for a discussion of milk
hygiene from the standpoint of the sanitary supervision
of market milk—from the side of the man who is to do
the practical work of protecting the milk supply—and it
is this demand that Professor Jensen’s book is planned
to meet.

Lronarp Prarson.

viii

PART 1.

INTRODUCTION,

Cow's milk has a peculiar place among our food
stuffs in that it is not only an important and indispens-
able part of the daily dietary of inost people, but it is
being used more and more for the feeding of infants and,
indeed, is often almost the exclusive food for children
during the first years of life. It is, therefore, quite natu-
ral that at present when the science of hygiene is receiv-
ing so much attention—especially in relation to the large
cities—that there should be a demand for a reliable
supervision of market milk. It is true that the milk
trade in cities has been subject to a certain inspection,
but attention has been directed to only one side of the
question, to the possibility of adulteration, and to pro-
vide that fat is not removed and that there is no
alteration in the composition of the milk. From the
standpoint of hygiene this is merely of secondary im-
portance because it is in other ways that milk aequires
dangerous properties and may, indeed, become the
means of spreading virulent diseases.

A properly organized milk control of the present
day ean not, therefore, be restricted to determining
that milk offered for sale is unadulterated. On the
contrary, it must be its chief purpose to prevent milk
possessing injurious properties from coming into the
market and to prevent market milk from acquiring such
properties during the time that it is being handled and
stored. Since it is possible only by means of a thor-

ough, tedious examination to determine whether a given
9

10 MILK HYGIENE

sample of milk is unwholesome, milk control can not be
restricted to a simple inspection of the milk or to taking
a sample for further examination. To insure real
safety, the inspection must be broadened to cover the
health and feeding of the cattle, the cleanliness of the
producing plant, the method of handling and caring for
the milk and the condition of health of the people who
come in contact with it. Milk control is, for the reason
stated, more difficult and more expensive than, for
example, meat inspection, and this is undoubtedly one
of the principal reasons why the control of milk produc-
tion and the milk trade is so defective in most countries.

During recent years, a somewhat comprehensive con-
trol of the milk trade in its various relations has been
carried out in a number of large cities, but a thoroughly
satisfactory system does not exist and will be difficult
to establish on account of its cost. Jn Denmark, a
long step has been taken in the matter of milk control
through the voluntary initiative of a single large com-
pany which, at a time when milk hygiene was receiving
little attention, inaugurated a very comprehensive
system of control, and thereby set an example that has
been followed by other large companies, not only in
Copenhagen but also in foreign countries. These com-
panies have, in some respects, carried their control to
a point far beyond that contemplated at the time by
the public authorities.

Copenhagen is on the point of supplementing its
health laws in relation to the milk trade within its
limits.

As it is chiefly through the work of Veterinarians
that meat inspection has gradually increased and is now
conducted in a scientific manner, so, to a large extent,
we have to thank the Veterinarians for the fact that-
the control of the production and sale of milk is grow-

INTRODUCTION LY

ing steadily. Not only is important scientific work
being carried on by them in several directions, which
supplements the work of chemists and physicians, but
the necessity for milk control is constantly being pointed
out in meetings of veterinarians, in the International
Veterinary Congresses and in the Congresses for
Hygiene. A special journal is devoted to «questions
pertaining to milk hygiene, in conjunction with meat
inspection, and separate courses in milk hygiene are
given in many Veterinary Colleges.

What follows is essentially the substance of lectures
given by the author in the Veterinary and Agricultural
College of Copenhagen. On some points in the prepara-
tion of the book, the lecture notes have heen expanded ;
for example, in citing the instances of disease resulting
from milk possessing injurious properties. Since vet-
erinarians are frequently consulted, hy sanitary officers
and by dairymen, in regard to the adulteration of milk,
it is considered to be desirable to discuss rather thor-
oughly the composition of milk, the variations that oceur
under different conditions, and the adulterations. It is
also considered to be appropriate to briefly treat upon
the use of milk as food for infants.

Division oF SuBJECT

The subject matter of this book is divided into the
following parts:

Milk and its composition.

Injurious properties that milk may possess.

Pasteurization and sterilization of milk.

The use of milk for infants.

In order to prevent the expansion of the book to
unnecessary proportions, the hygiene of other dairy
products as cheese and butter, and milk preparations
as condensed milk, milk powder, ete., is not discussed,

PART II.

MILK AND ITS COMPOSITION.

I. THE MILK GLANDS AND MILK SECRETION.

Tue tissue of the milk glands is shown by macro-
scopic examination (Fig. 1) to be composed of small
lobules separated by bands of connective tissue in which
lie the larger blood vessels, the nerves and the excretory
ducts and in which there is sometimes a considerable
quantity of fat tissue. The gland tissue itself is com-
posed of complexly branching glandular tubes which,
during the period of lactation, are provided with
numerous globular distensions, so that the type of the
milk gland is intermediate between that of the alveolar
and tubular types. The glandular pockets are provided
with a membrana propria (Fig. 2) and are lined with
epithelial cells. In young and farrow animals, the cells
are thin and square or high and narrow, and resemble
superficial epithelium. During the period of lactation
these cells become large and tense. This epithelium is
usually composed of but a single layer, although, in old
cows, it is sometimes found to be composed of several
layers.

Toward the end of gestation, the secretory function
of the udder begins with the production of colostrum or
the so-called ‘‘beast milk.’’ This is a thick, reddish or
yellowish fluid with a taste more salty than that of nor-
mal milk, and under the microscope (Fig. 3) it is seen
that it contains numerous free fat globules and a large
number of round or mulberry shaped cells—the so-called

colostrum bodies—that are filled with fat globules.
12

sectiou of udder tissue of uw cow. Low magnification. One entire lobule is shown and
parts of five others, Microphotograph.

Section of the udder tissue of a eow High magnification. Shows individual glandular
pockets with their endothelial lining and the connective-tissue framework, Miero-
photograph.

Colostrum.—The udder secretion of a cow that has recently ealved. Stamed lightly with
osmicacid, causing the fat globules to become dark, Shows several colostriin bodies
and fat globules. Microphotograph,

Milk.- The fat globules are shown as light circles on a dark background. Micro-
photograph.

THE MILK GLANDS 13

Some cells are seen that have a distinct amceboid
movement; these are leucocytes that have wandered
through the epithelium into the glandular pockets and
have taken up some globules of fat. Besides these,
there are to be found some epithelial cells that have
undergone more or less degeneration.

The chemical examination of colostrum shows its
principal constituents to be: water, proteids (especially
globulin and albumin, and also casein and nuclein com-
pounds), sugar, fats and cholesterin, and, besides these,
lecithin, various salts and other substances in smaller
quantities. Colostrum differs from normal] milk in its
higher percentage of solids and especially in its higher
content of globulin, albumin, nuclein compounds and
lecithin. The chemical composition of colostrum differs
slightly among animals of different species. In the
course of a few days, the secretion of colostrum passes
into milk seeretion so that at the expiration of about
one week, the secretion possesses the characteristic ap-
pearance and composition of milk.

The microscopic picture of milk is quite different
from that described above. .\ very large number of
fat droplets (milk globules, Fig. +) of varying sizes, and
a small number of more or less degenerated cells (eolos-
trum bodies, gland cells) are distributed uniformly in
a transparent fluid, the milk plasma.

It was formerly thought that milk secretion differed
in important particulars from other secretions in that,
it was considered, it occurred through partial destrue-
tion of the gland cells. It was supposed that during
secretion the cells became longer and swollen, that the
nucleus receded to the base of the cell while the part
pointing toward the cavity of the alveolus became filled
with numerous small fat globules. It was thought that
after this ‘‘ fatty degeneration ’’ reached a certain

14 MILK HYGIENE

stage, there was a pouring out and solution of this
part of the cell, that the fat globules were transformed
into milk globules and the albuminous part of the cell
protoplasm became part of the milk fluid and that the
remaining portion of the cell, with the nucleus, was soon
regenerated, whereupon a fatty degeneration again oc-
curred in the regenerated portion of the cell. Recently,
doubts have arisen as to whether, during the production
of milk, there is, after all, a material disintegration of
the cell protoplasm. Ottolenghis’s investigations appear
to show clearly that milk secretion is an active cell
process precisely as other secretions are, and that it
does not depend upon the destruction of the cell. The
destruction of entire cells and their elimination appears
to occur only to a limited degree, but the presence of
karyokinetic figures shows that, here and there, in the
gland, such a disintegration does occur with consequent
reproduction.

The milk from animals of different species contains
the same ingredients, namely: water, albuminoids (es-
pecially casein and albumin), milk sugar (lactose), fats
and inorganic salts. In regard to quantitative compo-
sition, there are marked differences between the milks
of animals of different species.

Among the ingredients of milk it is supposed that
casein is the direct product of the gland tissue, globulin
of the broken down parts of cells, while it is not known
whether albumin originates at the same source or comes
from the blood. Concerning the origin of lactose, there
are different opinions. Some investigators suppose this
material is formed in the liver from glycogen or related
materials, while others think, and indeed with reason,
that it is formed in the udder by synthetic building up
of glucose and galactose. The latter cannot, as such,
have been taken up with the food, but must have been

THE CONSTITUENTS OF MILK 15

formed in the body by a breaking down of the galac-
tins of the food. Others regard lactose as a product
of certain proteids (glycoproteids). Milk fat is de-
rived partly from the fat in the food, partly from the
fat tissues of the animal; but these fats undergo a
material transformation in the tissues of the udder,
so that certain easily recognizable fats, even when taken
up in quantity with the food, are either not visible at all
in the milk or appear in very small quantity or are
merely transitory. Doubtless, milk fat—just as fat tis-
sue—may also be derived from the carbohydrates of the
food. Among the other ingredients of milk, citric
acid does not originate in the food, but results from
metabolism.

Milk secretion, to a great degree, bears tlie impres-
sion of specific action of the cells which, however, may
be influenced by external circumstances, but usually only
temporarily. This is naturally of great importance for
the young aninal, which is nourished entirely or chiefly
on its mother’s milk, as frequent and sudden changes
in the composition of the milk would be harmful, if not
dangerous.

Milk secretion, it appears, may be checked through
the influence of the central nervous system, but is regu-
lated through the sympathetic nerve centres. In this
connection, observations agree that certain irritant
drugs (as pilocarpine) and other influences that decid-
edly affect the secretory function of other glands, influ-
ence milk secretion very little if at all; furthermore,
section of the nerve trunks of the udder does not disturb

secretion.
II. THE CONSTITUENTS OF MILK

As already mentioned, milk of different mammals
consists essentially of the same materials, namely:
water, protein, sugar, fats and inorganic matter; but

16 MILK HYGIENE

great differences are shown by quantitative analyses of
the milk of the different species.

Water. The quantity of water usually amounts to
80 to 90 per cent. of the weight of the milk; under certain
circumstances and with some animals it is even consider-
ably less. With the whale, the quantity of water is
scarcely 50 per cent.

Proteids. Of proteids, the three following are always
found: casein, lactalbumin and lactoglobulin. A kind of
albumose-like compound is sometimes found in insignifi-
cant quantity—the so-called animal gum—which is also
found in certain tissue and in the saliva, and probably
comes from the breaking down of glycoproteids (mucin,
ete.). Moreover, other proteids are often described as
normal constituents of milk (albumins, albumoses, meat
acids, ete.), but it is safe to conclude that these do not
occur in fresh milk, while such compounds are readily
formed by bacteria and ferments and can be formed by
chemical means.

Casein is a nucleo-albumin and, as such, it contains
phosphorus. It is insoluble in water, but, by virtue of
its property as an acid, it forms soluble salts with alka-
hes. There are two series of casein salts, basic and
neutral; the solutions of the latter have a milky appear-
ance. Casein is found dissolved in milk in the form of
a neutral lime salt, which aids in giving to milk its
white, opaque appearance. When boiled, a solution of
casein is overcast with a thin membrane of coagulated
casein; but a real coagulation, as it occurs in albumins
and globulins, does not take place. When the fluid has
reached a certain degree of acidity casein coagulates at
75° C. and the precipitated casein is not again soluble.
After the addition of diluted mineral acids or of acetic
acid, casein is precipitated as flakes or lumps, but under-
goes no chemical change and is again easily soluble in

THE CONSTITUENTS OF MILK TF

lime water and diluted alkalies. The separation depends
only and solely upon the breaking down of the casein
calcium compound. By rennet (chymosin, etc.) casein
is precipitated as flakes (human milk and donkey milk),
or as a firm gelatinous mass (e.g. cow’s milk). The dif-
ferent modes of precipitation do not appear to come
from the differences in the casein, but are due to the dif-
ferent salt content of the different kinds of milk. Under
the influence of chymosin, casein is transformed into
paracasein, Which in its compound with lime is insoluble
in water and, therefore, may be precipitated in this way.

The action of the rennet ferments is quite different
from the precipitation of casein by acids. With the pre-
cipitation of paracasein, an albumose-like proteid re-
mains in solution (whey proteid), so the action of the
rennet ferment is to split the casein. By the growth
of bacteria in milk, the casein is often thrown out of
solution, either as a result of the formation of acids
or by the chymosin-like effect of ferments produced hy
bacteria. Sometimes the separation occurs from the
joint action of the ferments and the acids that are
formed. In pepsin digestion, casein is dissolved with the
formation of albumoses (caseoses) and paranuclein,
which is rich in phosphorus. In the organism, para-
nuclein is dissolved by the pancreatic juice, is absorbed,
and is excreted with the urine as phosphorie acid.

Tt has often been said that casein, as it is found in
the milk of different animals, is not the same and, as
evidence of this, reference has, incorrectly, been made
to the different ways in which casein separates from
milks acted upon by rennet. A more important indica-
tion, although the observation requires confirmation, is
in the claim that in the pepsin digestion of human milk
no paranuclein is formed. According to Hammarsten’s
thorough work, casein appears to show no chemical dif-

o)

18 MILK HYGIENE

ference in different kinds of milk. The latest investiga-
tions concerning the powers of the organism to form
specific anti-albumins (precipitins) following the injec-
tion of albumin solutions, prove, however, that the
casein of different species of animals has certain dif-
ferences, even though these are so slight that they can-
not be detected chemically.

The lactalbumin is very similar to the albumin of the
blood, but it appears to differ from this in some particu-
lars. It coagulates at about 70° C., and, like all other
albumins, it is not precipitated in a neutral solution
of sodium chloride and magnesium sulphate, but it is
precipitated in a saturated solution of ammonium
sulphate.

The lactoglobulin occurs in milk in very small quan-
tity, merely in traces, while colostrum is comparatively
rich in this substance. It coagulates at 75° C.; it is pre-
cipitated in the same way as serum globulin and, like
serum globulin, is insoluble in water, but is soluble to
some extent in weak salt solution.

Carbohydrates. Of the carbohydrates, lactose, or milk
sugar, occurs as a constant constituent in the milk of
the cow and of most other mammals. Some investiga-
tors claim that in colostrum there is a monohexose,
which is probably glucose, and it is not unlikely that in
the milk of certain animals other kinds of sugar appear;
for example, it is cited that a peculiar kind of sugar,
tewficose, is found in considerable quantity in the milk
of the Egyptian buffalo.

Lactose (C,,H,,0,, + H,O) is a disaecharid which
is split by hydrolysis (e.g. by means of heating with
dilute acids, action of ferments) into glucose (grape
sugar) and galactose as follows:

Ci, Ay, OW + Hy O == Cs Hie Og +t Cs Hi, 0.

Lactose Glucose Galactose

TEE CONSTLITVENTS OF JTL 19

Lactose has been found only in milk and must be
formed in the organism; but this formation, as has
already heen stated, is not yet thoroughly understood.
Commercial lactose is derived from whey as hard rhom-
Ine crystals which have a slightly sweet taste and are
soluble in six parts of cold water. By the action of
Inicro-organisins, lactose may ferment in different ways.
Certain yeasts and bacteria cause an alcoholic fermen-
tation, while other bacteria split lactose, forming lactic
acid (causing ‘* souring ’’? of milk) and several other
substances as by-products (C'O., H, formic acid, butyric
acid, ete.) ; still other bacteria form as their chief pro-
duct, butylalcohol, succinic acid or acetic acid. Certain
moulds are able to forin oxalie acid from lactose by oxi-
dation. Lactose, like glucose, reduces Fehling’s solution
when heated.

Fats ave found in the milk as small droplets or elob-
ules, which accumulate upon standing into a layer of
cream, and which are easily separated from the other
constituents of milk by means of centrifugal force.
Upon shaking milk or cream, the globules of fat grad-
ually coalesce into larger drops and lumps (butter). It
was formerly thought that the fat globules were sur-
rounded by a membrane, but now it ix generally believed
that it is not so. However, under the microscope one
can see a border on certain individual fat globules,
which is to be regarded as a remainder of broken-down
cell protoplasin.

Milk fat consists of a mixture of different fats, the
principal of which are olein, palmitin and stearin,
which are the neutral triglycerides of the correspond-
ing fatty acids. Besides these are found the triglycer-
ides of myristic acid and of butyrie and eapronie acids
(the last two volatile) and also traces of triglyceride of
other fatty acids (vaprylic, caprinic, laurinie and arach-

20 MILK HYGIENE

inic). The composition of the fat is subject to numerous
variations and these are not alone racial peculiarities,
for individual traits, the composition of the food and
external conditions of life not infrequently influence it.

Other Substances. Milk contains other substances
in very slight quantities: urea, kreatin, kreatinin, leci-
thin, cholesterin and citric acid. It is not yet known if
these appear in the milk of all animals or whether some
of the substances are characteristic of certain animals
only.

Besides these substances, milk contains some inor-
ganic salts in solution, which remain after evaporating
and burning the milk. The ash consists of lime, potash,
sodium, small quantities of magnesia and traces of oxide
of iron in combination with phosphoric acid, chlorine
and sulphuric acid. The small surplus of basic sub-
stances in the ash were in combination with citric acid
and, perhaps, with other organic acids. Phosphoric acid
and lime exist partly as soluble compounds, partly in
combination with casein. <A little di- and tri-calcium
phosphate are held in solution by the action of the casein
and are therefore precipitated with it. The milk of dif-
ferent species and sometimes of different individuals,
shows a quantitative difference in the ash.

According to recent investigations, milk, at least
cow’s milk, always contains a ferment, the so-called
galactase (Babcock, Russell), which is capable of slowly
peptonizing protein. The significance of this ferment
and its composition are wholly unknown to us; possibly
it comes from the breaking down of the leucocyte
(Barthel).

Certain gases occur in the free state in milk.
Investigations on this subject have given varying re-
sults, in that some investigators have found distinct
quantities of oxygen in milk just drawn, others have

THE COMPOSITION OF MILK pal

detected only a trace, or none at all; moreover, milk
always contains considerable carbonic acid and a slight
quantity of nitrogen. Upon standing, this relation
changes, for carbonic acid escapes and oxygen is
absorbed.!

IN. THE COMPOSITION OF MILK OF DIFFERENT
SPECIES OF ANIMALS

It has been stated that the milks of different species
of animals consist of essentially the same materials, but
that in their quantitative composition they show quite a
little difference. As will be considered in detail later,
there are great variations with individual animals and,
therefore, the figures given are to be regarded as aver-
ages and they are to be accepted with some reserve, for
not all are the result of a sufficiently great number of
analyses; still, they give quite a good picture of the
striking peculiarities of the different kinds of milk.

Cow’s milk is white, opaque, lias a slightly sweetish
taste and a very slight odor. It shows amphoteric reac-
tion to litmus paper, c.y., it colors red litmus paper blu-
ish and blue reddish. To other indicators, milk some-
times shows itself to be acid, sometimes alkaline. Ac-
cording to Courant, it ean be demonstrated that 100 c.e.
of fresh cow’s milk shows the same amount of alkalinity
toward blue litmus as 41 e.c. of a one-tenth normal solu-
tion of sodium hydrate and the amount of acidity, as
measured by phenolphthalein, is equivalent to that of
19.5 «cc. of a one-tenth normal solution of sulphuric
acid. However, milk does not always react the same,
it changes especially during the course of the period
of lactation. The casein of cow’s milk is precipitated

1Richmond says: “.\s the milk is kept the amount of oxygen
devreases and that of carbon dioxide inereases; this is probably
due to aérobic microdrganisms, which absorb the oxygen and give

out carbon dioxide.” [L. P.]

22 MILK HYGIENE

by chymosin as a firm, jelly-like mass. The butter-fat
contains a yellow coloring stuff.

The qualitative composition of cow’s milk averages
as follows (Fleischmann): water, 87.75 per cent.; fat,
3.4 per cent.; casein, 3.0 per cent.; albumen, 0.5 per
cent.; lactose, 4.6 per cent.; salt, 0.75 per cent.2 Lacto-
globulin and lecithin are found only in very slight quan-
tity; citric acid is found in quantities of from 0.1 to
0.15 per cent. Analysis of the ash shows its constitu-
ents to be present in the following proportions:

K,O NaO CaO MgO FeO, PO; Cl SO,
2581 78 19.71 2.77 0.13 2311 16.15 4.07%

But there may be a considerable amount of variation,
especially in the potash, magnesia, chlorine and _ sul-
phurie acid, since the consumption of certain salts in
great quantity cause changes in the composition of the
ash. The quantitative composition of cow’s milk varies
greatly among the different breeds and individuals, and
at different stages of the period of lactation (see the
next section).

Zebu’s Milk coincides almost wholly in its properties

’ Richmond gives the following average composition of milk,
based on the analysis of 200,000 samples taken from the supply of a
dairy company in London:

Per cent. Per cent.
NWALEE oe ccs vats 87.10 Casein............ 3.00
Batt cc. gcichy cs aeons 3.90 Albumin... ...... 0.40
Milk sugar ........ 4.75 NS I es Sopra MEMES fs 0.74

A very large proportion of the cows producing milk for the
London market are of the Shorthorn breed. [L. P.]

The following is taken to represent “milk of good average
quality ” in Massachusetts:

Per cent. Per cent.
Water ...........- 87.00 Casein .o.6 ccna sce es 3.00
Hation Vu eiseeauny estes 4.00 Albumin.......... 0.50
Milk sugar ........ 4.80 ASH, savy sees es ee 0.70

(Bulletin 110, Hatch Experiment Station.) [L. P.]

THE COMPOSITION OF MILK “3

and quantitative composition with ordinary cow’s milk.

Buffalo’s milk, which possesses a slight, pleasing odor
and taste, is richer in solids than cow’s milk, since the
quantity of fat amounts to about S per cent., the proteids
to fully 4 per cent. and lactose to 4.75 to 5.2 per cent.

Goat’s milk is pure white, without especially pro-
nounced odor or taste. If, however, the milking takes
place in the stable in which male goats are kept, the
nulk very easily absorbs the same characteristic un-
pleasant odor. The chemical composition of goat’s
milk is sunilar to that of cow’s milk; frequently, though,
the fat content is a little greater. The butter-fat is white.

Sheep’s milk is a whitish yellow, rather thick and pos-
sesses a peculiar, somewhat unpleasant taste and odor.
It differs from cow’s milk and goat’s milk in its high
fat and casein content, averaging about 9.0 per cent. and
6.3 per cent. respectively. Moreover, the fat content is
very variable, for with some breeds it amounts to 11 to
12 per cent. and even more, while with others it amounts
to only 2 to 8 per cent. The examination of milk of 2,700"
sheep (Sartori) showed an average specifie gravity
1.0374 and the following composition: water 78.70 per
cent., fat 8.94 per cent., proteids 6.5 per cent., lactose
5.06 per eent., ash 1.015 per cent. The average analyses
for 250 other sheep (Fleischmann) were as follows:
water 75.54 per eent., fat 11.90 per cent., casein 5.83
per cent., albumin 1.53 per cent., lactose 3.43 per cent.,
ash 1.05 per cent.

Mare’s milk is usually distinctly alkaline to litmus,
but may be neutral. It is white or bluish in color and
has a somewhat pronounced sweet taste due to its high
lactose content (about 6.6 per cent.). The proportions
of fat and proteids are conspicuously small; as in the
averages of 15 analyses (Veith) only 1.09 per cent. fat
and 1.89 per cent. proteids (of which about a third was

24 MILK HYGIENE

albumin) were present. The inorganic salts (ash) are
present only in small quantity (0.31 per cent.).

Ass’s milk is essentially the same as that of the mare;
it has in common with the latter the low fat and proteid
content and the large quantity of lactose. The composi-
tion is given somewhat differently by different writers.
Ellenberger, Seeliger and Klimmer found as the aver-
age of a large number of analyses: water 91.20 per cent.,
fat 1.10 per cent., proteids 1.50 per cent., lactose 6.0 per
cent., ash 0.40 per cent. The reaction is decidedly alka-
line to litmus. On account of the small proportion of
salts, the casein is precipitated by rennet as a flocculent,
disunited mass. Milk of the ass more nearly resembles
human milk than does that of any other animal, and in
Southwestern Hurope, for the most part, milk of the ass
is the principal substitute used for the nourishment of
infants.

Woman’s milk, which reacts amphoterically, is regu-
larly somewhat richer in lactose than cow’s milk, but it
contains less proteids and also less ash, especially phos-
phorie acid and lime. While the lactalbumin in cow’s
milk constitutes but one-fifth to one-sixth of the protein,
in human milk during the first part of the period of
lactation, albumin and casein are present in almost
equal quantities; later, casein increases a little. The
average percentage of fat is approximately the same as
in cow’s milk, but it varies considerably, from 1.3 per
cent. to 7.8 per cent. Human milk is richer in lecithin,
but poorer in citric acid (about 0.5 per thousand) than
cow’s milk. According to E. Gottlieb the following
numbers represent the average composition of 104 sam-
ples: water 87.92 per cent., fat 3.43 per cent., casein 0.58
per cent., albumin 0.52 per cent., lactose 7.12 per cent.,
ash (salts), 0.25 per cent. Woman’s milk is subject to
individual variations to a great degree, as is shown by

THE COMPOSITION OF MILK ps

the table below, which is taken from Gottlieb’s analyses:

\ 1
Water. Fat. | Casein. ‘Albumin. Lactose. Ash,

| :
“Normal” milk....... 87.42 | 338 , O78 | 0.39 | 7.51 | 0.27
Rich milk: sacuyss Soeak 85.24 5.91 0.87 0.36 7.24 0.24
Poor milk ............ 89.65 1.66 0.57 0.27 TAT 0.23

Each number represents the average of four analyses
taken several days apart. Each sainple came from a
young woman who had been confined a few months
before.

It has often been said that casein in human milk dif-
fers chemically from that of cow’s milk; but, as stated
above, according to the investigations of recent years,
there is good reason to believe that this is not the case.
(Hamimersten, Cohnheim.)

Sow's milk is thick, slimy and of alkaline reaction. In chemieal
composition it is very variable, especially so in regard to the fat
content which varies between 1.0 per cent. to more than 12.0 per cent.
In some of the analyses reported, it appears that a distinction has
uot been made in relation to the proportion of fat of the milk
that was drawn first and that drawn last, but since the other
ingredients of the milk were found in different proportions, the
variation can not be doubted. The quantity of protein averages
about 6.0 per cent. but may vary from 5.7 to 15.5 per cent. The
quantity of lactose varies from 2.0 per cent. to 3.8 per cent., the
ash from 0.77 per cent. to 1.18 per cent. On the whole, it may be
said that sow's milk is quite concentrated.

Bitch’s milk is also quite variable in its composition. The
fat content varies between 4.0 per vent. and 12.0 per cent., the pro-
portion of eascin between about 3.5 per cent. and 6.0 per. cent.,
albumin is present in about the same quantity as casein, there is
about 2.0 per cent. to 3.0 per cent. of lactose and about 1.0 per
cent. of ash.

The milk of the cat has not received much study. According
to some analyses that have been made (by Cornaille), it is of about the

26 MILK HYGIENE

following composition: fat 3.33 per cent., casein 3.12 per cent., albu-
min 5.96 per cent., lactose about 4.9 per cent., and ash 0.59 per cent.

The rabbit and the reindeer give milk particularly rich in fat and
especially concentrated, but poor in lactose. The milk of the
elephant shows very great fat and sugar content and comparatively
little protein.

A milk differing greatly from the usual is that of the whale.
Tt contains only from 41.0 per cent. to 48.0 per cent. of water, and
fat in the enormous proportion of 43.0 per cent. to 45.0 per cent.
There is 7.5 per cent. to 11.0 per cent. of protein and only about
1.3 per cent. of sugar.

The table below shows the average analysis of human
milk and of the other kinds of milk used as food for man:

| Cow. Goat. Sheep. Ass | Mare. | | oman.
Water oriccas chueee eo: | 87.75 | 87.30 | 75.54 | 91.20 | 90.00 | 87.92
Caseitt:sccccns sagen est | 3.00 3.00 5.83 | 0.90 | 1 1.26 0.58
Albumin.............. 0.50 | 0.50 1.33 0.60 | 063 | 0.52
5 ca ee 3.40 3.90 | 11.90 1.10 ; 1.09 3.48
Lactose ............00. 4.60 | 4.40 3.43 6.00 6.65 ' 7.12
Salts. ....00... cece ee 0.75 | 080 | 1.05 ' O40 O31 ) 0.25
|

IV. VARIATIONS IN THE COMPOSITION
OF COW’S MILK

It has already been stated that the composition of
the milk of the cow, as well as that of other animals, may
vary more or less. So far as the variations of cow’s
milk are concerned, they are not very great, still they
are of sufficient importance to make it necessary to
take them into consideration in connection with its pro-
duction, sale and control. The above figures give ap-
proximately the average composition of cow’s milk and,
of course, correspond with the composition of market
milk, which consists of a mixture of milk of several or
many cows.* The separate constituents vary in quantity

“These are Danish figures; in America the average for market
milk is higher. [L. P.]

VARBEATIOSS IX COV" ATER ai

in different degrees, the fat content varying the most,
the albumin, Jaetose and ash ingredients less. In
‘rich "milk the fat content often considerably exceeds
the average, while the proportions of protein and lac-
tose are never much higher than the averages given.
On the other hand, with thin, poor milk the fat per cent.
may fall far below the average, while the proportions of
proteim and lactose depart but slightly from the average.
These variations are not due merely to the elimination
of water from the milk, that is, to a simple concentration,
but rather to a qualitative variation in the activities of
the gland cells.

Just as is the case with other glands, the milk
glands may be stimulated to ereater activity, so that the
quantity of secretion increases, but its chemical eoipo-
sition is not disturbed, or only slightly, or temporarily,
until the gland tissue has accustomed itself to the
new condition. Drinking a large quantity of water
causes no increase Inmilk secretion; the eland cells do
not secrete more water than the quantity required to
maintain the proper proportion to the milk solids. Food
containing much water has no permanent effect upon
the composition and the quantity of the milk. The
influence of such materials as piloearpine and atropine,
which increase or reduce other secretions in a great
deeree, have no direct, or only a very slight influence
on the milk secretion, apparently because this is con-
trolled by the sympathetie nerve centres. The various
conditions that have, or are believed to have, an influence
upon the chemical composition, and especially upon the
fat content of milk, are considered in the following para-
graphs.

1. Breed peculiarities. (‘ows of different breeds
give milk of somewhat different composition. In gen-
eral, it is believed that breeds from the highlands and

28 MILK HYGIENE

mountainous regions give a richer milk, while breeds
from the lowlands yield milk poorer in fat. There are,
it is true, exceptions to this rule, e.g., the Allgauer and
the brown Swiss cattle give rather a poor milk, while
the Devons and the Normandy cattle give milk rich in
fat. As an example of breeds that give milk especially
rich in fat we may mention the Jerseys and the Guern-
seys, whose milk contains an average of 4.5 per cent.
to 5.5 per cent. fat, also the Harz cattle, whose milk is
reported to contain an average of 5.8 per cent. fat. On
the other hand, milk of the Swiss cows has only 3.0
per cent. fat, that of the Angler and Breitenburger and
other breeds only about 3.13 per cent. to 3.15 per cent.
fat. The average of the Danish breeds can hardly be
placed higher, being about 3.2 per cent. to 3.4 per cent.
fat.

2. Individual peculiarities. The figures given above
are averages only. The milk of different individuals
varies more or less so that in the same breed there are
individuals that give milk rich in fat, and also those
whose milk has a percentage of fat below the average
of the breed in question. The production of rich milk is,
therefore, a distinctly individual property that is due
to the physiological peculiarities of the gland cells of the
animal, and which appears, to a great degree, to be
hereditary. Among cows of the same breed may be found
some whose milk contains 4.0 per cent. or more of fat
and, on the other hand, there are many that give milk
containing only about 2.5 per cent. fat; indeed, not infre-
quently the percentage of fat is still lower, and from
Germany there are records of cows that give milk con-
taining not more than 1.5 per cent. of fat. Such cows
are frequently and in large numbers excluded from the
best herds, so when herds are made up of purchased
cows, the mixed milk from such cattle often contains but

VARIATIONS IN COW’S MILK 29

little fat and may not exceed 2.25 per cent. to 2.75 per
cent.*

Wlule it is scarcely possible, as will be discussed
later, to influence the composition of milk materially or
permanently by alterations in the quantity and com-
position of the food, still it may not be entirely impossi-
ble to influence the young animal by skilful or by
appropriate feeding in such a way as to encourage it
later to produce milk rich in fat. But thoroughly
reliable data on this point are not available.

3. The age of the cow. Although the quantity of
milk varies according to the age of the cow, so that it is
usually greatest during the third to the fifth lactation
periods, the chemical composition appears to remain
almost unchanged from year to year (Hittcher) ; yet it
is apparent that fats as well as other ingredients
decrease with great age.

+. The stage of the lactation period. The colostrum
secretion is not especially important. The true milk
secretion very quickly attains a considerable volume, but
falls off gradually after a longer or shorter tine. until
the secretion ceases altogether or is insignificant to-
wards the end of the period of gestation. Some cows,
however, continue to milk very well up to ealving and
to the new period of lactation. It was emphasized
above that colostrum differs essentially, both morpho-
logically and chemically, from normal milk. Further-
more, the composition of milk during the first part of
tlie lactation period differs from that secreted toward
the close.

a. Colostrum. The first colostrum is whitish, vellow-
ish, or even reddish to brownish; it is slimy and has a

*It should be borne in mind that the cattle here referred to
are of heavy milking lowland breeds not represented in America.

[l, P.]

30 MILK HYGIENE

specific gravity of 1.040 to 1.080. Its microscopic ap-
pearance has been described before and, in part, its
chemical composition. Gradually, the appearance and
the composition of the secretion changes until, in the
course of about a week, it becomes pure milk. This
gradual development is illustrated by the following
analysis given by Eugling:

Number of hours after calving.
Normal
ilk.
ae 10 | om | 48 | 7 a
Water sac ivi teas avaaes an Wi 78.77 | 80.63 85.81 86.64 87.75
CASEIN idsaisan.. eeandoanes 2.65 4.28 4.50 3.25 3.33 3.00
Albumin , a 9 sox ’ 3 5
Gitlin. (1808 16.56 9.32 6.25 2.31 1.03 0.50
Extractives ........... 3.54 4.66 4.75 4.21 4.08 3.40
Sugar acevscina ccnudenss 3.00 1.42 2.85 3.46 4.10 4.60
ABSIT ac curcenc ht ahec da uhiateg 1.18 1.55 1.02 0.96 0.82 0.75

These figures show that the chief difference in the
composition of milk and colostrum consists in the
greater albumin and globulin content of the latter, which
arises partly from the presence of numerous colos-
trum bodies, in consequence of the presence of which
colostrum coagulates when heated. Another important
difference is the low sugar content o/ colostrum; accord-
ing to Tereg the sugar of colostrum is not lactose, but is
grape sugar, or perhaps a mixture of this and galactose.
Of the substances that are extracted with the fat, about
13.8 per cent. consists of cholesterin and 8.0 per cent.
of lecithin.

Among other peculiarities shown by colostrum of the
cow may be mentioned its acid reaction and the fact that
after the addition of rennet it does not coagulate at all,
or only very slowly.

b. Wilk. Shortly after calving, while the secretion

VARTATIONS IN COW'S MILE ol

is abundant, the milk is generally a little less rich in
solids and especially in fat than it is later when the
secretion begins to fall off; with some cows the differ-
ence is not very great, but with others it is considerable.
In the last month the secretion falls off rapidly and
often ceases entirely; at the same time the proportion
of solids usually increases and this is especially the case
in relation to fat. The milk gradually acquires a decided
alkaline reaction to litmus paper and not infrequently
develops a salty taste. The changes in composition
are shown in the following table, which gives the results
of analyses, made by Fleischmann, of the inilk of one
cow which calved January 28th.

With this cow, the percentage of fat during the
period of lactation rose from 3.055 to 8.500; but this
significant increase occurred almost entirely in the last
month when the cow had become an old milker. At the
sume time the quantity of albumin, lactose and salt
(i.c., solids not fat) increased only from 8.14 per cent.
to 9,00 per cent.

The chemical composition of milk of some cows does
not change noticeably during the whole period of Tac-
tation, and the percentage of fat as well as the other
solids may even fall off a little at the end of the lactation
period. Fleischmann gives a table showing analyses of
the milk of such a cow for the whole lactation period:
the daily quantity of milk in April was 19.5+ kg., on the
31st of January following it was 3.6 kg. The fat per-
centage, which had varied between 2.56 and 2.97, fell in
January to 242. 2.60, 2.32, and 2.48 upon different
analyses. The percentage of solids not fat also fella
little.

5. The time and method of milking. It is commonly
believed that there is always a slight difference between
the chemical composition of the morning and the even-

32 MILK HYGIENE

ing milk in that the latter is richer in fat than the for-
mer. Numerous investigations have given very varia-
ble results that may be explained by the short duration
of the test, by the daily variations of the composition
of the milk, ete. Some larger experiments relating to

LACTATION PERIOD

Daily - Solids Fat content
quantity Specific Fat. not fat. of the total
of a gravity. Per cent. Per cent. Baia

April sey ceaeeaes sewer 11.55 1.0291 3.033 8.140 27.15
Mig scedin cosa aoeu teats 11.95 1.0290 3.264 8.166 28.56
JUTC? ais 5 tS doe as Siar 10.45 1.0287 3.405 8.113 29.56
DU Se die sadn aaa anes 8.82 1.0283 3.458 8.027 30.11
ANU BUS be eice- sites see cana 9.66 1.0287 3.586 8.149 30.57
September. .......... 9.07 1.0289 3.650 8.230 30.72
October ses wesvae dsdwe 7.67 1.0292 3.434 8.247 29.39
November ............ 6.63 1.0299 3.823 8.501 31.01
December............. 5.11 1.0300 4.267 8.616 33.11
JaAnWMary Ves esdus alae 3.0 1.0302 5.050 8.823 36.40
VANUALY Be2sa2ce ganas 2.7 1.0300 5.400 8.843 37.91
January 4............ 2.8 1.0299 4.720 8.680 35.22
January 6............ ' 2.3 1.0307 5.470 * 9.082 37.71
January “Pes sayeea sland 2.4 1.0299 5.440 8.824 38.14
sanuary Sys cesceseges 2.3 1.0304 5.250 8.911 37.07
Jantary Sys vesesaceys 2.3 1.0310 5.200 9.054 36.48
VRNUELY TWO. yacwen ews 21 1.0308 5.090 8.980 36.17
January 11............ 22 1.0308 5.100 8.982 36.22
January 1l4............ | 1.9 1.0277 6.900 8.565 44.60
JanUary [Wsoswsccwrge 1.3 1.0301 8.300 9.446 46.77
January 18............ 14 1.0288 7.480 8.958 45.50

many animals and extending over a long period, have
proven that the morning milk does not differ from the
evening milk in fat content when the period between
the milkings is equally great and the feed, the amount
of drinking water taken, etc., are the same. But in prac-
tice this is not the case, because usually a small dif-
ference exists, so that where there is a larger quantity

VARIATIONS IN COW’S MILK 33

of milk there is a smaller percentage of fat. Fleisch-
inann found hy continuous investigations of one herd of
120 to 130 cows during one year, that on the average for
the whole year the morning milk contained a little more
fat than the evening milk (3.260 per cent. against 3.183
per cent.), while the quantity of morning milk was a
little less than that of the evening milk (4.143 kg. against
4.616 kg.).

There is a slight difference dependent upon the sea-
sons; it has been shown that in the summer the morning
nulk contains a slight excess of fat while in the winter
the evening milk is the richer. It follows that since the
quality of milk is influenced hy external influences, there
can be no general rule to define the difference between
morning and evening milk but, usually, if no other con-
ditions arise, this difference is comparatively small.

It is commonly believed that three milkings a day
cause not only the production of a greater quantity
of inilk, but also a somewhat greater percentage of fat,
but it can scarcely be said that there is definite proof of
an increase in the percentage of fat.

If the milking is done by a strange or inexperienced
person, the flow is diminished. This also influences the
quality of the milk. The first and the last milk drawn
differ greatly in fat content. It is supposed that the fat
globules adhere firmly to the walls of the duets, as a
layer of cream, and are freed from these only with dif-
ficulty. The following figures show the results of
analyses by de Vriezes, who found in the first streams
12 per cent. fat; after drawing about one-quarter the
quantity of milk, 2.1 per vent. fat; after drawing about
one-half the quantity of milk, 3.6 per cent. fat; after
drawing about three-quarters the quantity of milk, 5.2
per cent. fat; in the last milk. 7.1 per cent. fat; in the
very last drops of milk drawn, 10.0 per cent. fat.

3

34 MILK HYGIENE

Therefore, by milking a single cow, one can obtain
milk of the greatest variety of fat content, which must
be considered when samples are taken from individual
animals for the purpose of examination. According to
Hittcher’s investigations, the situation seems, singularly
enough, to be wholly changed if the calf is permitted to
suck the cow; the milk that remains is not rich, but is
much poorer in fat.

Fats. Percent. Solids not fat. Per cent.
Number of the
cow.
Minimum. Maximum. Minimum. Maximum.

1 2.621 4.698 7.859 8.771
2 2.160 3.404 7.293 8.707
4 2.163 3.965 7.702 8.743
5 2.543 3.900 7.636 8.577
6 2.096 3.446 7.753 8.893
7 2.257 3.837 7.974 8.914
8 2.690 4.117 7.943 8.897
9 2.566 4.709 8.197 10.050
10 2.464 6.000 7.728 8.939
i 2.741 4.649 8.305 9.371
12 2.509 5.505 8.582 9.550
13 2.645 4.724 8.389 9.623
14 2.097 4.173 8.394 9.131
15 2.437 4,234 8.031 9.046
16 2.326 4.637 8.040 9.363
18 2.537 4.390 8.098 9.170

The opinion expressed in recent years, that by
a special method of milking the average fat percent-
age of milk of mdividual cows may be raised, is in-
correct.

6. Daily variations. Daily examinations of milk of
individual cows show that not only the quantity of milk
undergoes change from day to day, but, at the same

VARIATIONS IX COMMS ALLE 30

time, strange to say, the chemical composition of the
milk is subjected to daily variations that may reach
considerable extent. Knowledge of this is naturally of
the greatest importance in the detection of milk adul-
teration. The table on page 34 is given by Fleischmann
to show the minimum and maximum fat percentages in
the milk of a series of cows examined daily during an
entire period of lactation.

As is shown, the percentages of fat differ consider-
ably even in milk from the same cow; one cow, number
12 in the table, produced milk differing in fat content
as much as 100 per cent., that is, from 2.509 to 5.505 per
cent.

Cow No. I. | Cow No. V. Cow No. VIL. Cow No. VITE.
3.214 3.040 2.566 | 3.591
2.869 2.825 is ateds 3.592
28nd 3 322 3.080 | 3.244
2.862 nae 3.314 2.932

nate 3.043 2 gee 2790
3.24 3.790 2.329 3.047
3.070 2.996 2.308 ee
2.847 3.369 2.616 ; 2.816
3.685 3.272 3.334 3.199
3.749 3.189 3.381 3.732
4.031 3.267 3.402 3.620
3.927 3.068 3.316 3.522
3.792 5.795 3.344 | 3.492
3.844 3.470 2.970 | 3.633

The variations are not always gradual, but occur
spasmodieally, as is evident from the figures above,
taken from Fleischmann’s work on milk. The numbers
in the perpendicular columns give the percentage of
fat for successive days; the figures above the dividing
line date from the beginning of the lactation period of
the cows, while below the line the figures given refer to

36 MILK HYGIENE

the end of the milking period. The examples are chosen
in order to make plain the daily variations with the
individual animals.

One inay find even greater variations by examining
the morning and evening milk. As examples, some re-
sults are given from the daily examinations of milk from
the above mentioned cows number I and number V, the
figures referring alternately to the morning and _ the
evening milk on successive days:

Cow No. 1. Cow No, V.

MOMs ac2cceuatanee cians eae Yeon. 3.180
BYCning 2 os cinix tak ew temragine aan eO40 2.940
MoTning ncccess ewicns cea Shenae. aed 3.240 2.710
HOMENING is tas Galcnae siege Sauane lg eee el 3.995 2.900
Mornings ecavey aden cxgris eels ieee 4 See 2740
HVGHING: v5 eae cede ane se dees Sede ae 3.700
Moning: Joys ann anetGaien raceebene 3.800 —
OV CWING, c.acci-oncapen tees Canes wa icals 3.250

MOP.» 2ch.ius ied Geode aoe ae 4.100 2.360
INVENIN GS 5 ay vaitin scene chan neers 3.815 3.560
Morning: jeauseag eaes peewee ese o4 oe 4.145 4.530
PVOnING 45.9: 444-8 25954 ¢4vudusee ges 6 3.485 3.180
MGEMIN GS 5 cose ceas n hio vad guangaetielels Uh dun 4 eg 4.085 3.220
VINGMINGE 2 ais: cede Reale Merny aa eaR nem 2.785 2.800
MORNIN Gins weagcereteee mhaee aeons 5.690
FENOTIN Ba cs dedaks a Pees e carte saqcncueBuO9O 3.100

The changes in the quantity of solids not fat (protein,
lactose and salts), as is apparent from the above tables,
are much less than those of the fat, and especially do
lactose and salts vary but little.

The reasons for these dail) variations in the quan-
titative composition of milk are not yet wholly under-
stood, but are to be sought in everything that in any
way has an unfavorable influence on the animal; changes
of food (see below) or of the times of feeding and drink-
ing, changing to a strange place, restlessness in the sta-
ble, storms, cestrum, changes at milking, ete. Very often
no definite reason can be discovered and it appears that

VARIATIONS IN -COW'S AIDE 37

such variations may take place without external causes.
With cows that have suckled their calves, after separa-
tion from the calf, there is usually a very noticeable de-
crease of fat in the milk, which is sometimes made good
by a subsequent considerable temporary increase.

7. The influence of food. It is an old and, in some
places, still commonly accepted opinion that the compo-
sition and the quantity of the food have an important
influence on the composition of the milk and more espe-
cially on its fat content. Paln and cocoanut meal and
several other food stuffs, are said to encourage the pro-
duction of rich milk, while, on the other hand, distillery
slops, for example, are said to cause the production of
poor milk. During recent years, numerous investiga-
tions undertaken abroad as well as in the experimental
laboratory in Copenhagen, seem to have proven that it
is not possible by changes of food to bring about a
noticeable permanent effect upon the composition of the
milk. The activity of the udder cells, as is shown from
the daily variation in the composition of milk, is easily
thrown out of equilibrium, but such a condition is only
temporary. With changes of feeding, this condition
appears quite plainly, nearly every change very
quickly causing a variation in the composition of the
milk, especially the fat percentage, so that sometimes
this rises, sometimes, ¢.g., When distillery slops and simi-
lar moist foods are fed, it falls off more or less. But
this variation always seems to be merely temporary : in
the course of a day or so, sometimes, however, not until
the end of a couple of weeks, the average percentage
returns. This is the case even when food of only one
kind, as distillery slop and, indeed, when food especially
rich in fat, is fed; in these eases, also, the change in
percentage will be only temporary (Henriques and C.
TIansen).

38 MILK HYGIENE

To be sure, there are many reports in print of
other results, but upon examination these are found to
extend over so short a period that the temporary
changes had not yet disappeared, or they refer to inves-
tigations with different cows whose milk was not suf-
ficiently examined, or to cows that did not receive the
same food in the beginning of the experiment, or, finally,
sufficient allowance was not made for the daily varia-
tions and for those that occur at different stages of the
lactation period.

The temporary changes in the composition of milk
which oceur after a change in the food, may be consid-
erable, but here, too, the question of individual peculiari-
ties enters, so that the changes shown by two cows under
the same conditions may differ materially.

It is of an old belief, that the change from dry food
to green causes an increase in the fat content of the milk.
The investigations in the Danish experimental labora-
tory have proven this; they show that the fat percent-
age under these conditions may increase 0.5 per cent.,
with some cows it increased even 1.0 per cent., but this
increase lasted only a few weeks. Also, when changing
the ration to include some of the oil cakes, a similar
increase in the percentage of fat has been observed, but
seldom more than about 0.5 per cent. On the other
hand, as stated before, there are observations of tem-
porary falling of the fat from 0.25 per cent. to 0.5 per
cent. when a change of food is made to distillery slops
or similar rations.

It is, then, possible to show that the udder reacts
rather characteristically to certain changes in the ration
and especially to some food stuffs; but this reaction is
lost when the cow has become accustomed to the new
food. Under such conditions, simultaneously with the
increase of the fat percentage there frequently occurs a

VARIATIONS EN COW'S MILK 39

decrease in the quantity of milk, while, on the other
hand, a lessening of the percentage of fat is often accom-
panied hy an increase in the volume of the milk.

Although recent experiments have thrown much
light upon the influence of food on the milk secretion, yet
there is need for further information on many points.
For instance, it is not known with certainty if it is pos-
sible hy long continued, particularly unfavorable, one-
sided composition of food, to produce lasting changes
in the fat content of milk and in the solids not fat.

Lactose occurs in milk in but one form and the char-
acter of proteids is not affected by the nature of the
foods. On the other hand, the milk fats vary, sometimes
there is more and sometimes less olein, which affects the
consistency of the butterfat, and the percentages of vola-
tile fatty acids may vary considerably. It has often been
said that the fats taken with the food do not pass un-
changed into the milk. Only when a great quantity of
food, rich in a kind of fat that can be distinguished
chemically, is fed, is if possible to find small quantities
of that fat in the butterfat of the milk.

But little is known positively concerning the causes
of the variations in the composition of the butter-
fat and especially eoneerning the influence of the food
upon it. The milk fat may originate in the fatty tissue
of the animal, from the fat stuffs taken with the food
and, apparently, also, direetly from the carbohydrates
consumed. There are a number of other conditions,
as the composition of the ration, excessive feeding
with fatty foods, starvation, ete., that have some in-
fluence in this direction but, as they are of no sanitary
importance, it is unnecessary to discuss them here in
detail.

It is generally believed that odors and tastes pass
from the food that is consumed into the milk. The

40 MILK HYGIENE

milk of the Alpine cows is noted for its aromatic
taste. Feeding with beet leaves, turnips, malt sprouts,
ete., is supposed to be the cause of the taste and odor of
beets or a burnt taste and odor in the milk. We do not
yet know how much influence is to be attributed to the
food. In some cases, the offensive odor and taste is
undoubtedly due to the activity of bacteria in the milk—
indeed, it is doubtful if the ‘‘ beet taste ’’ and the ‘‘ burnt
taste ’’ ever come from the food (see below). Peculiari-
ties of breed may possibly be the cause of the aro-
matic milk of the Alpine cows. On the whole, it is
highly probable that the food has some influence on the
taste and odor of the milk [this is unquestionable in the
ease of garlic,] but by no means all of the substances in
milk that have special odors and tastes are secreted
with the milk,

The ash ingredients of milk are not generally influ-
enced to a great extent by the amount of salts taken
with the food; even a considerable iron or phosphorie
acid content of the food causes no direct increase of
these materials in the milk; still, certain sulphates, as
Glauber’s salt, given in large quantities are excreted in
small quantity with the milk, and consequently cause
an increase in sulphuric acid in the ash.

While it is true that feeding influences the compo-
sition of milk only to a slight degree, it is nevertheless
true that the quantity of milk is dependent to a very
great degree on the amount and composition of the food.

8. The significance of sexual conditions. The occur-
rence of cestrum and pathological conditions of the
generative organs cause a decrease in the milk secre-
tion; therefore it has been assumed that these conditions
may also cause changes in the chemical composition of
the secretion, vet this does not always appear to be the
case.

VARTATIONS IN COW'S ALEK 41

a. Wstrian has a very different effect on the milk
secretion of individual cows. Kiihn found no effect, but
von Kleuze found such a great albumin content that the
milk could not he boiled, and Schaffer established a
remarkably high fat content. On the other hand, Fleisch-
mann found only 0.714 per cent. fat in the evening milk
of a cow that had come in heat in the course of the day,
though the morning milk contained 3.56 per cent. fat.
On the whole, it may be said that normal cestrum often
induces a passing disturbance of the normal secretory
activity of the udder,

b. Nymphomania, which has no slight influence on
the nature of the meat, and reduces the milk secretion
considerably, probably influences the nature of the milk
also. Only a single analysis of such milk is given by
Schaffer; the quantity of fat and lactose liad not
changed, but the quantity of protein was remarkably
high, namely, 5.72 per cent.

e. Ovariotomy. Asis known, it is frequently claimed
that spaying performed on healthy cows during the first
months of the lactation period causes a considerable
lengthening of this period, an inereased daily sceretion,
and greater fat content of the milk. Tlowever, it ean
hardly be said that this is sufficiently established; and
especially, it is not to be considered as proven that
ovariotomy is able to raise the fat content; in faet it is
most dmprobable. Ovariotomy performed on uympho-
maniac cows causes, among other things, the possibly
abnormal milk secretion to return again to normal.

d. wfbortion, The experiments that were conducted
by Schaffer and Hess have shown that abortion, whieh
has such great influence on the quantity of milk, has no
influence on its composition. The same statement ap-
plies to the retention of the afterbirth, in so far as this
causes no general illness,

42 MILK HYGIENE

9. Exercise and work. According to a number of
different experiments at hand (Dolgich, Torssell, and
several others) daily exercise increases milk secretion
so that not only the amount of milk increases, but also
the total quantity of fats. Sometimes, indeed, the per-
centage of fat increases, and, as a rule, the percentage of
casein diminishes, while the other constituents are
affected irregularly.

Work does not necessarily influence the milk secre-
tion to a great degree (Morgen), but generally causes a
slight diminution in quantity and there is an increase in
the percentage of fat and a proportionate but smaller
increase in the percentage of protein and ash. HExhaust-
ing work causes not only a material decrease in the
quantity of milk, but also a disturbance in the whole
secretion, so that even vegetable fats are excreted in
the milk in unchanged condition (Dolgich).

10. Disease of the cow often brings about a decrease
and sometimes even an entire cessation of the milk
secretion. In diseases of the udder, the milk under-
goes, as will be seen later, very important chemical
changes. There is very little positive knowledge of
the changes in the composition of milk during diseases
that are not localized in the udder. Apparently, it is
usually the rule that the daily variations in the composi-
tion increase, or, in other words, that the secretion is
thrown out of equilibrium. Frequently, in the beginning
of disease, there is found an abnormally large pecentage
of fat that results from the often sudden decrease of the
quantity of the secretion. <A salty taste which occurs not
infrequently, might possibly mean an increase in the
quantity of protein and ash (secretion of blood serum).
According to long-standing opinion, milk has an abnor-
mal taste in cases of indigestion of all sorts and under
these conditions it also curdles easily.

VARIATIONS IN COWS ATILK 43

11. Medicines. It is an old opinion that a number
of different medicines help to increase the milk secre-
tion and the fat content of milk, and for this reason, so-
called ‘‘ milk powders ’’ are still used. The different
materials (fennel, anise, caraway, calamus, bitters, sul-
phur, antimony compounds, ete.) cannot change the
secretion of normal animals, and it ix doubtful if they
are able to recall the milk secretion after it has been
checked through disease.

Other medicines as quinine, belladonna and alu, are
supposed to he able to check the secretion as, also, rub-
bing the udder with opodeldoc, oil of rosemary and the
hike; but their action is questionable. Drugs like iodine
and phosphorus, that act especially on gland tissue,
are able to check the secretion or cause it to stop alto-
gether. The excretion of medicines in the milk will be
considered later.

Summary. Irom the above, it is evident that the
gland cells of the udder of cach cow are adjusted to
secrete milk of a rather definite chemical composition
which, however, changes during the lactation period, but
that these cells react to a number of different influences
as a result of which they may temporarily secrete milk
of a somewhat changed composition.

As would be expected, the limits for the variations
in the composition of cow's milk are reported ditfer-
ently, but milk of a composition that is not included in
the limits below is indeed very rare.

Water Casein Albumin Fat Lactose Ash
SS—she PHS. OBY-ONs PA—ATHs 4-95.85 0.35—1.21%

It appears that the fat content 1s subject to great
variations; but, if we leave out of consideration old
milking cows, these variations are much less. The
quantity in milk of solids not fat (casein, albumin, lac-

44 MILK HYGIENE

tose and salts) is far less variable. This applies espe-
cially to lactose, which seldom shows the given mini-
mum and maximum percentage. In the detection of
adulterations, the percentage of lactose furnishes, there-
fore, a better guide than the percentage of fat.

By mixing the milk of the members of a herd, the
individual variations in composition are more or less
equalized, so the composition of the whole quantity
approaches the average for cow’s milk. There are,
however, some herds in the milk of which the percent-
age of fat is much higher than in others; this is a matter
of selection or of breed, so, of course, the composition
of milk of separate herds will not be the same. As cows
usually calve at certain seasons the number of fresh
cows and old milkers is not the same at all seasons and,
for this reason, the composition of the milk changes.
We have the following figures showing the average per-
centage of fat as found upon daily analyses of milk
from three large herds.

February May August November
a. 3.18 ael2 3.61 BAT
b. 3.69 3.56 3.04 BT
G 3.03 3.38 B51 3.32

In herds a and c¢, particularly, calving is distributed
unevenly, which causes the percentage of fat to be 0.5
per cent. lower in winter than in summer.

Many of the external influences that have been men-
tioned as applying to the individual animal and that
result in a temporary change in the composition of the
milk, may apply, at the same time, to all of the animals
in a herd and thereby influence the fat content of the
herd milk. This is seen when there is a change of food,
disturbance in the stable, storms, extreme heat and so
on. However, variations in the composition of the entire
quantity of milk caused in such ways are, in most eases,

CHANGES IN THE SECRETION 45

less than those of single animals, for all members of
the herd are not affected in the same degree and quite
often the animals react in opposite ways under the same
circumstances so that these variations are, in part, equal-
ized after the milk has been mixed together. The larger
the herd, the smaller the probability of all its members
lhemg influenced in the same way at the same time—
and, therefore, the variations from the normal will be
so much less. For the same reason, the variations are
considerably less when the milk of several, but always
the same, herds, is mixed.

So far as we know, there are no data in Denmark
concerning the limits of the composition of normal mar-
ket milk, and these are not sufficiently established in
other places—yet it may be assumed that the specific
gravity does not vary beyoud 1.029 to 1.034, the content
of solids not fat does not exceed 8.6 to 8.8 per cent., and
the fat varies from 2.75 to 3.5 per cent. "

V. CHANGES IN THE SECRETION DURING
DISEASES OF THE UDDER

Diseases of the udder that cause material changes in
the character and the composition of the udder secretion
are: udder contusion, udder cedema, embolism and
thrombosis, mastitis, udder tuberculosis, udder actino-
mycosis and tumors.

1. Contusions of the udder and the teats which fre-
quently are caused by cuffing and blows and hy kicking
and tramping by other cows, éte., produce hemorrhage
of the udder tissues, bloody serous infiltration, or,
possibly, death of the udder tissue. The changes in

‘Jersey herds, ete., not included.

“The figures given above relate to Danish cattle, practically
all of which are of two breeds which furnish milk containing a
much Jower percentage of fat than is furnished by most of the
herds producing market milk in Ameriea. [L. P.]

46 MILK HYGIENE

the secretion consist, in part, of an admixture of blood
plasma that is usually invisible and, in part, of blood.
The latter may appear in freshly drawn milk as drops
of blood or as little clots. When more bleeding occurs,
the milk is liable to be diffusely colored reddish and it
will color the milk from the other quarters, and even
colors the milk of other cows reddish when mixed with
it. This admixture of blood cannot be proven by the
common guaiae method, for fresh milk will give the
same reaction. The proof is most easily gained by
means of microscopic examination of the sediment
obtained by centrifuging the milk, whereupon the red
blood corpuscles are easily recognized among the milk
globules.

2. Udder edema. It may be supposed that in udder
cedema, which frequently is very severe soon after calv-
ing, there is an admixture of transudate with the secre--
tion, but, so far as known, no investigations have been
made in regard to this matter.

3. Embolism and thrombosis occur occasionally in
the udder and cause gangrene of a gland or of a part of
one; frequently there is gangrene of the skin and of the
teat of the quarter affected. Milk secretion ceases and
in its place there is a bloody serous exudate.

4. Mastitis. Inflammations of the udder cause quite
characteristic changes in the secretion, which often stops
entirely to give place to a purulent exudate.

a. Mucous catarrh. When drawn, the milk contains
small yellowish flakes and lumps which, upon standing,
unite into a slimy, dirty, grayish sediment or, together
with the cream, form a lumpy, dirty colored layer on the
top of the milk. In severe attacks the secretion may be
viscid, slimy and sticky.

b. Purulent catarrh. In the beginning, the secretion
is unchanged but for the presence of small flakes of pus

CHANGES IN THE SECRETION 47

and fibrin. The milk secretion decreases more or less
quickly while the pus cells and fibrin increase in number
and, finally, the secretion is replaced by a viscid, whitish
or yellowish purulent exudate or by a quantity of yel-
lowish serous exudate which contains clumps of pus and
fibrin. In many cases, the udder shrinks and the exuda-
tion ceases without the return of the milk secretion; in
other cases, milk secretion returns either during the
same period of lactation or after the birth of the next
calf. In catarrh of the udder, lactese decreases in quan-
tity while the other ingredients—except asl—undergo
no quantitative change in the mildest cases. Among the
ash ingredients, phosphoric acid, lime, magnesia and
potash decrease materially in quantity, while sodium
chloride occurs in more than normal quantity. In cases
when the secretion is mixed largely with exudate, the
quantity of lactose still further decreases and the casein
content drops, while albumin and globulin (also fibrin)
increase.

e. Parenchymatous mastitis. The changes in the
secretion correspond essentially with the changes in
purulent catarrh, but they occur very suddenly and may
disappear as rapidly. The chemical analysis shows
changes similar to those in eatarrh; the lactose often dis-
appears entirely, while the albumin and globulin in-
crease greatly in quantity. The fats may increase or
decrease, the salts change as in eatarrh.

d. Gangrenous mastitis. The real milk secretion
ceases while a bloody-serous liquid is secreted which, on
account of the existence of bacteria of putrefaction, is
frequently mixed with gas and has the odor of putre-
faction.

The chemical changes that take place in mastitis
are mainly traced to partial or entire cessation of the
real milk secretion and to a simultaneous elimination of

48 MILK HYGIENE

an exudate having a greater or less admixture of pus
cells.

e. Udder tuberculosis. In many cases, the secretion
remains almost imperceptibly changed for a long period,
as only very small flakes are intermixed with it. Later
on, it decreases in quantity, grows thinner and contains
more flakes, and, finally, it is yellowish or reddish, se-
rous, contains clumps and flakes and becomes more like
pus. Chemically, the milk gradually undergoes the same
change as in cases of other forms of mastitis (Storch).

f. Actinomycosis and tumors of the udder no doubt
cause changes in the appearance and the composition of
the secretion, but no investigations have been made on
these subjects.

In mastitis, tuberculosis and actinomycosis of the
udder pathogenic bacteria are found in the milk; these
will be discussed later.

VI EXCRETION OF FOREIGN MATTER
WITH THE MILK

The milk glands may serve to excrete foreign mat-
ter which, in some way, has found entrance into the
organ, just as the kidneys and other glands do. Such
an excretion does not take place to as great an extent as
was formerly believed, which, considered from a biologi-
cal standpoint, seems most natural, for the excretion of
foreign matter would prove a great danger to the young
animal dependent on its mother’s milk for food. Yet
there are not a few, and sometimes very harmful, sub-
stances that are excreted from the organism through the
udder and, therefore, it is one of the problems of milk
hygiene to prevent the milk of such cows as are affected
in this way, from being used, just as the physician must
always consider, in the treatment of mothers and wet
nurses, what influence medicines to be given may have
on the nursing child.

EXCRETION OF FOREIGN MATTER = 49

Reports differ as to what foreign substances are
excreted with the milk. These differences of opinion
may be accounted for in part by the fact that many sub-
stances are not excreted in noticeable quantity until the
animal has taken relatively large amounts of them.
Sometimes individual peculiarities operate, for it may
be that some inflammation not entirely healed, local
induration or similar changes in the tissues of the udder,
in short, the injuries that remain after mammitis, favor
such an excretion.

It has been mentioned before that the milk contains
only traces of iron, and this fact alone is a proof that
iron compounds are not usually excreted with the milk;
even after the consumption of a great quantity of iron
during a long time, the iron content does not rise. (on-
cerning other metals, compounds of copper, lead and
antimony? are excreted only in very small quantity, so
that even a prolonged adininstration of these substances
to mileh cows usually brings about no harmful effects.
According to investigations by Baum and Neeliger, the
lead content of milk does not increase beyond 0.0009 to
0.002 per cent., even after treating cows with large doses,
and this quantity is without importance, even to quite
small children.

On the other hand, mereury is easily excreted
through the udder, when this substance is taken through
the digestive organs or when absorbed after applications
to the skin. Todine and arsenie also easily enter the milk
in considerable quantity.

Opinions differ concerning alkaloids. It is a fact,
however, that morphine, strychnine, atropine and vera-
trin are, under certain circumstances, excreted with the

7In the older Hterature, there are recorded a number of observa-
tions which indicate that tartar emetie may be exereted with the
milk in large quantity

4

50 MILK HYGIENE

milk in such large quantities as to be dangerous to chil-
dren. Other substances which can easily be excreted
with milk are salicylic acid, earbolic acid, aloes, croton
oil and senna, also the active principles of colchicum,
hyoseyamus and euphorbium. This is also supposed to
be the case with mustard; still there is good reason to
believe that it is true only if mustard is taken with the
food in large quantities.

It has often been observed that diarrhoea occurs in
people who have used the milk of cows fed upon food
that is moulded, or that has undergone putrefactive
fermentation. It is presumed, therefore, that some of
the substances which are formed under these conditions
in the food materials of the cow may be excreted with
the milk. But it is possible that in such cases there is
contamination of the milk from the food during milking
and so, in this way, bacterial changes may occur; these
have not been entirely excluded.

It was stated above that aromatic substances in for-
age plants are apparently excreted in slight quantity
and may give a ‘‘taste’’ to the milk. [The garlicky taste
that is so common in milk in the Spring in the Hastern
United States is due to garlic in the pastures.] We find,
too, that strongly smelling medicines (asafcetida, ether,
certain volatile oils, but not all) that are given to the
cows may impart a taste to the milk.

It is highly probable that toxic substances which are
formed in the organism during disease, and also such
substances that, for example, are reabsorbed from the
uterus, may sometimes be excreted in the milk, but there
is no definite information on this subject. On the other
hand, we know that antitoxins are in part eliminated
from the blood of the mother animal through the udder
and, through this channel, they may be used by the young
to its benefit.

CHANGES IN MILK ol

VII. CHANGES IN MILK CAUSED BY
MICRO-ORGANISMS

Milk found in the glandular passages and cisterns of
the healthy udder is usually sterile. On the other hand,
the ducts of the teats and, still more, the ends of the
teats usually contain bacteria and, therefore, the milk
when drawn is infected with them. This is more apt to
he the case when the milk comes in contact with the
hands of the milkers, or when it is poured into the not
always sterile bucket, or when particles of dirt and dust
from the udder or the skin of the cow, from the clothing
of the milkers or from the air, drop into the milk.
Before the milking is finished, a considerable number of
different bacteria have been added to the milk and
though, for a time, it has bactericidal properties, that
is, It is able to kill bacteria or, at least, to prevent their
growth, vet the number of bacteria does not diminish
noticeably but, in the course of time, imereases enor-
mously. Shortly after milking, thousands, even hun-
dreds of thousands, of bacteria may be found in each
cubie centimetre.

In inflammatory processes, eatarrh, tuberculosis and
ectinomycosis of the udder, infected wounds at the open-
ing of the teat, ete., bacteria are more or less numerous
in the milk before it is drawn. In benign udder inflam-
mations bacteria disappear almost entirely with the
cessation of the disease, but oceasionally it happens that
the bacterial growth continues for a time in the milk
contained in the glandular passages, after the seeretion
has become apparently quite normal and after all signs
of inflammation have disappeared.

In general infections, not localized in the udder, as
a rule no microbes are excreted with the milk. An excep-
tion to this is foot-and-mouth disease (aphthous fever),
in which the milk of the affected cows often contains vir-

02 MILK HYGIENE

ulent material, the nature of which is not definitely
established. During this disease, several noticeable
changes occur in the milk and it is, therefore, very prob-
able that pathological processes take place in the cells,
of the gland and so an excretion of virus is only to be
expected. In other acute diseases, as anthrax, hemor-
rhages may occur in the tissues of the udder and the
admixture of bacteria from the blood follows naturally.

The changes in the milk caused by microbes, and par-
ticularly by bacteria, which comprise by far the greatest
number of micro-organisms of milk, are very numerous.
These are most readily studied by working with sterile
milk (the best way is to use milk which was taken from
the udder in sterile condition, for milk undergoes quite
essential changes when heated) and with pure cultures
of bacteria. The most important changes are the
following:

a. The milk is unchanged in appearance, reaction,
odor and taste in spite of bacterial growth.

b. The bacteria form alkali (probably ammonia) ;
the reaction grows more and more alkaline and when,
after some time, a certain alkalinity is reached, the fat
is saponified, the neutral casein-lime compound becomes
a base and, as a result of this, the milk is changed to a
yellowish translucent, whey-like liquid.

c. The bacteria split up the lactose, forming acid.
The main product of this division is lactic acid, some-
times d-lactic acid, sometimes l-lactic acid, sometimes a
mixture of both, i-lactic acid. The reaction may be ex-
pressed by this formula: C,,H,,0,,+H,0O—4(C,H,0O,).
In fact, however, this process is far more complicated
for beside the lactic acids, a number of other com-
pounds are formed in small quantity as by-products:
alcohol, valeric acid, acetic acid, succinic acid, carbonic
acid, ete. After a certain amount of free lactic acid has

CHANGES IN MILK 53

been formed, coagulation of the casein occurs—at room
temperature—which either is precipitated as flakes or
thickens to a firm, jelly-like substance (curdling of
milk) and frequently contains small gas bubbles. At a
higher temperature, coagulation occurs in the presence
of a smaller percentage of acid. If coagulation is caused
by acid, alone, the process unquestionably is a simple
separation of the casein-lime compound by which the
casein, insoluble in water, is precipitated unchanged.
When the casein is filtered out and treated with lime
water, it dissolves readily. In heating sour milk to 70°
C. and above, a real coagulation will occur, however, and
the precipitated casein cannot be dissolved in lime water.

After the formation of lactic acid has reached a cer-
tain degree (about 0.8 per cent., which corresponds to
an amount of acid in 100 c.c. of milk that requires for its
neutralization about 100 ¢.c. of a one-tenth normal solu-
tion of Na.Q), the activity of the bacteria ceases, for
they cannot thrive in the strongly acid liquid, and the
greater number of bacteria rather quickly perish. The
different bacteria and yeast fungi which may be the
cause of lactic acid fermentation, are not sensitive to the
same degree of acidity, and under the influence of these
various forms, the milk becomes sour irregularly. These
various organisms are influenced very largely by exter-
nal conditions, in respect to their ability to produce
lactic acid, so that sometimes a longer and sometimes a
shorter time is required to sour milk, while, in other
cases, their ability to produce this change is almost lost.
Of the micro-organisms which ean produce a lactic acid
fermentation, are to be considered the lactic acid bacte-
ria used in creameries (a group, the various species of
which have not been definitely differentiated), certain
veast-like fungi (Saccharomyces lactis and Saccharo-
myces acidi lactici) the Bacillus coli communis, strep-

o¢ MILK HYGIENE

tococci and the pyogenic staphylococci. Some of these, ~
in addition to producing an acid, develop a ferment
which has an action somewhat similar to that of rennet
(see below).

d. Bacteria may form a rennet-like ferment which
causes the milk to form a coagulum of the consistency of
jelly, without souring. The ferment, which can be iso-
lated comparatively easily from many bacteria, has
effect in the same manner and under similar conditions
as chymosin. The precipitated casein cannot be dis-
solved again by treatment with diluted lime water, and
it may be assumed that the ferment has produced a
change of the casein into paracasein, whose compound
with lime is not soluble, as is well known. A great
number of bacteria are known which change the milk in
this manner; for example, forms that belong to the
typhoid-colon group, many bacilli that are included in
the large group of spore-bearing hay bacilli, among
them those named by Duclaux, Tyrothrix tenuis, scaber,
filiformis, ete. Bacilli belonging to this last group are
often found in milk, because they are usually frequent
in the soil and dust and in the exerement of the
cattle, so that they always find their way into the milk
when it is drawn. The bacteria under consideration
have different influences on the milk. While some,
apparently, only cause the milk to curdle (they also
separate, at the same time, small quantities of albumose-
like substances—probably caseoses and peptone), others
are able to redissolve the casein curd by means of a
peptonizing ferment (‘‘ casease ’’?)—and thus increase
the quantity of caseoses. Still others not only dissolve
the curd, but also break up the molecule of albumin, so
that in the fluid such products appear as peptone, leu-
cin, tyrosin, ammonia, butyric acid, ete. Sometimes the
development of butyric acid is so considerable that it

CHANGES IN MILK a)

causes the cultures to stink (butyric acid fermentation).
Finally, the milk is changed into a watery mixture
which contains some fat lumps and has a more or less
disagreeable odor.

¢, Bacteria cause coagulation of milk partly by the
production of acid and partly by the action of ferments.
Many bacteria as, for example, certain lactic acid
bacteria and some members of the colon group, coagulate
milk through the production of acid. The precipitated
casein is, however, insoluble in diluted lime water, which
isan indication that it has been changed, by the action of
ferments, into paracasein.

/. Bacteria may produce a slimy condition in milk or
in cream. In this condition, these fluids become thick
and their consistency is so great that long strings may
he drawn out. The milk may, at the same time, beeome
acid, although usually this is not the case. There are
many bacteria of different kinds that are capable of
causing this change. In some cases, the sticky condition
comes from the rapid swelling of the slimy capsules of
fhe bacteria, while in other cases the change is thought
to be due to unidentified changes in some constituents of
the milk, presumably the lactose. It has been thought
that this slimy condition may be caused by feeding a
certain plant, Pinguiciuda vulgaris, in the same manner
that placing the leaves of this plant in milk may produce
the change.

Jonsson has found that there are bacteria on the
leaves of this plant that make milk slimy or stringy,
therefore it is, no doubt, safe to conelude that feeding
with this plant is without special significance in this
particular. Stringy milk is not unwholesome; in north-
ern Sweden it is eaten in the same manner as coagulated
milk is used elsewhere.

y. Bacteria may cause abnormal odors and tastes in

56 MILK HYGIENE

milk without producing an alteration in appearance or
any of the changes above noted.

The Bacillus fatidus lactis described by Jensen is
one of the colon group which has the property of pro-
ducing in milk an unpleasant odor similar to the odor
of turnips, and also a corresponding sweetish, bitter, re-
pulsive taste. This organism, and closely related forms,
are probably the real causes of the so-called turnip taste
of milk. Various micrococci and bacilli are capable of
producing a very strong bitter taste without altering the
milk in other respects. This change is sometimes due to
the production of peptone and, no doubt, to the
elaboration of other compounds.

Jensen has described a small bacterium that pro-
duces in milk an exceedingly strong burnt taste and
odor, that resembles the odor and taste of malt. This
was so strong as to cause a malty odor throughout an
infected creamery. It may be that this bacterium is the
real cause of the so-called ‘‘ malty taste ’’ of milk and
butter. Another organism—a micrococcus—was found
to give milk an unpleasant fatty, burnt taste.

A bacillus studied by Veigman and Zorn produces an
unpleasant soapy taste, while a bacterium mentioned
by Storch gives rise to an oily taste in coagulated milk.
Other bacteria cause other less clearly marked tastes
and odors that cannot be more definitely characterized
than as unclean.

h. Bacteria may cause abnormal coloration of milk;
the most important abnormalities of this class are:

Blue milk is caused by the Pseudomonas syncyanea
(Bacillus cyanogenus), which produces a grayish color
on the surface of milk, while in sour milk distinct blue
spots appear, that may become confluent.

Red milk. Certain bacteria, as the Bacillus prodigio-
sus and the Sarcina rosacea, grow on the surface of milk,

CHANGES IN MILK o7

producing a red color partly as spots and partly as a
diffuse discoloration covering the entire surface. The
Bacterium lactis erythrogenes, isolated by Grotenfeldt,
coagulates milk and afterwards dissolves the coagulum
into a red fluid.

Yellow milk is produced by a number of organisms
that cause the development of yellow or orange-colored
spots on the surface. Bacillus synxanthus is an exam-
ple of these organisms that are derived from the
atmosphere.

Summary. Milk that is not sterile and that is left
to itself, usually undergoes lactic acid fermentation for
the reason that lactic acid bacteria are present in large
numbers, and by breaking up the milk sugar to form
acid, most of the other forms of bacteria are repressed
fo a high degree. Curdled milk may have a clean, sour
taste, or a more or less unpleasant, bitter, offensive or
oily taste. The latter condition comes from cither
simultaneous development of other bacteria or from the
peculiar effects of special lactic acid bacteria which have
caused the acid formation. Coagulated milk left to itself
is usually quickly covered with a thin, whitish, consist-
ent layer formed of milk moulds (Oidiwm lactis) and,
not infrequently, colored spots appear that are caused
by bacteria or fungi, as Penicilliaan glaucum. By
degrees the coagulated milk undergoes a putrefactive
transformation accompanied by a foul-smelling disin-
tegration of the casein.

Less frequently, the milk quickly becomes slimy or
stringy before it has become acid, or while it is begin-
ning to sour. Or it may early aequire a bitter taste
and an unpleasant, loathsome odor; very often it does
not sour and coagulate, but gradually putrefies: the
usual lactic acid fermentation has not appeared and
cheeked the increase of the bacteria of putrefaction.

58 MILK HYGIENE

It sometimes happens that milk coagulates quickly
without souring; the coagulum is quite firm, the taste
sweetish, often slightly unpleasant. In this case, the
lactic acid fermentation has ceased, while the bacteria
referred to in paragraph d have grown freely. Left
to itself, such milk will quickly become putrid.

VIII. CHANGES IN MILK AT HIGH TEMPERATURES

When milk is boiled in an open vessel, it becomes
covered with a coating of coagulated casein; after this is
removed, a new membrane is immediately formed. If
the milk is constantly stirred, the membrane is not
formed. The origin of this coating is not entirely clear,
but it is possible that it comes from a partial drying of
a superficial layer of milk.

Viscosity is diminished upon boiling or long pasteur-
ization, so that boiled milk appears to be thinner than
raw milk. This is expressed by Babcock by the fol-
lowing figures relating to two samples of milk tested:
265 raw, and 250 pasteurized; 275 raw, and 257 boiled.
The specific gravity of milk changes so little upon heat-
ing as to be practically of no account.

Lactose is not changed when simply boiled, but heat-
ing at a higher temperature causes a burnt condition
(caramel formation) and partial separation into lactic
acid, causing the milk to become slightly acid.

Albumin and globulin coagulate upon heating the
milk for a short time to 70° to 80° C., and it is probable
that casein also undergoes a change, but it has scarcely
any significance and has been studied but little up to
this time. But if milk possesses a certain degree of
acidity, heating causes coagulation of the casein. Boiled
milk is not influenced at all, or only very slightly, by
rennet ferment; the reason for this is not to be found
in change in the casein, but lies in the partial transfor-

CHANGES IN MILK a1)

mation and separation of the calcium phosphate, as
discussed below.

A number of investigations have been conducted to
determine whether or not casein, when boiled, undergoes
a change in respect to digestibility ; although the results
do not wholly agree, such a change does not appear
to take place.

Pasteurization and hoiling cause no material change
in the fats of milk; the number of the globules is not
reduced, there is no fusing of the globules. Possibly
the quantity of volatile acids decreases, but no investi-
gations have been made on this subject.

The salts of milk undergo a change upon heating, as
the soluble calcium salts become, in part, insoluble phos-
phate of lime, especially tricalcium phosphate, Ca ,P.O,.

As already mentioned, there is much reason to
believe that fresh milk contains a peptonizing ferment,
galactase; if this is the case, boiling or simply pasteur-
izing must, of course, destroy it. This also destroys
antitoxins that may be inanilk. It is also safe to say
that toxic substances which result from diseases of the
cow or come from bacterial growth in milk, are made
at least partially harmless by continued boiling.

It is a well-known fact that the taste and odor of
milk are changed by boiling; the ** boiled taste" ap-
pears when it is heated to from S0° to S5° C., but this
is less strong than that produced at a higher tempera-
ture and is considerably lessened by prompt cooling,
immediately after heating. It also appears that the
‘* boiled taste’? is less marked when the milk is heated
in at closed vessel, so that the absorbed ecarbonie acid
gas may not escape, or when the milk is boiled in the
presence of carbonic acid gas.

The action that pasteurization and boiling have upon
bacterial growth in milk will be taken up later.

PART III.

HARMFUL PROPERTIES WHICH MILK
MAY POSSESS.

Unper certain conditions, milk may possess harm-
ful properties. When the cow is diseased, poisonous
substances may occur in the milk, and the composi-
tion of the milk may differ widely from normal; in
udder infections, milk contains an admixture of patho-
genic bacteria, and such contaminations may also occur
during or after milking. Milk may also take on injuri-
ous properties through the action of saprophytic organ-
isms and through accidental or intentional additions of
harmful substances, as preservatives. While, in some
cases, there is only an altered appearance, taste or odor
that serves to make the milk unappetizing and to cause
nausea or, perhaps, vomiting, in other cases the milk
may be decidedly injurious and cause, under certain
conditions, serious illness, even an epidemic.

I. EXCRETION OF POISONOUS SUBSTANCES
WITH MILK

It has been stated that different foreign materials
may be excreted through the udder tissue. This applies
principally to mereury, preparations of arsenic, various
alkalies, iodine, irritant substances (euphorbium, etc.)
and certain volatile oils. Although these substances are
not often present in great quantities, vet milk may be
flavored by them, and in this case it may be dangerous
for small children and weak persons. Since it is safe
to affirm that many materials that are not usually

60

ADDITION OF ANTISEPTICS 61

excreted through the udder may be excreted under cer-
tain conditions, and by some cows, it will be wise to
regard as suspicious all milk from cows that are treated
medically with remedies that are toxic, and to forbid its
sale for human food.

Further, since it is quite probable that toxic sub-
stances formed in the organism during the course of
acute infectious diseases may be excreted through the
udder, there is good reason, also, to prevent the use of
milk of such animals.

II. ADDITION OF ANTISEPTICS (PRESERVATIVES)

The addition of antiseptics is frequently undertaken
hy dealers, in order to increase the keeping quality of
milk. In some places the addition of preservatives 1s
very common and quite a number of antiseptics are
used, As most antiseptics are harmful not only to the
lower fungi, but also to the cells of the higher animals,
and are to be considered as poisons for animals and
man, it is self-evident that the addition of antisepties
should be undertaken with great care or, much better,
omitted altogether. In this connection, it must he kept
in mind that one person may be peculiarly affeeted hy
substances that have no effect on another, and that even
a small addition of an antiseptic may be harmful to
some people.

The addition of antiseptics prevents acidulation and
coagulation, and so may conceal the fact that the milk
is already half spoiled. Some substances, in very slight
quantity, directly prevent the increase of acid-forming
bacteria, and so, indirectly, they may promote the
growth of the more resistant bacteria of putrefaction.

Tn most countries the addition of antiseptics to milk
and other foods is prohibited by law.

The preservatives most used are: boric acid, sali-

62 MILK HYGIENE

eylic acid, benzoic acid, potassium bicromate and for-
malin. Rarely, peroxide of hydrogen and fluorides are
used.

a. Boric acid is sometimes used as such, sometimes
as borax, and is able, when added in the proportion of
0.1 per cent. to 0.2 per cent., to prevent bacterial growth
for several days so that coagulation does not take place.
It is said that boric acid is a harmless substance, and it
is true that it has been used as medicine in quite large
doses without injurious effect being perceived. On the
other hand, observations and investigations have been
made which fully prove that boric acid may cause
illness, vomiting and diarrhoea, and if given for a
prolonged time, may injure tle kidneys and cause some-
what rapid and not inconsiderable loss of weight; the
latter depends partly on the fact that the food is not well
assimilated and partly on the increase of metabolism
(Rubner). Experiments on animals have confirmed the
results of these investigations and, indeed, demonstrate
that boric acid may even cause a fatal poisoning; for
example, Annett fed five kids with milk that was mixed
with 1 gr. boric acid to the litre; all five died in the
course of 2 to + weeks. It may be said, further, that
boric acid is excreted from the organism slowly so that
the toxte effect is not temporary and transitory, so boric
acid must be considered to be an injurious substance and
its addition to milk and other food is to be forbidden.

Borie acid may be detected in milk in different ways:

According to Villiers and Fayolle, milk is evaporated
to dryness and ignited, the ash is wet with sulphuric acid,
3 ¢@e. methyl aleohol is added and the solution is distilled
until sulphuric acid vapor begins to appear. The vapor
is ignited and if borie acid be present, in even a very
small quantity, this will burn with a green flame.

Meiss] recommends the following method: 100 ¢.c. of

ADDITION OF ANTISEPTICS 63

milk are mixed with milk of lime, evaporated and
ignited; the ash is dissolved in a very little concentrated
hydrochloric acid; the carbon is filtered out, the filtrate
is made slightly alkaline and evaporated to dryness.
This salt is treated with a little turmeric tincture and
with some very dilute sulphuric acid and is evaporated
in a water bath. If borie acid is present, the mass is
colored a distinct cherry red.

[Leffmann* gives the following method: ‘‘A few
drops of the sample are nixed with a drop of hydro-
chlorie acid and a drop of strong alcoholic solution of
turmeric, evaporated to dryness at a gentle heat, and a
drop of ammonium hydroxide added to the residue when
cold. .\ dull green stain shows that borie acid is pres-
ent.’”

Richmond ® offers this method: ‘* To a little milk add
a few drops of phenolphthalein, and sodium hydroxide
solution, drop by drop, till a faint pink color is pro-
duced; place some of the milk in two test tubes, dilute
one with an equal volume of water, and the other with»
neutral 50 per cent. solution of glycerin; in the absence
of borie acid the two tubes will have almost the same
color, in its presence the glycerin: tube will be the
lighter, and usually white.’?) L.P.]

b. Salicylic acid in a quantity equivalent to 0.04 per
cent. can prevent the souring of milk for 36 hours, even
when the milk remains at 18°C. It is very hard to
dissolve and has not been extensively used to preserve
milk.

Salieylic acid has the effect of checking digestion and,
with some persons, it may cause irritation of the kid-
neys; particularly for children, sahieylic acid should he

S Analysis of Milk and Milk Produets.
* Laboratory Book of Dairy .Analysis.

64 MILK HYGIENE

considered injurious. On this account its use should be
prohibited.

The presence of salicylic acid in milk is determined
in the following ways:

To 20 e.c. of milk add 2 to 3 drops of sulphuric acid
and about the same amount of ether, then shake the
mixture. The ether dissolves the fats and the salicylic
acid that is present. The ether solution is evaporated
and the residue is extracted with 40 per cent. solution of
alcohol and filtered. The addition of a few drops of
ferric chloride solution to the filtrate gives a violet color
if salicylic acid be present. (Remont.)

Girard mixes 100 parts milk with 100 parts water at
60° C., and then adds a few drops of acetic acid and a
few drops of a solution of mercuric nitrate, the mixture
is then shaken vigorously and filtered. The filtrate is
shaken with ether, which dissolves the salicylic acid.
The ether layer is then filtered and is evaporated in the
air; if salicylic acid be present it remains behind as a
white crystalline mass, which, after solution in alcohol,
is colored violet by a weak solution of ferric chloride.

c. Benzoic acid possesses very powerful antiseptic
properties, but is difficult of solution, and is little used
as a preservative of milk. Benzoic acid appears to be
somewhat harmful to man, and may be poisonous in
large doses; there is little definite knowledge as to its
special effect on young children.

The tests for benzoic acid in milk are more compli-
eated. 400 ec. to 500 ec. of milk is made alkaline by
the addition of lime water and evaporated to about
one-fourth its volume; this is then mixed with pulverized
pumice stone until it forms a thick pap, which is evap-
orated to dryness over a water bath. The mass is pul-
verized, moistened with diluted sulphuric acid and
shaken with a double quantity of 50 per cent. alcohol.

ADDITION OF ANTISEPTICS 65

The alcoholic liquid is neutralized with baryta water
and evaporated to about 10 ¢.c. Dilute sulphuric acid is
again added and the liquid is shaken 3 or + times with a
little ether, which is collected each time with a pipette.
The ether is evaporated and the benzoic acid remains in
almost pure condition. The mass is dissolved in a little
warm water and a drop of a solution of sodium acetate
and a drop of a neutral solution of ferric chloride are
added. If benzoic acid be present, a reddish sediment
of benzoate ferric oxide appears (Meissl) ; or a little of
the dried mass may be treated with a drop of concen-
trated nitric acid, the latter evaporated and the residue
mixed with sand and heated to a high temperature in a
glass tube. The benzoin is indicated by the odor of
bitter almonds (nitrobenzol).

[The method of Peters, as given hy Leffmann, is as
follows: ‘* The material is made slightly acid and ex-
tracted with chloroform, which is then evaporated spon-
taneously. The vessel containing the residue is placed
in melting ice, 2 ¢.c. of sulphuric acid added, and stirred
until the residue is dissolved. Barium dioxide is dusted
into the mass, with constant stirring, until the liquid
begins to foam, when 3 c.c. of hydrogen dioxide (3 per
cent.) are added drop by drop. The dish is then re-
moved from the cold bath, the contents diluted with
water to convenient bulk, and filtered. The acid filtrate
is extracted with chloroform. The benzoie acid will have
heen converted into salicylic aeid by the process and the
latter may he deteeted by dilute solution of ferric
chloride or ammonio-ferrie sulphate."’ L.P.]

d. Potassium bichromate is used by chemists as a
preservative for milk samples. It is seldom used as a
preservative of market milk. This poisonous material is
casily detected, if one mixes together equal quantities
of milk and of a 1 per cent. solution of nitrate of silver.

a

66 MILK HYGIENE

If potassium bichromate be present, the mixture has a
yellow or reddish-yellow color.

e. Formalin or formol is a 40 per cent. solution in
water of formaldehyde. It is a superior disinfectant
and is being employed more and more. The presence of
0.008 per cent. formaldehyde (—0.02 per cent. formalin)
is able to check coagulation of milk for 100 hours. The
addition of formalin causes no change in the fats, there-
fore it may be used to advantage in samples taken for
fat determinations. Formaldehyde has, however, a very
decided effect on albumin and as it has a deadly effect on
the protoplasma of bacteria, so it is also a powerful poi-
son for the animal cells and tissues. Investigations by
Annett have proven that the addition of formalin to
milk, even in the proportion of 1 to 50,000 may be injur-
ious, especially for young animals, and even to the point
of causing death. The addition of formalin to milk
should therefore be rigorously prohibited.

There are many ways of detecting formalin in milk:

1. 100 «ec. of milk are distilled; when about 20 cc.
are evaporated, the distillate is tested by the addition
of 5 drops of ammoniacal solution of silver nitrate (1 gr.
silver nitrate is dissolved in 30 parts of water and
enough diluted ammonia water is added so that the sedi-
ment which appears is again dissolved; then it is diluted
to 50 e.c.). After the tube has been shaken, it is left
standing in the dark for some hours. The presence of
formalin is shown by a black sediment or by a black color
of the liquid (Thompson).

2. In many eases it is sufficient to add the silver solu-
tion directly to the milk, since this either colors it black
at once or gives it a brownish color if left standing in
the dark.

3. According to Lebbins, a test may be made by the
addition of a little resorcin and 50 per cent. solution of

ADDITION OF ANTISEPTICS 67

sodium hydroxide followed by boiling. Distinct red
color shows the presence of formalin.

4. Denigés recommends the fuchsin method: To 40
c.c. of a 0.5 per cent. solution of fuchsin are added 250
c.c. of water, 10 cc. of a solution of sodium bisulphite
and 100 cc. pure sulphuric acid. Upon standing, the
liquid becomes decolorized. To 10 ¢.c. of the milk under
examination is added 1 ¢.c. of the prepared decolorized
fuchsin solution; after 5 to 6 minutes at the most, if for-
inaldehyde be present, an intense carmine red appears,
which becomes violet blue upon the addition of 2 ce.
hvdroehlorie acid.

[5. Richmond has modified and simplified Helners’
test so that it is most convenient in milk inspection. It
is made as follows: To a small quantity of milk, in a
test tube, add an equal quantity of water. Pour a little
90 per cent. commercial sulphuric acid down the wall of
the tube so that it will form a layer at the hottom. Tf
formaldehyde be present, a bluish or violet zone devel-
ops at the junction of the acid and milk. If no formal-
dehyde be present, a faint, slightly greenish ring forms.
This test is effective even when so little formaldehyde is
present as 1 part in 200,000.

6. Leffmann ' recommends the following test, as one
of the most delicate and positive: ** To a few e.e. of the
suspected liquid, a pinch of phenylhydrazin hydrochlo-
ride is added, the liquid shaken and a drop of a dilute
solution of sodium nitroprusside added and then a few
drops of sodium hydroxide. Milk containing formalde-
hyde gives a grayish green. If the test is applied to the
pure solution obtained by distilling the sample a char-
acteristic deep blue is produced.”’

In distilling milk to obtain a distillate containing for-

10 Analysis of Milk and Milk Products.

68 MILK HYGIENE

maldehyde for testing it is important to know that,
according to the researches of Smith and Leonard, only
a small part of the formaldehyde is distilled over; if
the milk is rendered alkaline even less is collected, but
if the milk is acidulated a larger proportion goes into
the distillate. B. H. Smith (as reported by Leffmann)
has shown that if 100 cc. of the milk sample be mixed
with 1 c.c. of dilute sulphuric acid, of a strength of one
of acid to three of water, and distilled, one-third of the
formaldehyde present will come over in the first 20 c.c.
of the distillate. L.P.]

f. Alkalies. In connection with antisepties, the ad-
dition of alkalies should be mentioned. To be sure,
these do not have an antiseptic effect, but still, by the
neutralization of the acid formed, they hide changes and
eonceal the fact that the milk is, perhaps, already
spoiled. In this connection the substances to be consid-
ered are carbonate and bicarbonate of soda, also chalk
and potash. A distinct alkaline reaction of milk to lit-
mus paper points to such an addition of alkali and
demands a further test with rosolie acid.

Ten e.c. of milk are mixed with 10 ¢.c. aleohol (96 per
cent.) and a few drops of a 1 per cent. solution of rosolic
acid are added. Pure milk will become brownish yel-
low, while milk treated with alkalies takes on a rose red
color. (Hilger, C. Schmidt.)

Ill. ABSORPTION OF ODORS

Milk possesses a peculiar power to absorb odors. It
was mentioned above that goat’s milk which is drawn in
the stable in which the bucks are stalled absorbs some-
thing of the same clinging, unpleasant, characteristic
odor. Likewise, cow’s milk assumes a foreign odor and
a false taste when it stands in a place where there are
strongly smelling substances and especially when it is

ABSORPTION OF ODORS 69

milked, poured or aérated in such a place. The odor of
tobacco is taken up by milk. Oil of turpentine, other
volatile oils and asafoetida may give an unpleasant odor
and taste to milk. In this respect some of the worst
substances are carbolic acid, cresol preparations (creo-
lin, lysol, ete.) and chlorine, when these materials are
used for disinfecting stables or dairies. The odor may
last in these places for several days and the milk will
take the abnormal taste just as long. A mixture of car-
bolic acid or eresol preparations (crude carbolic acid)
and chloride of lime has been used for the purpose of
inaking the disinfectant more effective. This is not to
he recommended, as trichlorphenol or trichloreresol are
formed, compounds that have a more penetrating and
lasting “ carbolie odor’ than the separate materials.
Milk which is drawn in stables or kept in places which
are disinfected in this way is useless, sometimes for
weeks.

St. Friis has given a good example of this: a large
dairy in Copenhagen was in a state of tumult because
some of the customers complained that the milk deliv-
ered tasted of carbolic aeid. The next day the milk
from the farms was examined separately, and it: was
found that all the milk, about 500 quarts, from a certain
herd of 50 cows, smelled and tasted so strongly of ear-
holie acid that it was declared unfit for use as food. So
this milk was ehurned, as it was also the following
days; but the butter had the same taint and was almost
worthless. Not till the fifth day was the milk so
free from taint that it could be used. This is the
explanation of the origin of the trouble: the stable on
the farm in question was cleaned and disinfected with
a 2 per cent. solution of earbolic acid to which was
added a small quantity of chloride of lime. The stable
was aired for two days before it was: used again,

7 MILK HYGIENE

when the milk in which the defect was discovered was
drawn.

IV. TRANSMISSION OF INFECTION BY MILK
FROM CATTLE TO MAN

A series of specific diseases are common to cattle and
man, and the pyogenic bacteria of man occur in different
diseases of cattle. Therefore, the question is pertinent :
Can milk, before it is drawn, contain bacteria that are
pathogenic for man? It is quite natural that this may
occur when the disease affects the udder; but how is it
with diseases without this local manifestation? Differ-
ent answers have been given; some investigators affirm
that such an excretion of bacteria regularly takes place
through the udder; others (Jensen, Gartner, ete.) insist
that this is not the case, that such exeretion is gen-
erally limited to cases in which, during the course of the
disease, local changes appear in the udder tissue (hem-
orrhage, inflammation), and that anthrax bacilli, for
example, by no means always pass from the blood to the
milk of the infected cow. An exceptional condition
occurs in foot-and-mouth disease, as in this malady the
milk contains much infectious matter. But it will be
shown later that the milk from cows with this disease
shows a decided departure from the normal, so that it is
probable that here, too, the excretion of infectious mate-
rial is associated with pathological change in the udder
tissue.

In the case of certain diseases of cows, it may oceur
that pathogenic micro-organisms become mixed with the
milk during milking and, from a practical standpoint,
this has, in effect, the same significance as an excretion
through the udder.

more minute account of the diseases of cattle
which may cause a direct contamination of milk with
pathogenic microbes will be given below.

INFECTION BY MILK tl

a. Tuberculosis. During recent years quite reliable
information has been obtained concerning the preva-
lence of tuberculosis in cattle, partly from the abattoirs
and partly from the use of the tuberculin test.

The abattoir statistics of Denmark show differences
in the prevalence of this disease. In Copenhagen, 30 per
cent. of the mature cattle are affected; the same is true in
Odense, while .\rrhus reports a greater percentage.

In consequence of the results obtained from the
tuberculin test, Bang regards it as probable that in Den-
mark half of the small herds of from 1 to 9 members are
free from tuberculosis, but only a fourth of the herds of
medium size of from 10 to 49 animals are free, and of
the large herds only a few are exempt. Concerning the
proportions in certain herds, the most of the animals
may be healthy and tuberculosis limited to a few individ-
uals, but usually the disease is more widely distributed
and, in large herds, often from 80 to 90 per cent., or even
a larger number are affected.

The conditions in neighboring countries are about
the same. Tuberculosis of cattle, for example, is
scarcely less extended in Sweden, North Germany,
Belgium and England than in Denmark, while it is less
frequent in Norway and South Germany. [This disease
is also prevalent in certain parts of America, especially
in the leading dairy sections of the Eastern United
States. ]

The localization of tuberculosis in the udder is of
especial interest in connection with milk control, since,
when this condition is present, milk is always contam-
inated with tubercle bacilli. But in certain other forms,
as uterine and intestinal tuberculosis, great quantities of
bacilli are eliminated with the discharges and the exere-
tions that soil the hind quarters, so these forms may
easily be the indirect cause of infection of the milk. This

2 MILK HYGIENE

applies also, to a less degree, to animals that have
tuberculous broncho-pneumonia.

There are no reliable statistics to show the preva-
lence of udder tuberculosis of the cow in Denmark; but
the operation of the law requiring the compulsory
slaughter of cows with tuberculosis of the udder shows
it to be of quite common occurrence. For this cause 407
cows were killed during 1898-99; 592 in 1899-1900; 610
the following year; and 584 in 1901-1902. From Saxony
it is reported that from 1888 to 1897, 1.1 to 3.7 per cent.
of the tuberculous cows killed in the slaughter houses
were affected with udder tuberculosis, and in the whole
German Empire in 1888-89, the percentage of udder
tuberculosis among the tuberculous cows killed was 1.62.
Ostertag rates the prevalence of udder tuberculosis at
+ per cent. of all tuberculous cows. Probably cows
reacting to the tuberculin test are not to be understood
among these, but only such as are found after slaughter,
by superficial examination, to be tuberculous. The num-
ber of cows with udder tuberculosis is, without doubt,
very great, and in connection with the control of milk
one cannot rate the significance of this disease too
highly.

There is no information at hand concerning the prev-
alence of tuberculosis of the uterus. Judging from the
numerous specimens showing this lesion, received from
the city abattoir of Copenhagen, it appears to be prob-
able that this manifestation is quite common.

In regard to tuberculosis of the intestines, it is
known that in mature cattle the disease follows tuber-
culosis of the lungs and liver, especially in the later
stages; and it is recognized with difficulty by clinical
examination.

It has been affirmed—within recent vears, by Rabin-
owitsch and Kempner—that the excretion of tubercle

TUBERCULOSIS 73

bacilli in milk quite frequently occurs not only from
cows that have advanced tuberculosis, but often even
from animals which react to the tuberculin test, but
show no clinical signs of disease. Numerous investiga-
tions (Bang, Nocard, Ostertag and several others) do not
agree with the results of Rabinowitsch and Iempner.
It appears to be prohable that an excretion of tubercle
bacilli in the milk takes place only when lesions of tuber-
culosis are present in the udder tissue; but these may be
so voung and small that they are not apparent upon
clinical examination, and are also difficult to see in dis-
section. It is not impossible, however, that when bacilli
circulate in the blood in great quantity they may pass
directly into the milk; but this cannot be a frequent
occurrence. As early stages of udder tuberculosis are
not revealed by climeal examination, one must act upon
the assumption that not only cows with evident udder
or miliary tuberculosis give milk containing tuberele
bacill, but also that this may be the ease with many cows
having advanced tuberculosis, vet without changes in
the udder that can be detected by clinical examination.
Kven cows that are apparently affected with tubereu-
losis only to a slight degree, or those that appear by
clinical examination to be perfeetly sound, may give
tuberculous milk, in some cases, because very early
metastases ovcur to the udder and in others because this
organ appears occasionally to be the seat of primary
tuberculous infection.

Tt has been claimed that cows—even those appearing
clinically sound—frequently give milk containing tuber-
cle bacilli after a tuberculin reaction and, therefore, it
has been advised to prohibit the use of unboiled milk
from such cows, for a few months after the tuberculin
test. This assertion is wholly untenable and is com-
pletely lacking in proof.

74+ MILK HYGIENE

On account of the great extent of tuberculosis among
cattle and on account of the frequency with which udder
tuberculosis occurs, it is to be expected, as is the case,
that market milk very often contains tubercle bacilli
in appreciable quantity. It is an established fact that
mixed milk from the co-operative creameries contributes
to a great degree to the spread of tuberculosis among
swine and calves. It has been proven, too, that feeding
the dirt removed by the milk separator (centrifugal
slime) to swine, may be dangerous. It is conclu-
sively established that the obligatory pasteurization of
skim milk in the various creameries, that has been
adopted in Denmark in recent years, has greatly aided
in checking the spread of tuberculosis among swine and
calves.

It is quite natural, under these conditions, that it has
also been possible to show that milk sold in the cities
contains tuberele bacilli in considerable quantity. St.
Friis made some investigations of the milk supply of
Copenhagen in this connection; in testing samples of
milk from twenty-eight herds in Copenhagen and vicin-
ity, he found four tuberculous, while 33 samples from
small farms in Seeland were shown to be incapable of
producing tuberculosis when inoculated upon animals.
These results are better than those reached elsewhere
through similar investigations. In the table on page 75,
essentially after Klmmer, a review is given of such
results from different cities.

These results were gained chiefly by intraperitoneal
inoculations of milk upon rabbits and guinea pigs and
are, therefore, to be regarded, to a great degree, as
authentie.

The tubercle bacilli are sufficiently resistant to live
through the souring and other processes necessary in the
manufacture of milk into butter and cheese, so that but-

TUBERCULOSIS 5)

ter, as well as cheese, nay contain tubercle bacilli. In
some places this has been proven by a comparatively
large number of butter tests.

In this connection, the question is naturally raised:
Ts tuberculosis transmissible to man through milk and

Rue fb: Sumer of
- Number of | samples Paciia imation
a ae, eee made Dy”
| were found,

Copenhagen.........-.-- Us 4 St. Friis
Copenhagen. ....--..-.+.5: 33 0 St. Friis
Berliti-ss2cacieees vars kes 40 a Obermuller
BER os eases esses 3 8 Obermuller
BOR aceccsendaheen 2.2 sserctenels 64 9 ' Petri
Talléicce sanagedaendee's 9 | a Buege
CRONIOA) 4 SEEb aa ca dass 33 | 3 Massone
Schwiibisch-Gmtind...... 3 5 A Ott
Schwiibisch-Gmiind...... Os 3 » Ott
Wii ir decaley deacuen'ans bt | 4 | Fiorentini
st. Petersburg ........... 71 | 4 . Sacharbekoff
Donpittt..0.eyecss sae ene 40 | 1 | Kudinow
KYARSN i is> Raha ser 60 2 . Bujwid
AVGINA cs yee cuaaai ase 22 12 Nonewitseh
Tl@ISiiehtits. scram auineres 21 s y. Hellens
Pans cesses ayalenin 30 | 6 | Girard
LAN GRP OGD is: cece ie tance oe 144 3 Y Boxee, Woodhead
Liverpool access ic anes oes v4 7 ) and others
Lixerpool soncc cones vgee ss Hts) o | Delépine
Liverpool gssv.2s dees ses | 125 22 © Delépine
LINGrpoul % oseccanseaeaens lay ile, Boyce
Liverpiaal) ase 4 cesceae nex 91 16 Boyce

ond Git e4- esed wedene dee 100 ‘ ii © Klein

dairy products? Avian tuberculosis has been shown to
differ essentially from tuberculosis of mammals; then
is tuberculosis of man identical with that of cattle?
With the discovery of the tuberele bacillus, this ques-
tion was answered affirmatively, and this gave impetus
to the movement for meat inspection and dairy inspec-

76 MILK HYGIENE

tion. Through the discovery of the prevalence of feed-
ing tuberculosis in swine, horses and cattle, veterina-
rians have emphasized the great danger that may come
to man by the use of meat and, especially, of the raw
milk of tuberculous animals. Many physicians have
taken the same ground, while others would minimize
this danger to a great degree, or combat its existence
entirely, by pointing out the great infrequency of
primary intestinal tuberculosis in man, and they claim
that tuberculosis of man, almost without exception,
begins in the lungs and is an infection by inhalation.
There is still disagreement on this subject. It cannot be
denied that there is a remarkable difference between
the prevalence of feeding tuberculosis of calves and pigs
on the one side, and the prevalence of the unmistakable
feeding tuberculosis of man.

Since avian tuberculosis has been shown to differ
from tuberculosis of mammals, and since tuberculosis
of dogs is not transmissible to rabbits, but evokes only
a temporary local process (Jensen), it has become neces-
sary to consider the differences between tubercle bacilli
from different sources and, especially, to study experi-
mentally the relation of cattle tuberculosis to tubercu-
losis of man. Of investigations undertaken in this line,
those of Th. Smith and Frothingham are valuable
because they show a certain difference in the bacilli of
cattle from those of man and prove that tubercle bacilli
of man possess but slight virulence for cattle. This
question has become especially interesting since the
tuberculosis congress in London in 1901, when Koch
gave the results of experiments that he had conducted
in connection with Schiitz and, on the basis of these, he
believed he could affirm that tuberculosis of man is not
transmissible to cattle and, on the other hand, that
tuberculosis of cattle is probably not transferred to

TUBERCULOSIS v0

man. In support of the latter statement, Koch produced
statistics which were said to prove the great infrequency
of man’s infection with tuberculosis through food.

It is evident that the question of the identity or non-
identity of tuberculosis of man and cattle is of great
importance in the control of the milk supply. Koch, con-
sequently, drew the conclusion from his investigations
that the control of meat and milk, so far as tuberculosis
is concerned, is superfluous and unnecessary. There-
fore, we have all the nore reason for a closer consid-
eration of the three questions placed in the foreground
by Koch’s report.

1. Is tuberculosis from food infection rare in man?

2. Can human tuberculosis be transmitted to cattle?

3. Can it be proven that tuberculosis of cattle is
transmissible to man?

If we first consider the question of the frequency of
the occurrence of tuberculosis in man from infection
through his food, it will be seen at once that differences
of opinion exist concerning the modes of infection. The
usual opinion (until quite recently) is that by far the
greatest number of cases of tubereulosis in man are
caused by inhaling the dry bacilli; there is, however,
opposition to this view. Ribbert and Autrecht have
concluded that tuberculosis of the lungs is of embolic
origin and others (CGrawitz) have found the tonsils to be
among the most favorable places for the admission of
bacilli. Observations on animals, particularly on swine
and monkeys, caution us not to draw definite conclusions
in relation to the mode of infection from the gross ana-
tomical lesions. Thus, for example, with swine that
are infected almost exclusively through the digestive
canal, tuberculosis of the intestines is an exception,
while miliary tuberculosis of the lungs often leads to a
rapidly developing caseous pneumonia.

78 MILK HYGIENE

Moreover, tuberculosis is undoubtedly not so infre-
quently caused by the food (primary tuberculosis of
the intestines and mesenteric glands) as Koch affirms.
The available statistics concerning the prevalence of
abdominal tuberculosis differ considerably. While the
English tables show the prevalence of ‘‘ tabes mesen-
terica ’’ at about 10 per cent. of all cases of tuberculo-
sis and at about 30 per cent. of all cases of tuberculosis
in children, the corresponding figures for Berlin are
(1898) 1.8 per cent. and 2.8 per cent., for Paris
(1897) 1.33 per cent. and 1.65 per cent., for New York
(1899) 0.47 per cent. and 2.86 per cent. and, finally, for
Boston (1900) 1.14 per cent. and 4.35 per cent.”

This difference is, no doubt, largely due to differ-
ent interpretations of the post-mortem findings [and to
the different degrees of prevalence of tuberculosis among
cattle] but a partial explanation may also be found in
the fact that most of the milk in England is used in the
raw state. From some of the German states there are
reports (Heller and Seitz) concerning the rather frequent
occurrence of ‘‘alimentary tuberculosis’’ in children. As
for Copenhagen, Fibiger has stated that primary in-
fection of the intestines and of the mesenteric glands is
not infrequent with children. Cases also occur in adults
that are most naturally pronounced to be primary
intestinal tuberculosis.

In reference to the second question—the possibility
of the transmission of human tuberculosis to cattle—
investigations have been going on for some time that
prove that transmission may be effected by inoculation.
After Koch’s report appeared, a great number of experi-
ments were undertaken to throw light upon this ques-
tion, the results of which are partially published. Fib-

11 Salmon: Relation of bovine tuberculosis to the public health.
1901.

TUBERCULOSIS eo

iger has given a review of these: in 61 series of experi-
ments, 81 calves, heifers, cows and oxen were inoculated
with human tuberculosis; in 41 experiments on 51 ani-
mals the result of the inoculation was positive. In
many cases the inoculation caused only local processes
extending to near-by glands, but the experimental ani-
mals were all killed comparatively early, so that the dis-
ease could well have spread further if the animals had
lived longer. .\s is known, tuberculosis of cattle fre-
quently remains local for a long time. Sometimes the
inoculations caused violent tuberculosis in the experi-
mental calves, and this was particularly the case when
the inoculation material came from patients affected
with ‘* feeding tuberculosis.’’? (Ravenel, Wolff, Fibiger
and Jensen, Westenhoeffer.)

The clinical observations that may he cited in answer
to the third question seem to prove that bovine tubereu-
losis is transmissible to man. There are many observa-
tions, principally upon veterinarians and butchers, of
tuberculous inoculation communieated to the hands and
fingers through euts while working with tuberculous
organs of cattle. In some eases these were only local
lesions that were healed by surgical means; in others,
the disease extended to the sheaths of the tendons and
glands, and in still others, in the course of time, it
appeared to develop into lung tuberculosis. Greater
interest attaches to cases of feeding tuberculosis which
may with great probability be traced to infection
through milk of tuberculous animals. .\ large number of
such cases have been given, from which the following
have been chosen:

1. The 17-year-old daughter of Prof. Gosse died of abdominal
tuberculosis after drinking milk from eows affeeted with udder
tuberculosis. Other sources of infection could not be discovered.

2. Olivicr’s observation coneerns one of the best proven cases

80 MILK HYGIENE

of transmission by milk: In a boarding school 12 young girls
became i] with signs of intestinal tuberculosis, and 5 of them
died. All came from healthy families and no source of infection
was found but one cow which supplied milk for the school and was
shown to be affected with tuberculosis of the udder.

3. Demme has reported the following: In the children’s hospital
Bern, four children died of intestinal and mesenteric glandular tuber-
culosis. He was able to exclude all other sources of infection and to
prove that the milk came from tuberculous cows.

4. Hills tells of a 21 months old child that was affected with
intestinal tubereulosis three months after making an eight-day visit
to an uncle where it had drunk the milk of a cow having advanced
tubereulosis. The child died of tuberculosis. Other sources of
infection were excluded and another ehild fed only with sterilized
milk remained healthy.

5. Ernst reports that three children of the same family died
of tuberculosis after drinking milk from a cow that later died of
general tuberculosis with udder involvement.

Leonhardt, Sonntag, Hermsdorff, Klebs, Rotch,
Lydtin and Stang, Johne and many others have reported
quite similar observations.

Of particular interest are the cases reported by
Ravenel, Fibiger and Jensen, and many others, of tuber-
culosis of children with prominent lesions in the diges-
tive canal, while the tubercle bacilli present were so:
virulent for cattle that the origin of the cases in ques-
tion were referred, with the greatest probability, to
infection through the milk.

If one considers that feeding tuberculosis is by no
means infrequent in man, and occurs quite frequently in
children, that human tuberculosis is often transmissible
to cattle, and that clinical knowledge argues for trans-
mission of bovine tuberculosis to man, and if one con-
siders that tubercle bacilli from cattle have been proven
at least as dangerous and generally more virulent for
all animals than tubercle bacilli from man, then milk
containing tubercle bacilli must be regarded. as most

TUBERCULOSIS 81

dangerous to health. Therefore, it must be one of the
most important purposes in milk control to prevent the
sale of such milk.

It is a difficult task to detect tubercle bacilli in milk.
Intraperitoneal injections of the milk into guinea pigs
and rabbits may be made, but sometimes many of the
aninals die from other infections (cocci; other bacteria).
Sometimes so long a time elapses before the results are
available that the experiment has lost much of its prac-
tical value. Moreover, certain similar bacteria (acid-
fast bacteria) may cause alterations in the experimental
animals which can hardly be distinguished from tuber-
culosis, The detection of tubercle bacilli in milk by
nucroscopic examination is difficult; a direct examina-
tion will very seldom give results; so one must depend
either on centrifuging, whereby all the little flakes to
which the bacilli usually adhere may be thrown down,
and then examined, or other means for separation must
be used (see below) so that the bacilli may be precipi-
tated without too great a quantity of sediment.

Since the number of tubercle bacilli in mixed milk is,
at most, but small, only a positive result of the examina-
tion can be final, and even then the result is doubtful
since, as mentioned before, ‘* pseudotuberele bacilli
may appear in milk (see below) which are like the tuber-
ele bacilli in respect to staining and are similar also in
morphology.

We must, therefore, depend on the clinical examina-
tion of the cows in the herd itself, if we would check the
passage of tubercle bacilli into milk. This inspection
must be directed especially to tuberculosis of the udder,
uterus and intestines and, at the same time, to miliary
tuberculosis and to all eases of lung tuberculosis suf-
ficiently developed to cause the appearance of clinical

signs. But the inspection must not be clinical alone; in
6

82 MILK HYGIENE

respect to the first forms of tuberculosis mentioned, it
must be microscopic as well, for tubercle bacilli may be
found in the milk, in the uterine secretion and some-
times in the excrement when the clinical symptoms are
such as merely to arouse suspicion. Such an examina-
tion of the herd, to be efficient, should occur frequently,
at least every fortnight, since this disease, and especially
tuberculosis of the udder, may develop materially in this
time.”

It can hardly be stated, in general, how strict the
regulations regarding tuberculous animals should be.
In some countries it is only forbidden by law to use milk
unboiled from cows with udder tuberculosis. Milk from
cows with tuberculosis of the uterus, of the intestines
and miliary tuberculosis, and also from cows that are
eachectic, should not be permitted to be sold. It would be
best, if it could be arranged, to allow the sale of milk
from herds in which there are tuberculous animals only
under declaration of the condition of the herd; but on
account of the great extent of tuberculosis no such
requirement has been made. It is a reasonable and, at
the same time, an absolutely necessary requirement that
the so-called ‘‘ nursery milk,’’ milk intended especially
for small children and invalids, should come from a
herd which is entirely free from tuberculosis, that is, a
herd composed of cows none of which have reacted to
the tuberculin test.

Tests.—The discovery of tubercle bacilli in the milk
of individual cows with advanced udder tuberculosis and
in the discharge from the uterus, is usually easy. A
small quantity of the fluid or a little flake or lump is
spread upon a cover glass, it is fixed in the usual way in
the flame and then stained according to one of the
methods given below.

™ This relates to herds known to be infected. [L. P.]

TUBERCULOSIS 83

L. Aiehl-Neelsen method. One grm. of fuchsin is dis-
solved in 10 ¢.c. aleohol and 100 ce. 5 per cent. phenol
water and the solution is filtered. By means of a
pipette, a liberal quantity of this staining fluid is
dropped on the cover glass which is held by pincers
above a flame a couple of minutes until the fluid
boils briskly, but without drying. Then the cover glass
is rinsed with water and treated for a few seconds
with 25 per cent. sulphuric acid and again rinsed with
water. If the red color is still distinet, the treatment
with acid is repeated and the cover glass is rinsed
earefully with a little alcohol. Finally, a few drops of
watery solution of methylene blue are dropped upon it,
after which it is again rinsed with water and mounted.

2. Nitt’s method. To 100 ¢.c. saturated anilin water
are added 1 ¢.c. of a 1 per cent. sodium hydrate solution
and 4+ to 5 grm. of fuchsin. Or, the above mentioned
phenol-fuchsin solution may be used. The cover glass 1s
treated as deseribed above, then rinsed and dipped for
one-half minute ina fluid consisting of 50 ¢.c. alcohol, 50
ce. Water and 20 ee. nitric aeid, to which has been
added as much methylene blue as the fluid will dissolve.
Finally, the slide is rinsed with water.

3. Ceaplewshki’s method. The staining is done by
heating with phenol-fuehsin solution as given above.
Allow the staining fluid to run off and, without rinsing,
dip the cover glass six to ten times into a concentrated
aleoholic solution of fluoreseein (1 grm. in 100 e.c. alco-
hol). The double staining comes from repeatedly
dipping the cover slips in concentrated alcoholic solution
of methylene blue (5 to 100); then they are rinsed in
water. By this method, a decoloration of tubercle bacilli
is avoided with certainty.

In all cases, the preparation is mounted and ex-

84 MILK HYGIENE

amined in the usual way with an immersion lens and
Abbé condenser. The tubercle bacilli are colored red,
other bacteria and the rest of the preparation are
colored blue.

So-ealled ‘‘ acid-fast’? bacilli may occur in milk
and butter as well as in the excrement of the cow. These
bacilli, which by the above methods are also colored red,
are difficult to distinguish with certainty from the real
tubercle bacilli, even by microscopic examination, al-
though they are usually thicker and shorter. Unfortu-
nately, we know but little of the conditions governing
their occurrence in milk. There is reason to believe that
they usually occur as a result of accidental contamina-
tion after the milk is drawn. In order that one may
be quite safe in his conclusions from this examina-
tion, and be able to avoid confusing the acid-fast and
tubercle bacilli, the udder secretion or the discharge
from the uterus that is to be examined microscopically
must be taken as pure as possible in a clean tube and, if
the examination cannot be made at once, an antiseptic (a
little ether or chloroform, a few drops of formalin)
should be added. Acid-fast bacilli accidentally added,
will not increase under these conditions, and their num-
ber will always be so small that they can hardly be de-
tected. It is, however, not wholly disproven that such
bacilli may appear in the milk before it is drawn. De
Jong has reported a case of mastitis caused by acid-fast
bacilli, but this is the only case of the sort reported up
to this time. From knowledge gained during the last
four or five years in the experimental laboratory of
Copenhagen from investigations of milk samples and
the control of the diagnosis of udder tuberculosis from
small samples of tissue from condemned and slaughtered
cows, it follows that errors very seldom occur as a result
of confusing these organisms.

PSEUDO-TUBERCLE BACILLI 85

When it comes to the examination of milk of normal
appearance, the question is usually more difficult, be-
cause the number of tubercle bacilli is less. A direct
microscopic examination of the milk is rarely useful; it
is better to pour a little of it on a dark surface and pick
out with a needle the small flakes which are usually
present and form the little lumps of fibrous exudate to
which the bacilli adhere. Still better results are reached
by centrifuging the milk and examining the sediment.
Any milk centrifuge may be used for this purpose (in-
cluding those used for determining the amount of fat)
and it may be driven by steam or by hand power. Of
course, a large centrifuge of high speed is best.

Instead of the centrifuge, the separation of tubercle
bacilli hy other means has been suggested.

Tor this purpose Biedert employs the following
method: 100 e.¢. milk are mixed with 4 to 8 drops of solu-
tion of sodium hydroxide; the mixture is well shaken
until the small flakes and lumps are dissolved, then it is
boiled. The cloudy fluid is poured into a conical glass
and left standing for some time. The sediment that
collects in the point of the glass may be drawn off hy a
pipette and examined microscopically.

The practice has also been followed of submitting the
milk to special treatment with chemicals before it is
centrifuged.

Thus, Ott mixed together 25 e.c. milk, 2 ¢.e. concen-
trated ammonia water and 100 e.e. of a mixture of equal
parts of ether and petroleum ether, in a separator flask
with a glass stopper. After being shaken and allowed
to stand, the ammonia-ecasein solution, in which the
bacilli are found, is drawn off from the bottom and
centrifuged.

Hammond’s method is as follows: 100 ¢.c. of milk are
mixed with 5 ec. of phenol; 15 to 30 ¢.c. of the mixture

86 MILK HYGIENE

are placed into two tubes and centrifuged for 15 min-
utes. The fluid is poured off and 3 ec. of a 5 per cent.
solution of potassium hydroxide are added to the sedi-
ment. After violent shaking, the liquid is allowed to
stand 2 to 3 minutes, then 15 ¢.c. of water are added to
it; it is shaken and centrifuged 20 minutes. Then, 15 ¢.c.
of the liquid are drawn off from above, while the residue
is examined microscopically in the usual way.

The detection of tubercle bacilli in milk by cultiva-
tion is most difficult and without practical utility. In
doubtful cases, where the result of the microscopic exam-
ination is uncertain, it is advantageous to ‘‘ harpoon ”’
the udder, thereby removing a small sample of the deep
tissue of the udder for examination microscopically or
by the inoculation of experimental animals, as guinea
pigs.

Statements of the temperature at which tubercle
bacilli are killed, vary greatly. While, in the first in-
stance, Bang and other investigators found that momen-
tary heating to 85° C. killed, Legay and Bech reported
that brief boiling was not always sufficient, and Volsch
found that even repeated boiling would not always kill
tuberele bacilli. On the other hand, Th. Smith reached
the conclusion that even a far lower temperature than
those originally given would kill with certainty if the
formation of a pellicle during heating was prevented.
According to the most recent investigations, carried out
with the greatest accuracy by Bang and Stribolt, it is to
be considered as proven that heating at 65° C. for 5
minutes or momentary heating at 70° C. kills the bacilli
with certainty and that the former uncertainty on this
subject arose principally from faulty methods in the
experiments. The observations by Legay, Bech and sev-
eral others show, however, that in practice a very
high degree of heat must be attained to be safe, and that

FOOT-AND-MOUTH DISEASE 87

even boiling for a short time without especial precau-
tionary measures, is not always sure to kill all bacilli,
because there is a part of the milk (little drops on the
upper part on the vessel, bubbles, scum or froth on the
surface) which is not thoroughly heated. It is, there-
fore, a matter of great importance to determine whether
the forms of apparatus used for pasteurization are
really so constructed that all of the milk is equally heated
to a desired temperature. At present, nothing definite
can be said about this, since no investigations have been
made to determine the amount of froth formation and
the temperature the froth reaches in the different forms
of apparatus. When market milk is pasteurized the
functional capacity of the apparatus should be very
carefully tested.

b. Foot-and-mouth disease. It lias long been known
that milk from cows with foot-and-mouth disease is infec-
tious, and may carry the disease to man. .\ hundred
years ago, in South Germany, the use of milk from such
cows was prohibited for use as food for man. In the
lighter forms of the diseave the milk remains unchanged,
but with cows badly affected, there is not only a decided
diminution in quantity, but its appearance and composi-
tion are changed. Tn sueh cases, the milk becomes thin,
separates a slimy layer of cream, of dirty color, and there
is quite abundant sediment or, as happens infrequently,
it becomes richer in fat with a simultaneous falling off
in quantity. Under the microscope, leucoeytes and
broken-down tissue-cells are found in greater quan-
tity than usual, sometimes red corpuscles also. The
milk contains a greater quantity of albumin and globulin
than usual, so that when boiled, large clumps and flakes
separate and the sugar and casein fall off in quantity—
all changes which are symptomatic of an admixture of
inflammatory exudate.

88 MILK HYGIENE

Just how often the milk of the affected cows is viru-
lent, is not known. Apparently, this is frequently the
case, and certainly it is when the milk shows the changes
mentioned. The virus may, moreover, enter the milk as
it is being drawn, if vesicles occur on the teats or udder.
The quantity of milk decreases noticeably during the
course of the disease and it seldom reaches its original
flow after recovery.

This disease is very easily communicated by the milk
to other cattle, to swine and, as is known, to man. Chil-
dren are especially susceptible. Brussenius and Siegel
have collected a large number of the cases mentioned in
the literature of foot-and-mouth disease in man. Dur-
ing the years from 1878 to 1886, 16 different epidemics
of the disease in man were observed. Not only were all
the members of single families attacked, but also numer-
ous inhabitants of whole villages and towns. During
one epidemic, 36 died; during another, 23 and during a
third, 16. All the epidemics occurred simultaneously
with foot-and-mouth disease of cattle in the affected
districts and, almost without exception, the infection
came from the use of raw milk. From 1886 to 1896, 172
cases in man were reported in the annual reports of the
German Imperial Health Office, 66 of which were traced
to infection through milk, while one case occurred from
the use of butter made from the milk of an infected cow.

The course of the disease in man may be light or
severe and, as said, the disease may end in death. The
symptoms are: fever and weakness, conjunctivitis, for-
mation of vesicles on the mucous membrane of the
mouth, the lips, the ears, the nose, fingers or, less fre-
quently, on other places on the body; besides, nausea,
vomiting, diarrhea; sometimes redness of the skin and
arthralgia. It is transmissible from man to man.

The virus of foot-and-mouth disease may occur even

COWPOX 89

in butter, buttermilk and cheese, since it is not killed
by the treatment which milk undergoes in their
manufacture.

This virus, the appearance of which is wholly un-
known (probably on account of its ultramicroseopic
size), is not particularly resistant. It has been proven
by experiments made during recent years in Germany
that the virus dies after 10 minutes’ exposure at 70° C.
and by being heated to 100° C. for an instant. Experi-
ments made in Deninark seem to have shown that pas-
teurization at 80° to 85° C., as is done in our cooperative
creamerics, is, without doubt, enough to destroy the
virus.

c. Cowpox. This disease attacks particularly the
teats of the cow, and therefore it cannot be doubted that
during milking the virus held in the vesicles sometimes
falls into the milk. Since the vaccine virus is known to
be very potent, and since man is peculiarly susceptible
to it, it ix evident that the disease ts transmissible
through milk to man. But, while there are numerous
examples of direct infection on the hands and fave of
the milker, there are only a few observations of an
infection through the use of such milk. The infrequeney
of such cases may come partly from two conditions,
namely, that most persons are early immunized hy com-
pulsory vaccination and that small children usually drink
the milk after it has been boiled or, at least, heated.

Among the examples of this disease in children, which
have oceurred through the use of milk from infected
cows and which are to be taken as unmistakable trans-
mission of the disease, the following observation by
Stern may be given: Cowpox broke out in a herd of
milech cows; a large number of children that had used
milk from this herd became affected with an eruption on
the face, which healed, leaving scars.

90 MILK HYGIENE

During the course of cowpox, milk may undergo quite
noticeable changes in that it becomes thin and bluish and
coagulates very easily. This change has not yet been
closely studied, and it does not appear to be constant.

d. Anthrax. During the course of anthrax, the secre-
tion of milk falls off suddenly and decidedly. The milk
secreted is thin and its composition is supposed to be
abnormal. According to a report of Monatzkows, the
percentage of sugar and fat is increased and the albu-
min decreased. Perdix states that the milk contains
ammonia.

Chamberland and Roux, Nocard and several other
investigators have observed that the milk of cows af-
fected with anthrax contains virulent bacilli. According
to the experiments of Monatzkows and of Jensen, this is
not always the case. Since the milk is often mixed with
blood, following slight hemorrhages in the udder tissue,
it is probable that the admixture of bacilli occurs only
when such hemorrhages take place.

As anthrax bacilli are able to penetrate the mucous
membrane of the digestive canal in man, the milk of a
cow suffering with anthrax is to be considered very dan-
gerous. This was mentioned long ago by Heusinger,
but so far as is known to the author there is only a
single questionable observation of such transmission
(IXarlinski).

The milk from healthy cows in a herd in which a
ease of anthrax has occurred must be regarded as harm-
less, for the disease is accompanied by striking symp-
toms and bacilli are not to be found in the milk before
the late stages of the disease. Cows that still appear
healthy, give milk free from bacilli even though they be
affected. Apropos of this, the following statement is
contained in Section 26 of the instructions to the Danish
veterinary police: ‘‘ Milk from sick [anthrax] animals

RABIES OL

must not be used for food for man or beast. The owner
may dispose of milk from the healthy members of the
herd—in so far as the sanitary police give no other
order—unhindered, under the condition that he pledges
himself to observe closely the condition of the health of
the herd and to separate at once those animals which
show suspicious symptoms, such as lack of appetite,
cessation of rumination, diminution of milk yield and
the like. Milk from animals that are separated must
not be mixed with that of the healthy animals.’’

The health authorities may, however, have good rea-
son to forbid the sale of unboiled milk in cases when the
disease breaks out violently in a herd, as then the danger
exists that bacilli may enter the milk when it is drawn,
for the sick animals excrete bacilli with the bloody ex-
crement and the stable, in spite of all care and disinfee-
tion, may be so thoroughly infeeted that there is the
possibility of contaminating the milk.

ce. Rabies. The virus of rabies, yet unknown, ix espe-
cially associated with the central nervous system and the
salivary glands. Frequently it may be found in other
glands and even in the udder. A number of observa-
tions hy Noeard, Perroncito, Bardach and several others,
have proven that the virus may be secreted with the milk.
All attempts to convey the disease to healthy animals,
through food containing infectious material, have thus
far resulted negatively, and henee numerous opinions
have been expressed to the effect that there is apparently
no danger to man in the use of milk from cows that have
heen bitten by a mad dog and that are themselves rabid.

Yet, since the possibility is always present that infec-
tion may occur through a slight lesion of the mouth or
pharynx, milk from cows infected with rabies (cows
that have been bitten by rabid dogs) is to be regarded
us most dangerous to health.

92 MILK HYGIENE

f. Lung plague. According to the few investigations
that have been made, milk undergoes a considerable
change during the course of this disease. The fat con-
tent is lessened and the albumin increases in quantity.
After standing, the milk is quickly separated into a
layer of cream and a lower serum-like layer. Haukold
affirms that the milk has a peculiar odor and taste, and
may cause vomiting in man. Wiedermann, Lécuyer
and Randou have observed some cases where, according
to their opinion, lung plague has been carried to chil-
dren through the use of milk from infected cows.
Though at least one case, in respect to its pathological
anatomy, showed great similarity to the peculiar pneu-
monia that occurs in this disease of cattle, it should not
be regarded as established that man is susceptible to
this disease, and especially is transmission through milk
unlikely, because it is not possible to prove the presence
of the specific virus in the blood or in the milk by
inoculation.

The changed condition of the milk is enough, how-
ever, to prohibit its use. But such an interdiction is
unnecessary in almost all civilized countries on account
of the regulations of the veterinary police regarding
this disease.

g. Actinomycosis. Actinomycosis belongs to the
comparatively frequent diseases of the udder of the cow
where it apparently originates primarily. Sometimes
it appears as miliary actinomycosis with a number of
quite small lesions distributed throughout the gland af-
fected, and in this form it may resemble a fresh udder
tuberculosis. More often, actinomycosis appears as sin-
gle or multiple nodules from the size of a nut to that of
an egg—these are surrounded by newly formed connec-
tive tissue and may break through the skin of the udder.

There are no recorded investigations concerning the

MASTITIS 93

changes in milk secretion during this disease, nor have
the actinomyses or ray fungi vet been found in milk,
in which they probably occur. Man may be infected
through the digestive canal (the mouth and intestines),
just as cattle are, and on this account the possibility of
contagion through milk should not be disregarded.
Therefore, milk from cows affected with udder actino-
mycosis (which, however, is not often diagnosed in liv-
ing cows) should not be used as food for man.

h. Inflammation of the udder (mastitis). The forms
of inflammation of the udder occurring in the cow may
be divided into the following principal classes, which
differ chiefly according to the grade of inflammation,
the extent to which the milk secretion is checked and the
character of the exudate:

1. Mucous catarrh;

2. Purulent catarrh;

5. Parenchymatous, purulent mastitis, ultimately
accompanied by abscesses ;

+. Gangrenous inastitis.

These forms cannot always be distinctly separated.
The changes caused through inflammation of the udder,
in the chemical composition of milk were described
above.

The various forms of mastitis are of microbie origin.
There are many kinds of bacteria which, if admitted
to the milk cistern, may cause inflammation of the glands
and, upon examination of the spontaneous cases, quite a
large number of mastitis bacteria have been found,
chiefly such as cause inflammation elsewhere in the
organism. By far the most cases of udder inflammation
arise from bacteria which belong to one of the following
groups:

1. Streptococci, which usually cause chronic mucous
(slimy) or purulent catarrh, ending with atrophy of the

94 MILK HYGIENE

udder tissue and agalactia. More rarely, streptococci
occur as causative factors of a mild catarrh of the udder.

2. Staphylococci, which sometimes cause a milder
form of udder catarrh, and sometimes cause a lght
or moderately severe parenchymatous inflammation,
which may end in recovery, in abscess formation or in
contraction of the udder. The Staphylococcus pyogenes
aureus and albus are found, but others occur as well.
In this group, as is known, the differentiation is
difficult.

3. The colon group. The parenchymatous forms of
mastitis caused by organisms of this group may be mild,
medium or severe, and they may end in spontaneous
recovery, necrosis, gangrene and formation of abscesses,
or in induration. The systemic manifestations may
be very marked, and the infection may even result
fatally.

It is impossible to determine hy clinical signs which
bacteria are present. In order to decide this, it is
necessary to resort to microscopic and bacteriological
examination.

It is important for us to note that streptococcus
forms of mastitis not infrequently appear as a con-
tagious disease and little by little extend to a large pro-
portion of the cows of the herd. It is also important to
note that streptococci in certain forms of mastitis may
continue in the secretion after the principal clinical signs
have disappeared, and are able to again cause a breaking
out of inflammation of the gland when lactation begins
anew.

The adinixture of pus gives the milk a most unappe-
tizing appearance, often causes an unpleasant taste and
frequently causes it to putrefy quickly, or to curdle. On
this account, it is necessary to prevent the mixing of the
secretion from infected glands with the other milk. Be-

MASTITIS BACTERIA 95

sides, it is highly probable that the pus itself may be
harmful if it is taken ly small children. The greatest
weight, however, is to be placed on the possibility that
the bacteria contained in the mastitis milk may cause
disease in iman, if they are taken into the digestive canal.
We know that staphylococci and streptococci which have
reached the human digestive canal in other ways have
sometimes proven to be most virulent, and we may sup-
pose that the same is true of mastitiscoce: and possibly
also of the coli-aérogenic formes.

Inflammation of the udder is a very common condi-
tion of the cow and, therefore, it might be expected that
there would be frequent opportunity to observe the
harmful effect of infected milk upon man. That this is
not the case may be due partly to the relatively low
virwence of some of the mastitis bacteria for man, and
heeause it is only in the rarest cases that it is possible
for the physician to gain sufficient information to trace
the special disease of his patient to the use of milk, and
then to trace this to a certain diseased cow. Further,
there is the fact that most milk for small children is used
boiled, so that the bacteria present have, for the most
part been killed.) As examples of the danger of using
the milk from cows with mastitis, the following cases of
disease may be mentioned :

1. In Christiana, in 1894, A. Tlolst observed acute
catarrh of the stomach and intestines in four adults and
four children, who lived in three separate houses. They
had all drunk milk some hours before the attack. Those
members of the household who had taken little, or boiled,
milk remained in good health. The milk in question had
aw normal appearance, but was slightly acid and con-
tained masses of short or long streptocoeci. The milk

18Tn Denmark, as in other countries of Continental Europe, very
little raw milk is fed to children. [L. P.]

96 MILK HYGIENE

came from a herd in which a cow with mastitis was
found, and it was explained that her secretion had been
mixed with the common supply that very day.

2. Prof. Holst has also reperted the following cases:
Five persons were attacked with acute catarrh of the
stomach and intestines a couple of hours after drinking
milk from the same milk shop. The milk came from a
herd in which a case of inflammation of the udder,
caused by streptococci, was discovered by special inves-
tigation. Here, also, it was shown that mastitis secretion
had been mixed on the same day with the other milk,
through the mistake of a new servant.

3. Dr. Johnnesen observed, likewise in Christiana,
two cases of diarrhcea (mother and child) which began
two hours after the use of raw milk which contained
numerous diplococei and streptococci. The examination
of a herd that had furnished the milk revealed that two
cows suffered with inflammation of the udder, and in
their secretion these cocci were found. Apparently still
other cases arose from the use of the same milk, but
these were not investigated closely.

4. Four children of one family were attacked with
acute catarrh of the stomach and intestines, also a child
of another family. The disease, in both cases, was
traced to the same milk. This appeared by superficial
examination to be normal, but by microscopic examina-
tion it was shown to be rich in diplo- and streptococci.
Here, also, it appeared with practical certainty that the
harmful quality of the milk was derived from a case of
mastitis.

5. In Stockholm the members of nine families be-
came ill with the following symptoms: fever, languor,
faintness, nausea, vomiting and diarrhea, together with

14 Zeitsehrift fiir Fleisch und Milehhygiene, x. p. 280.

MASTITIS ot

cramps in the legs. The disease was traced to the use
of milk from the same herd. This herd comprised 14
cows, one of which was proven to be afflicted with mas-
titis. Two persons working in the stable were sick with
these same symptoms. The same forms of bacteria were
found in the faces of the sick persons that were found in
the udder secretion of the diseased cow.

6. Moro '* has reported the following case due to the
use of the milk of a goat suffering with a necrotic
inflammation of the udder: six persons who had taken
the milk in coffee became very sick one to two hours
afterward; they bad chills, were nauseated and had
headache; 11 hours later colic, vomiting and great thirst.

7. Lameris and van Harrevelt '° mention an outbreak
of diarrhaa among a number of persons in a hospital.
The disease was traced with comparative certainty to
the use of milk. This came from a herd in which several
‘vases of streptocoecus mastitis were found. The infee-
tion probably came from the use of milk from a cow that
appeared to have recovered, but whose milk still con-
tained streptococci. As the milk was used only after
being boiled it was thought that the disease was really
due to the presence of toxins, but it is very probable that
streptococci may have lived through boiling of milk, as
tubercle bacilli have, that is in the film, froth, scum or
on the spoon, ete.

An observation by Edwards and Severn '* seems to
belong here. It concerns an epidemic of follicular in-
flanmation of the tonsils which was traced to the milk,
probably from one cow, which contained staphylococei
and streptococei, which bacteria were also found in the
coating of the throat of the affected persons.

™ Arehiv f. Wissensch. u. prakt. Tierheilkunde, 1586, p. 411.
™ Zeit, t. Fleisch u. Milehhygiene, xi. p. 114.
1 Britisu. Medical Journal, i. Ws97, p. 939.

ie

98 MILK HYGIENE

In the literature there are reports of numerous simi-
lar epidemics of inflammation of the throat in man
which had their origin in infection through milk, but
there are no proofs that these were caused by cases of
mastitis. They may have come from a later contamina-
tion of the milk with pathogenic bacteria.

[A large number of cases of this sort are recorded by
Swithinbank and Newman in their ‘‘ Bacteriology of
Milk,’’ published in 19038. L. P.]

Since cases of udder inflammation in which the secre-
tion contains bacteria harmful to man cannot be differ-
entiated by clinical means from the less dangerous, the
milk of every cow affected with mastitis should be re-
garded as injurious to health. This applies not alone
to the altered secretion, but also to the apparently nor-
mal milk from the parts of the udder not affected. The
diseased secretion will always soil the udder and teats,
and therefore there is no warranty that the bacteria in
question do not fall into the milk when drawn from a
healthy section of the udder. This is true especially
when the improper practice is followed of milking the
diseased secretion on the floor.

If a case of gangrenous mastitis appears in the
herd, the affected animal must be removed from the
stable, since it is possible that the milk will be contam-
inated with bacteria that are often especially virulent
and that multiply very rapidly. Upon the occurrence of
infectious inflammations of the udder in a milch herd it
may be necessary to forbid the sale of milk that is not
boiled. Milk from a herd affected with this disease
should never be used as ‘‘ nursery milk.’’

i. Acute croupous and hemorrhagic enteritis. Some-
times a virulent enteritis occurs among young cattle; it
appears less often among mature cattle; it may appear
as a sporadic disease or as a smal! -pidemic. This dis-

INFECTION BY MILK og

ease ix accompanied by fever and signs of great consti-
tutional disturbance, and it quite often ends in death.
The pathological changes have been studied compara-
tively little up to this time. It may, however, be stated
that there ix sometimes found a diffuse inflammatory
hyperemia in the mucous membrane of the whole small
intestine, sometimes very extensive pseudo-membranes
form a cast within the intestine, while in other cases
swelling and hemorrhagic infiltration of Peyer's patches
are found which, at the same time, may be ulcerated, or
covered with erupo-diphtheritic exudate. The mesen-
teri¢ glands, usually other glands, too, are swollen and
more or less hyperemic, or even hemorrhagic ; the spleen
may be enormously swollen. In some cases the lesions
somewhat resemble typhoid fever in man, vet the disease
is not identical with it.

The investigations that have been made by Jensen
indicate that these forms of enteritis are, as a rule,
caused by bacteria which belong to the hog cholera group
and that are therefore closely related to the typhoid
bacillus. The flesh of the infected animals may be most
dangerous to health; not a few of the so-called ‘* meat
poisoning,’ epidemics have been traced directly to these
forms of enteritis, and most of the bacteria isolated in
meat poisoning cases belong to the hog cholera group.

It is not impossible that in virulent enteritis bacteria
that have entered the blood may, now and then, be
exereted in the milk as, for example, when there are
slight hemorrhages in the udder tissue; doubtless,
however, a serious contamination may oecur during
milking, for in this disease diarrhea is a prominent
symptom and the afflicted animals are much soiled by
their feces.

A. positive example of the transmission of such a
form of enteritis to man through milk, has been given

100 MILK HYGIENE

by Follenius and Gaffky.*’ It is as follows: In the lab-
oratory of hygiene at Giessen, two assistants and a ser-
vant became very ill after drinking raw milk which was
proven to have come from a cow with hemorrhagic ente-
ritis. The symptoms were headache, weakness and diar-
rhea. In the servant, the disease seemed to resemble
cholera, with the others it was more like typhoid fever.
Gaffky isolated from the feces of the sick persons, as
well as from the feces of the cow, a member of the colon
group which grew rapidly and was very virulent. The
organism was the same in all cases.

It is probable that a case of disease mentioned hy
Rehn,'® was caused in a similar way. A child two and a
quarter years old was attacked by a typhoid-like disease
after drinking raw milk, which was rich in colon bacilli.
He recovered in the course of five weeks. <A sister some-
what older had a lighter attack.

As, doubtless, every case of such virulent enteritis
of cattle offers opportunity for the infection of the milk
with pathogenic bacteria, which apparently are virulent
for man, every animal affected with a severe, bloody or
febrile diarrhea, should be removed from the stable at
once. The contaminated part of the stable should be
earefully cleansed and disinfected. If a number of cases
of the disease occur, the sale of the milk of the whole
herd must be prohibited, for a longer or shorter time.

In this connection, observations by A. Holst 2° con-
cerning cases of poisoning through ‘‘ pultost ’’ (a kind
of cheese) should be mentioned, since the bacillus found
belongs to the same group, although it is not proven that
its occurrence in the cheese was due to contamination
with bacteria from cases of enteritis of cattle.

18 Ref. in the Zeitseh. fiir Hygiene, III.
19 Hyeien. Rundsehau, IV, No. 21.
20 Zentralblat fiir Bact., NX, 1896.

ISPECTION BY MII. 101

Indigestion of cows very often leads to a lessening of
nulk secretion and, at the same time, to a change in its
taste and composition. The milk may have a bitter or
salty taste and appear to be thinner, is sometimes yel-
lowish in color and coagulates very easily. When such
changes are present, or when there is simply a disturb-
ance of digestion, the milk should not be mixed with
other milk designed for sale. The question here is not,
however, one of the contaminating micro-organisins, nor
does it relate strictly to the passage of a disease from
eattle to man.

y. “Calf cholera.” It is well known that under this
common term are grouped infections of the intestines
(usually caused by colon bacilli, less often by proteus
forms) and wmnbilical infection, with or without local
inflammation, (arthritis, pyamic processes, bacteria-
mia); the latter infection is sometimes caused by colon
forms, sometimes by staphylococet and streptococe: and,
rarely, by necrosis baeillt or other bacteria.

An endemic outbreak of these infectious diseases
signifies a great propagation of the causative bacteria
in the cow stable and, therefore, it is most probable that
the milk hecomes infeeted while being drawn. There are
no positive cases that prove that milk from a farm where
calf cholera is prevalent, has caused disease of children
or adults, but as no special attention has heen given to
this matter, it is quite natural that such vases as may
oceur are not fully understood. Milk from such a herd
should he regarded as suspicious and its sale as ‘* nurs-
ery milk "’ should not be allowed until conditions on the
farm have been improved.

k. Septic metritis. In septic inflammation of the
uterus, which is specially prevalent in herds where cows
in calf are purchased from dealers, great quantities of
ichorous exudate are secreted and expelled from the

102 MILK HYGIENE

vagina, and this exudate contains pathogenic bacteria
(streptococci, staphylococci, colon forms, ete.) as well
as bacteria of putrefaction (proteus varieties among
them). During milking, some of this pathological mate-
rial may fall directly into the milk and the udder, tail,
thighs and flanks are usually so dirty that contamination
of the milk is scarcely avoidable. There are no definite
observations of disease that has been caused in man
through the milk of such animals, but since these organ-
isms are known to be harmful there can be no doubt that
the milk may be injurious to health; therefore, its use
should not be permitted under any conditions. Since it
is readily possible that the cows standing beside the af-
fected animals are contaminated by the excretions from
the uterus, sick animals should not be allowed to remain
in the stable oceupied by the milk producing herd.

The same applies to cows which retain the afterbirth,
but without suffering from septic metritis. The danger
of contamination with pathogenic bacteria in this case
is not great but the milk may be contaminated very
easily by the entrance into it of the bacteria of putre-
faction that are present in the purulent discharges.
Moreover, the milk—even that of healthy animals—may
absorb foul odors during milking, odors which are often
very pronounced throughout the whole stable where such
an animal is stalled; or the odor of earbolic acid or creo-
lin used for treating the animal may enter the milk.
Hence, such cows should be taken to an isolated part of
the stable where other cows cannot come in contact with
them and their milk should, under no circumstances, be
added to the market milk.

1. Suppurative processes. What has been said of
septic metritis applies, essentially, to diffuse cellulitis
and extensive suppurating’ sores. When animals with
such conditions are in the stable, there is great danger

INFICTION BY AITLK 103

that the milk may be infected with bacteria of suppura-
tion, among which streptococci are able to cause enteritis
in man. With wounds and ulcerations of the teats (pox,
gangrenous buckwheat eruption, etc.), the danger is
present and the milk of such cows should, at least, not be
used for nursery milk. If there are single small sores
that no longer suppurate, the milk may be sold, pro-
vided the teats are carefully washed before milking.

m, Other infectious diseases. The secretory function
of the milk glands is affected to no small degree in many
severe infectious diseases. This is shown principally by
the diminished quantity of milk but often, at the same
time, by changes in its composition. In this way the
milk may acquire an unpleasant or salty taste; its layer
of cream has often a dirty color and, when it is boiled,
little lumps separate due to the increased quantity of
albumin or globulin. It is probable that under these con-
ditions abnormal products of metabolism and, now and
then, pathogenic bacteria find their way into the milk;
therefore, milk should not be used in severe cases of
fever, as rinderpest, malignant catarrhal fever, croup,
malignant broncho-pnewnonia, pywmic and septiewmic
processes, ete.

n. Milk sickness. .\ curious disease called ** milk
sickness ’’ is found in the central part of the United
States; it was formerly confused with anthrax, and has
occurred as an epidemic among animals and man but
seems to disappear with improved cultivation. Accord-
ing to the reports of Dr. Kimmell the disease occurs
among horses and ruminants, when they are pastured in
certain places. After a period of incubation, violent
trembling and great restlessness appear which increase
during the succeeding days. The animal may fall and
die suddenly but often it lies for several days in a para-
lyzed, half dead condition. Through the ingestion of

104 MILK HYGIENE

meat, milk and dairy products, the disease is communi-
cable to man. It may develop mildly with severe vomit-
ing and difficult breathing as the prominent symptoms,
or, on the other hand, it may end in death, preceded by
subnormal temperature, paralysis of a great part of the
body and progressive dyspnea. Death approaches
imperceptibly and without the supervention of rigor
mortis. This mysterious disease, which was formerly
attributed to poisonous plants eaten by the cattle with
their food and whose toxic principles were supposed to
be secreted in the milk, is probably, according to the pre-
ceding, an infectious disease.

V. CONTAMINATION WITH ORGANISMS OF
SPECIFIC DISEASES OF MAN

Milk may be contaminated with specific organisms
from persons suffering with infectious diseases. Such
contamination may take place during milking, during its
handling on the farm or, later, while it is being handled
or stored in the dairy or market-place. Sometimes this
occurs from sick persons coming directly into contact
with the milk, sometimes it occurs in an indirect way.
The method of contamination differs in respect to dif-
ferent diseases, since infectious material may come not
only directly or indirectly from persons but may also
come from the water used for cleansing the milk vessels.

In the literature of recent years, there are numerous
reports of very significant epidemics supposed to be due
to infection carried by milk. Such ‘‘ milk epidemics ”’
are especially frequent in England and America and this
may, no doubt, be accounted for by the fact that it is
not so customary in England and America to boil milk
as it is, for example, in Denmark and Germany. Most
of the epidemics relate to typhoid fever, diphtheria and
scarlet fever; but cholera and several other diseases may

CONTAMINATION WITH ORGANISMS 105

be spread by means of milk. In some cases, no doubt,
epidemics have wrongly been ascribed to the use of milk,
for their origin might be explained in another way, but
a very great number of cases remain wherein the respon-
sibility of milk as a distributor of contagion cannot be
doubted.

[In most eases, the conclusion that a given outbreak
of disease is caused hy the use of infected milk does not
rest on the evidence of the discovery of the specific
organism in the milk, but on the manner in which the
outbreak occurs and upon the various attendant cireum-
stances. For this there are two reasons; first, none of
the specific germs may be present in the drop or two sub-
jected to examination, even though they are relatively
numerous in the whole supply, for such organisms are
not in solution and are not evenly distributed and, see-
ond, infectious diseases do not occur until after a certain
period of incubation, and when this time has elapsed the
milk that carried the specifie organisms is no longer in
existence. But the evidence of the transfer of such dis-
eases by milk is none the less convincing. Tt is as clear,
for example, as the evidence that typhoid fever is ear-
ried by contaminated water, and this evidence is re-
garded as sufficient to justify the expenditure by cities
of vast sums to secure pure water.

Milk epidemics are often characterized, according to
the observations of Swithinbank and Newman?! by the
following features:

1. Special incidences of disease, as among the cus-
tomers of a certain milkman; in families using the great-
est quantities of milk; among persons who drink most
milk and, for this reason, among women and children.

2, A velatively short period of incubation.

“The Bacteriology of Milk, London, 1903.

106 MILK HYGIENE

3. Sudden onset and rapid decline of the outbreak.

4. Certain clinical characteristics of the milk-borne
disease, especially a somewhat milder form of disease
than is customary.

5. A lower mortality rate than when the disease is
transmitted by other means, as shown by the following
table:

DISEASE | MORTALITY PERCENTAGES
Milk-Borne Outbreaks Not Milk-Borne
Scarlet fever.......... | 12.0 16.2
Typhoid fever........ 11.0 74
Diphtheria........... 18.9 30.3
|

The above table is made by Swithinbank and New-
man (whose chapters on this subject should be read)
from a study of many thousands of cases of milk-borne
disease. It should be stated that the mortality percent-
ages in the first column are actual, and taken from the
records, while those of the second column are based on
estimates from other writers. L.P.]

a. Typhoid fever. During recent years, especially,
there have been numerous reports from city and coun-
try, of typhoid epidemics which have been traced to con-
tamination of the milk by typhoid bacilli, and to the dis-
semination of disease through such milk. At first, the
correctness of the observations was doubted, since it
was not possible to find the typhoid bacillus in milk, but
recently the observations have so increased in number
and accuracy that it is not to be denied that the principal
means by which typhoid fever is distributed in places
where there is a safe and hygienic water supply, is
through the milk. Although it cannot be said that
typhoid fever is especially prevalent in Denmark, yet a

TYPHOID FEVER 107

number of epidemics during recent years, nay be pointed
out that can be traced with more or less certainty to
infection through milk, or with which milk was con-
cerned in the great spread of the contagion. Dr. Carée =?
has reported about 90 large and small typhoid epidemics
which occurred outside of Copenhagen during the period
from 1878-96 and which probably were due to infection
from milk, also 5 milk epidemics which occurred in
Copenhagen during the years 1879-1895. In 1900, no
less than 3 milk epidemics occurred in Copenhagen, and
it does not appear that these were related to each other.
The sanitary inspector, A. Ulrik,?? made a detailed re-
port on these outbreaks, and since they show very char-
acteristically the conditions that oecur in milk epidem-
ies, they are cited as examples.

In the first epidemic, the cases were grouped about
a city mileh herd and the two sales places connected
with it. Some cases of typhoid appeared in this quar-
ter of the city in August, but the origin of these was not
perfectly clear. At this time, a saleswoman in charge
of one of the milk shops became ill of typhoid fever and
was taken to the hospital. It was discovered that she
had suffered with severe diarrhea for about fourteen
days but she had not been under the physician’s care
until high fever developed. By degrees, 35 cases in all
broke out, among them the woman in charge of the other
milk shop and these cases were, in part, traced directly
tu infective milk; in part they must have originated from
contagion carried from one person to another. It was
found during the time that the disease prevailed that the
milk had twice been infective—at the beginning and in
the middle of .\ugust—but it was not possible to prove
the exact channel through which bacilli entered.

22 Tidsskrift) for Sunudhespleje, VI. 1sus.
2: Tiddskrift) for Sundhespleje. VITT, 1901.

108 MILK HYGIENE

The state of health of the herd and the condition of
cleanliness of the premises aroused no suspicion. After
cleansing and disinfecting and after discontinuing the
business for a short period, the epidemic ceased at once,
although a few individual cases still occurred that were
caused by infection that had taken place earlier.

The milk of these same shops was infected anew
in the middle of October, probably by a girl who was
believed to have become infected during a stay in a place
near Copenhagen. Shortly afterward, the two sons of
the herdsman were infected by the milk, and later three
other persons. By means of a temporary prohibition
of the sale of raw milk and raw cream from the herd and
by thorough cleansing, the epidemic was checked.

The third epidemic was of greater extent. In the
middle of November a number of typhoid cases were
found in a certain section of the city and suspicion soon
fell on a certain milk shop. The further development of
the epidemic, during which the shopkeeper became ill,
confirmed these suspicions. Altogether, 71 persons were
infected directly or indirectly through the milk, which
must have been most contaminated from October 26th to
November Ist, judging from the times of appearance
of disease and the number of persons affected. Despite
the investigation which was instituted, the ultimate ori-
gin of the infection was not discovered.

H. Moller has observed and described as follows an
epidemic caused by milk from a codperative dairy, which
is rather characteristic:*4 Seven farms supported a
cooperative dairy. <A case of typhoid fever occurred on
one of the farms; the dairy continued to receive the milk
but did not boil the skim milk that was returned. With
brief intermissions, 40 persons, altogether, became in-

24 Ugeskrift for Laeger, 1890, p. 128.

TYPHOID FEVER 109

fected with typhoid fever on the dairy farm first
infected, on the farm upon which the creamery was sit-
uated and on + other farms, only one farm remaining
exempt. Through contagion, the disease was carried
from these farms to 7 other families and 14 more per-
sons became affected.

Hart’s and Freeman’s collections of the milk epi-
demics in the literature gave an idea of the importance
of this method of transinission of typhoid fever. Hart
collected the established milk epidemics from 1857-81
and found accounts of 51, with 3500 cases of the disease
and 590 deaths, while Freeman found 53 epidemics from
1880-96. The number of milk epidemies observed since
then is proportionately greater, no doubt because this
means of transmission is better known and, therefore, is
more frequently recognized than before.

Wiile in the case of some epidemics it is quite easy
to prove that the fection of the milk came from a sick
person working with the milk, in other cases everything
points to the producing farm as the seat of infection, but
may not reveal the ultimate origin of the contagion. Tn
such cases attempts have been made to traee the infee-
tion to a disease of the cows, but without sound basis,
for no stance is known wherein domestic animals have
suffered from any disease caused by the typhoid
bacillus.

From our knowledge of the epidemiology of typhoid
fever, it may be said with assurance that milk may be
infected with typhoid bacilli through the addition of
water (in washing the vessels or through adulteration
with water) or by bacteria from patients or conva-
lescents.

It is a well known fact that many epidemics of this
disease have been traced to infection from impure drink-
ing water, and it is self evident that milk, which is favor-

110 MILK HYGIENE

able to the growth of typhoid bacilli, may be infected in
this way. Water from open or thin walled springs or
wells may be directly infected by the entrance of water
which has been contaminated by the excretions of the
sick. [All surface streams are liable to become contam-
inated either directly or indirectly, through carelessness
or imperfect drainage systems.

Typhoid bacilli may be blown about in dust, car-
ried on the boots of persons who walk over infected sur-
faces and they may also be carried by flies, as was
abundantly proven during the Spanish-American and
the South African wars. Cloths used for washing milk
cans may earry this infection. In one instance, in Phila-
delphia, it was found that a small milk dealer was in the
habit of washing his milk bottles in the family wash tub.
Milk has become contaminated during cooling, either by
a leak in the tubular cooler or by the entrance of water
into a submerged can. L. P.]

Concerning direct or indirect infection from sick per-
sons or convalescents, emphasis should be laid upon the
fact that the disease often runs so light a course that the
diagnosis of typhoid fever is not established; further,
that feces, and often urine, contain bacilli in great num-
ber and that convalescents often have bacteriurea for
months after typhoid fever and daily excrete number-
less bacilli with the urine. Neufeld *> has collected some
reports on this subject: of 210 typhoid patients not less
than 45 (more than 20%) excreted bacilli with the urine,
and Petruschky °° found that the number of bacilli in the
urine exceeded 170,000,000 per ec. It will be evident
to every one who is familiar with existing conditions and
customs, especially in the country, that under these
circumstances no extreme or unusual carelessness or

25 Deutches med. Wochenscehr., 1890, p. 824.
26 Zentralbl. f. Bakteriologie, XXIII, 1898, No. 14.

TYPHOID FEVER an

accident is necessary to afford an indirect or direct
means of carrying typhoid bacilli into the water or milk.

The typhoid bacillus can multiply rapidly in milk
and greatly increase in number in the course of a short
time, it resists the commencement of acid formation but
is partly checked and killed by great acidity; yet it is
not certainly killed by the degree of scouring to which
cream is subjected before churning. Bolley and Field
have found that typhoid bacilli will live at least ten days
in butter [and Bruck has shown that they were virulent
after 27 days]. Hence, not only milk and cream but
also buttermilk (epidemic in Hamburg; Frinkel and
Koster), newly made butter and fresh cheese may be
bearers of virulent typhoid bacilli. The typhoid bacillus
is destroyed by pasteurization at 80° C. (176° F.) and
heating for a few minutes at 70° to 75) C. (158) to 1677
F.) will kill it. Care must be taken to heat the whole
volume of milk to this temperature. (See ‘* Pasteuri-
zation.’’)

In pure culture, the typhoid bacillus does not change
the appearance of milk and alters its reaction but little.
It is very difficult to detect it in milk, as it is in drinking
water, for its colonies in gelatin are very similar to
those of the colon bacilli. To detect it, the milk must be
sown in the usual method in gelatin plates and then as
great a number as possible of suspicious colonies iso-
lated. These are then implanted in fermentation bulbs
in bouillon, some of which contain grape sugar and some
sugar of milk. Those forms which cause an acid reac-
tion in the milk sugar bouillon or those which ferment
the grape sugar with the formation of gas or which do
not change the reaction of the grape sugar bouillon are
to be rejected. Only those cultures which give a strong
acid reaction without producing gas in the grape sugar
bouillon, are really suspicious and these must be sub-

Ai? MILK HYGIENE

jected to a far more searching examination before they
can be identified as typhoid bacilli.27 It is unnecessary to
pursue this subject further, since the demonstration of
the typhoid bacillus in market milk is not, as yet, a prac-
ticable procedure in milk inspection.

Jensen’s investigations have shown that there are
several kinds of typhoid bacilli, distinguished from each
other by a somewhat different fermentative power. It
appears to be possible that by means of cultures from
different patients one may determine what cases of
typhoid belong to one and the same epidemic.

b. Diphtheria. Diphtheria not infrequently appears
to be spread by milk from milk shops or by that deliv-
ered from codperative dairies, but less frequently than
typhoid fever.

N. Flindt ** has given a detailed account of such an
epidemic in the neighborhood of Holbeak in which the
disease was being spread for a long time by milk from
a cooperative dairy. He states: The epidemic occurred
in June, 1889, and soon became violent. Fifty-one per-
sons were sick at the end of the month, 16 cases occurred
the following month and in August and September 6
more; 3 patients died. Everything tended to prove that
milk delivered from the codperative dairy had contained
the contagion and this belief was strengthened by the
fact that two persons from the dairy were affected. The
exact mode of entrance of the infectious material into
the milk was not traced. The case is remarkable in that
the milk appears to have been contaminated for quite a
long period.

**C. O. Jensen: On Vanskelighederne ved Typhusbacillens Diag-
nose og om Racer af Typhusbacillen. (On the Difficulties of Diag-
nosing Typhoid bacilli and on the Races of Typhoid bacilli)
Hospitalstidende, 1901, p. 1193.

*8 Ugeskrift for Laeger, 1890, p. 405.

DIPHTHERIA 113

A large epidemic of diphtheria 2? which broke out
among the inhabitants of the villages along the coast
north of (‘openhagen, in 1881, offered conditions of prop-
agation which strongly signified that milk was the means
of spreading the contagion.

In 1893 a small epidemic was noted in Lund, Sweden,
when eight persons in different families were sick with
diphtheria. These cases were traced to the use of milk
from a farm near Lund which was infected with diph-
theria.“°

Quite an extended epidemic occurred in 1886 in Frim-
ley, Mngland; in the course of a few days 70 cases of
diphtheria occurred, distributed in more than 30 fam-
ilies, 15 eases being fatal. All the sick had received milk
from the same dairy. Not one case of diphtheria oc-
eurred during this time among those using milk from
other dairies.*!

[The medical literature of recent years contains
many reports of milk-borne outbreaks of diphtheria, a
number of which are gathered and summarized by
Swithinbank and Newman."* The following case, cited
in their summary, is instructive. At Ashtabula, Olnio.,
100 persons became affeeted with diphtheria in Decem-
ber, 1894. The houses in which the disease oecurred
were widely separated but milk was taken at all of them
from the same dairyman. On the farm of this dairyman,
a workman had a very sore throat, probably diphthe-
ritie. This person had assisted in the work of the dairy
while suffering acutely from sore throat. Of 44 house-
holds investigated, it was found that 32 had received

2" Veeskrift for Lacger, SSL.

29 Tfospitalstidende, 1805.

“Ret. in Milehzeitung, 1886, p. S35,
= Bacteriology of Milk.

s

114 MILK HYGIENE

milk directly from this sick person; the other 12 had
received milk from the same dairy but it had been deliv-
ered by another man. In this outbreak there were 24
deaths. L.P.] <A great many other reported cases
might be quoted.

As yet the diphtheria bacillus has rarely been iso-
lated from market milk but, notwithstanding this, there
can be no doubt of its occurrence in milk and that it may
thus cause epidemics like those mentioned above. The
bacillus must come directly or indirectly from the oral
cavity of people who are or have been recently attacked
by diphtheria. Just as the typhoid bacillus is main-
tained in many cases in the urine of convalescents, it is
also very common for diphtheria bacilli to retain life for
months, even for a whole year, in the oral cavity and
on the mucous membrane of the nose in persons who
have been affected, but who have entirely recovered from
the disease. It is on this account that it was possible in
only a few epidemics of milk-borne diphtheria to dis-
cover the original source of infection and it is difficult,
not to say impossible, to wholly guard against the occa-
sional infection of inilk by diphtheria bacilli. Fortun-
ately, these bacilli are frequently of low virulence.

The opinion, that was held formerly by some, that
diphtheria in man could come from a disease of milch
cows, is entirely erroneous.

Tt has been stated that diphtheria bacilli grow readily
in raw milk and that they thrive less well in boiled milk
(Schottelius) ; but from the experiments made by Meyer,
it appears that diphtheria bacilli act as other bacilli; that
is, that they are checked by the germicidal power of
fresh raw milk and grow best in boiled milk.

Diphtheria bacilli withstand acidity and may there-
fore be present in the different dairy products, but the
infectivity of the latter has not yet been determined.

SCARLET FEVER 115

It is certainly very difficult to prove the presence of
diphtheria bacilli in market milk because even if the
milk has been the cause of the epidemic, they are pres-
ent in only very small quantity and, usually, but for a
limited time. If one wishes to experiment in this direc-
tion the hest method of proceeding is to make a culture
on blood serum (Loffler’s) in a manner similar to that
employed in the examination of the throat of a diph-
theritic patient. If the culture tubes are brought to
body heat for 24 hours, the conditions will be more
favorable for the increase of the diphtheria bacilli
than for the greater number of milk bacteria. One
must then make a careful study of the colonies that have
developed.

c. Scarlet fever. Reports of scarlet fever epidemics
that are presumably to be attributed to the spread of
infection through the milk, come eliefly from Tengland
and America. The infectious material must come from
affected persons and may enter the milk directly through
their contact with it when it is being drawn, in the sales-
places, ete., or it may reach the milk in an indirect way.
Since the organism of this disease is unknown, it is diffi-
cult to form a well founded opinion concerning these
possibilities, and one cannot ascertain whether there is
an increase of the infectious material in milk.

About 18 years ago some searlet fever epidemics
arouscd great attention in England because it was
thought that, without doubt, they could be traced to an
infection through milk and to a peculiar new eruptive
disease upon the teats and udders of cows. From the
evidence that is now available, one is justified in regard-
ing it as established that the outbreaks of scarlet fever
referred to had no relation to the disease of cows,
which was in reality only a somewhat unusual form of
COW PON,

116 MILK HYGIENE

Malet ** cites an example of a milk epidemic wherein
from August 21st to the 2d of September, 18 persons be-
longing to 11 households were attacked with scarlet
fever after drinking milk from a farm where there was
a searlet fever patient.

[The cases next following are selected from among
those cited by Swithinbank and Newman.**

Buffalo, New York (reported by Wende). ‘‘ Two
outbreaks of scarlet fever occurring in 1899 in Buffalo
were traced to an infected milk supply. The first out-
break was that of 57 children, the second was less severe
and numbered only 20 cases. The channel of infection
was well traced out in the former, and it was found that
on the implicated dairy premises there were two cases
of desquamating scarlet fever. One was a child, aged 9,
the other a young man aged 19 who did the milking and
in other ways assisted in the dairy during his illness.
The 57 cases were almost simultaneous in occurrence,
and the severity of the attack appeared to depend upon
the quantity of the implicated milk consumed.”’

London, 1901. The total number of cases was 293, all
resulting from one polluted milk source. ‘‘ The out-
break occurred on the delivery course of a certain con-
tractor in London. He obtained milk from 38 farms.
On one of these farms there were four cases of scarlet
fever, the farmer, his wife, son and daughter. The cows
were healthy.’’ The cases were widely scattered in Lon-
don but were all directly traceable to milk from the im-
plicated farm. ‘‘ The large number of adults attacked
differentiated this outbreak from those of ordinary type.
After the regular distribution had been stopped the con-

33 Reference in Recueil de méd. vétr., 1895.
°4 Bacteriology of Milk. For original references to cases cited,
see this work.

ASIATIC CHOLERA iar

tractor then sent his milk to other consumers, who then
contracted scarlet fever.’’

Beverly and Salem, Massachusetts, 1901. The num-
ber of cases was 60, all resulting from one polluted
source, ‘* The dairyman in this outbreak produced 5
eans of milk daily and obtained 14 other cans from 3
neighbors. On one of these 3 farms, 3 children had been
ill; a girl of 16 had sore throat, another girl of 12 anda
hoy of 14 followed a few days later with a similar affec-
tion, namely, swelling of the glands in the neck, and gen-
eral malaise. One of them had a slight rash. .\fter the
recovery from acute condition they assisted in handling
the milk. The outbreak was very sudden, and promptly
declined from a time dating a few days after the milk
supply from the farm was stopped. The fatality was
high, as many as 11 deaths occurring. The distribution
of the cases of scarlet fever was localized to the distri-
bution of the milk in question.’’ L. P.]

d. Asiatic cholera. From what we now know of the
epidemiology of cholera it cannot be doubted that the
spread of the germs of cholera is due chiefly to drinking
water; nevertheless the possibility of its spread through
milk and other foods cannot be left out of consideration.
Examples of transmission through milk are certainly
not nuncrous; one of the best established is the follow-
ing reported by Simpson: On board a ship in the harbor
of Caleutta, 10 persons fell victims to cholera after
drinking milk sold by a native. Four patients died, 5
others were seriously ill, and one who drank but little
of the milk was slightly affected. It was learned that
the milk had been diluted with water from a tank into
which the excrement of a cholera patient had been
thrown a few days before. Among those who did not
drink the milk there was no illness.

Simpson was able also to trace a small cholera epi-

118 MILK HYGIENE

demic in a prison in Caleutta, with considerable cer-
tainty, to the distribution of the cholera bacilli through
the milk, and it was probable that the milk was already
infected before delivery. Gaffky also reported an epi-
demic caused by infection through milk.

In quite fresh milk, cholera bacilli appear to succumb
readily to its bactericidal action, but they increase
rapidly in older milk but are again checked and, at last,
killed, as the acidity increases.

€. Tuberculosis. Tubercle bacilli may enter milk not
only from tuberculous cows and infected stables but also,
without doubt, from tuberculous people. Of course
there is no definite illustration—for obvious reasons—of
transmission of tuberculosis in this way; but if one con-
siders what a quantity of tubercle bacilli may be ex-
ereted daily by a consumptive, the possibility of such
transmission can scarcely be disputed, although the dan-
ger is considerably lessened by the fact that the number
of tubercle bacilli will not increase while the milk is kept.
It is justifiable, therefore, to forbid tuberculous people
working with market milk.

f. Other diseases. It is stated in text books that there
are instances of the transmission of syphilis, and there
are reports in English journals of epidemics of sore
throat and of erysipelas which are said to have come
from infection through milk. In these latter cases, how-
ever, it is doubtful if the infectious material came di-
rectly from sick people, for the microbes concerned
(chiefly streptococci) may gain access to milk from other
sources.

[As illustrations of such outbreaks of sore throat,
the three following cases are taken from among those
summarized by Swithinbank and Newman.**

%5 Bacteriology of Milk.

SEPTIC SORE THROAT 119

In Anglesey, in 1897, 15 people who took milk of one
dairy, became affected at about the same time with sore
throat. Several persons in the affected families who
consumed milk from the same source but in a boiled state
escaped the sore throat, the chief evidence of which was
tonsilitis. The bacteriological examination of the milk
revealed the presence of Streptococcus pyogenes and
Staphylococcus pyogenes, but no Bacterium diphtheriae.
Bacteriological examination of the patients’ throats
yielded precisely similar results.

‘*In May, 1902, an outbreak occurred in Lincoln,
affecting a large number of persons. Dr. Brook had
seventy-five eases in his own practice. The chief svmp-
toms were erythema of the face, and sore throat. In
many cases a drab colored fur covered the tonsils. A
roscolous, papular eruption, in some cases appearing to
he urticarial, occurred in two-thirds of the cases. There
was no marked fever, except in cases having complica-
tions. The pulse rate was not increased, and no albu-
minuria occurred. The onset was sudden, and in no
case out of the seventy-five investigated by Dr. Brook
was infection communicated to others by contact.
Nearly all of the patients were adults, and well advanced
in years. The complication most commonly met with
was swelling and tenderness of the cervieal glands.
With one doubtful exception, all the patients had had
milk from the same dairy. Boiling the milk appeared to
prevent persons from taking the complaint. The poison
seemed to be present particularly in the cream. The
differences between the disease and scarlet fever were
very marked.

‘+ A sudden outbreak of a severe form of ‘septic sore
throat’ occurred at Bedford at the end of June, 1902.
On 27th June, the first case occurred; on 29th June, +
eases occurred; 30th June, 15 cases occurred; Ist

120 MILK HYGIENE

July, 13 cases; 2nd July, 3 cases; 3rd July, 2 cases; and
4th July to 8th July, 4 cases—making a total of 42 cases
in 22 families. The symptoms included redness, swell-
ing of the throat, fauces, palate, and uvula, with numer-
ous spots, patches of exudation, and in some cases
ulcers. The general symptoms consisted of severe head-
aches, giddiness, backache, and pains in the limbs, very
much like an attack of influenza. The temperature was
about 102° to 103° F., but in a few cases was higher. In
some cases there was gastric and intestinal disturbance.
Great weakness was also present. In every case the
milk supply was obtained from the same dairy. On
Sunday, 30th June, many persons consumed cream with
fruit, and these included nearly all the worst cases. In
some families children who drank boiled milk escaped,
whilst parents who consumed unboiled milk or cream
were attacked. One man took cream in the form of ice-
cream, and had a severe attack.’’

It must, however, be regarded as possible that these
cases of sore throat were caused not by contamination
of the milk from a human source but to the presence of
organisms of suppuration eliminated by cows with dis-
eased udders. L. P.]

The transmission of measles, small-pox, pest, dysen-
tery, or cerebro-spinal meningitis by milk has not been
observed, but the possibility of such transmission can
scarcely be doubted.

VI. CONTAMINATION WITH OTHER BACTERIA

Milk becomes infected with bacteria during the act of
milking. These contaminating organisms come partly
from the teat canal, partly from dirt, hairs, and dandruff
on the skin of the cow, partly from the hands and cloth-
ing of the milkers, partly from the dust of the stable.
Still more are added when the milk is collected and

CONTAMINATION WITH BACTERIA = 121

stored in unsterilized vessels or when it is exposed to
the air. It is evident that the number of bacteria found
in freshly drawn milk varies greatly according to the
conditions of cleanliness of the stable and the cows, and
as to the cleanliness and carefulness observed during
milking.

Freshly drawn milk possesses a certain bactericidal
action which, however, does not seem to affect all forms
of bacteria. The number of living bacteria in milk may
be lessened appreciably in the course of a few hours as
a result of this activity, but the action does not last and,
under appropriate temperature conditions, bacteria
soon begin to increase and their number, at times, be-
comes enormous. The rapidity with which the bacteria
increase after milking is dependent entirely upon the
temperature at which the milk is kept.

If the milk is cooled immediately after being drawn
and is kept at a temperature not higher than 10° C.
(50° F.) there is no material increase of bacteria during
the first 2+ to 36 hours; even at 14° to 150 (. (97.2 to
59° F.) the increase is relatively slight. But as the
temperature rises, the number of bacteria mereases
rapidly and bacteria are very numerous in milk that
has stood at 20)" to 9° C. (68° to 77 ~ .) for 12 hours,

In order to illustrate the importance of cleanliness
in the stable and during milking, the following figures
determined hy Grotenfeld may be of use. In one e.c. of
milk from cows particularly well cared for, he found 106
bacteria, while the freshly drawn milk of cows in a dirty
stable contained 617,000 bacteria per e.c. Therefore, one
cannot generalize as to the number of bacteria in freshly
drawn milk, but milk from well-eared-for and carefully
milked cows wil, as a rule, contain hardly more than
1000 to GOOO bacteria per e.c. The following results show
the potent effect of cold in checking the increase of bac-

1Z2 MILK HYGIENE

teria. The milk used contained about 9300 bacteria in
one ¢.c. and was kept at 15°, 25°, and 35° C.:

AT 15°C, (59° F.) | Av 25°C. (77° F.) | AT 35° C. (95° F.)
Beginning of the test. 9,300 9,300 9,300
After 3 hours 10,000 18,000 30,000
After 6 hours 25,000 172,000 12,000,000
After 9 hours 46,000 1,000,000 35,280,000
After 24 hours 5,700,000 50,000,000 577,500,000

At the low temperature, it is seen that the increase
is at first very slight. Moore found that the number of
bacteria in milk kept at 21° C. (70° F.) did not increase
during the first 6 to 9 hours but then increased rapidly ;
he also found that in the course of from 36 to 48 hours,
no appreciable increase in the number took place, if
the temperature did not rise above 12° to 13° C. (53.6°
to 55.4° F.) and that a still lower temperature, as 4° to
5° CL. (389.2° to 41° F.), could prevent the increase of
bacteria for a longer period. Meyer found, through
experiments carried on in Jensen’s laboratory, that
cooling the milk to 10° to 12° C. (50° to 53.6° F.) checks
the growth of bacteria for a long time.

It is evident, from all of this, that the quick and per-
manent cooling of the milk to 10° to 12° C. (50° to 53.6°
F.) is most important in preserving it.

Of course the number of bacteria in market milk
varies greatly according to its age and care and to the
temperature of the air. Experience gained in most of
the larger cities shows the bacterial content of market
milk to be seldom below 50,000 to 100,000 per ¢.c. but it is
often greater, varying between 1,000,000 to 30,000,000;
indeed, not infrequently, even from 100,000,000 to 150,-
000,000 have been found. And such milk may not be
noticeably tainted.

SPONTANEOUS CHANGES IN MILK 123

If the question be asked: What is the sanitary signifi-
cance of the existence of this mass of bacteria? we must
consider the changes which bacteria in pure culture may
cause in milk, and which were mentioned above, for it
is evident that these same changes occur, although often
very much less clearly marked, in market milk rich in
bacteria. When inilk is kept a long time it may become
altered in one of several ways, of which the following
are the most common:

1. The well known coagulation (curdling), following
the formation of acid, is the most frequent.

2. Less often, a more or less disagreeable (putrid)
odor and taste occur without much acid formation and
without coagulation.

5. Still Jess frequently, the milk hecomes slimy or
stringy,’’ either without souring, or accompanying
the process of souring.

Sour milk. It is known that sour milk has no harmful
effect on healthy people. But it is different with those
suffering with catarrh of the stomach, and with small
children. In these cases a degree of acidity not be-
traved by coagulation or appreciable sour taste appar-
ently may cause vomiting and indigestion, possibly be-
cause the numerous lactic acid bacteria rapidly increase
with the warming of the milk in the stomach, and cause
coagulation before the gastric juiee can check their
growth. Milk in which the lactic acid fermentation is so
far advanced that it will not stand boiling, or the taste
of which is slightly sour, must therefore be regarded as
unfit for food for small children. The number of bac-
teria in milk does not give us a safe criterion for judging
it in this connection, but the degree of acidity furnishes
a reliable guide. (See below.)

Putrid milk. Even though the taste is not vet decid-
edly foul, but is only bitter (formation of peptone)

ee

124 MILK HYGIENE

nausea and vomiting may be caused, even in adults, and
there are many instances of the poisoning of large num-
bers of people by such milk. This alteration is most fre-
quently observed in summer when the milk is not prop-
erly cooled, and occurs especially in milk that has been
warmed or even boiled for a short time [pasteurized],
without sufficient cooling afterward.

Slimy milk. According to information at hand, the
slimy change seems to have no harmful effect, although
it may make the milk most unappetizing. In Sweden,
however, this change is produced and ‘‘ langmjolk ’’ is
prepared for food, as sour milk (curds and whey) is
prepared in other countries. Milk that is inclined to the
shmy change should not, at any rate, be fed to small
children.

Some bacteria that occur in milk but which, on ac-
count of their properties or small number, do not have
any noticeable effect upon the appearance or changes
of the milk, may still be harmful. These are sporulat-
ing forms, as the hay bacilli or members of the group of
butyric acid bacilli, which may break up the casein with
the formation of albumoses, peptones and amid- and am-
monia compounds. Sometimes there are bacteria which
generate special poisons that go into solution in the milk
or that remain attached to the bacteria cells. Little is
known of these forms, although the opinion has been
frequently expressed that these very bacteria play an
important part in the etiology of diarrhea in children.
Finally, there may be bacteria which are pathogenic for
animals and for man and that are capable of causing
inflammation. Such bacteria are very common in mar-
ket milk. In the examination of 56 samples of market
milk in Berlin, Beck found streptococci in 34, which
caused fatal enteritis when fed to rabbits and guinea
pigs. In injecting milk in the abdominal cavity of rab-

SPONTANEOUS CHANGES IN MILK 125

bits Gin order to test it for tubercle bacilli) Friis discov-
ered that 15 of the 28 samples contained bacteria which
caused either peritonitis or abscesses or pvemia.
Guinea pigs were generally useless for his experiments
because they all died of peritonitis. Similar results have
been obtained hy many others.

The forms of bacteria considered in this connection
are chiefly streptococci, staphylocoeci and members of
the colon group, some of which are generally present,
although, perhaps, in quite sinall amounts, in market
milk; besides these, there are still many other kinds,
some of them occurring regularly, in small numbers, and
some are only met with now and then. Where do these
hacteria come from? Primarily from the dirt that gets
into the milk when it is drawn,—it is a well-known fact
that the excrement contains numerous, and sometimes
pathogenic, bacteria. They may also come from cases
of mastitis and metritis in the stable; moreover these
forms of bacteria are widespread and probably they
very often occur in cow stables, as is shown by the fre-
quent occurrence of calf cholera. ** Calf cholera“ is a
conuon name for a group of fatal diseases of new-born
ealves among which the most usual forms are navel
infection (most frequently caused by streptococci, colon
bacilli and pseudo-colon bacilli) and diarrhea or dysen-
tery of calves (in most cases caused by colon bacilli).

Tt does not follow that all milk containing strepto-
cocci or the other bacteria referred to above is harmful
or dangerous. But if these are present in large num-
bers, they make the milk suspicious and there are many
evidences that such milk has been most injurious. It is
highly probable that a very great part of the gastro-
enteritis, so harmful to small children, is traceable di-
rectly to these bacteria. The fact that the mortality
among sinall children in general has decreased to a great

126 MILK HYGIENE

extent where the milk is bacteriologically clean or has
been sterilized according to Soxhlet’s method, is one
of the arguments in favor of this view. Heubner is of
the opinion that infant mortality has been diminished in
this way to the extent of 27 per cent.

In order to prevent too great contamination by such
bacteria—it is difficult to wholly exclude them—there is
no other way than strictly to guard the health of the
herds, as well as the cleanliness of the stable [of the
utensils and receptacles] and of the attendants. The
eventual danger may be partly removed by pasteurizing
or boiling the milk.

VII. ADMIXTURE OF DIRT

As has already been stated, it is customary for milk
to become more or less contaminated with particles of
dirt and their adherent bacteria during milking. The
dirt consists, principally, of bits of manure and, besides
this, hairs, dandruff, particles of food, earth and dust.

Usually, after milking each cow, the milk is passed
through a strainer which retains particles of dirt; but if
the strainer is not cleaned very frequently, the particles
of dung and dirt are softened in the milk, bacteria are
washed through and substances that carry abnormal
odors and tastes are set free in the milk. By straining,
then, one accomplishes only the removal of the larger
and more solid particles of dirt that are quite harmless
in themselves, such as hairs, cellulose, sand, ete.

When unclean milk is permitted to stand, a distinct
sediment is formed and its presence signifies lack of
cleanliness in respect to production.

The importance of dirt contamination is due chiefly
to the addition of bacteria with the dirt and to the solu-
tion of fecal matter; the visible dirt is important only
as it makes the milk unappetizing. It follows that a

ADMIXNTURE OF DIRT 127

greater or less dirt content has a great influence upon
the healthfulness and keeping quality of the milk; this
is emphasized hy a study of the bacterial content of cow
dung. Wiithrich and Freudenreich found this to vary
according to the kind of feed; the bacteria in the dung
of cows fed with hay appeared to be most numerous;
1 gramme of such exerement contained 375,000,000
bacteria.

Of course the quantity of dirt in market milk differs
very greatly. .An investigation in Hamburg showed that
the quantity varied from 0.0 to 183.5 milligrams per
liter; on the average, there were 13.5 milligrains of dry
dirt ina liter of milk. In other experiments, Schimelk in
Christiania found an average of 11 milligrams in a liter,
von Ilellens (Ielsingfors) found only 1.79; in Berlin,
Renk showed the average to be 10.3; in Halle, 14.92;
in Leipsig, 3.8 and in Munich, 9.0. The maximum quan-
tity im each ease was much greater than the averages
mentioned, although it never reached the maximum for
Hamburg milk.

In Dresden the standard regarding market milk
states that it must not contain more than 8 milligrams of
dirt per liter,

In Dennark there are no general regulations con-
cerning the dirt content of milk; *" there, too, it varies
considerably, it is great in the milk from distillery fed
herds and less in milk delivered by the large companies.

26 Ty 1805, the Copenhagen health commission had 39 samples of
milk tested for dirt, which was found in small quantity, varying be-
tween 1 and 13 milligrams per liter.

PART IV.

PASTEURIZATION AND STERILIZATION

In the household, milk is boiled to make it keep
longer and this process serves also to kill any pathogenic
bacteria that may be present. Little by little, the public
has learned that milk often contains disease producing
germs and that small children are especially exposed to
their harmful effects, so the custom has become more or
less general of sterilizing milk intended for infants.
Quite naturally, the idea developed to sterilize market
milk, by heating before it was offered for sale. By
this means, the following desired results have been ob-
tained: the milk keeps for a longer time, it loses its
capacity for infection, and the annoying process of ster-
ilization in the home is avoided. In most large cities
there are one or more companies engaged in the sale of
sterilized or pasteurized milk.

The difference between pasteurization and steriliza-
tion consists, essentially, in the greater degree of heat
applied during the latter process.

I, PASTEURIZATION

By pasteurizing a fluid is generally understood heat-
ing it to a certain temperature which is sufficient to in-
crease its keeping qualities. It is sometimes used to -
indicate heating to 50° to 60° C. (122° to 140° F.) and
sometimes to the use of a higher temperature. In ref-
erence to milk and dairy products, the term ‘‘ pasteur-

ization ’’ is used in a more definite sense. In butter-
128

PASTEURIZATION 129

making pasteurization is understood to mean a brief
heating of the cream and whole milk to 80° to 85° C.
(176 to 185 ~F.), the purpose of which is to kill most
of the existing bacteria, in order to prevent those fer-
mentations of the cream which might cause the butter to
he of inferior quality. At the same time, pathogenic
micro-organisms (particularly tubercle bacilli) are made
harmless. In some places, ‘‘pasteurized butter’’ is made
solely for the latter purpose.

In Denmark, on account of the danger of spreading
tuberculosis among animals, it is provided by law that
skim milk and buttermilk delivered from creameries to
be used as food for animals must have been heated to 85°
C. (185° F.). In this connection, however, the law does
not mention pasteurization but, in practice, pasteurized
separator milk (or buttermilk) is understood to be milk
that has been subjected approximately to the above men-
tioned temperature and that does not react to Storch’s
or to the guaiac tests.

Since market milk is pasteurized especially in order
to render harmless any disease producing germs that
may possibly be present, and since the majority of con-
sumers are, doubtless, of the opinion that pasteurized
milk may be used with perfect safety without further
heating, it should be strictly required that market milk
sold as ‘‘ pasteurized ’’ shall have been subjected to a
sufficient degree of heat to kill with certainty all of the
pathogenic micro-organisms that are present.

The pathogenic bacteria that are of importance in
this connection are the germs of tuberculosis, typhoid
fever, diphtheria, cholera and pest and pyogenic cocei
and the virus of foot-and-mouth disease. These have
been shown by recent investigations to be killed by mo-
mentary heating to 70° to 80° C (158° to 176° F.) and
they die at a temperature of 65° C. (150° F.), if this

9

130 MILK HYGIENE

degree of heat is maintained long enough. This is also
true of many bacteria occurring in milk which may be
injurious, yet which cause no specific disease. There-
fore, milk may be pasteurized either by a brief heating
at a higher temperature or a longer heating at a lower
temperature. But the spores of bacteria and the thermo-
philic forms that are specially capable of resisting heat,
are not destroyed by these methods, so pasteurization
does not have the same effect as sterilization. Milk may
be pasteurized in different ways. The following three
methods are those most commonly used:

2. The milk is heated during one-quarter to one hour
at from 80° to 85° (176° to 185° F.) while it is flowing
through an appropriate pasteurizing apparatus; then it
is cooled immediately.

2. The milk is heated from one quarter to one hour
at about 65° C. (150° F.) in a tank or vat. The milk
flows directly from this vessel into the one in which it
is to be sold, or it is first passed through a cooler.

3. The milk is poured into well cleansed or sterilized
bottles or metal vessels, is then heated for a consid-
erable time at 65° to 80° C. (150° to 176° F.), then the
bottles or vessels are sealed and quickly cooled.

For sanitary reasons the last of these methods is
unquestionably to be preferred, but it has not been
adopted extensively on account of its cost. Heating
many small vessels requires a great amount of heat and
causes great loss in bottles, if such are used. The initial
cost, also, and the amount of labor required are con-
siderable.

If one of the first two methods is employed, the pas-
teurized milk must be drawn into vessels (bottles or
metal cans) which have previously been properly
sterilized.

Pasteurizing milk and then placing it in unsterilized

PASTEURIZATION 131

vessels has no effect. Indeed, if bottles are used, this is
to be forbidden as injurious to health. Very often the
milk is drunk directly from the bottle, which may be
infected hy this means and, in spite of washing, fresh
milk may be infected as it is poured out. In this connec-
tion, What is to be understood hy sterilization? The aim
is, SO far as possible, to kill all microbes. The task is
not difficult with metal vessels because, after thorough
mechanical cleansing, these can be subjected to very hot
steam or can be scalded. With glass bottles, the task is
more difficult, because strong heat causes much break-
age, and if the price of the milk is not such as to cover
this loss, another imethod must be used. Thorough me-
chanical cleansing, scouring the outside as well as the
inside, followed by long soaking, in a strong, warm solu-
tion of washing soda at 70° CO) (158° EF.) and rinsing in
pure, lukewarm water, 1s believed to kill with reasonable
certainty all pathogenic forms and also the majority of
other milk bacteria.

AC very large number of machines for the quick pas-
teurization of milk have been built, chiefly for use in
ereameries. The principle of these machines is dif-
ferent. One of the first pasteurizers was that made by
Fjord; it consists, as the diagrams (Figs. 5 and 6, pp.
152 and 133) show, of a tinned copper tank provided with
an insulated steain jacket. The tank contains rotating
arms by which the milk is thrown against the heated
walls. The milk is admitted at the bottom through pipe
H and leaves the apparatus at the top.

By regulating the quantity of milk admitted, the
rapidity of the revolving arms and the amount of steam,
the milk may be heated as desired. Many other pasteur-
izing machines are built according to the same principle.

In other pasteurizers, the milk is heated while it
flows in thin layers over heated metal surfaces, or while

132 MILK HYGIENE

forced between two surfaces lying close to each other,
or while it is being passed through a system of heated
pipes. In some pasteurizers hot water serves as the
source of heat for the metal surfaces or pipes, while
steam is used in others.

hi

tl

}

Fjord’s pasteurizing apparatus.

Since one can hardly be sure that every particle of
the whole volume of milk is heated to a given tempera-
ture by this method of pasteurization, it should be re-
quired that the temperature of the milk, when it leaves
the apparatus, shall he at least 80° C. (176° F.). If this

PASTEURIZATION 133

is not done, it cannot be regarded as certain that the
milk has been freed from pathogenic micro-organisms.
Moreover, a pasteurizer which is to prepare milk for
use as food must fulfil the following requirements :

1. The entire quantity of milk, including the froth
formed during heating, must be heated equally to the
desired temperature.

Fic, 6.

il -( I
cm an | | i

Fjord’s pasteurizing apparatus.

2. The apparatus must work reliably, im order that
there shall be no danger that at times the milk is not
sufficiently heated.

3. The machine must be casy to clean.

134 MILK HYGIENE

All pasteurizing apparatus must be under the con-
stant inspection of a reliable man, or must be provided
with a self regulator. A regulator which shuts off the
milk automatically if the temperature of the contents
of the machine falls below the given standard, was de-
vised by Henriques and Stribolt. Up to the present
time, this principle is not widely applied, but doubtless
it deserves to be introduced into the better plants which
prepare and sell pasteurized milk. Fig. 6 shows a
Fjord pasteurizer with a self regulator; the latter con-
sists of a metal thermometer (see Fig. 7) whose free
arm (n) is attached to a horizontal rod (+ y) which may
move a valve placed in the entrance pipe to the pasteur-

izer.
Fia. 7.

Automatic temperature-regulator, as devised by Henriques and Stribolt,

The construction is shown by Fig. 7. As the temperature of the
milk in the machine rises, the two arms of the thermometer approach
each other and the valve m dc is thus pressed back by the horizontal
rod r w, which presses against m so that the opening at b & is free

PASTEURIZATION 155

and the milk can pass from o to p. If the temperature falls, the
pressure of the horizontal rod is withdrawn from the valve, which is
then caused to close the opening by means of a spring, s, so that the
milk cannot flow to the pasteurizer; thereupon the discharge of milk
immediately ceases, and not until the milk has been sufficiently
heated will the valve open again, so that fresh milk may enter and
expel that already heated from the apparatus.

Fig. 8.

Schmidt’s milk-cooler; a, entrance for cold water; b, exit for cold water.

From the pasteurizer, the milk must be passed over
or through a cooler in order to lower the temperature as
much as possible, for otherwise it would soon spoil.

From the cooler, the milk should be drawn directly
into the container from which it is to be sold. Fig. 8
represents a cooler which consists of a spirally fluted

136 MILK HYGIENE

metal tank, through which cold water or, better, ice
water is passed and over the surface of which milk
slowly flows.

For pasteurizing milk in bottles or in cans an appa-
ratus of different construction is used. Some consist
simply of a water bath; a large shallow metal tank is
partly filled with water and the bottles are so placed in
this that they are submerged as close as possible to the
neck, then the tank is closed by a cover and the water is
heated with steam.

Other pasteurizers are built according to the follow-
ing principle: there is a perforated drawer in a large
metal tank upon which the filled bottles are placed close
together (Fig. 9); after the tank has been tightly closed
by means of a cover or door, steam is admitted until the
desired temperature is reached. Of course these ma-
chines are also adapted to sterilizing at a higher tem-
perature (100° to 110° C., 212° to 230° F.). After
from one-half to one hour’s heating, the bottles are
allowed to cool a little before the tank is opened, then
they are immediately sealed. In some machines, all of
the bottles are sealed before the tank is opened, by
means of a specially arranged mechanism. The further
cooling of the bottles is attended with certain difficulties,
as they crack easily. This may be accomplished by
passing the bottles through several tanks of water of
progressively lower temperature, or by slowly lowering
the temperature of the water surrounding them.

While the fact of the previous heating of milk to not
less than 80° C. (176° F.) may be established with cer-
tainty by the Storch or guaiac tests, it is not possible to
determine whether or not the milk has been subjected to
a less degree of heat; moreover, since a brief heating at
80° C. (176° F.) is cheaper and far more convenient than
a longer heating at, for instance, 65° C. (150° F.), there

PASTBL RIAXTION 137

is much to be said in favor of the establishment of a fixed
rule that all milk designated as pasteurized shall be
heated to at least 80° C’. (176° F.), that is, a temperature
that can be determined by the Storch or guaiac test. But
there is another side to the question. In the medical

Fie. 9.

Flaack's apparatus for sterilizing bottled milk.

world the sentiment against pasteurizing at high tem-
peratures has been growing during recent years, for it
has been claimed that this eauses a change in the pro-
teids which makes them less digestible. In many places,
therefore, tlhe longer heating at a lower temperature. has

138 MILK HYGIENE

been adopted. All milk from Bolles’ great establish-
ment in Berlin, is handled in this way.

Under these conditions, such a requirement as that
mentioned above could scarcely be maintained but, with-
out doubt, regulations with regard to the sale of pas-
teurized milk should be laid down, and the following
appear to be appropriate:

1. Milk sold as “‘ pasteurized ’’ without a more ex-
plicit statement must have been heated to at least 80° C.
(176° F.).

2. Milk that has been pasteurized by heating at a
lower temperature, shall be sold as “‘ pasteurized ’’ only
if it is marked with a label giving the degree of heat ap-
plied, and not until after the health authorities are con-
vinced that the establishment in question is prepared to
pasteurize in an approved and effective way.

The advantages derived from pasteurizing market
milk, from a hygienic standpoint, are as follows:

1. The specific pathogenic bacteria are destroyed.

2. Most of the other bacteria are likewise killed and,
therefore, the milk keeps better.

3. Pasteurization necessitates a better method of de-
livering milk than that commonly employed in many
places.

By means of pasteurization, as has been said, the
pathogenic bacteria and the larger part of the other
bacteria are killed. Since the bacterial content of ordi-
nary milk is most variable, and since the forms are by
no means always alike, the number of bacteria that live
through pasteurization—even after heating to the same
temperature—is not even approximately the same. In
other words, the average bacterial content of milk that
has been pasteurized a short time cannot be stated.
There are usually only very few bacteria per ¢.c. in pas-
teurized milk that was freshly drawn and handled in a

PASTEURIZATION 139

cleanly way; while under other conditions hundreds,
even thousands of bacteria are to be found in every c.c.
of pasteurized milk. Lactic acid forming bacteria in
milk are killed by pasteurizing, while certain harmless
bacteria, many bacteria of putrefaction and spore form-
ing bacilli survive; for this reason pasteurized milk sel-
dom sours bit gradually putrefies.

No absolute conclusions can be drawn concerning the
effectiveness of pasteurization from the bacterial con-
tent of pasteurized milk sold in the retail market, for
one does not know the nature of the milk before pas-
teurization, the length of time the miik has been kept
since pasteurization or the temperature at which it has
been kept, and these factors are largely responsible for
an abundance of bacteria.

The objections to pasteurization are:

1, Even hy the use of a self-regulating pasteurizer, it
is difficult to provide absolute guarantee that all milk
has heen heated to the required temperature,

2. Pasteurization incurs expense, therefore the milk
costs more.

5. Toa certain ‘legrec, pasteurization may conceal a
tainted condition which exists before heating. Quite an
abundance of bacteria of putrefaction and other bacteria
may be present, or the lactie acid fermentation may have
hegun to take place; these bacteria are killed by pas-
teurization, consequently the fermentations and changes
that were under way are interrupted. Under such cir-
cumstances, one cannot tell by the appearance or taste
of inilk that it is damaged and that it contains the
products of decomposition of the albumen, or, possibly,
even toxic substances. On the whole, there is no way,
at the present time, of determining whether or not pas-
teurized milk was damaged hefore it was heated, while,
with respect to raw milk, the keeping quality and bac-

140 MILK HYGIENE

terial content furnish sufficient evidence regarding its
true condition.

+. The bacteria surviving pasteurization are, for the
most part, the quick growing bacteria of putrefaction
which are inhibited in raw milk by the lactic acid bac-
teria, but in pasteurized milk they multiply very fast and
undoubtedly they are capable of generating poisonous
substances. It has been suggested, therefore, that a
pure culture of lactic acid bacteria be added to milk
after pasteurization in order to check the bacteria of
putrefaction.

5. In purchasing pasteurized milk, one cannot tell if

| NUMBER OF SAMPLES

NUMBER OF BACTERIA IN 1 C.C.

Ordinary whole milk Pasteuriz’d whole milk

0-10 2 2

10-50 -
100-500 = 2
500-1,000 = 4
1,000-5,000 = 1
5,000-10,000 = 10
10,000-20,000 = 6
20,000-50,000 12
50,000-100,000 2 7
100, 000-1, 000,000 7 66
1,000,000-5,000,000 1 20
5,000, 000-10,000,000 = 9
Above 10,000,000 1 3

Total number of samples... 9 142

it be fresh or old and cannot determine, from its appear-
ance, if putrefaction has begun or if only a few bacteria
are present. That this objection to the sale of pasteur-
ized milk is valid, is shown by the Copenhagen health

PASTEURIZATION 141

Commission, in its report, especially that for 1899, on
the nuinber of bacteria in pasteurized milk, as compared
with the number in unpasteurized milk.

It is evident that these figures do not seem to favor
pasteurized milk, and the situation is still less favorable
if one considers that the bacteria in raw whole milk are
chiefly lactic acid bacteria, while in pasteurized milk
the greater part consist of bacteria of putrefaction. The
figures above cited for the year 1899 are especially high,
but the summary given below is made from examina-
tions of pasteurized milk extending through a period of
several vears 237

NUMBER OF COLONIES IN
Jd GER: 1896 Tsu7 1Sys Tsita 1900
one =
Below 100,000 22 26 12 44 | 40
100,000-1 000,000 1 5} {9 (8 | By
Above 1,000,000 l 17 ie | 26
Total number of sumples 23 ne 48 142 | 105

This increase in the number of strongly infected sam-
ples occurs coincidently with the equipment of many
milk establishments for the production of ‘* pasteur-
ized *? milk and apparently without such careful direc-
tion as to make it certain that the whole quantity of
milk was really heated to the required temperature ; that
this was the case is indicated by the result of ivestiga-
tions of the health commission in the year 1899, which
show that of 36 samples of pasteurized cream 2, and of

99

389 samples of pasteurized milk 23 could not stand the

“7 Stadslacvens Aarsberetninger (Annual Report of the City Phy-
sieian). Copenhagen.

142 MILK HYGIENE

Storch test, which showed that they had not been heated
to 80° C. (176° F.).

When we compare the advantages and disadvantages
it will be found that there is serious doubt as to whether
it 1s advisable to endeavor to obtain general pasteuriza-
tion of market milk, as has been suggested by many. A
well organized and well conducted large milk business
may be in position to carry out pasteurization with
safety and to obtain all the various advantages that
result from this process but, undoubtedly, it would be
necessary for the great majority of establishments to
be kept under comprehensive, strict and expensive con-
trol by the health authorities which, even then, could
searcely be effective.

II. STERILIZATION

By sterilization of milk is understood a long contin-
ued boiling, or heating to a temperature above the boil-
ing point as 105° to 110° C. (220° to 230° F.). The
superiority that is claimed for sterilization over pasteur-
ization is that all of the bacteria are killed and the milk,
consequently, will keep for an unlimited time. But
nearly al] the examinations of ‘‘sterilized milk’’ bought
in the market, that have been made, up to the present
time, have shown that the milk is not sterile but con-
tains the spores of bacteria. On the whole, sterilization
offers no special advantage over pasteurization, on ac-
count of the unpleasant taste of sterilized milk, due to
changes in the albumen and lactose, and on account of
the greater expense connected with it. Sterilization has
the advantage only when it is a question of keeping the
milk a long time or transporting it a long distance, and
in this case the principle followed is essentially the
same as that followed in the preparation of preserves in

STERILIZATION 143

hermetically sealed cans. Considerable advance has
been made in recent vears in regard to the preparation
of such preserved, canned, milk, in that the boiled and

Fic. 10.

Kleemann’s high-pressure pasteurizer and regenerative heater. a, water of condensation
b, to the cooler.

burnt taste las been prevented by pumping the air out
of the milk before heating it and by the exclusion of
oxygen during heating, so that a high temperature is
possible and a safer sterilization is accomplished without
seriously affecting the taste. Another difficulty which
it has been necessary to contend with, the separation of
cream, and of butter formation during storage, seems
hy degrees to have been overcome.

For the purpose of sterlizing milk, instead of the
usual apparatus built according to the Fjord system,
tightly closed machines are used, so that the tempera-
ture of the milk van be raised above the boiling point,
and through these the milk is forced by means of a small

144 MILK HYGIENE

pump. There is a large number of such machines. In
Germany they are commonly used for simple pasteuriza-
tion. Of the machines most used in recent years, the

Fig. 11.

©

Section, to show construction of apparatus shown in Fig. 10. u, entrance for milk; }.
exit for milk ; ¢, steam-chamber; d,steam-opening ; e, safety-valve.

so-called ‘‘ regenerative heater ’’ is to be commended be-
cause it saves much steam. It is built according to the
principle that the hot milk flows past the entering cold

STERILIZATION 145

milk (only a thin metal plate separating them) so that
both streams of milk have opposite directions; by this
means, there is the advantage that the hot milk, even be-
fore it leaves the sterilizer, is somewhat cooled without
expense, While the cold milk gains quite a little heat be-
fore it is heated by the action of the steam. In this way,

Fig. 12.

Mor's regenerative milk-heater.

steain, as well as ice, is saved. Machines built in accord-

ance with this principle differ much in appearance.

Some, for example the apparatus shown in Fig. 10, which

is one of the newest, consists really of two parts, the ster-

ilizer proper (the ‘* high pressure pasteurizer *') and an

apparatus quite similar (‘* the regenerative heater ’’)
10

146 MILK HYGIENE

in which the stream of warm milk works upon the incom-
ing cold milk. Both parts have the same construction,
which is easily seen from Figs. 10 and 11. Other ma-
chines of this kind (for example, Mor’s regenerative milk
heater, Fig. 12), are simpler in that both processes take
place in the same machine. For sterilizing milk meas-
ured into bottles, machines which are described and
figured on pages 136 and 137 (Fig. 9) are used.

PART V.

THE USE OF MILK FOR INFANTS

THe advantages of inilk as a general food for man
are so well known that no further discussion is neces-
sary; but the special use of milk for infants, as a sub-
stitute for mother’s milk, offers certain points of inter-
est which merit further consideration. It is logical first
to review the behavior of milk and the changes that
occur in it during digestion.

Under the influence of the gastric juice, the proteids
undergo a process of splitting up in the stomach. The
albumin and = globulin are’ first changed into) syn-
tonin and then separated into albumoses and, probably,
peptone. Casein behaves somewhat differently. Tt is
transformed by the hydroehloric acid of the gastrie juice
into an acid calcium salt and then, under the influence of
rennin, it undergoes a change, during which whey albu-
min ix formed, into ealeie paracasein, whieh separates as
acurd. The ealcie paraeasein is then split by pepsin into
albumin and paranuclein (pseudoneuclein) which is pre-
cipitated but which is afterwards dissolved hy the pro-
longed action of the gastric juice, being broken up into
an albumin-like material and phosphoric acid. The albu-
mins that are formed by splitting of the casein are later
changed into albumoses (caseoses) and peptone. Ac-
cording to recent investigations it appears that these
substances may undergo still other changes before they
are absorbed. Through the action of rennin, an albu-

min-like substanee (plastein) is formed and through the
147

148 MILK HYGIENE

action of an intestinal ferment (erepsin) the splitting
of peptone is continued into di- and mon-amido acids.
Little is known as to the resorption and use of these
substances.

There is a difference of opinion regarding the fate
of the milk sugar; some think it is absorbed from the
intestines unchanged, but others are convinced that it is
first inverted into dextrose and galactose. The absorp-
tion takes place more slowly than is the case with glu-
cose, maltose and cane sugar.

The absorption of milk-fat takes place as that of
other fats, with a preceding saponification.

It is well known that cow’s milk is being used more
and more as food for infants and for small children. As
a substitute for mother’s milk, there are some objections
to it, however, and if used for nursing babes, it must
receive especial treatment. This is on account of the
fact that it differs materially in chemical composition
from human milk and that it constantly contains micro-
organisms, and, sometimes, even pathogenic forms.

The differences in composition of human milk and
cow’s milk are shown hy the averages given below:

Water. Casein. Albumin. Fats. Lactose. Salts.
Woman’s milk... 87.92 0.58 0.52 3.43 12 0.2
Cow’s milk...... 87.75 3.00 0.50 3.40 4.60 SHOTS

[Human milk appears to vary more in composition
than cow’s milk. This may be due in part to the greater
difficulty in obtaining a fair sample than is the case with
cow’s milk. It is known, for example, that the compo-
sition of the fore milk and the strippings differ consid-
erably, and if small samples of milk are drawn from a
cow’s udder at irregular times during the day, before
and after regular milkings, the samples will be of very
different composition. Besides this, the less regular life

MILK FOR INFANTS 149

of the woman and the nervous influences to which she is
subject may tend to make her milk more variable than
that of the even-going cow.

The figures, however, that are given in the above
table show less proteids than were found hy most of
the leading authorities. The average composition of
woman’s milk, as determined by a large number of
andlvses, is given by Richmond as follows:

Water. Proteids. Fat. Lactose. Ash.
Woman’s milk................ 88.2 a) 3.3 8.8 02.

Johanssen, however, found but 1.1 per cent. of pro-
teids, as an average for 25 samples, thus agreeing, in
this respect, with the figures given on page 148 which
are from Gottlieb. L. P.]

The first thing to he considered is that the quantity
of total proteids in cow’s milk is more than three times
[or more than twice] the quantity in human milk, so
that a child nourished with cow’s milk has apparently a
considerably greater nitrogen assimilation than a child
nourished in the natural way. It is not known with cer-
tainty what significance this has for the health of the
child, but it is not safe, off hand, to eonelude that the
highly nitrogenous diet is advantageous. Moreover, the
chief part of the protein of ecow’s milk consists of a
casein, Which, in contrast with the casein of human milk
(the proteids of human milk do not give a curd with ren-
net), is precipitated in the stomach as large curds and in
a form that apparently makes it less digestible.

Great importance has been attributed by some to the
fact that human milk often contains more fat than cow’s
milk and, it is affirmed, on this account the nutritive
value of human milk is greater than cow's milk. But
since we know that the fat content of human milk is sub-
ject to great variation (for individual peculiarities see
page 24) no particular importance can be attributed, in

150 MILK HYGIENE

general, to this difference. On the other hand, the fact
must be considered that the fats in the two kinds of milk
differ somewhat chemically, and that cow’s milk contains
much more volatile fat (butyric acid) than human milk.
These other important conditions should be mentioned:
the decided different proportions of lactose which,
doubtless, is of value in the nourishment of the child, and
the small quantity of lecithin in cow’s milk, to which
great importance is now ascribed in metabolism. It is
doubtful if the greater quantity of citric acid and of
inorganic salts in cow’s milk has an unfavorable influ-
ence on the nourishment of the ehild.

Many attempts have been made to correct the defects
of cow’s milk and to make it a more appropriate food
for infants.

By diluting cow’s milk with water, the percentage
of salt is proportionately decreased so that the casein
coagulates in the stomach in flakes, just as the casein of
human milk, and at the same time there is a proportion-
ate diminution in the percentage of the total proteids.
But there is also a decrease in the quantity of albumin
as well as of the other ingredients of great nutri-
tive importance—lecithin, lactose and fat—which is
decidedly disadvantageous. In order to remedy this,
the milk is often diluted with barley- or oat-water or the
proper quantity of milk- or grape-sugar is added.
Others have used cream diluted with water; by this
means an appropriate quantity of protein and fat can
be had, and since fat may be substituted for lactose, the
deficiency of the latter makes little difference.

To make cow’s milk approach human milk more
closely, and to make it more easy of digestion many
methods of preparation, some of them rather complex,
have been proposed, and some have been used commer-
cially. The following are examples of such preparations :

MILK FOR INFANTS 151

“Gartner’s fut milk ’’ is prepared in the following
way: cow’s milk is diluted with water to such an extent
that the casein content corresponds to human milk, then
it is so centrifuged that the milk flowing from the cream
tube has a fat content which agrees with that of human
milk. The milk is put into bottles and sterilized. The
composition of the ‘‘ fat milk ’’ may, of course, be
changed at will; the average composition of such a prep-
aration made in Germany is: fat, 3.7 per cent.; proteids,
1.5 per cent.; lactose, 2.2 per cent.

“ Voltmer’s mother’s milk ’’ is the name given to a
milk preparation that is sometimes marketed in the form
of ‘‘ milk,’’ and sometimes is condensed and sold in
cans. The preparation is somewhat complicated; fresh
centrifuged cow’s milk is heated to 100° C. (212° F.)
and distilled water, cream and sugar are added to it in
such quantity that the content of proteids, fat and sugar
correspond to human milk; the mixture is now exposed
to the action of pancreas ferment which proccss changes
the casein into albumoses. The preparation is sterilized
at LOS” to 10a! (.. (215.6° to. 221° B.) or evaporated
and poured into cans which are sterilized after solder-
ing. .\ccording to several analyses, the composition of
the commercial product is, approximately: fat, 2.8 per
ecnt.; proteids, LS per cent. (about three-fourths of
this is albumose); sugar, 6.2 per cent.; and salt, 0.4
per cent.

“Backhaus'’s infants’ milk’’ is similarly prepared.
The cream is separated by the centrifuge; the skimmed
milk is heated to 40° C, (104° F.) and rennet and trypsin
are added. In the course of half an hour the precipi-
tated cheesy mass is filtered out; by this means a part
of the casein can be taken out, while the rest is trans-
formed into easily digestible albumoses. The action of
the ferments is stopped by heating, and cream and sugar

152 MILK HYGIENE

of milk are now added. The preparation, which is mar-
keted in a sterilized condition, has been widely recog-
nized. Its composition may easily be varied. For small
children a preparation of about the following composi-
tion is made: fat, 3.1 per cent.; casein, 0.6 per cent.;
albumin, 1.0 per cent.; lactose, 6 per cent.; ash, 0.4 per
cent.

Gottlieb has proposed that sweet whey, cream, sugar
of milk and lime’ water may be mixed together in such
proportions that the composition of the mixture will
closely resemble human milk.

[‘‘ Modified milk’? as developed and prepared by
the Walker-Gordon Laboratory Company, with the
scientific aid of Dr. T. M. Roach, has been in use in the
larger cities of America and in London for a number
of years; it was first prepared and sold in Boston in
1891. Such milk is dispensed upon physicians’ prescrip-
tions, and is prepared by mixing whole milk, cream,
whey, skim milk, lactose and water or other substances,
if ordered, as lime water, starch, barley-water. etc., in the
proportions required to give accurately the desired per-
centages of protein, fat, sugar, ete. It is dispensed in
round bottles (‘‘ tubes ’’) each of which contains suffi-
cient milk for a single feeding. The bottles are plugged
with cotton-wool. The milk is produced on farms be-
longing to or under the control of the company and most
exacting precautions are taken to protect it from con-
tamination.

The milk is served raw, pasteurized or sterilized, as
ordered. Usually it is pasteurized and if the proteids
consist chiefly of those present in whey, the tempera-
ture reached during pasteurization is not permitted to
exceed 155° F. By means of modified milk the nutritive
requirements of the individual child can be supplied.
In Po

MILK FOR INFANTS 153

Many special preparations similar to the above have
been used abroad and have received the approval of
pediatrists. In Denmark, however, they are used but
little and they will never have a very broad field on ac-
count of their high price.

In France, asses’ milk is quite commonly used as a
substitute for human milk and in Dresden an establish-
ment has been started for the production of asses’ milk,
which is desired partly because of its great similarity to
human milk and partly because of its favorable effect
in indigestion of children. On account of the small milk
yield of the donkey, this milk is much too expensive to be
used generally. For the same reason, mare’s milk has
been used in some places, but only to a limited extent.

Goat’s milk has been suggested as food for infants,
and large herds of goats have been maintained in some
places for this purpose—principally on account of fear
of tuberculous infection from cow’s milk. The prevalent
opinion of the infrequency of tuberculosis in goats is
untenable, since they are very easily infected and may
suffer, just as cows do, with udder tuberculosis. There-
fore, there is no reason to prefer goat’s milk to cow’s
milk.

In by far the majority of cases in which the mother
has not enough milk, or her child will not nurse, cow’s
milk is used as a substitute. The question has often been
discussed as to whether and, if so, what special require-
ments should be made for milk intended for infants, and
different answers are given. It was formerly thought
that the composition of the cow’s food had a marked
influence on the chemical composition of her milk, and
upon its character, and on account of this opinion it was
formerly required in Germany that cows kept for this
purpose must be fed nothing but dry food the entire
year. The price of such milk has been considerably in-

154 MILK HYGIENE

creased on this account. In Denmark also, similar,
though less strict, requirements were made for the pro-
duction of milk for infants. During recent years, how-
ever, views concerning the effect of the forage on the
quality of the milk have changed materially, and it has
been observed by many that babies have been fed with-
out discoverable detriment on milk from cows fed with
green fodder, turnips, oil cakes, etc., and, indeed, in some
instances, with brewery grains. There does not appear
to be adequate ground for the requirement that cows
kept to produce nursery milk should be restricted to this
one sided diet. On the other hand, there is need for an
active control of the sanitary conditions of the produc-
ing herd, for the public must be assured that milk sold
at a high price especially for the use of infants may be
fed to them without danger of a grave infection of some
kind. The nature of the requirements which, in our
judgment, should be made concerning the production,
handling and sale of ‘‘ nursery milk ’’ are considered
later.

The mortality among children during the first year
of life is very significant. In Norway and Sweden, from
1891 to 1895, on the average, 10 per cent. died each year;
in Denmark, 14 per cent.; in Finland and Switzerland,
15 per cent.; in Prussia, 20.5 per cent.; in Baden, 22 per
cent.; in Wurtemberg, 25 per cent.; in Bavaria, 27 per
cent.; and in Saxony, 28 per cent., while the mortality in
Austria and Hungary is 25 to 28 per cent. The mor-
tality is greatest in large cites, somewhat less in small
cities and least in the country.

Different cities show different death rates; for ex-
ample, from 1886 to 1895, on an average, each year 13
per cent. of the children less than one year old died in
Lyons, 15 per cent. in Christiania, 16 per cent. in Paris
and London, and the death rate in Berlin reached 25.3

MILK FOR INFANTS 155

per cent., in Budapest 28 per cent., in Munich 31.4 per
cent. and in Ingolstadt even 40.9 per cent.”*

In Copenhagen, the mortality, during the first year
of life, has decreased significantly; 1877 to 1886, 20.83
per vent. died each year; in the next decade 19.04 per
cent., during 1897 to 1899, 17.87 per cent., while only
15.55 per cent. died in 1900. Infant mortality is also
on the deerease in the provincial cities, and this is
certainly true of many large cities abroad.

A comparison of normally fed children with chil-
dren fed on raw or prepared cow’s milk, shows a far
greater death rate among the latter. If the cases of dis-
eases and death are arranged according to the separate
months, it is noticed that in most cities there is a marked
increase of deaths in July and August and a propor-
tionate decrease in September, and this increased mor-
tality pertains almost exclusively to children fed arti-
ficially.

By far the greater part of the fatal diseases are af-
fections of the stomach and the intestines as eatarrh,
colics and cholera infantum. Although the causal con-
ditions are not fully explained, it may be stated that
cow’s milk appears to induce a predisposition to intes-
tinal infections, on account of its varying and hetero-
gencous composition. The diseases are to be attributed
to the action of microbes; possibly in some cases to bae-
teria that have formed toxie substances during their
development in the milk, but in the greater number of
cases it is, doubtless, a question of the presence of patho-
venice microbes in milk (streptococci, proteus- and colon
forms). Therefore, milk intended for infants should be
sterilized. Opinions differ as to whether heating with
steam for an hour (Noxhlet’s method) is to be preferred

“S These Heures are taken from Ohlens’ Die Mileh und ihre Beden-
tuug, 1905.

156 MILK HYGIENE

to brief boiling or to pasteurization, since it is thought
that long cooking affects the digestibility of the casein.

Through the zealous efforts of physicians, it has been
possible, during recent years, to cause the general ac-
ceptance of the practice of sterilizing milk for infants
and the reports show that this has had a favorable influ-
ence in preventing disease and death.

There are, however, some children with whom cooked
cow’s milk does not agree, as it causes continual indiges-
tion and loss of weight so that, indeed, when six months
old they may weigh less than at birth (infantile atro-
phy). This condition is often improved at once if a wet
nurse is procured for the child or if asses’ milk is used; or
a change to raw cow’s milk may lead to quick recovery.
An explanation of these different effects of cooked or
raw cow’s milk cannot be given here, since there is no
convincing reason for the opinion that cooked milk is
harder to digest than raw. Possibly the favorable effect
of raw milk can be attributed to the presence of sub-
stances antitoxic to some of the poisons absorbed from
the intestinal canal, which antitoxins are destroyed by
heating the milk. [In America, the balance of opinion
among pediatrists appears to be in favor of clean, raw
milk, specially produced, of low bacterial content and
from a reliable source (‘‘ certified milk ’’) ; or milk that
has been pasteurized at a moderate temperature (155°
to 185° F.) and that has not been boiled. L. P.]

PART VI.

PUBLIC CONTROL OF THE PRODUCTION
AND HANDLING OF MILK

NATURALLY there are great differences in different
countries in the way cities are supplied with milk and in
the manner in which it is handled after it reaches the
cities. Tn general, it may be said that there is no diffi-
culty in supplying small towns, as herds are sometimes
to he found within their limits and usually enough milk
is brought in from the immediately outlying districts.
It is different with the larger cities and, with respect to
them, the milk business has been greatly changed dur-
ing the last 20 to 30 years. The conditions in Copenha-
gen may serve as an example, as they do net differ mate.
rially from those found in other large Huropean cities.
Copenhagen was once supplied with milk chictly from
the brewery herds and other herds within the city, and
by farmers from the adjoming country, who delivered
milk to their own regular customers in the city; new the
conditions are wholly changed.

The continual growth of the city and the constantly
increasing lygienie demands have caused the almost
complete discontinuance of cattle keeping within the
city, and proximity to the large city has greatly affected
the character of the farming nearby, so that the breed-
ing of cattle and dairying have fallen off. On the other
hand, on aecount of easy transportation bv railroad,
farmers living at quite a distance van deliver their milk
to advantage in Copenhagen, and at this time the city is

137

158 MILK HYGIENE

supplied with milk not only from the island upon which
it is situated but also from the surrounding islands.
This facility of transportation by railroad and boat has
led to the establishment of milk depots that receive the
milk from the farms, handle it appropriately and deliver
it to their customers, selling it either from established
sales places, or from wagons.

This evolution in the handling of milk, which has
occurred in most of the large cities of other countries as
well, marks an important advance in hygienic methods.
The mileh herds in the cities and the retail shops con-
nected with them were very often the source of grave
epidemics; the uncontrolled sale of milk by small farm-
ers has had the same unfortunate result, and there is
danger, too, inthe small shops, as the limited space makes
it difficult to prevent the various members of the family
from coming into too close contact with the milk contain-
ers and with the milk itself.

Large companies are better able to bear the expense
resulting from the observance of hygienic requirements,
and the sanitary control of these may be much more
easily effected than in the case of numerous small con-
cerns. It is to be observed also that many of the large
milk establishments have voluntarily adopted standards
for the production and handling of milk that are in ad-
vance of requirements of the health authorities. There
are no proven cases of milk epidemics traced to infec-
tion through milk from well conducted large concerns;
no doubt the mixing of a large quantity of milk lessens
the danger of infection, since usually a certain amount
of infectious material is necessary to produce infec-
tion. On the other hand, however, the mixing together
of a great quantity of milk, weder unfavorable condi-
tions, may be particularly dangerous because if a milk
epidemic were caused it would be very widely spread.

HANDLING OF MILK 159

A strictly enforced control is, therefore, no less neces-
sary for large establishments than for small.

The first large milk company established in Co-
penhagen was the Copenhagen Milk Supply Company
which, more than 25 years ago, at a time when milk
hygiene was still on a low plane in Denmark, as it was
abroad, established, voluntarily, a comprehensive stand-
ard covering the condition of health, the cleanliness and
the feeding of the herd, the health of the milkers and
other employees and the proper handling of the milk.
This company rapidly developed a very important busi-
ness and has been imitated in Denmark and in other
countries. Several new companies have made even
greater advances in the adoption and enforcement of
livgienic requirements. Moreover, the large, well organ-
ized milk companies have had a very great influence in
foreing the small coneerns to handle their milk with
much greater cleanliness and eare.

The most familiar ways of retailing milk in cities,
are: the milk is drawn and sold in established shops or
it is drawn or dipped from tanks carried on wagons, or,
thirdly, the milk is fivst bottled, or is placed in cans that
are closed and sealed. The last method is decidedly the
best and it is now rapidly displacing the other methods.
When milk is measured out on the street, it may easily
be contaminated by dust and dirt blown about by the
wind, and as the delivery buckets are carried from one
kitchen to another, there is a possibility that ther may
carry contagion, This method of delivery is also at-
tended by the possibility of defective measuring, ete.,
by the deliveryman.

The hygienic requirements that should be established
with relation to the milk supplies of cities, will doubtless
lead to a further change in the milk business as this is
apparently going more and more into the hands of a

160 MILK HYGIENE

few large companies while the number of small con-
cerns is steadily decreasing.

[In America this tendency toward centralization of
the business is very marked in most large cities, and
especially in New York and Boston. The reason, how-
ever, is economic and is similar to the causes for con-
solidation in other lines of trade. L. P.]

Since milk, as has been said, can acquire harmful
properties in different ways, since its composition may
vary considerably, and since it may be adulterated in
many ways, the milk business must be supervised by
public authority, under appropriate laws or ordinances.
Formerly, in most large cities, the occasional examina-
tions had reference only to the fat content of the milk
(transparency test, determination of the specific gravity,
ete.), and in many places, even at the present time, no
further progress nas been made. But our present
knowledge makes it obvious that such an examination,
in comparison with the standard that should be estab-
lished to guard against dangerous milk, has relatively
little importance. The public control, therefore, is not
to be limited to an examination for adulteration and
souring or ‘‘ spoiling ’’ of milk on the market, but must
extend to the production and the care and treatment of
the milk (including the condition of health of those per-
sons who come into direct or indirect contact with it).
The enforcement of complete regulations for this pur-
pose, of course, is accompanied with great difficulties,
and there is no city in the world whose measures in this
respect can be said to be ideal. A point to be avoided in
such a control is a great increase in expense which would
raise the price of milk. This would be a hardship for the
public, the importance of which from the economic and
hygienic view points, must not be underrated. In the
inauguration of a thorough-going supervision it may

HANDLING OF MILK 161

be necessary to interfere considerably with the methods
of producing and handling milk as these have gradually
developed. Local conditions will have an important in-
fluence on the establishment of a system of control and
will determine the rapidity with which the various re-
quirements can be fulfilled.

General laws governing the production and handling
of milk, are lacking in most countries. Only a few coun-
tries (i.¢., Portugal in 1900) have enacted such Jaws and
there is not much evidence as to the practical success of
these requirements for a whole country. Ina large num-
ber of the cities of Europe somewhat detailed regula-
tions have been adopted in regard to the milk trade; but
these regulations, even in the same country, differ very
much. Dresden may be mentioned as an example of a
large city with excellent modern regulations for the
handling of milk. (Published July 31st, 1900, with
amendments of February 26th, 1901.) In order to estab-
lish a uniform system in Prussia, the Prussian govern-
ment in 1899 published a circular of information to mu-
nicipalities with detailed instructions for a judicious
regulation and supervision of the milk trade. In many
of the small cities there is either no control at all or a
very defective one.

[The following table from a report by H. E. Alvord
and R. A. Pearson on the milk supply of 200 cities and
towns in the United States shows the subjects of most
frequent legislation in connection with market milk in
126 cities, the milk ordinances and regulations of whieh
were examined with especial care. The most popular
subjects for legislation are readily seen.

ll

162 MILK HYGIENE

I

SUBJECTS. | NOMBRE. SUBJECTS alge
OF CITIES OF CITIES
Dairies: '|Care of milk:
License or permitrequired| 12 Milk vessels to be nonab-
Special authority for in- sorbent ...........+++- 55
spections.............. 58 Milk vessels to be thor-
Pure water supply....... 8 oughly cleaned ........ 32
Drainage of barnyards...; 12 Milk to be promptly re-
Stables : moved from the stable..| 11
Proximity to other build- Straining ......-.----.+-- 9
Tit ee ee ee 6 Cooling and aérating..... 15
DiGht dcuindareda saan wees « 15 Conditions of storage..... 23
Vertilattotics.siarccnsees 32 |/Sale of milk:
Floor space.........-.--- 15 Licenses, or permits...... 92
Air space ............06. 10 Licenses to be publicly
Cleanliness............-. 47 displayed ........... 24
Removal of manure...... 25 Source of supply to be
Drainage.............05- bye Posted i c202346 aeons 14
Other than dairy animals General inspectionin cities} 75
to be excluded......... 4 Signs on wagons ......... 79
Sanitary milk room...... 14 Unsanitary milk prohib-
Employees : ited.. pea vive ats Peigihates 109
P 1 cleanliness ..... 20 Conhseaties gt Jmpare
ersonal clean ;
Contagious disease (to be milk Khueies esse ena aes 30
reported) ............. 15 Desuie standard for com-
If exposed to contagious position Fetes tenes 67
disSeaS@s ses sis¢4 eraces 25 Skimmed mill prohibited} 12
Skimmed milk permitted
secitats conditionally .......... 61
Provisions for examina- Bottling at farm.......... 8
tion 66.0... ee eee eee 58 Storage of milk forsale...| 23
Diseased cows ........... 24 Milk tickets to be used but
Unwholesome food for- ONCE a. kopedsades sareas 16
bidden:: i: si.ssseosn ees 77 Milk wagons to becovered| 12
Pure water supply....... 40 Milk wagons not to carry
Cleaning cows........... 27 garbage ............... 5
Milk rejected at calving Sellers to register custom-
THING is ev cae aa arcoeew es 33 Ci R eda Leite titan cs 7

HANDLING OF MILK 163

While the establishment of milk control on the part
of the public leaves much to be desired, private initia-
tive, as mentioned before, has led to significant sanitary
improvement, in that large stock companies have been
formed in many cities to provide sanitary milk and have
voluntarily subjected themselves to extra expense for
guaranteeing and controlling it. In some respects, this
voluntary control far surpasses what the public could
impose at this time. Appendix T gives the require-
ments of the youngest company in Copenhagen (‘* Tri-
folium ’’), which shows how far a private company may
varry this sanitary control, and these regulations may
well serve as a model for other places.

Wiile the companies referred to established their
own requirements and determined the extent of the con-
trol to which they submitted, another very successful
plan has been inaugurated in Stockholm, which consisted
in the establishment, in 1885, by private initiative, of a
milk commission of 9 members, including + physicians, 1
veterinarian and 1 chemist. The members of this com-
mission are chosen in part by the Board of Health and
in part by the Medical Society. This commission has
outlined a comprehensive control, which ineludes all who
desire it and who are ready to bear the expense con-
nected with it. The business advantages of this control
are such that a higher price than usual is obtained for
the milk produced under it.

Since the legal requirements in the different cities
vary and are adapted to the local conditions, it is
not possible to give a concise, epitomized view of

existing regulations; *® the following, however, is an

*” For a review of the local milk inspection laws of the United
States and recommendations, see * The Milk Supply of Two Hundred
Cities and Towns,” by H. E. Alvord and R.A. Pearson. U.S. Dept.
of Avr, B. A. I. Bulletin No. 46, Washington, 1903.

164 MILK HYGIENE

attempt to define the requirements which, from a sani-
tary standpoint, are to be considered necessary or
desirable.

In order to be effective, the legal or police require-
ments covering the milk trade, must contain detailed
regulations concerning :

The production of milk.

The care and handling of milk.

The prevention of adulteration.

The prevention of the sale of tainted or damaged
milk.

In respect to the enforcement of these regulations in
cities, the supervision will rest—at least in Denmark—
with the local health authorities, and preferably with a
veterinarian appointed by this authority, who will con-
duct the inspection of the milk establishments with the
codperation of the police, and take the necessary sam-
ples for further examination. In small cities, the inspec-
tion of the production of the milk may also be under-
taken by the same veterinarian; but in the larger cities,
as a rule, this is left to the local veterinarians in the coun-
try, and the various dealers or herd owners are required
to furnish certificates, that should be drawn up on a
prepared blank and be submitted to the health office con-
cerned.

I. REGULATIONS REGARDING THE PRODUCTION
OF MILK

Public supervision of the production of iuilk presents
great difficulties and has been carried out in but a few
places. In the ordinances of most cities, there are cer-
tain requirements pertaining to the production of milk,
but their enforcement is not always provided for. In
several cities every owner of cattle who delivers milk in
the city, either directly or indirectly, is obliged to appear
before a public authority and pledge himself to observe

REGULATION OF PRODUCTION 165

the existing legal requirements or those that may be
made later, and especially to report every change in the
make up of his herd. This isa good arrangement. The
actual observance of these requirements should he con-
trolled hy frequent visits of a veterinarian appointed
hy a central authority or by occasional visits of the
local veterinarian, but the latter plan is not so satisfac-
tory.

Such a regulation would, of course, be particularly
diffieult in large cities as, for example, Copenhagen,
which receives milk not only from a very large number
of large and small herds, the cows in which are often
changed, but is supplied with milk from a large part of
the country. On the other hand, the regulations men-
tioned can be adopted without great diffeulty in small
cities, although they might cause dissatisfaction at first
among the dairy farmers. In most of the larger cities,
up to the present time, little has heen done except to
publish notices in regard to the regulations respecting
the production of milk, but no reports have been de-
manded of producers and no special control las been
provided to enforce these regulations. The local boards
of health have the right to investigate cases which are
reported and if necessary to forbid the sale of milk from
the premises involved.

[In the United States, there is a certain amount of
dairy farm inspection under the authority of the states.
In Massachusetts, herds are inspected by the Cattle Bu-
reau of the Board of Agriculture, in Pennsylvania by
the State Livestock Sanitary Board, on request from
local boards of health that their milk supplies be exam-
ined into; in several states, herds and premises are in-
spected under authority of the State Dairy and Food
Commissioner, the Commissioner of Agriculture or the
State Board of Health. In no state, however, is there a

166 MILK HYGIENE

systematic inspection of all dairy herds, excepting in
Massachusetts, where the inspection is made for the pur-
pose of controlling bovine tuberculosis. A number of
cities, on the other hand, require periodical inspection
of the herds from which they obtain their milk supply.
Pa

The control to which a number of large milk com-
panies have submitted voluntarily, either from philan-
thropic motives or because driven to it by competition,
consists chiefly in frequent, regular visits from vet-
erinarians to the milk producing herds, during which
not only the conditions of health of the cows but also
their food, the cleanliness of the stables, the handling
of the milk, and the health of the milkers are the objects
of a more or less effective supervision. Some establish-
ments have provided a separate organization for super-
vising the health of the employees. It is self-evident
that the methods of such companies, however good their
private supervision may be, must be subject to the supe-
rior control of health officers.

[It will be observed that the author dwells not so
much on the importance of the recognition of infective
organisms in milk as on their exclusion. Unquestion-
ably it is infinitely better, from the standpoint of the
public health, to prevent the contamination of milk than,
by means of laboratory examination, to discover evi-
dences of contamination in a sample representing a
quantity of milk that has already been consumed.

Milk is not a food that is kept long; it cannot be put
away in storage until a sanitary examination has been
made, and then released for consumption, or destroyed,
according to the result of the examination. Only the
briefest inspections can be made while the milk is ex
route from the producer to the consumer.

The supply continues as a flowing stream, and is

REGULATION OF PRODUCTION 167

never just alike at different times or places. The lab-
oratory examination of a milk sample gives some infor-
mation as to the condition of that sample and, by infer-
ence, as to the conditions under which a certain quantity
of milk was produced and handled on a given day. But
some of the contaminations of milk that are most dan-
gerous cannot be detected by routine examinations in
the laboratory, if at all, excepting by their effects on the
consumer; among such contaminations are those caused
by the specific organisms of tuberculosis, typhoid fever,
diphtheria, scarlet fever and the materices morbi of
many diseases of cows. Therefore, so far as the pre-
vention of the infection or pollution of milk is concerned,
it is more important that the milk be produced under
such conditions that contamination is well guarded
against than to know the condition of a vertain quantity
that has already heen used.

The laboratory examination of milk is, however, of
much value in checking and controlling the accuracy of
farm and herd inspections, which inspections are de-
signed to prevent infection and pollution, while the lab-
oratory discovers contaminations that have already
occurred.

The author’s position on this general subject is quite
analogous to the opinion that is now held by sanitarians
in regard to the way in which the purity of the water
supply should be obtained and insured; that is, by clean-
ing and guarding the source.

It ix well to lock the stable door before the horse is
stolen. But it has, thus far, been impossible in America,
excepting in a few isolated instances, to impress the
public sufficiently to lead to the establishment of a sys-
tematic inspection of the sources and methods of hand-
ling and transporting milk. Reasons for this condition
are, the paucity of specially trained men for this ser-

168 MILK HYGIENE

vice and, on this account, the difficulty health officers
have experienced in securing inspectors to do such work
in a satisfactory way and, secondly, the expense. A
properly equipped dairy farm inspector must have had
special training, and must be familiar with, and be able
to apply, facts from pathology, bacteriology, zodtechnics
and dairy husbandry.

Dr. William T. Sedgwick has emphasized the impor-
tance of control of the source of the milk supply, to pre-
vent pollution, as follows: *°

‘“ Tt should never be forgotten that if water were to
be drawn, as milk is, from the body of a cow standing in
a stable, by the hands of workmen of questionable clean-
liness, and then stored and transported over long dis-
tances in imperfectly cleaned, closed cans, being further
manipulated more or less, and finally left at the doors
at an uncertain hour of the day, few would care to drink
it, because its pollution and staleness would be obvious.
It is clear, moreover, that it requires and deserves more
eareful treatment than water, for it is more valuble,
more trusted and more readily falsified or decomposed.”’

Dr. Rowland G. Freeman has stated his opinion as to
the importance of controlling the source of the milk sup-
ply, rather than to attempt to determine its character by
bacteria counts, in these words: ‘‘ It seems to me that
while the counts of bacteria are exceedingly valuable as
an exponent of cleanliness and proper handling of milk,
they should be used only to prevent carelessness at the
dairy and to stimulate better methods and discipline.

‘¢ The opinion of a milk commission of representa-
tive men (experts) based on an actual knowledge of the
management of the dairy is of vastly more value to the

40 Sedewiek, Principles of Sanitary Science and the Public
Health. New York and London, 1902, page 279.

REGULATION OF PRODUCTION 169

medical profession and to the public than any statement
regarding the precise number of bacteria in the milk
upon any given day or days. The most important
things, after all, are such a régime as shall make con-
tamination by pathogenic organisms improbable, and
at the same time insure that the milk is produced under
such conditions of cleanliness that other bacterial con-
taminations will be reduced to the minimum.’’ L. P.]

a. The condition of health of the herd. The ideal
requirement that only milk from a perfectly healthy
herd may be marketed, cannot be maintained. The pub-
lic, therefore, must be satisfied to demand that the health
condition of the herd is such that its milk docs not pos-
sess Injurious qualities. If infectious diseases which are
transnussible, through milk, to man, break out in the
herd, the sale of the milk should be forbidden as long as
danger of infection be present. If individual cases of
infectious or other diseases oceur which may lvad to the
contamination of the milk of the affected cows by patho-
genic bacteria or toxins, it must be the duty of the owner
to prevent this milk being mixed with the other milk,
and, indeed, wholly to prevent its use as food for man.

Such regulations as the following may be regarded
as necessary :

The use of the milk from the whole herd is to be dis-
continued if foot-and-anouth disease, lung plague or
anthrax occur, also in the case of extended outbreaks of
transinissible infections of the udder, septic enteritis,
cowpox, or of any toxic disease of a large part of the
herd.

The milk of individual cows should not be used, and
affected animals are immediately to be removed from
the stable, in cases of tuberculosis affecting the udder,
the uterus or the intestines and when the lungs are so
affected as to occasion physieal symptoms: also, milk

170 MILK HYGIENE

from cows suffering from anthrax or rabies (bitten by
affected animals), and that from cows with mastitis,
with inflammation of the uterus and retention of the
afterbirth, inflammation of the intestines or severe
diarrhea, and with severe cellulitis or abscesses and
suppurating wounds.

Milk should not be used from cows suffering from
any sort of febrile disease or intoxication, with pox or
suppurating sores on the teats, with inflammation or
other disease of the udder, constipation or diarrhea,
Moreover, it should not be used from cows that are being
treated with medicines that have a strong odor (volatile
oils, ether, asafcetida and the like), with alkaloids or
potent glycosides, with preparations of iodine, arsenic,
mercury, antimony or lead.

A very proper requirement is that milk from cows
that have recently calved is not to be mixed with the rest
of the milk, for the beast milk (colostrum) differs
greatly in composition from normal milk and may have
a harmful effect on small children. For 6 to 8 days
after calving, the milk should not be mixed with the
other milk. Also, milk from cows approaching the
end of the period of gestation and which are only
giving a little milk, should not be mixed with that
intended for sale, because it is often quite alkaline and
may differ a good deal in its composition from normal
milk.

The complete observance of these requirements is,
evidently, very difficult to control. In part, one must
rely on the honesty of the owner, who should be held
responsible for failure to comply with the legal require-
ments. When a dairyman is under contract to furnish
milk to a company having its own conditions and regula-
tions, he may be held accountable for failure to fulfil
the obligations he has undertaken. In general, it can be

REGULATION OF PRODUCTION ia |

said that the observance of the conditions that are out-
lined above, as well as those that will be mentioned later,
can he expected only when the dairy farm is under the
ispection of a veterinarian who is entirely independent
of the owner.

Therefore, when it is possible, one should endeavor
strongly to arrange for such veterinary supervision.
Naturally, it is of some advantage to make inspections
now and then, at irregular times, but if the control is to
be really effective, the visits must take place frequently,
and with some degree of regularity. Preferably, the
visits should not be more than fourteen days apart be-
cause, in that time, tuberculosis may attain such develop-
ment that bacilli may be excreted with the milk, and dis-
eases of the udder often develop acutely and follow a
short and rapid course, thus making frequent examina-
tions necessary. Only in cases in which the milk is sub-
jected to a really safe process of pasteurization before it
is sold, should a less frequent inspection be considered
sufficient.

[This amount of supervision, a visit to each produc-
ing farm every two weeks, is not attainable with relation
to the milk supply of the large cities of the United
States, nor is it to be regarded, in the present provi-
sional state of the sanitary development of the country,
as necessary. That producing farms should be under
some supervision, all agree. The amount of supervision
that is necessary varies with the conditions. Ifa given
herd is known to be infected with tuberculosis and
infested with other diseases, if the premises are bad and
the owner careless, then frequent inspections should be
made until there is decided improvement; on the other
hand, if a certain herd is known to be clear of tuber-
culosis, calf cholera, infectious gargets, ete., if the prem-
ixex ave good and well kept and the owner intelligent and

172 MILK HYGIENE

careful, longer intervals may safely be permitted to
elapse between visits. After an inspector has gone over
his ground and has become acquainted with local condi-
tions, and the individuals, the question of frequency of
visits should be left to a larger extent to him.

The number of inspectors required is of course in
direct proportion to the frequency of inspections. If a
single inspector could visit all of the dairy farms sup-
plying a given city in one year, about twelve inspectors
would be required to visit these farms each month. It
is estimated that the number of inspectors that would
be required to carry out an adequate system of dairy
farm inspection for the city of Philadelphia is about 20.
About 60 to 80 country inspectors would be required
for the city of New York. L. P.]

For herds supplying “S nursery milk ’’ or ‘* infants’
milk,’’ decidedly rigid requirements must be made be-
cause, so far as possible, this milk must be so produced
that it can be used in its raw state by children and
invalids without any danger whatever.

Therefore, dealers should not be permitted to sell
milk under these names if the herds are not under the
inspection of a public veterinary officer; and the inspec-
tions should take place at least every fourteen days,
preferably every week. It must be required that ‘‘ nurs-
ery milk ’’ shall come only from herds absolutely free
from tuberculosis (7.e., herds that are tested with tuber-
culin at least once every year, and to which only abso-
lutely healthy animals are allowed to be added), be-
cause the diagnosis of some dangerous forms of tuber-
culosis is often very difficult and, in the earlier stages,
even impossible, and because it has been proven impossi-
ble to prevent the occurrence of the dangerous forms
merely by the removal of animals in which tuberculosis
is clinically apparent. Besides, the definite requirement

oe

REGULATION OF PRODUCTION 173

must be made that the delivery of milk must cease in-
stantly if numerous cases of septic enteritis or strepto-
coccus mastitis appear and also if ‘* calf cholera ’’ occurs
malignantly or endemically.

Moreover, the prompt removal from the herd is de-
sired of every animal that has fever, or any kind of
infectious disease. It is the duty of the owner himself
to discontinue the delivery of the milk and to undertake
the necessary isolation, when occasion may arise be-
tween the visits of the veterinarian, and he should eall
the veterinarian as soon as any suspicious disease may
appear.

These requirements are already enforced hy private
companies and so there ean be no question as to whether
it is possible to carry them into effect but, up to the pres-
ent time, they are enforced by the public in only a few
cities.

b. Feeding the herd. As has already been stated,
it is now the belief that the composition of the milk does
not depend in any material degree on the composition
of the food, and that injurious substances are not ex-
creted through the udder to the extent that was formerly
supposed. Therefore, one is not justified in forbidding
the use of such a number of foods as has been done and
is still done by some large cities. Only such foods
should be prohibited as are decomposed (inouldy, putrid
or fermenting), or materials containing great numbers
of resistant bacteria of fermentation (creamery refuse,
frozen forage, the offal of root crops, ete.), or excessive
quantities of unnatural food materials (the refuse of
some manufactories, distillers’ slops, malt, molasses
ete.), and strongly smelling vegetable matter (turnip
tops, cabbage, green forage containing poisonous plants,
ete.). The use of other food stuffs should be forbidden
in such quantities as are injurious to the cow (turnips

174 MILK HYGIENE

causing diarrhea, concentrated feed causing indigestion,
poisoning by cotton-seed and nut-cake, etc.).

It has been required in some cases that cows supply-
ing ‘‘ nursery milk ’’ shall be fed only upon dried fod-
der, and the use of oil meals has been restricted. By
this means, milk has been obtained which is good and
uniform, but it is so very expensive that its use is re-
stricted. Our present knowledge of the effect of food
upon milk does not sustain this requirement. But, it
should be observed, the stable and cows can be kept clean
much more easily if the cows are fed exclusively upon
dry foods than when they are fed in part upon turnips or
other green food. Therefore, if this one-sided method
of feeding is not demanded, great emphasis must be
placed on cleanliness with respect to herds supplying
nursery milk. It is not inappropriate, however, to make
some extra requirements in regard to feeding cows pro-
ducing nursery milk. For example, food stuffs, such as
distillers’ slops, malt and molasses, as well as all fodder
which, fed in large quantities, may be injurious to cows,
should not be used (buckwheat, lupine, mustard, rape,
cakes mixed with mustard, cotton-seed meal, nut-cakes,
potatoes, ete.). Of course it is difficult to prove that a
ration containing a small quantity of these materials
would impart injurious properties to the milk; but it is
safest, when it concerns milk for small children, to avoid
any possible danger connected with the use of such
foods; the more so, as this prohibition would have
no influence at all upon the cost of production of the
milk. Nor should one be allowed to give so great a
quantity of turnips or green fodder to cows that are
stabled that they suffer from diarrhea, even to a slight
degree.

[There has been much discussion and, in the past,
much difference of opinion, as to the propriety of using

REGULATION OF PRODUCTION 175

silage as a food for milch cows, and especially as food
for cows producing nursery or certified milk.

The building of silos and the ensiloing of crops are
new procedures in America, as elsewhere, and methods
both of construction and filling have undergone rapid
development. Only a few years ago, when square,
poorly built silos were used, some of them built as pits,
below ground, and before silage cutters and elevators
had been developed, and when it was the practice in
some cases to ensilo green maize stalks without cutting,
and in bundles, there was much decomposed, putrid and
mouldy silage, which had a very offensive odor and
which was decidedly objectionable as food for dairy
cows or, indeed, for any animals.

In these days, however, silos are better made and
better filled; they are usually round or octagonal, thus
facilitating even filling and settling, machinery for cut-
ting has heen perfected, so that the silage is divided
into short lengths of from one-half to one inch, and
Indian corn, the chief silage crop, is no longer used in
the soft, immature state, but is permitted to come al-
most to maturity. Putrefaction does not occur in prop-
erly handled silage. The fermentation that takes place
is caused partly by bacteria and partly by enzymes in
the maize plant. Good silage is a wholesome, nutritious
food that is appetizing and comparatively easy of di-
gestion.

Silage is fed to cows on nearly, if not quite, all of
the large farms in America devoted to the production of
certified and nursery milk. It is not known to be subject
to any objection other than if fed in too large quantity
it produces an undesirable degree of laxativeness, and
if fed just before or during milking, if it is not first class,
the odor of the silage may be eliminated with or ab-
sorbed by the milk. This is avoided by feeding it after

176 MILK HYGIENE

milking and by not allowing the residues to accumulate
in or about the stable.

Frasier +? has shown by some tests made with milk
from cows fed silage of good quality that no objection-
able flavor or odor was imparted to the milk either when
the silage was fed before, during, or after milking. In-
deed, in 372 tests made, silage milk was preferred in
233, or 60 per cent. L. P.]

A further demand in reference to herds supplying
nursery milk should be established—that frequent and
sudden changes in food should be forbidden, as the com-
position of the milk immediately after such a change is
often materially altered, and it is more probable that
when the udder is ‘‘ surprised’’ by such a sudden
change the secretory function is thrown out of equilib-
rium and abnormal, and possibly injurious, substances
are secreted with the milk.

¢. Cleanliness in the stable and during milking. In
order to guard, so far as possible, during milking,
against pollution with dirt and, at the same time, with
bacteria, the most thorough cleanliness of the cows and
the stable, and care on the part of the milkers, is to be
desired. However, it is very difficult to establish detailed
regulations in this respect, and no less difficult to en-
force them. We usually find that the regulations under
this heading are confined to the concisely stated orders
that cows and stables must be kept clean; that, at milk-
ing, the greatest possible cleanliness must be observed
and that, just before milking, the udder and teats are to
be washed.

However, where the conditions permit the establish-
ment of more detailed regulations, as in the larger milk

41 Wilber J. Frasier, Bulletin No. 101, Agricultural Experiment
Station, University of Hlinois, Urbana, 1905.

REGULATION OF PRODUCTION Lat

companies, which are under private control, this should
be done. In this connection, the following regulations
which, first, the Copenhagen Milk Supply Company and,
afterward, other companies in Copenhagen, have fur-
nished to their producers stand as an example to be
imitated :

1. The stable must be so built that the urine has an
unobstructed exit and the floor must be of such nature
that it may easily be kept cleau. The cows must be well
bedded and, for this purpose, no spoiled or rotten straw
or hay can be used, nor straw or hay that has previously
been used for packing. The stable must be kept as clean
as possible. In the morning, the manure must not be
removed until after milking; in the afternoon, at least
one hour should pass after mucking out before milking.
After cleaning the stable, it should be thoroughly aired,
unless the ventilating system is particularly good, so as
to render this unnecessary.

2. In order to prevent the hind quarters of the cow
from becoming too dirty, the hair of the tail, on the
udder, the flanks and on the outer side and the rear of
the thighs should he clipped before the cow is stabled in
the fall. Besides this, the cow should be cleaned with a
eurry comb and brushed every day. Definite and more
stringent regulations concerning the cleanliness of the
stable and the cows should be made in summer, if they
are fed in the stable, and in winter if green (laxative)
fodder is used.

5. When the cows are kept in the stable, their teats
are to he washed with clean water and dried with a clean
cloth. If the udder is dirty, this, also, must be washed
and dried. If the cows are milked in pasture, this
cleansing cannot be done so satisfactorily [and there
is less occasion for it], so it is usually best to confine
the washing of the teats and udder to such of the cows

12

178 MILK HYGIENE

as are apparently soiled with manure or earth. If there
are sores upon the teats these must be carefully washed
off. Instead of washing, one may rub the udder with a
dry cloth or brush it and then rub in a little neutral fat
[as vaseline ].**

4. The milkers must have a special dress to be used
only during milking, and this must be washed as often
as necessary. The milkers must wash their hands be-
fore milking, and during milking they must have plenty
of clean water and clean cloths at hand with which to
wash not only the teats but also their own hands, as
often as is necessary.

5. Milk pails, milk strainers and milk cans must be
carefully cleaned in the dairy house. If it be necessary
to rinse out the pails or strainers when milking in the
pasture, only clean water which has been carried to the
place must be used and not that from a reservoir in the
pasture.

d. The health of the attendants. A very important
point in milk hygiene is the condition of health among
the workers in the dairy and of the milkers and, indeed,
among all persons who are connected with milk produc-
tion. As has already been emphasized, there are a num-
ber of infectious diseases of man which can easily be
transmitted through milk and which have appeared in
many instances as extended ‘‘ milk epidemies.’’ Fre-
quent inspection hy a physician of all persons connected

42 (This reference to milking cows at pasture, which has now
become unusual in most parts of America, is explained by the Danish
custom of keeping cows tethered out of doors the entire summer.
During this season, the cows are allowed to graze on grass and
especially planted forage crops, which are harvested by the cows
without waste, as the tether pin to which the tie rope is attached
is moved but a few feet at a time and is not moved again until the
forage within reach has been consumed. Water is carried to the
cows in tanks on wagons. L. P.]

REGULATION OF PRODUCTION 179

with the business is searcely feasible, both because it
would be an expensive procedure and because, in most
casex, it would meet with great opposition and tend to
increase labor difficulties.

But the following regulations are regarded as neces-
sary and they should be incorporated in public ordi-
nances :

The sale of milk shall cease immediately if typhoid
fever, searlet fever, diphtheria, or other malignant in-
fectious disease breaks out among people living in the
farmstead ; 4” the sale shall not be resumed until a physi-
cian’s certificate has been received showing that all dan-
ger of infection is over."!

Care must be taken that the milk does not come in
contact in any way with persons in whose household one
of the above-mentioned diseases exists, nor those who
have discharging sores or skin diseases of the arms,
hands or face.

In addition, the local authoritics should have the
right to forbid the sale of milk if this is known, or be-
lieved, to be the eause of an epidemic, even though no
source of infection be proven on the farms in question.

Several of the large milk companies of Copenhagen
have established even more rigid regulations in regard
to the health of the personnel and they insure the en-
forcement of these rules by allowing the producer full
value for his milk, when he holds it back on account of
the occurrence of disease. The value of such a provision
is obvious.

ec, The water supply. Sinee typhoid bacteria (and

4° 7The farmer’s residence and the cow stable adjoin, so that they
are, practically, parts of the same building, on most of the small
farms of Denmark.]

44°The danger of infection from persons recovering from typhoid
fever and diphtheria continues for a long time.]

180 MILK HYGIENE

other pathogenic bacteria) may gain access to milk
through water used to wash the milk vessels, care must
be taken that pure water be provided on the farms from
which market milk is sold, and that polluted or infected
water is not used for cleansing the dairy utensils, nor
the udder, nor shall it be used for the cows. [Contam-
inated water has also done harm when used for cooling
milk and it is believed to have led to the infection of
milk, indirectly, through the soiling of the skin of the.
cow, as when wading through a foul stream. L. P.]

f. The care of the milk. Immediately after milking
each cow, the milk must be run through a fine metal
strainer into a container. The strainer holds back only
the larger pieces of dirt and some of these are dissolved
by the continuous pouring of the milk, and bacteria are
washed through, so it is advisable, so far as possible, to
prevent the dirt that has been removed from coming into
contact with the milk that is to follow. But it cannot be
said that a strainer has yet been made that solves this
problem in a satisfactory way; therefore one must get
along by frequently cleansing the strainer from the par-
ticles of dirt. Of course, it is very difficult to insure the
observance of such a stipulation. Sufficiently rigid re-
quirements in regard to the cleanliness of the milk sold
and the seizure of impure milk, followed, perhaps, by the
imposition of a fine would aid in enforcing the regula-
tion.

After the milk is drawn, it must be carried to a place
prepared for this use and which must be used for no
other purpose. This room must be well ventilated, clean
and have an impervious floor.

The milk must be cooled as soon as possible by pass-
ing it over a cooler or by putting the cans into tanks
containing ice water. If it is nursery milk, the cooling
must be very carefully done, so that the temperature

REGULATION OF PRODUCTION 181

may not execved 10° C. (50° F.). Milk should be kept
chilled until it is ready to be shipped and then it must be
guarded carefully against high temperature by protect-
ing it from the sun, transportation hy night, ete.

If the transportation of milk requires a long time, it
must be cooled to a low point, and, while it is not well to
allow the whole quantity to freeze, in recent years a
partly frozen milk (the outside layer frozen in the cans)
_or the addition of frozen iilk to the other milk have
been successfully used.

[Milk shipped long distances in America is sent in
refrigerator cars. Some milk is on the railroad 10 hours
before it reaches market. Milk shipped short distances
is usually not sent in refrigerator ears hecause, on the
short runs, the cars have to be opened so often at local
stations that there would be a great consumption of ice.
Tf such milk is thoroughly chilled by the use of ice before
it is shipped, it usually arrives in good condition; but
if it ix cooled only by the use of well or spring water it
is an uncertain commodity in the hottest weather. Bot-
tled milk is shipped in wooden boxes with broken ice
packed around the bottles.

Helm‘ has proposed that milk shall be shipped in
square, instead of round, eans, so that they may be
packed more closely and thus make a solid block, of
low temperature, which may be covered over if neves-
sary, and which will remain cold much longer than a
loose collection of round eans, between which the
warm air may freely cireulate. This style of can is
shown in figure 14. L. P.]

Only well-tinned metal cans which are easily cleaned
should be used for keeping milk (Fig. 13); these should
be closed and sealed when transported by rail or boat.

4° Wilhelm Helm, Die Milehbehandlung, Liepziz, 1903.

182 MILK HYGIENE

Il. REGULATIONS CONCERNING THE SALE
AND DELIVERY OF MILK

Just as supervision is necessary of the herds which
produce the milk, and in regard to the care of milk at
its source, so also is supervision necessary after it comes
into the hands of the wholesale and retail dealers. This
supervision is much easier to carry out than that with
relation to production.

The regulations governing sale and delivery must
embrace not only the methods of handling the milk and

Fig. 14.
Fig. 13,

ff \_
ri | fae

Mo

Danish milk-cans. Helm’s milk-eans.

the health of the attendants, but there should also be
rules concerning the place in which the milk is sold, the
manner of selling it and the labelling of the goods.

a. Preparing the milk for delivery. Although small
concerns subject the milk to no especial treatment from
the time it is received until it is sold, this is not the case
with the large companies. These have considerable
work to perform in the handling of milk and its delivery
to customers. The milk [under the Danish system] is
received from the stations in a more or less cool condi-

REGULATION OF SALE 183

tion and the cans are put into ice water in order to chill
the milk sufficiently. It is then poured into a tank and
mixed, thus making its composition uniform. Then fol-
lows a process of cleansing, wherein the milk is either
passed through a centrifuge, so constructed that the
cream and the milk are not separated, but only particles
of dirt are thrown out, or it is passed through a filtering
apparatus which holds back some of these particles. A
gravel filter is frequently used for filtering. This is a
tank which is filled with layers of gravel of different
degrees of fineness, through which the milk is slowly
forced. The gravel is cleansed daily by washing
and roasting. Only the particles of dirt are removed
by this process; the number of bacteria is not appre-
ciably reduced. A filter made of numerous layers of fine
linen, tightly stretched, has been used successfully in-
stead of the gravel filter. The cloth part is renewed
after cach use. This method has, among others, the ad-
vantage that the filtering may take place directly into
the can from which the milk is drawn off for sale, or the
apparatus may be so arranged that while the milk is
being filtered and run off, it is at the same time cooled.

The ‘‘ clarified ’’ milk is put into metal cans or glass
bottles in which it is to be sold. This filling is sometimes
done automatically, so that incorrect measuring is not
possible, and sometimes by means of a machine similar
in construetion to those used in filling beer bottles.

If the milk is to be pasteurized, it is first filtered, then
run through the pasteurizer and over the cooler, into
the delivery can; or it is placed in the clean bottles or
cans that go into the pasteurizer or sterilizer (see page
139).

The public will searcely require ordinances contain-
ing exactly detailed regulations in regard to these differ-
ent processes. Generally it is required only that the

184 MILK HYGIENE

vessels and apparatus used shall be entirely clean, that
the milk be handled with the greatest cleanliness and be
kept in well-tinned metal cans or in glass or earthenware
vessels with perfect glazing, containing no lead, and that
all vessels shall be so constructed that they will not be
difficult to clean.

Special regulations should be established for the pas-
teurization of milk. If the heating is of short duration,
it is desirable that the milk be heated to 80° C. (176° F.)
and cooled immediately afterward. The following re-
quirements should be established for heating at a lower
temperature: Milk should be raised to a temperature
of 65° to 70° C. (149° to 158° F.) and held there for one-
fourth hour or it should be kept for one-half hour at a
temperature of 60° to 65° C. (140° to 149° F.). The
pasteurizer should be known to act accurately enough
to attain the required temperature with certainty.

b. The places for keeping and selling milk. The places
in which milk is handled must be light, airy and easy to
keep clean; therefore, they must be provided with an
impervious floor and a good drain, and good, pure water
must be easily accessible.

The salesplaces must likewise be bright, airy and
clean and, in addition, there are a number of special
requirements. Milk should not be allowed to be sold in
the same shop with other goods, with the exception of
certain foods (as bread, honey, flour, butter, margarin
and eggs), which cannot, either by their odor or in any
other way, have a deleterious influence on the flavor and
the keeping quality of the milk. Conducting a laundry,
or a similar business, in the same place in which milk is
kept or handled, should not be permitted. Of course,
the apartment must not be used as a dwelling or a sleep-
ing room, and it should not be in direct communication
with sleeping rooms. If the place used for keeping and

REGULATION OF SALE 185

selling milk is in communication with living rooms, as
happens in small premises, then it is positively neces-
sary to have the apartments separated by a thick door,
which shall be kept closed.

c. The condition of health of the attendants. The same
rules that apply to attendants in the places of production
should he binding upon those at the salesplaces. How-
ever, as the enforcement of these rules naturally meets
very great difficulties, in imost cities action has been
limited to making the regulation and then punishing
those guilty of offences that are, by chance, discovered.

Several large concerns (¢.g., some in Copenhagen)
have voluntarily enforced strict regulations in regard to
the health of attendants. In order to be sure that no
suspicious disease among them or in their houscholds
shall escape being reported, they provide free medical
services and also pay full wages to every employee
who is temporarily absent from his work on account of
illness in his family. (Compare regulations governing
the producers for this society, page 178, and Appendix
I, page 241.)

Moreover, the public health department of the gov-
ernment must be authorized—possibly upon the pay-
ment of indemnity—to close milk businesses for a longer
or shorter time, which are known to spread contagion,
even though it cannot be shown just where the infection
comes from. This authority must also apply to milk
shops, when eases of typhoid fever, scarlet fever or
diphtheria exist among people who work with the milk.
If it is proven that the infection did not occur in the
shop, the milk and the cream may be sold after steriliza-
tion, if care is taken to see that this is thoroughly done.
A milk shop is to be kept closed as long as there is dan-
ger that it may distribute infection.

(d. Marking and packing the milk. The requirements

186 MILK HYGIENE

in respect to marking milk for sale form quite an impor-
tant part of the regulations on the handling of milk, be-
cause these have a very important bearing on the pre-
vention of adulteration. The kinds of milk and milk
products which are of importance are whole milk, ‘‘ half
milk,’’ skim milk, cream and buttermilk.

Whole milk is the usual name for normal cow’s milk
which has not been deprived of any of its fat or other
ingredients. As the fat content of milk is far from being
uniform, and as partial skimming, or the addition of
skimmed milk, is, therefore, not easily detected, many
attempts are made to deceive by these falsifications. In
order to prevent the sale of milk that may be unadulter-
ated but which is too poor in fats, and in order to lessen
the number of adulterations, a minimum content of fat
and solids has been established in many cities, as well as
the limits of the specific gravity. Milk which does not
contain the required amount of fat cannot be sold as
whole milk; if it is so sold it is considered adulterated.

Reinsch ** has made a comparison of these require-
ments in the German cities. Among 63 ordinances, 60
contain such a minimum limit for fat; 37 of these place
the limit at 2.7 per cent., 5 at 2.4 per cent. to 2.5 per
eent., 7 at 2.8 per cent., 9 at 3 per cent. and only 2 have
established a higher minimum at 3.2 per cent. to 3.3
per cent. In 19 ordinances, the minimum content of
solids varies between 10.5 per cent. and 12 per cent.;
most require 11 per cent. to 11.5 per cent. Twenty-
five place the limits of specific gravity; 10 of these as
1.028 to 1.034, 8 as 1.029 to 1.033 and 5 as 1.029 to 1.034,
while a single one provides 1.027 to 1.034.

[The German standards are low because the fat con-
tent of the milk of some of the breeds of dairy cows

*6Die gesetzliche Regelung des Milehverkehrs in Deutschland,
Hamburg, 1903.

REGULATION OF SALE 187

in Germany is very low. It would be quite impracti-
cable tou enforce higher standards under such cireum-
stances.

In 26 states of the United States there are laws estab-
lishing inilk standards.** The limits for fat are from 3
per cent. (in one state only is the limit below 3 per cent. ;
in Rhode Island it is 2.5 per cent.) to 3.5 per cent. (in one
state, Massachusetts, for half the year, the limit is 3.7
per cent.). For total solids, the limits are from 12 per
cent. (in one state only is the standard lower: Ohio,
during May and June, it is 11.5 per cent.) to 13 per
cent.

The standards for cities and towns vary within the
same limits; some are established by the state standard
and some by the cities themselves. L. P.]

It is evident from the above requirements that it is
difficult to agree on percentages and standards which
may be considered perfectly Just and reasonable. If the
requirements are placed too high, the owners of a num-
ber of herds (especially those made up of purchased
cows) soon find it impossible to deliver milk in the cities ;
if the requirements are placed too low, the object of reg-
ulation is attained only to a very limited extent. There-
fore, it has been suggested that different grades of whole
milk be established. Leipzig and Dresden have such
w provision, under which only milk with a minimum fat
content of 2.8 per cent. to 3 per cent. is permitted to be
sold as ‘‘whole milk I quality,’’ while unadulterated
cow's milk of less fat content ean be sold under the
name ‘‘whole milk Il quality’’; in Leipzig, however,
this ean be marketed only with the designation of the
fat content. Several other Saxon cities have similar

“ H. E. Alvord and R. A. Pearson, The Milk Supply of 200
Cities and Towns, US. Dept. of Agr., B. A. T.. Bulletin No. 46,
Washington, 1903.

188 MILK HYGIENE

provisions, under which milk containing less than 2.8
per cent. fat can be sold only with a definite statement
of the fat content.

It must depend upon local conditions whether such a
provision is desirable or not, and also whether it is re-
garded as wise to establish a minimum fat (and solid)
content, and at what point these should be placed.

[Legal standards for milk are, by some, objected to
on two grounds; first, that it is unfair to establish a mini-
mum standard so high that it will exclude the milk
from some cows, and, second, that if the standard is
low it will encourage dealers to dilute rich milk to a point
just above the standard.

As to the first objection, it does not appear to be un-
reasonable that an article of food sold as milk shall be
required to contain a certain minimum amount of nutri-
ment. Entirely aside from the adulteration of milk,
which such standards are established to check, it is pos-
sible to select and develop herds of cows of certain
breeds that will furnish milk of very low fat and solids—
not fat content. What has occurred in this direction
is shown by reports on the weekly analyses of the milk
of a herd of cows at Jaschkowitz,** where the milk ran
down to 2.47 per cent. fats and 7.88 per cent. solids not
fat. The lowest average for the herd for a month was:
fat, 2.60 per cent.; solids not fat, 8.06 per cent.; total
solids, 10.66 per cent. The official records of Holstein
cows *? show that many individuals yield milk contain-
ing less than 3.0 per cent. of fat, and some as little, for
a time at least, as 2.6 per cent. This tendency could,
undoubtedly, be intensified if the absence of milk stand-

48 Bericht iiber die Tatigkeit des Milchwirtschaftlichen Instituts
zu Proskau fiir das Jahr 1905-1906.

49°C. B. Lane, Record of Dairy Cows in the United States, U. S.
Dept. of Agr., B. A. I., Bulletin No. 75, Washington, 1905.

REGULATION OF SALE 189

ards favored it. In other words, the milk could be wa-
tered through the cow. The tendency among breeders
of Netherland cattle in America (and largely on account
of milk standards) is to inerease the fat content of their
milk, and many such cows yield milk containing 4 per
cent. to 4.5 per cent., and, exceptionally, even 5 per
cent. of fat.

In regard to the second objection, the dilution of rich
milk is scarcely more likely to be practiced if there is a
minimum standard than if there is none, and it ean be
prevented quite as effectively by law, inspection and
penalty with a minimum standard, as without one.

All of the existing standards in the United States
are much below the average quality of the milk sold in
the cities to which the standards apply. It is proposed
by Wing *® that no special standard he established, but
that each dealer be required to guarantee his own stand-
ard, and that he be held responsible if his milk be found
below this guarantee. Some dealers now sell bottled
milk of different grades, containing cither 4+ per cent.
or 5 per cent. of fat, but all of it is above the minimum
standard, L. P.]

Special rules must he made for milk sold under the
name ** infants’ milk” or nursery milk,” and it must
be required that this shall come absolutely from herds
that are under constant veterinary inspection and whose
condition of health and cleanliness and feed are gov-
erned by special requirements (see page 17+). In
a number of German ordinances, in addition to these re-
quirements, the minimum fat content is placed at 5.0 per
eent., Which is considered fair. [In the United States
“Certified milk’? is usually required to contain + per
cent. fat.] | Another regulation which is justly put upon

OH, H. Wing, Milk and its Products, New York and London,
1899,

190 MILK HYGIENE

the dealer in nursery milk is that the milk shall be sold
only in clear glass bottles and that the bottles shall
be cleansed or sterilized before they are filled.

It should be required that milk sold as ‘‘ controlled ”’
(‘‘certified’’ or ‘‘guaranteed’’) shall come from herds
that are under constant and competent veterinary in-
spection.

Half skimmed or ‘‘ half milk ’’ is milk from which
a part of the fat has been removed. It is well to estab-
lish a minimum fat content of 1 to 1.5 per cent., as
already has been done in some German cities.

[In most cities in America, milk that is below the
minimum standard, as half skimmed milk is, can be sold
legally only as skimmed milk. There is no grade for
milk between whole milk and skimmed milk. The desira-
bility of establishing such a grade may well receive care-
ful consideration. The same end could be gained by the
adoption of Wing’s suggestion, but its enforcement
would entail administrative difficulties. L. P.]

[Skimmed milk is milk from which the cream has
been removed by hand skimming or from which the but-
ter-fat has been extracted by means of a centrifugal sep-
arator. The former kind may contain from 0.5 per
cent. to 1.5 per cent. fat, while the latter rarely con-
tains more than 0.3 per cent. fat and sometimes as little
as 0.01 per cent. The sale of skimmed milk is wholly
prohibited in some American cities, as in New York.
This prohibition is placed on account of the great in-
clination on the part of some dealers to sell skimmed
milk as whole milk and the difficulty of detecting and
preventing this practice. It is possible, however, to
secure a proper observance of the law on this subject, as
is proven by the experience of cities in all countries, and
it would be far better for the rich City of New York to
employ more inspectors, if necessary, to prevent fraud

REGULATION OF SALE 191

in the sale of skim milk than to deprive the poor of
this wholesome, nutritious and cheap food.

It should be required in every case that vessels con-
taining skim milk shall be permanently and conspicu-
ously marked. To deliver or to store skimmed milk in an
unmarked container on the premises or wagon of a
dealer should he regarded as evidence of intent to de-
fraud and should subject the violator to penalty.

Skimmed milk should contain not less than 9.25 per
cent. of milk solids. L. P.]

Cream, for the production of which the same sani-
tary requirements are necessary as for milk, should be
sold with the fat content designated, if there is no local
regulation to grade it or establish fat percentages.
[The percentage of fat in cream varies from 8 per
cent. to 50 per cent. or more. The usual quality, as
sold in the market, contains about 15 per cent. to 20 per
cent. fat. The standard for cream, as established by
the U. S. Department of Agriculture, ix 1S per cent.
Heavy, rich cream contains from 30 per eent. to 40
per cent. fat. L. P.]

[Buttermilk requires no special standard except that
it be made from clean milk, and in a cleanly way. It is
largely used as a summer beverage and, as typhoid
bacilli and other pathogenic forms will live in it for
some time, it is important that it be protected from con-
tamination. An imitation of buttermilk is sometimes
made in eity milk shops by churning sour skimmed milk.
LP]

Pasteurized milk, The following regulations are
proposed for milk that has been heated and that is to be
sold ax ** pasteurized ’?: Under this name, and without
a more detailed statement, should be understood milk
that has been heated to at least 80° (. (176° F.); if the
milk is pasteurized at a lower temperature, this must be

192 MILK HYGIENE

distinctly marked upon the bottle or can, and the milk
must not be permitted to go upon the market until the
method has received official sanction. Sterilized milk
should be sold only with a statement of the way in which
sterilization has been done, and not until after the
method has been inspected and approved. But it is not
enough merely to establish such requirements; the sani-
tary officers must see to their enforcement, partly by vis-
iting the pasteurizing and sterilizing establishments,
partly by taking samples and examining the milk sold.
Fortunately, it is possible to determine by chemical
means whether milk has been heated to 80° C. (176° F.)
or not. These tests are based on an observation by
Arnold and have been developed by Babcock, Storch and
others.5!— The principles are the following:

Storch’s method: 5 ¢.. of milk are poured into a test tube; a
drop of weak solution of hydrogen dioxide (about 0.2 per cent.),
which contains about 0.1 per cent. sulphurie acid, is added, and 2
drops of a 2 per eent. solution of paraphenylendiamin, then the
fluid is shaken. If the milk or the cream becomes, at once, indigo
blue, or the whey violet or reddish brown, then this has not been
heated or, at all events, it has not been heated higher than 78° C.
(172.5° F.); if the milk becomes a light bluish gray immediately or
in the course of half a minute, then it has been heated to 79° to 80°
C. (174.2° to 176° F.). If the color remains white, the milk has been
heated at least to 80° C. (176° F.). In the examination of sour milk
or sour buttermilk, lime water must be added, as the color reaction is
not shown in acid solution.

arnold’s guaiac method: a little milk is poured into a test tube
aud a little tincture of guaiae is added, drop by drop. If the milk
has not been heated to 80° C. (176° F.), a blue zone is formed
between the two fluids; heated milk gives no reaction, but remains

51 Vfeating milk to a high temperature coagulates the albumin
and globulin and the milk loses its property of curdling by the
action of rennet. By this change one may discover that it has
been heated, but not determine whether the milk has been heated
to 80° C. (176°F.), that is, if it has been pasteurized.

REGULATION OF SALE 193

white. The guaiae tincture should not be used perfectly fresh but
should have stood a few days and its potency have been determined.
According to the observations by Glage, the guaiac-wood tincture
appears to be more reliable than the harz tincture. Zink recommends
the addition of a few drops of weak solution of hydrogen dioxide,
as this causes the reaction to be much surer and sharper.

Of the two methods, the guaiae method is preferable in that the
tincture is very lasting and may be kept a year without becoming
ineffective, while the paraphenylendiamin solution must be renewed
quite often; on the other hand, the guaiae method is, perhaps, hardly
so accurate as the Storch method.

Other substances are useful as reagents in combination with
hydrogen dioxide, as solution of potassium iodide with starch
(Storch, du Roi, Kohler and others) and ursol (Utz); besides these,
a methylene-blue-formalin solution (Sehardinger) has been suggested
for this purpose.

[Storch’s test may also be used for the purpose of
detecting the adulteration of fresh milk with diluted
condensed milk. In this case it is well to make the test
comparative by running a parallel sample of milk known
not to have been heated. L. P.}

The sale of milk preparations which are made either
by using foreign additions or by some special manipula-
tion of the milk should be permitted only when the milk
has been produced under the requirements above stated
and only on declaration of the composition of the prep-
aration.

Milk containers. In ease the milk is retailed in
containers, there should be some stipulation in
regard to these. Metal cans should be of tinned iron;
for tinning, no tin should be used that has more lead
than is absolutely necessary; the form must be such
that they can be easily cleaned. Bottles are to be made
of clear glass so that every impurity is noticeable;
their form must, likewise, make satisfactory cleansing
possible.

In recent years, the large milk companies have en-

13

194 MILK HYGIENE

deavored in their own interest, as well as in that of the
public, to provide sealed stoppers or covers for delivery
bottles and cans, which more surely prevents their being
opened before delivery and which makes it impossible
for an unscrupulous person to fill anew, with milk or
cream, the vessel which, from accident or improper rea-
sons, was partly or wholly emptied. With metal cans,
this security is most easily effected by the use of a
simple lead and wire seal, applied after filling. <A per-
fectly reliable closure for the bottles, on the other hand,
offers some difficulty, because it is so expensive. The
accompanying illustrations show some of the methods
used. Fig. 15 shows a method of closing which corre-
sponds to that used on mineral-water bottles. After
closing, a label is pasted over the top; this method is
somewhat expensive and does not furnish a satisfactory
guarantee as the label is easily loosened. Fig. 17 shows

Fie. 15.

Copenhagen. The upper part of the neck is perforated,
and after the bottle has been closed by the insertion of
the stopper, a wire is drawn through the holes and se-
cured with a lead seal; this method gives efficient pro-
tection but is somewhat expensive. Fig. 16 shows a
method used during recent years in Germany, which is
cheap and quite satisfactory. In the inside of the neck

REGULATION OF SALE 195

there is a small groove; after the bottle is filled, it is
closed with a paraffined pulpboard cap which is pressed
down into the neck of the bottle by means of a stamp,
with its edges in the groove; at the same time, the cap
is marked, and it cannot be taken out without being torn.
A similar cover, a pasteboard cap which is pressed a
little way into the bottle (without the groove), is used by
many milk concerns, but this gives little security, as the
cap can easily be taken out and a new one substituted.

[Paper or wood-pulp discs (sterilized) used as stop-
pers may be sealed by pouring on top of them a little
melted paraffine. This method is used by some dairies
that produce certified milk. The customary method,
however, among the best dairymen, is to cover the top
of the bottle, after it is closed with the usual disc, with
a cap of parchment paper, held around the neck of the
bottle with a wire, cord or rubber band; or a eap of
heavy tin foil is used, which is pressed down around the
shoulder at the mouth of the bottle, and this holds its
position quite well. Both of these methods have the ad-
vantage of thoroughly guarding the mouth of the bottle
and the dise that confines the milk. The lip of the bottle,
over which the milk must be poured, is prevented from
becoming soiled. These methods, however, do not afford
such complete protection against tampering with the
contents of the package as is furnished by a lead seal.
However, if the box in which the bottles of milk are
shipped from the farm to the distributing point, or to
the customer, is sealed with a lead seal, as is done by
some producers, the protection is sufficient.

The usual practice among average dairymen is to
depend on unparaffined and unsterilized wood-pulp dises,
upon which is often printed the name of the dealer.

Small dealers (and some large ones as well) some-
times indulge in the most vicious and unsanitary prac-

196 MILK HYGIENE

tices in regard to bottling milk. They pour milk into
bottles from cans in their wagons or hand carts on the
street, exposing it to dirt, and, worst of all, they some-
times fill bottles that have not been cleaned, or that have
not been properly cleansed. Milkmen have been known
to take a soiled bottle from the house of a customer, fill
it with milk on a dirty wagon, while the wind is blowing
dust about, close it with a dise taken from a coat pocket,
perhaps from alongside a handkerchief, and then deliver
it in the next house. It is not surprising that it has been
seriously proposed to prohibit the use of milk bottles.
But the bottling of milk marks-a distinct sanitary ad-
vance, where it is carried out in a proper manner. It
should be provided by public regulation that milk shall be
delivered in bottles only under the following conditions :

1. Before they are filled, bottles shall be washed and
sterilized, or they shall be cleansed by the use of some
method that has the approval of the sanitary authorities.

2. Stoppers for the bottles shall be clean (preferably
sterilized) and shall be kept only in sterile packages or
in a clean metal or glass receptacle provided exclusively
for this use.

3. Bottles shall be filled with milk only in a clean
room provided for this purpose, and they shall not be
removed from this room until they are stoppered. L. P.]

Ill. PUBLIC SUPERVISION TO PREVENT ADULTERATION

Just as many foods can be adulterated, so also can
milk and cream. As the fat is the most valuable ingredi-
ent of milk, a common adulteration consists in partial
skimming, or in the addition of skimmed milk or water ;
less frequently, foreign material is added to the milk in
order to give it a better appearance. It can be only
excessively rarely that gross adulterations occur, such
as the one reported by Sullivan, wherein a sample of

PUBLIC SUPERVISION ioe

‘“milk *? was found to consist of a mixture of water,
white pigment, common salt and a little skimmed milk.
There is no general rule as to the frequency of adul-
teration. In some cities, it does not appear to be partic-
ularly frequent, while in others it is very common.

Besides the adulterations found upon official exam-
inations of the market milk in cities, the question of
fraud sometimes arises in connection with the milk deliv-
ered to creameries. In the creameries, it is customary
to use some quick method for determining the approx-
imate fat content of the milk that is delivered by the
various patrons.

In the official control of milk in cities two provisional
or preliminary tests have long been uxed and these are
still depended on to some extent; they consist in the de-
termination of the specific gravity and in a test of the
transparency. Even when used in conjunction, these
tests are not to be relied upon very far, but they can be
used, if with sufficient caution, to determine whether a
more thorough examination be necessary. If it is de-
cided that a laboratory examination is required, a sam-
ple should he taken with great care, and sealed and
delivered to the appropriate expert for analysis.

The specific gravity of cow's milk varies between
about 1.027 and 1.040 at 15° C. (60° F.) ; but such differ-
ences are to be found only in the milk of certain indi-
vidual cows. The specifie gravity of mixed-herd milk
usually falls between 1.028 and 1.054. If the specifie
gravity is either above or below these limits it is always
suspicious. [The average specifie gravity is 1.032. ]

Many different forms of apparatus have been pro-
posed for measuring the transparency of milk, to deter-
mine if it is or is not diluted. However, these instru-
ments are all defective and the results obtained by their
use are not to be regarded as of any value except to indi-

198 MILK HYGIENE

cate whether a sample of the milk should be taken for
analysis. The transparency of milk is dependent partly
on the size and number of the fat globules, and partly on
the casein in solution. As milk with fewer, but large, fat
globules has not the same transparency as milk with
more, but smaller, ones, even if the fat per cent. be the
same, it is evident that these methods of examination
may give misleading results.

Feser’s lactoscope is the simplest and best instru-
ment made for this purpose. As Fig. 18 shows, it con-
sists of a glass tube which narrows toward the bottom
and is closed with a metal cap which supports a short
vertical glass column on which are six black lines; the
upper part of the glass has divisions marked with a
double row of figures. Four e.c. of milk to be examined
are poured into the tube, then enough water is added
so that it will reach figure 40 (that is, 36 ¢.c. of water) ;
the fluid is now mixed by shaking. If it is not possible
to see the lines on the glass column inside the tube, a
little water is added and the tube is again shaken; this is
continued until the lines become visible. When they can
be seen through the diluted milk, the fat per cent. can
be read from the seale. For example, if so much water
has been added that the fluid reaches figure 60 (60 c.c.
water and milk), then the milk has 3 per cent. fat. As
already stated, this result cannot be relied upon; in the
examination of skimmed milk, quite too high a per-
centage of fat is always indicated and, in regard to
whole milk, the test may show from 0.5 per cent. to 1
per cent. too much or too little.

On account of the unreliability of this method in
many places this preliminary test is no longer used and
the inspectors take samples, without preliminary inspec-
tion, for examination in the laboratory.

[In the use of the lactoscope, the individual coeffi-

LRASBPARENGY “LEST BS 2

cient is of great moment. Different inspectors will in-
terpret the same result quite differently. When one is
experienced in examining with the lactoscope the milk
of a given breed of cows, he may become so proficient
that he can make a fair estimate of the fat content, but

FIG; 19;

Feser’s Lactoscope. Quevenne’s Lactodensimeter.

when another kind of milk is examined the result may
not be so accurate. If milk tests normally, both in re-
spect to specifie gravity and lactoscopically, it is not apt
to be much skimmed or watered.

The following is from Leach : **

52.4. BE. Leaeh, Pood Inspection and Analysis. New York, 1905.

200 MILK HYGIENE

“As in the case of the lactometer, the purity of a milk sample
eannot be positively established by the lactoscope alone. For instance,
a watered milk abnormally high in fat would often be found to read
within the limits of pure milk, when as a matter of fact its solids
would be below standard. By a careful comparison of the readings
of both the lactoseope and the lactometer, however, it is rare that a
skimmed or watered sample could escape detection.

“Thus, if the specifie gravity by the lactometer is well within
the limits of pure milk, and the fat, as shown by the lactoscope, is
above 3] per cent., the sample may be safely passed as pure, or
as conforming to the standard.

‘“A normal lactometer reading in connection with an abnormally
low lactoscope reading shows both watering and skimming, and
with an abnormally high lactoscope reading shows a milk high in
fat, or a cream. With the lactoseope reading below three, and a
low lactometer reading, watering is indicated. A lactometer reading
above thirty-three, and a low lactoscope reading, indicate skim-
ming.” L. P.J

IV. METHODS OF EXAMINATION

In order to determine whether adulteration has taken
place or not, the examination should cover the follow-
ing: The specific gravity of the milk and of the whey,
the fat content of the milk, the amount of milk solids,
the amount of solids not fat, the specific gravity of the
solids, the quantity of fat [and the percentage of
ash]. Sometimes, the examination is extended to
include the taking of a herd sample under special
conditions in order to make a comparison between
the sample officially collected and the milk offered for
sale. Finally, foreign ingredients are tested for, as ni-
trates, starch, [preservatives, artificial color, ‘‘ visco-
gen,’’ gelatin, ete.].

a. Taking samples for laboratory examination must be
conducted with great care. Upon standing, the cream
quickly rises to the top, so that the upper part of the
milk contains more fat, even though no definite layer of
cream has yet been formed. Therefore, before the test

METHODS OF EXAMINATION 201

is made, the milk should be well mixed. In milk that has
been thoroughly chilled, it is diffieult to again mix the
cream equally, so one must be very exact in taking the
sample. It often happens, in the milk shops, that the
milk is not well mixed when sold and an examination
of what is left may show so low a percentage of fat that
one immediately becomes suspicious that adulteration
has taken place, although it may not he so.

b. Preserving the sample for analysis. If the milk sam-
ple is to be kept or shipped, it is necessary to add a pre-
servative. For this, potassium dichromate (1 grm. to 1
liter) is used, which keeps the milk fluid for a long time;
this addition causes an increase in the specifie gravity
and the result of the chemical examination is also af-
fected. This must be taken into consideration at the
final test. It is generally better to add 20 drops of fomua-
lin to every liter, yet in this case it is possible that the
specific gravity of the whey may be affected, on account
of a partial splitting of the casein. It is still better to boil
the filled bottle and then close it with a sterilized cork.
In taking the sample, it is also necessary to avoid adding
water even in the slightest quantity (rinse the bottles
with milk), in order that no nitrate shall be added.

c. The herd sample. In cases in which adulteration is
suspected, comparison may be made of the milk under
suspicion with that of the herd milked under super-
vision. The importance of the stable, or herd test has
been much overestimated. The great variations in the
composition of the milk of individual animals, leads one
to be careful in putting confidence in a comparison of the
fat content of milk on different days; but comparisons
may fairly be made between the quantities of solids not
fat and the specifie gravity of the whey, which are fairly
regular. The stable or herd test is very uncertain,
therefore, for individual cows, or small herds, but it may

202 MILK HYGIENE

sometimes be used with advantage for large herds, al-
though there is seldom cause, even in this case, to
apply it.

In taking a herd sample, the feeding and the care of
the animals should not be varied in any respect, the
milking should be conducted by the usual persons at the
usual times and in the usual way; less thorough milking
gives lower fat content, while particularly thorough
milking raises the percentage of fat. The quantity of
milk for the day must be mixed together and the sample
taken from the whole. As transitory changes occur in
the composition of the milk, surer results will be gained
from daily examinations for several days than from but
one examination.

d. Determining the specific gravity of milk and whey.
Various instruments are used for this purpose: different
areometers, the pycnometer or the hydrostatic scale.
The areometer method is the simplest and, at the same
time, it is sufficiently accurate, so there is no occasion to
describe more in detail the other methods, which require
weighings.

Quevenne’s lactodensimeter, in some one of its sev-
eral modifications, is the areometer in common use.
This is made like an ordinary areometer and divided
into degrees which correspond to a specific gravity from
1.014 to 1.040, or only from 1.022 to 1.038, since, by the
latter division, a greater space is gained between the
different degrees, without unduly lengthening the in-
strument. From such a lactodensimeter one can easily
read off four decimal places.

The milk whose specific gravity is to be determined
is well shaken and poured into a high glass cylinder of
suitable diameter; the areometer is dropped in slowly,
in order to prevent its bobbing up and down. [The bulb
should be free from adhering air bubbles.] The figures

LACTOMETER TESTS 203

on the stem are the second and third decimals of the
numbers of the specific gravity, so that 34 is to be read
1.034. For this examination, the temperature of the
milk must be 15° C. (60° F.); if it is not, the specific
gravity of the milk at 15° C. must be calculated from
the specific gravity found and from the temperature,
for in milk inspection and analysis this is the standard.
With the aid of the tables on pages 204 and 205, one
of which is valid for whole milk and the other for
skimmed milk, one can easily compute specific gravity
for 15° C. from that found at another temperature.

If the temperature of the whole milk is 18 C., and
the lactodensimeter reads 29, one finds in the table, at
the intersection of the perpendicular column 18° C and
the horizontal line 1.029, the number 29.6; the specific
gravity is therefore equal to 10296 at 15) CL (See
tables, pages 204 and 205.)

In several of the lactodensimeters (¢.g., Soxhlet’s)
there is a thermometer in the instrument, whose scale
does not show the degree of heat but gives directly the
decimal to be added to or subtracted from the reading
on the stem of the laetodensimeter, as the specific grav-
itv. If the latter number is, for example, 29, and if the
thermometer registers 3.5 above zero, the specific grav-
iis at Lor 1s Lee.

[The so-called New York Board of [Health lactometer
has an arbitrary scale divided into 120 equal parts. One
hundred on this seale corresponds with a specific gravity
of 1.029, which was supposed to represent the lowest
specific gravity of pure milk, and 0 represents 1.000, the
specifie gravity of water. If the specific gravity of a
sample of milk fell to 90 it was supposed to be 90 per
cent. pure, that is, to contain 10 per cent. of added
water. But the specifie gravity of milk varies so that
this cannot be relied on and there is no single advantage

MILK HYGIENE

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206 MILK HYGIENE

in this arbitrary scale, which is very confusing. Un-
fortunately, however, it has come into rather general
use among milk inspectors, especially in the Hastern
States.

To convert readings of this lactometer into corre-
sponding readings of the Quevenne scale, they must be
multiplied by 0.29, or, the following table may be used:

QUEVENNE LACTOMETER DEGREES CORRESPONDING

TO NEW YORK BOARD OF HEALTH
LACTOMETER DEGREES.

Board of Board of j Board of
Ra cece | ES) aces | | sees
61 17-7 81 23-5 101 29-3
62 18-0 82 23-8 102 29-6
63 18-3 83 24-1 103 29-9
64 18-6 84 24-4 104 30-2
65 18-8 85 24-6 105 30-5
66 19-1 86 24-9 106 30-7
67 19-4 87 25-2 107 31-0
68 19-7 88 25-5 108 31-3
69 20-0 89 25-8 109 31-6
70 20-3 90 26-1 110 31-9
71 20-6 91 26-4 111 32-2
72 20-9 92 26-7 112 32-5
73 21-2 93 27-0 113 32-8
74 21-5 94 27-3 114 33-1
75 21-7 95 27-6 : 115 33-4
76 22-0 96 27-8 116 33-6
77 22-3 97 28-1 117 33-9
78 22-6 98 28-4 118 34-2
79 22-9 99 28-7 119 34-5
80 23-2 100 29-0 120 34-8

L.P.]

Specific gravity of the whey. In many cases it is of
value to determine the specific gravity of the whey be-
cause this is much more constant than that of milk,
for the reason that the lactose and salt vary less than
the fat.

SPECIFIC GRAVITY OF WHEY 207

Lescoeur warms the milk to 45° C. (113° F.) and adds rennet;
after about one-half hour the whey is pressed out and filtered, then
it is cooled to exactly 15° C.; the specific gravity may then vary
between 1.029 and 1.031, but if water has been added it decreases
significantly, as shown below:

Whey of pure milk = 1.0300
Whey of milk+ 10 per cent. water = 1.0275
Whey of milk +20 per cent. water == 1.0251
Whey of milk +30 per cent. water = 1.0230

Reich recommends that 20 ¢.c. glacial acetic acid be added to
500 ee. milk, that the mixture be well shaken and heated for
5 to 6 minutes to 60° to 65° C. (140° to 150° F.) ina elosed flask, then
cooled and filtered; the filtrate is to be heated in a flask until the albu-
min coagulates, then filtered again and the spevifie eravity determined
after cooling to 15° C. Aceording to his results, this varies between
1.027 and 1.029; a specific gravity of 1.026 is always a sign of the
addition of water.

If one wishes to apply the determination of specific
gravity of whey to milk inspection, it is necessary to
develop a definite method, which must be followed out
exactly, for, otherwise, the result is uncertain; and he-
fore basing a prosecution on the results of this method,
one must have made eareful comparisons, with the same
method, of normal and watered milks.

From investigations that were undertaken in Copen-
hagen under Jensen’s direction, it appears that these
two methods do not give uniform results. From 35
milk samples the following results were obtained:

Rennet method Acid method
Specifie eravity Speeifie gravity
7 samples 1.0270 to 1.0274 2 samples 1.0257 to 1.0259

7 eS 1.0275 to 1.0279 10 . 1.0260 to 1.0264
15 - 1.0280 to 1.0284 15 1.0265 to 1.0269
6 " 1.0285 to 1.0290 Ss S 1.0270 to 1.0276

208 MILK HYGIENE

The addition of water causes a lower specific gravity
of the whey. In the examination of adulterated
skimmed milk, he found the figures to be 1.0256, 1.0246,
1.0254 and 1.0257 (rennet method) and 1.0242, 1.0234,
1.0238 and 1.0241 (acid method).

e. The determination of the fat content of milk. There
are many methods for determining the fat content of
milk; some of these are too inexact to be considered
(e.g., the above mentioned transparency test by means
of the lactoscope, and the like), others give very good
results but require rather expensive apparatus, still
others require exact weighings and work that can be
done only in chemical laboratories. Some simple tests
are, however, so accurate and so practical that they are
available for the work of milk inspection.

Among the methods used, besides the transparency
test already mentioned, the creamometer should be
named, that is, the measurement of the layer of cream
which rises when the milk is allowed to stand. Since,
however, the thickness of the layer of cream furnishes
uo reliable gauge as to the fat content, this method can-
not be used if there is to be a prosecution. The separa-
tion of the cream by a centrifuge of high velocity
(Fjord’s test), and subsequently measuring the layer of
cream, gives better results and is often used in cream-
eries for comparing milks. For general use, however,
it is impractical, and not sufficiently accurate.

The available methods are, principally, Soxhlet’s
method, which was formerly used to a greater extent
than it is now; Gerber’s method, [the Leffmann-Beam
and the Babcock methods] and methods of chemical
analysis.

Soxhlet’s method is founded upon the following prin-
ciple: the solution of the fat in ether and the determina-
tion of the specific gravity of this solution.

GERBER’S FAT DETERMINATION 209

The following appliances are necessary for this examination (see
Fig. 20): (1) three pipettes of 200, 60 and 10 ec.; (2) several
half liter bottles; (3) two delicate areometers with thermometer,
one for whole milk and the other for skimmed milk; (4) one large
glas- tube (A) adjusted for flowing water; (5) a smaller glass
tube (B) enclosed in A; (6) a rubber bulb with a tube; (7) a larger
container filled with water heated to 17° to 18° (. Besides these, the
following chemicals are necessary: (S) potassium hydroxide solution
of specitie gravity 1.27 (400 er. potassium hydroxide is dissolyed in
water and after the solution has cooled it is made up to 1 liter); (9)
ether, shaken with one-fifth its volume of water and decanted oft;
(10) ordinary ether.

The milk to be examined is warmed in a water bath to 18° C. and
is well shaken. By means of a pipette, 200 ¢.. of this are drawn
off and inixed in a bottle with 10 ee. of the potassium hydroxide
solution. Then, 60 ¢.c. of ether are added. The bottle is immediately
elosed by a perfectly tight stopper, is violently shaken and allowed to
stand one-fourth hour im water at 18° C., durine which time it must be
shaken frequently. Gradually, the ether dissolves the fat and a
transparent layer is formed on the surface. Now the stopper of
the bottle is replaced by another (D) and, by means of a bulb, the
transparent fat-containing ether is driven up into the tube B which is
surrounded in tube A by water warmed to 18° C. The areometer
(() is in the inner tube, and after the fluid rises so high that it
ean float, the flow is cheeked hy means of a valve q, then the
specifie gravity is read. The quantity of fat disselved is shown, and
from this the fat content of the milk can be ealeulated. Soxhlet’s
apparatus is xecompanied by tables from which the fat content of the
milk ean easily be read, if one has determined the specitie gravity
of the fat-ether, and has read its temperature.

Gerber’s acidobutyrometer affords a very convenient
and aceurate way of determining fat, that is widely
used. The method consists in measuring the quantity
of fat in an aceurately measured quantity of milk, after
the fat has been separated and dissolved in amyl-aleo-
hol. Gerber’s instrument (see figs. 21 and 22), consists
of a centrifuge, bottles (G) of special shape, and 3
pipettes, .e.: 1 acid pipette to hold 10 e.c.(H) and 2 small
pipettes (1, K) of 1 and 11 ¢.e. eapacity. These chem-

4

210 MILK HYGIENE

icals are required: crude sulphuric acid of a specific
gravity at 15° C. (60° F.) of 1.825, and amyl-alcohol.
The examination is made in the following way: 10 ce.

Fic. 20.

| rt I

nq
ih
|

i
1

Soxhlet’s apparatus for fat-determination.

of sulphuric acid are measured out by the acid pipette,
this is permitted to flow slowly into the bottle G; 1 ¢.e.
of amyl-alcohol is measured and poured carefully into

GERBER’S FAT DETERMINATION ul.

the glass so that it forms a layer upon the surface of
the sulphuric acid. Now, exactly 11 ¢.c. of well mixed
milk that has been heated to 15° C. (60° F.) are measured
and poured into the bottle, which is closed by a rubber
stopper and then it is well shaken. The milk dissolves
with the generation of considerable heat. The stopper
is driven in so far that in the inverted bottle, the fluid

Fie, 21

Gerber’s apparatus for fat-determination.

reaches the mark 0 on the seale; the bottle is put into the
centrifuge and this is set in motion, after it has been
well balanced. If the sample is not to be centrifuged at
onee, the bottle should be placed in a water bath at 60°
to 65 C. (140° to 150° F.). The process of centrifuging
lasts 10 minutes with such a machine as shown in figure
21; and in order to keep up speed it is necessary to ac-

212 MILK HYGIENE

celerate the motion three times, by drawing the strap.
[With some patterns of centrifuge, these that have a
velocity of 800 to 1000 per minute, the whirling is com-
pleted in 3 to t minutes.] After centrifuging, the bottle
is taken out and placed in a water bath at 60° C. (140°
F.). The fat forms a clear layer in the top of the tube.
Through shifting the stopper, the lower border of the

Test bottles and pipettes used in connection with Gerber s method for fat-determination.

fat layer can be brought into the same plane with one of
the division lines and the thickness of the layer of fat
can be read off. One should read from the lower part
of the curved upper line. The upper, narrow part of
the tube is divided in 90 parts, each line corresponds to
0.1 per cent. fat; for example, if the fat laver reaches
line 35, then the fat content of the milk is 3.5 per cent.

LEFFMANW?S FAT DETERMINATION 213

[The Leffmann-Beam method (sometimes, improp-
erly, called the Beimling test) was worked out in ad-
vance of the Gerber test, which resembles it. The fol-
lowing description is from Leffmann:** ‘‘ The dis-
tinctive feature is the use of fusel oil, the effect of which
is to produce a greater difference in surface tension
between the fat and the liquid in which it is suspended,
and thus promote its readier separation. This effect
has been found to be heightened by the presence of a
small amount of hydrochloric acid.

‘“'The test bottles have a capacity of about 30 cc.
and are provided with a graduated neck, cach division
of which represents 0.1 per cent., by weight, of butter
fat.

‘“ Pifteen ¢.c. of the milk are incasured into the bot-
tle, 3 cc. of a mixture of equal parts of amyl-aleohol
and strong hydrochloric acid added, mixed, the bottle
filled nearly to the neck with concentrated sulphuric acid,
and the liquids mixed by holding the bottle by the neck
and giving it a gyratory motion. The neck is now filled
to about the zero point with a mixture of sulphuric acid
and water prepared at the time. It is then placed in
the centrifugal machine, whieh is so arranged that when
at rest the bottles are in a vertical position. If only one
test is to be made, the equilibrium of the machine is
maintained hy means of a test bottle, or bottles, filled
with a mixture of equal parts of sulphuric acid and
water. .\fter rotation for from one to two minutes, the
fat will collect in the neck of the bottle and the percent-
age may be read off. It is convenient to use a pair of
dividers in making the reading. The legs of these are
placed at the upper and lower limits respectively of the
fat, allowance being made for the meniscus; one leg is

63 VIenry Leffmann, Analysis of Milk and Milk Products. Phila-
delphia, 1900.

214 MILK HYGIENE

then placed at the zero point and the reading made with
the other. Experience by analysts in various parts of
the world has shown that with properly graduated
bottles the results are reliable. As a rule, they do not
differ more than 0.1 per cent. from those obtained by
the Adam’s process, and are generally even closer.

‘¢The mixture of fusel oil and hydrochloric acid
seems to become less satisfactory when lorg kept. It
should be clear and not very dark in color. It is best
kept in a bottle provided with a pipette, which can be
filled to the mark by dipping. Rigid accuracy in the
measurement is not needed.’’

The Babcock method or ‘‘ test ’’ is, in America, by
far the best known and most used centrifugal test for fat
in milk. The Leffmann-Beam and the Gerber tests are,
however, being used more and more, on account of the
shorter time required.

In careful hands, the Babcock test is very accurate.
Small or large outfits, the centrifuges to be driven by
hand or power, may be purchased from any dairy sup-
ply establishment. The test is made by placing in the
special test bottle 18 grams (17.6 cc.) of milk. To this
is added, from a pipette, burette or measuring bottle,
17.5 ec. commercial sulphuric acid of a specific gravity
of 1.82 to 1.83. The contents of the bottle are carefully
and thoroughly mixed by a rotary motion. The mixture
becomes brown and heat is generated. The test bottle is
now placed in a properly balanced centrifuge and
whirled for five minutes at a speed of from 800 to 1200
revolutions per minute. Hot water is then added to fill
the bottle to the lower part of the neck, after which it
is again whirled for two minutes. Now, enough hot
water is added to float the column of fat into the grad-
uated portion of the neck of the bottle, and the whirling
is repeated for a minute.

BABCOCK’S FAT DETERMINATION = 215

The amount of fat is read while the neck of the bottle
is still hot. The reading is from the upper limits of the
mensicus instead of the lower, as with the Gerber and
the Leffmann-Beam tests. A pair of calipers is of as-
sistance in measuring the column of fat. L. P.]

The chemical methods consist in accurately weighing
the fat separated from a definite quantity of milk. The

Fie. 23.

wu

One form of Babcock’s apparatus for fat-determination.*

most exact result is gained by the evaporation of a defi-
nite amount of milk (see below) and by the extraction
of the fat from the evaporated mass by ether or benzine,
which is then evaporated. Quite accurate results are
also gained without evaporating the milk, by separating

* From * Principles and Practice of Butter-Making,” by McKay
and Larsen, by permission of Messrs. John Wiley & Sons, the
publishers.

216 MILK HYGIENE

the fats from the other ingredients and ascertaining
their weight.

Gottleib’s method gives results sufficiently accurate for our use.
For this method one requires, as apparatus, only a cylinder of 40 c.c.
capacity, divided to measure quantities of 0.5 ¢.c., some glass flasks
and a long, thin glass syphon. 10 grm. of milk are accurately weighed
into one of the small flasks and poured into the glass cylinder; the
amount of milk left adhering to the walls of the flask is determined
by a second weighing, so that one may know exactly how much
has been poured into the cylinder. 1 ¢.c. of 10 per cent. ammonia
water (specific gravity 0.96) is mixed with the milk and shaken,
then 10 ¢.e. aleohol (95 per cent.) are added and it is shaken again,
after which 25 e.c. ether are added. The cylinder is well closed with
a cork that has been moistened in water, and shaken hard. 25 ee.
petroleum benzine are added and, after repeated shaking, the bottle
should be allowed to stand undisturbed at least 6 hours. By that
time, the fluid is separated into two sharply marked layers; the
upper one is the ether-benzine-fat mixture, the under one contains
the water, the lactose and proteids; a whitish sediment consists of
phosphates. The volume of the upper layer of the fluid is read off
and a determined quantity of it is syphoned off into a small weighed
flask. The ether and benzine are now evaporated by mild heat.
Thereupon, the flask is allowed to stand a couple of hours in a drying
chamber at 100° C., is cooled in an exsiceator and, finally, weighed.
From the total volume of the mixture of ether, benzine and fat,
and from the quantity of fat in the portion evaporated, the weight of
the total fat content of the milk sample can be ecaleulated, and thus
the percentage is determined.

f. Determination of the total solids in milk. The total
solids in milk are determined chemically in the following
way: Exactly 10 ¢.c. of milk are measured into a plat-
inum or porcelain vessel, the weight of which is already
known; the vessel is heated in a water bath to 100° C.
until all the water is evaporated. After cooling in an
exsiccator, the vessel and its contents are weighed. The
difference between the weight found and the original
weight of the dish gives the total amount of solids in
the milk. If the amount of fat, found in another way, is

DETERMINATION OF SOLIDS cae

subtracted, one gets the quantity of solids not fat. By
incinerating the contents of the vessel, in a muffle oven,
and again weighing, the amount of salts, or ash, is deter-
mined. If it is desired to extract the fat from the other
solids, to determine the fat percentage, it is necessary
before drying the milk to mix with it a weighed quantity
of roasted pumice stone; then, after evaporation, the fat
is removed hy ineans of ether (or benzine) in an ordi-
nary fat extraction apparatus, and is determined by
weighing, after evaporating the ether. This work is
quite particular and requires a well appointed labora-
tory. Moreover, in practical milk control, gravimetrie
analyses are not indispensable, for one can easily cal-
culate the quantity of solids from the specific gravity
and the fat, according to the formula derived hy Fleisch-
mann. If total solids are represented hy t, the fat per
cent. by f and the specifie gravity by s, one has:

100s — 1000
s

t= "2% £ + 2.605

207

That is, if wesay f- 3.55 and s == 1.0327, we get

12.697

2 appre _ LOOX 1.0327 —- 100 ae Son Bye7
t= 12 3.454 (2.005 asa: ) = 420 setts

Another formula proposed by Bertschinger gives quite
accurate results:

5f + 100s
uae aaa + 0.07

Moreover, tables have been worked out from which
the total solids can be read off, if both the other factors
are known. Ackermann has constructed an ‘‘ automatic
reckoner *’ from which one ean read off one of the fac-
tors when both of the others are known, by simply turn-
ing circular dises. [Richmond has devised a sliding rule
for the same purpose. ]

The computation of the solids not fat is very easy.

218 MILK HYGIENE

One has only to subtract the fat percentage found from
the computed percentage of total solids. The percent-
age of fat (p) in the total solids is easily computed
according to the formula:

p= +x 100

To use the above illustration:

p= Boas x 100 == 27.95
Likewise, it is quite easy to determine the specific
gravity (m) of the dry milk solids by a simple computa-
tion, according to this formula:

st

™ = st — (100s — 100)

Using the same illustration again:

1.03827 >< 12.697 13.112

= 10887 < 12.697 — (103.27 100) ~ I3a12—s.a7 — 138?

m

The specific gravity of the dry solids of whole milk
varies, according to the fat content, between about 1.31
and 1.36.

V. ADULTERATION AND ITS DETECTION.

The most frequent adulterations of whole milk con-
sist in partial skimming, dilution with skimmed milk,
dilution with water or a combination of these. Skimmed
milk is adulterated by the addition of water, and cream
by starch, flour, ete.

a. Partial skimming of whole milk or dilution with
skimmed milk produce the same result; in both cases
the fat content is lessened, while the percentage of solids
not fat is increased very slightly, and the specific gravity
is increased. If the skimming is not so great as to cause
the fat percentage to fall below the minimum limit for

DETECTION OF ADUELTERATION 219

mixed milk and the specific gravity to rise above its
maximum (1.034), this adulteration is difficult to dis-
cover, as the considerable variations in normal milk
would lead one to expect. It is in these cases that com-
parison was formerly made with the stable or herd sam-
ples, but, as stated before, these are worth but little in
relation to small herds, and even in the case of large
ones they are not entirely trustworthy. When it is pos-
sible to compare the figures of inspected milk with the
results of the herd test, an opinion can be formed as to
how great a percentage of the fat content is lacking,
from this formula:

F—f

x- 100 -
x I

in which F shows the fat percentage in the herd sample
and f the fat percentage of the sample under suspicion.

Where there is reason for suspicion, the best method
for proving the existence of such adulteration ts,
in many eases, furnished by the judicial hearing of the
persons charged, and the witnesses. In many places, as
has already been stated, to prevent such adulterations a
minimum standard has been established for the fat con-
tent of whole milk.

[In America, where there are legal standards calling
for 3 to 3.5 per cent. of fat in whole milk, prosecutions
for partial skimming or dilution with skimmed milk are
not often brought if the sample comes up to this estab-
lished standard, although such adulteration may be
suspected from a marked disproportion between the
fat and the solids not fat. But this proportion is, at
best, so variable that it furnishes no definite guide.
Ix P.]

Ul. The dilution of whole milk with water causes an
increase of volume and, therefore, a decrease in the per-
centage of fat, of solids and of the specific gravity of the

220 MILK HYGIENE

milk, as well as of the whey. Feser gives the following
example:

Start with 9 liters of milk of the composition: 3.95
per cent., fat; 8.9 per cent., solids not fat; 1.031, specific
gravity.

To this add 1 liter of water of this composition: 0 per
cent., fat; 0 per cent., solids not fat; 1.000, specific
gravity.

This gives 10 liters of adulterated milk of the com-
position: 3.55 per cent., fat; about 8.0 per cent., solids
not fat; 1.028, specific gravity.

Further evidence of this adulteration is found in the
lower specific gravity of the whey and in the fact that
the specific gravity of the dry solids (m) and the fat
content (p) of the solids are, practically, normal; in the
above example, then: *4

ees sT ee 1.031 X 12.85 13.24 _ 4 on5
~ $T — (00S — 100) 1.031 x 12.85 — (100 X 1.031 — 100) 10.14 —~CO*
a st on 1.028 ¥ 11.55 — 1873 _ 4 597
Be (100s — 100) 1.028 7 11.55 — (100 % 1.028 — 100) ~ 9.073 ~~”
Lae 3.95 ana
P= + X 100 tags ~ 100 = 30.738
= x 100 = 3 x 100 = 30.736
p= t” * ie5 = A390.

If milk samples are available which may be justly com-
pared with the milk under suspicion (herd samples
taken under fixed conditions; milk from the same large
herd; other milk sent by the same shipper or from the
same can in the dealer’s possession), then the percent-
age of water added can be computed according to Vo-
gel’s formula:

x=7&X 100 > 100

54M and P represent the specific gravity of the total solids and
the percentage of fat in the total solids of whole milk, and m and
p the same factors in adulterated milk.]

DETECTION OF ADULTERATION 227).

In the example just given we have F —=3.95 and f
= 5.59, then

B95 ‘
ga 100 + 1000 11.11%

x

that is, exactly 1 part to 9 parts. On account of the
great variations in the percentage of fat, one must be
very careful with this computation.

In detecting this adulteration, the herd sample is of
some value, since the solids not fat are subject only to
shght variations. In drawing conclusions, therefore,
these other factors must have full consideration (esti-
mated solids not fat, specifie gravity of the whey), and
are of more value as a guide than the percentage of fat.

[The percentage of solids not fat should not he less
than 8.5 or 9. The percentage of ash is of considerable
value in detecting adulteration by adding water. This
factor is rather constant, and in pure milk is usually
between 0.70 and 0.75 per cent. L.P.]

It has been suggested that use be made of the deter-
mining of the freezing point of milk and of its conducti-
bility for clectricity, since these qualities are consid-
erably changed by the addition of water. But these
methods are not vet sufficiently developed to he avail-
able. On the other hand, there may be some advantage
in determining the acidity of the milk, since this is less-
ened by dilution (see page 227), yet the lessened acidity
may come from other causes.

The addition of lactose or cane sugar to milk diluted
with water, renders judgment more difficult, since, by
this means, the specific gravity of the milk as well as
that of the whey, and also the amount of solids not fat,
is Increased.

While milk is always free of nitrates and nitrites,
even if the animals have taken such substances with

222 MILK HYGIENE

their food, these are frequently present in water in small
quantity. The presence of nitrates or nitrites in the
milk, therefore, shows, with certainty, that water has
been added. However, the lack of nitrates does not ex-
elude this, as all water does not contain nitrates. Even
a very small quantity of nitrates and nitrites can be
detected as follows:

1.5 ee. of a 20 per cent. calcium chloride solution is added to
100 ec. of milk; the mixture is boiled and filtered. A little of the
filtrate is mixed with enough of a 2 per cent. solution of diphenylamin
in sulphuric acid to make it milky; a little concentrated sulphurie acid
is poured into a test tube and the mixture is added slowly, so that
the fluids do not mix; if nitrie acid or nitrous acid is present, a blue
zone is formed at the plane of contact. (Soxhlet.)

[A simpler test for nitrates is that devised by Richmond. The
following description of this test is from Farrington and Woll.®®
“Place a small quantity of diphenylamin at the bottom of a porcelain
dish, and add to it about 1 ¢e. of pure, concentrated sulphuric acid;
allow a few drops of the milk serum (obtained by adding a little
acetic acid to the milk and warming) to flow down the sides of
the dish and over the surface of the acid. If a blue color develops in
the course of ten minutes, though it may be faint, it shows the
presence of nitrates, after ten minutes a reddish-brown color is
always developed from the action of the acid on the serum. There
should be no difficulty in detecting an addition of 10 per cent. of
water to the milk by this test, if the water added contained 5 parts
of nitric acid, or more, per 100,000.” L. P.]

c. The skimming of whole milk in conjunction with
the addition of water, or the addition of skimmed milk
as well as water, are common methods of adulteration.
Tt is easily understood that the fat content is consid-
erably lessened in this way, and that also the solids not
fat decrease; it is evident, besides, that the percentage
of solids not fat (p) 1s lessened and, consequently, the

55 Warrington and Woll. Testing Milk and its Products, 13th
edition. Madison, 1904.

DETECTION OF ADULTERATION Boa

specific gravity of the solids (m) must be increased. The
specific gravity of adulterated milk can vary consider-
ably, often it ix nearly normal, but frequently it is
slightly diminished. Feser has given the following ex-
ample of such adulteration:

The unadulterated milk had 3.95 per cent., fat; 8.9
per cent., solids not fat; 1.031 specific gravity; by par-
tial skimming, it was changed to 2.19 per cent., fat;
ahout 8.9 per cent., solids not fat; 1.034, specific gravity ;
hy the addition of water it was further changed to 1.21
per cent., fat; about & per cent., fat free solids; 1.0305,
specific gravity.

Decisive points for determining if such adulterations
exist are the low solid contents, the low fat per cent.,
the almost normal specifie gravity of the milk, the in-
creased specific gravity of the solids (m) which, in the
above example, was changed from 1.305 to 1.473, and in
the low specific gravity of the whey. If nitrates are
proven in the milk there is further support for the con-
clusion that it is watered.

When a sample of adulterated milk can fairly be
compared with another whieh is known to be unadulter-
ated (samples taken from the same dealer the same day,
milk of a large herd, cte.) [or with an accepted stand-
ard] one can form an opinion of the extent of the
adulteration by means of a formula derived from Bohm-
lander:

R

M- _ xw—W

i 100 (; _ He
Ir

M shows the quantity of water added to 100 grm. of
milk; W is the per cent. of water in the unadulterated
and w in the adulterated, or suspected, sample; R and r
are the percentages in these two samples of solids not

224 MILK HYGIENE

fat; EX represents the percentages of fat removed by
skimming, while F and f show the peneentage of fat in
the two samples,

In the above case one could find by computation:

M = “3 < 90.79 + 87.15 = 1.112 & 90.79 — 87.15 == 13.81

1.21 “% 8.9 10.77
E = 100 (1 — 3.95 02 a) =10 (1 — = 66

Or, in other words, about 14 grm. of water are added
to each 100 grm. of milk and about 66 grm. of fat have
been taken from each 100 grm. of fat.

The effects of the various adulterations may be
shown in tabular form as follows :*

=
a be 3 Bb gS
Bad Se ro) 68 = 24 38 So “3
sia ga By ov eS oo 2 5
ba | be | p | Pe [me | Pe | Pe | eke
oo Oe 2 £5 ote | ead b=} ogee
es eo & ag esu |] sad a. aos
Su oe 5 es | Sle |] €es os as
ex) oe Ea EZ | REE | ESE | 52 | Sas
wm wm A Ay | uw i iam Ay
1.029 to
. Wk 1.034 |1.029to|] « z | 85to | 1.30to |] 20to 0.7 to
Normal mille sate aver. | 1.031 | °'5 | “Jos | Lad 34 0.75 0
| 1.082
Skimmed or diluted (||. no very
with skimmed milk 5 | higher change lower slightly’ higher} lower | higher 0
' higher |
Water added ........ f) 3 ' fe | no no
oe 1 lower | lower | lower | lower change |change lower | + or0
water added....... { ‘change lower | lower | lower | higher| lower | lower | + or0

Although each form of adulteration has its own char-
acteristics yet, in practice, it is: often very hard to deter-
mine whether a slight adulteration has occurred, be-
cause the composition of milk, as explained above, dif-
fers so much physiologically—and with the same animal
from day to day. Unless there is a distinct departure
from the normal, one should be careful in expressing
his opinion, especially if he does not know the herd con-

* This table is changed somewhat from the one prepared by Jensen [L. P.]

DETECTION OF ADULTERATION 22)

cerned. Usually, the presence of nitrates is positive,
still it must not be forgotten that when the milk can is
rinsed a little water may be left, which, if it is rich in
nitrates, may cause the milk to show a slight reaction,
so that it might appear that water has been intentionally
added. Usually water does not contain such a quantity
of nitrates as to cause a suspicious reaction when the
milk has not really been adulterated.

d. Adulteration of partly skimmed and skimmed
‘milk. In most cities no minimum limit is fixed for the
fat content of the half skimmed and the skimmed milk,
and the only form of adulteration to he considered in
this connection is the addition of water. This causes a
lowering of the specifie gravity of the milk (from 1.030
to 1.036 to from 1.032 to 1.040) and whey, as well as a
diminution in the amount of solids. .\ possible trace of
nitrates proves that the milk has been watered. In
cities, in which the minimum limit of fat content for
partially skimmed milk or skimmed milk has been cs-
tablished, the milk is, of course, considered adulterated
when it falls below this standard. [In some places there
is a standard of 9.25 per cent. total solids for skimmed
milk as provided by the U. S. Department of Agricul-
ture. |

ec. Adulteration of cream. Cream is sold in different
forms, with fat content varying between about 10 per
cent. and 30 per cent. (40 per cent.). In some cities, the
minimum content of different grades is defined, so in
such eases public control must be extended to determin-
ing the amount of fat in cream. Of the different adul-
terations, the addition of starch and flour are to be
mentioned particularly. This is done to make the cream
thicker and to give it the appearance of being better
than it really is. In raw eream, the proof by micro-
scopic examination is simple, as the starch grains are

15

226 MILK HYGIENE

shown as irregular, round concentrically formed bodies.
Amyloid bodies have been found in milk by Herz; these
are like similar bodies previously found in the pros-
tates, and somewhat resemble starch grains, but are
hardly to be found in such great quantity that, in prac-
tice, they have any influence on this examination. After
the cream is boiled, the starch grains burst, and cannot
be recognized under the microscope. In this case, the
chemical test must be applied, which may be used with
raw cream also. The simple addition of a diluted solu-
tion of iodine, in many cases, gives the milk the well-
known blue color; it is better, however, to add a little
acetic acid, boil and filter and apply the iodine test to
the filtrate. [The presence of ‘‘viscogen”’ is indicated
by the greater percentage of ash. ]

The detection of other foreign substances, as white
earth, emulsion of brain substance, etc., is best made by
means of microscopic examination.

VI. PUBLIC SUPERVISION TO PREVENT THE SALE OF
DETERIORATED MILK

The public should not only make and enforce regula-
tions regarding the production and handling of milk to
prevent adulteration, but it should make regulations to
prevent milk being sold in a damaged or spoiled con-
dition and, by frequent inspection, these regulations
should be enforced. The milk samples that are taken
must not only be used for the purpose of determining
possible falsification but, at the same time, they should
be subjected to a number of other examinations.

a. Determination of the appearance, odor and taste. All
milk differing from normal in color or appearance (mix-
ture of blood or exudate, abnormal secretion, secretion
of coloring matter, bacterial alterations), or by odor or
taste (abnormal composition, the excretion of odorifer-

DETECTION OF DETERIORATION a

ous substances, absorption of strongly odorous matter,
addition of foreign matter, bitter, stale, sour, microbic
changes) must not be sold and should be condemned.

b. Determination of the reaction. This may be done by
using red and blue litmus paper. Normal, quite fresh
milk has an amphoteric reaction. If the test shows ex-
cessive alkaline or acid reaction, it should be examined
more closely. An alkaline reaction is frequently shown
in the milk of old milking cows; mixed milk, on the
contrary, is never alkaline. Sometimes an alkali is
added; if so, it can be proven by the test previously
mentioned, or, quite easily, by titrating with tenth-
normal sodium hydrate solution, with which phenol-
phthalin is used as indicator. Normal milk shows an
acid reaction to phenolphthalin, so that from 18 to 19
c.c. of tenth-normal sodium hydrate solution must be
added to 100 ¢.e. of milk to make the red color appear;
if the milk becomes red at once when phenolphthalin is
added, then it is abnormally alkaline and, as a rule, alkali
has been added; if a smaller quantity of sodium hydrate
solution is necessary, the milk may either have been
treated with alkali or diluted with water.

If the litmus paper indicates an acid reaction, the
degree of acidity of the milk may be determined by
means of titrating with tenthnormal solution of so-
dium hydrate, using phenolphthalin as indicator. If, to
neutralize 100 ¢.e., requires more than 18 to 19 c.c. of
tenth-normal sodium hydrate solution, then the for-
mation of lactic acid has commenced, and its extent can
be measured exactly by determining the amount of
standard alkali required to neutralize it.

For titrating, an ordinary burette is used with a scale
divided into spaces showing 0.1 ec. After the addition
of about 0.25 e¢.c. phenolphthalin solution to the milk, the
standard sodium solution is dropped in, little by little,

228 MILK HYGIENE

until, after thorough shaking, the milk becomes faintly
reddish. Then the exact amount of solution that has
been used for neutralization is read off, and the degree
of acidity determined. If one has to make many titra-
tions it is most convenient to use a burette with a supply
from a larger tank; such a titrating apparatus can be
procured from any dealer in chemical apparatus.

[A rapid method for determining the acidity of milk
has been devised, which depends on the use of an accu-
rately measured amount of alkali dispensed in the form
of a tablet. This makes it possible to quickly prepare a
standard solution, and the method is very useful for in-
spections in the field. If the indicator, phenolphthalin,
is included in the tablet, the test is still more convenient.
It is made as follows:

Tablets are dissolved in a measured quantity of dis-
tilled water, sufficient to give a solution of standard
strength (usually five tablets make 100 cc. of solution,
but this varies with the brand of tablet and the manu-
facturer’s instructions must be observed) 18 grm. (17.6
c.c., being measured in the pipette used for the Babcock
test) of milk are measured into a white porcelain cup
and the alkali solution is added from a measure (burette
or graduated cylinder) until the pink color becomes
permanent. The amount of solution used shows the
percentage of acid in the sample.

If a standard of 0.2 per cent. lactic acid has been
adopted, then the amount of alkali solution required to
show any excess above this limit may be placed directly
in the cup and the measured sample of milk added to it.
If the pink color remains, there is less than 0.2 per cent.
of acid in the sample; if it disappears, there is more
than 0.2 per cent. of acid. L. P.]

Only a few German regulations give a standard for
the acid permitted in market milk. Sometimes, the

THE FERMENTATION TEST 229

requirement is made that the milk shall withstand the
test of boiling it in a test tube without the separation of
flakes or curds, and be able to withstand the, so-called,
alcohol test, which is made as follows :5"

Exactly equal parts of milk and alcohol (68 per cent.)
are carefully mixed in a tube and observed closely.
Fresh milk shows no precipitation; in that which is be-
ginning to sour, fine flocules are deposited on the walls
of the glass and, with greater acidity, flakes and lumps
are separated.

c. The fermentation test is used to show whether there
isan excess of bacteria of putrefaction in the milk. It
consists simply in incubating a sample of milk at body
temperature for 8 to 16 hours, followed by an examina-
tion as to its appearance, odor and flavor. The examina-
tion is easily made as follows: Into large test tubes
holding at least 25 ¢.c., that have been carefully cleaned
and sterilized, the milk samples, warmed to about 36° C.
(97° T*.), are poured. The tubes are closed hy cotton
and placed in an incubator or closet, where they are kept
at 30° to 55° CL (86° to 95° F.). In the course of eight
ov ten hours, and again later, the contents of the tubes
are examined, (ood, undeteriorated milk is then sour
and curdled and forms a homogeneous coagulun, without
much separation of whey or formation of gas. Fre-
quently, gas bubbles have split the coagulum and con-
siderable fluid has separated. This change, however,
does not necessarily signify that the milk was particu-
larly rich in bacteria of putrefaction. On the other
hand, if the milk curdles and has an offensive odor, or

’ As a result of boiling, separation occurs not only where the
milk has reached a certain degree of acidity but also in eases where,
as a result of disease of the cow, abnormally large quantities of
albumin and of globulin are present, or when there is admixture of

colostrum.

230 MILK HYGIENE

if the coagulum is beginning to dissolve, or if the milk
remains in a fluid state but has a bad odor and taste,
these are signs that the milk is contaminated with bac-
teria of putrefaction. In the application of this test, it
is important not to allow the milk sample to stand too
long before the examination is begun, and precautions
must be taken to prevent contamination while gathering
the sample and during the test.

In pasteurized milk, the fermentation test may give
general information concerning the bacterial content,
through noting the time that passes until appreciable
changes take place. Usually such milk does not
‘“ sour.’’ But no precipitate conclusion should be drawn
from the results of this test.

By boiling the milk for a short time and then incu-
bating the samples, a serviceable guide can be obtained
concerning the quantity of the spore bearing bacteria
in the milk. These will survive the heating, and, as they
are not checked in their growth by the lactic acid form-
ing bacteria, they increase rapidly and cause the milk to
eurdle, by the action of ferments.

[Russell 57 describes a curd fermentation test used by
cheese makers, as follows: ‘‘ When the milk is 95° F.,
about 10 drops of rennet extract are added to each sam-
ple and mixed thoroughly with the milk. The jar should
then remain undisturbed until the milk is completely
curdled; then the curd is cut inte small pieces with a
case knife and stirred, to expel the whey. The whey
should be poured off at frequent intervals until the curd
mats. If the sample be kept at blood heat (98° F.), for
six to eight hours, it will be ready to examine.

‘«The curd from a good milk has a firm, solid tex-

57 H. L. Russell, Dairy Bacteriology, Sixth Edition. Madison.
1905.

BACTERIOLOGICAL EXAMINATIONS 231

ture, and should contain at most only a few small ‘ pin’
holes. It may have some large, irregular ‘ mechan-
ical’ holes where the curd particles have failed to ce-
ment. If gas-producing bacteria are very prevalent in
the milk, the conditions under which the test is made
cause such a rapid growth of the same that the evidence
of the abnormal fermentation may be readily seen in the
spongy texture of the curd. If the undesirable organ-
isms are not very abundant and the conditions are not
especially suited to their growth, the ‘ pin’ holes will
be less frequent.

— ** Sometimes the curds show no evidence of gas, but
their abnormal condition may be recognized by the
‘imushy ’ texture and the presence of ‘ off’ flavors,
that are rendered more apparent by keeping them in
closed bottles. This condition is abnormal ani is apt to
produce quite as serious results as if gas was formed.”’

Curd fermentation tests have been suggested for use
in connection with the supervision of market milk, and
C. Ia. Marshall has made some observations that tend
to show their usefulness for this purpose. L. P.]

To make regulations in relation to the behavior of
milk to these tests would be premature. The general
requirement that market milk, and especially infants’
milk, shall not be rich in bacteria of putrefaetion is suf-
ficient for the present.

d. Bacteriological examinations are made when more
information is desired regarding the number and kind of
bacteria in milk. .\s has been said, this differs greatly,
even in freshly drawn milk, and it is searcely possible
to state a passing average for the bacterial content of
market milk. Nor does it seem to be possible to estab-
lish a maximum by ordinance, the violation of which
would Jead to the condemnation of the milk. Yet, it is
of importance to health officers to have an examination
made of the number of bacteria in milk sold, since, by

232 MILK HYGIENE

so doing, an opinion can be formed as to the genuine-
ness of the claims of the milk companies, as well as the
cleanliness and care with which the milk has been han-
dled from the time it was drawn until it was sold. There
are special reasons for making regular bacteriological
examinations of nursery milk; it must be required not
only that this shall come from healthy animals and not
be exposed to infection with pathogenic bacteria, but,
at the same time, it is well to require that it shall not
contain an excess of bacteria at the time it is delivered
to customers. In this connection, it would be very ad-
vantageous to make a stipulation to the effect that ves-
sels [bottles] in which infants’ milk is sold shall be pro-
vided with a label giving the day on which the milk was
produced. <A bacteriological examination of infants’
milk is of importance as indicating the thoroughness and
effectiveness of the methods of the concern and as indi-
eating the need, perhaps, of subjecting these methods to
thorough revision.

There are other reasons for establishing a bacterio-
logical examination of pasteurized (and sterilized) milk,
since, in this way, most important information may be
gained concerning the reliability or the inefficiency of
the methods in use by the various concerns. It would
also be of advantage, in connection with this inspection,
to require that the containers of pasteurized milk shall
be marked with a tag showing the day and method of
pasteurization (or sterilization).

The counting of bacteria in milk is not a difficult
matter, but when many samples are to be examined in
this way much time is required. The method is, in gen-
eral, the same as that used for estimating the number
of bacteria in water or other fluids (see the text-books on
bacteriology). It is best to use gelatin that has been
made with milk. A good way is to add 100 grms. of gela-

BACTERIOLOGICAL EXAMINATIONS — 233

tin to one liter of milk, boil, filter, neutralize, boil and
filter again. Or, one can use agar-agar in place of gela-
tin in making this culture medium. In this case, it is
necessary to first remove the casein hy the use of ren-
net. By this method, one may obtain agar or gelatin
that is fairly transparent. The culture media should be
placed in test tubes in the usual way. The examination
can be made as follows: By the use of an ordinary
cover glass preparation, examined under the microscope,
one ascertains whether the milk is especially rich in bae-
teria. If there are only a few bacteria, usually three gel-
atin tubes will suffice, otherwise four or fivemust be used.
One c.c. of milk is measured out and is mixed with 9 ce.
of fluid gelatin in a test tube. After mixing, one e.e.
of the mixture is placed in another tube containing 9 e.e.
of fluid gelatin. From this mixture a third tube is inoe-
ulated, and so on. In this way different dilutions of milk
are obtained. Tube no. 1 contains 0.9 ee. of milk;
no. 2, 0.09; no. 3, 0.009; no, 4, 0.0009; no. 56, 0.0001. Tf
nothing is taken out of tubes 2,5 and 4 for the purpose
of making further dilutions, they contain 0.1, 0.01 and
0.001 ce. of milk. Of course one ean make mixtures in
any other desired proportion.

After making the proper dilutions the fluid is poured
ina Petri dish which, of course, must have been steril-
ized. After the mass of gelatin becomes firm, the covered
dish is put away and is kept at an appropriate tempera-
ture. In the course of time more or less colonies form
on the gelatin, these are counted on the whole plate or
on a definite sub-division, and by this means the approx-
imate number of bacteria in one e.c. of milk may he
estimated. The result of the count is by no means exact
for a number of reasons, but this method gives an
approximation that is sufficient for practical purposes.
[The milk may he diluted with water instead of being

234 MILK HYGIENE

diluted through the gelatin tubes. Agar-agar is pre-
ferred to gelatin because it can be used for plates to be
incubated. If comparative counts are to be made the
apparatus and temperatures of incubation and the char-
acter of culture media should be the same. Porous
Petri dish covers are preferred to glass covers because
they tend to prevent spreading colonies. For a descrip-
tion of the method used in the bacteriological examina-
tion of milk in the laboratory of the Boston Board of
Health see a paper by Slack in the Journal of Infectious
Diseases, Supplement No. 2, February, 1906. L. P.]

The detection of specific pathogenic bacteria is so
difficult and the examination gives such unreliable re-
sults that practically it is not worth while to search for
them. The bacteria of typhoid fever and diphtheria have
rarely been discovered through the use of cultural meth-
ods; the tubercle bacillus may sometimes be discovered
under the microscope but usually it is present in such
small amounts that it cannot be detected. The best way
to examine milk for tubercle bacilli is by inoculation of
experimental animals. A conclusion, however, cannot
be drawn from this experiment until one or two months
have elapsed.

e. [Examination for pus. The examination of milk for
pus was first suggested by Dr. Stokes, of Baltimore,
and has since been carried out in a number of public
health laboratories in different parts of the United
States. The researches of Stokes, Bergey, Stewart,
Doane, Slack, and others have shown that cells are pres-
ent in practically all samples of milk and that in some
samples the cellular content is much higher than is usual.
Where the number of cells is high it is customary to
regard them as pus cells, but there is no general agree-
ment as to where the line should be drawn. The question
is a difficult one because pus cells and dead leucocytes

EXAMINATION FOR DIRT 230

are morphologically the same and so can not be differ-
entiated by their appearance alone. Doane has pro-
posed that milk shall be regarded as containing pus if
there is high cellular content accompanied by threads
of fibrin. Bergey proposes that pus shall be diagnosed
if there are 10 cells to the field of the 1,12 immersion
lens. Stewart centrifuges 1 ¢.c. of milk in small tubes
and if he find 23 cells to the field of the 1/12 immersion
lens, when the sediment of this amount of milk is spread
over 1 square em., he reports pus. Slack*proposes that
the sediment of 2 ¢.¢ milk shall be spread over + square
em. and that pus shall be reported if 50 cells are seen
to the 1/12 immersion field.

Since there is much doubt, in many cases, as to
whether high cellular content actually denotes pus,—that
is, as to whether the cells found are pus cells or leuco-
cytes, and as to whether the cells themselves are in-
jurious, it would appear to be desirable, for the present,
to report pus only where there is high cellular content,
as Judged by one of the above methods, accompanied by
the presence of streptococet. L. P.]

f. Examination for dirt. The sale of unclean or dirty
milk should be forbidden. A number of cities in Ger-
many have established the requirement that milk shall
not contain over a definite amount of dirt; the limit va-
ries from 5 to 10 milligrams of dry dirt to a liter of milk.
An examination for dirt can be made as follows: The
milk is placed in bottles, which are centrifuged, the milk
is decanted and the sediment is dried at a temperature a
little above that of boiling water. This material is
weighed and its quantity per liter is caleulated.

Instead of this rather formidable method it is usu-
ally sufficient to centrifuge the milk and then measure
the sediment. Or, one can pour the milk in a high glass
of conical shape and ascertain the amount of sediment

236 MILK HYGIENE

that collects in a given time. Gerber has constructed a
special apparatus for this purpose by means of which a
fair approximation of the amount of dirt in milk can be
made by simply measuring it.

Generally, the only requirement on this point is that
market milk shall not deposit visible sediment upon
standing for two hours. [An apparatus for this purpose
has also been devised by Otto, which can easily be under-
stood by the accompanying figure. The bottle, A, which
contains the milk is open at each end. The mouth of the
bottle must be closed by a cork held upon a rod, C. A

\

=

Otto’s apparatus for estimating dirt in milk.

fine tube, B, with a still finer point and closed at the thin
end, is attached to the mouth of the bottle by a short
rubber tube after which the cork on the rod C is with-
drawn. The milk is then permitted to stand in this
container, held in a rack, for a given time. At the end
of this time, the stopper is replaced in the mouth of
the bottle, the small tube is detached and the amount

EXAMINATION FOR PRESERVATIVES 237

of dirt is read from the seale. Stewart has devised a
method that gives good results in the laboratory of the
Board of Health in Philadelphia. It consists in the use
of small glass tubes, open at each end; the lower open-
ing is closed with a small rubber stopper. The tubes
are filled with milk, and are centrifuged. The dirt is
thrown upon the rubber stopper and adheres thereto
when the stopper is withdrawn. It may easily be trans-
ferred to a slide for microscopic examination. Pus cells
are collected in the same way. L. P.]

g. Examination for preservatives. One of the most im-
portant regulations with regard to the milk trade is
that milk shall not be preserved by the use of antiseptics
or alkalies, and one of the most important functions of
the milk inspector is to see that this regulation is ob-
served. An occasional test for preservatives may be
made by standing the samples aside at room tempera-
ture. If the milk does not change within the time that is
customary for good milk, the presence of artificial pre-
servatives may be suspected. Methods for the detec-
tion of preservatives by chemical means have already
been given.

Tf the increased keeping power of the milk is due to
the addition of alkalies, this may be indicated by a simple
test with litmus paper.

APPENDIX I.

THE REGULATIONS GOVERNING THE TRI-
FOLIUM MILK SUPPLY COMPANY
IN COPENHAGEN, DENMARK.

I. THE WORK OF THE COMPANY SHALL BE UNDER THE SUPER-
VISION OF A COMMITTEE OF CONTROL CONSISTING OF A
PHYSICIAN AND A VETERINARIAN.

Il. THE OBLIGATIONS OF THE COMPANY TO THE COMMITTEE OF
CONTROL SHALL BE AS FOLLOWS.

1. Milk may be taken only from herds that have been ap-
proved by the conunittee, and that furnish milk containing at
least 3 per cent. fat.

2. Nursery (children’s) milk shall come only from herds
that are proven to be entirely free from tuberetdosis hy the
use of the tubereulin test, and these herds shall be retested at
least once a year. Milk anay be reeeived from a tubereulosis-
free part of a herd only after the committee has investigated
the conditions, and has given its approval. In this case, the
healthy part of the herd is to be kept entirely apart from
the reacting section, it is to be retested at least once a veur,
and the reacting animals are gradually to be disposed of.

Tf a calf plague (ealf cholera, contagious pneumonia.
pyiemia, ete.) oecurs in the herd the committee may require
shipments of milk to be discontinued until further notice,

3. The eompany pays one or more veterinarians, who are ap-
pointed by and are responsible to the committee of control.

Farms that supply the reeular whole milk, skimmed milk
and cream are to be imspeeted by the veterinarian twice a
month, unless in summer the cows are kept stabled, in which
cause four visits per month are to be made. Herds that supply
nursery milk are to be inspeeted the vear through four times a
month. Travelling expenses are paid by the company.

4+. Nursery milk is to be shipped only in containers that

239

240 MILK HYGIENE

are easily distinguished by their shape and color from the
containers used for the regular milk.

5. The company shall not employ any weakly persons, nor
any that are afflicted with an infectious disease or with any
repulsive skin disease, as tuberculosis or syphilis. Any em-
ployee so affected is to be dismissed.

If any one of the employees shall contract typhoid fever,
gastric fever, diphtheria, scarlet fever, erysipelas or any
other virulent infectious disease, the affected person shall not
come upon the premises of the company or resume his work
until he shall present a certificate from a physician to the
effect that he is no longer capable of conveying infection. The
same applies to employees in whose dwelling any one of the
above named diseases may occur.

If any one of the employees shall be afflicted with discharg-
ing or suppurating wounds on the face, hands or arms or
with any transmissible or repulsive disease or with severe
diarrheea, the affected person shall not be employed, during
the continuance of the condition, in any work in which he
would come into direct or indirect contact with milk, nor
shall he be permitted to wash bottles.

Every employee who may not work on account of illness,
or on account of disease in his family, is to receive his full
pay as though working. A physician is appointed with whom
the employees and the members of their familiessmay consult
and who shall make frequent visits to the dairy premises and
keep an oversight of the employees as to their health.

The company shall keep a special record showing the em-
ployees that are ill, when they are laid off, and the nature of
the illness.

6. The milk shall be cooled to 5° C. (41° F.) as it is re-
ceived from the producers and shall be kept at this or a lower
temperature.

7. All containers** are to be thoroughly cleaned by a
method approved by the committee. The bottles for nursery

58 The milk is delivered to customers only in sealed cans or, in the
ease of nursery milk, in bottles.

COMPANY REGULATIONS 241

milk are to be cleaned and heated in accordance with the
instructions of the committee.

8. The herds and all of the premises connected with the
business are to be open to the members of the committee at
all times. All necessary travelling expenses are to be paid.

9. All announcements and communications regarding the
business, so far as these relate to the technical matters under
the supervision of the committee, are tou be approved by the
committee before they are published.

10. A member of the committee of control shall be privi-
leged to resign (a) at any time when in his opinion the hygienic
regulations relating to the conduct of the business are not
properly observed and, similarly, if later regulations made by
order of the committee are not complied with, or (b) [under
other circumstances] he may resign after three months’ notice.

III. REGULATIONS CONCERNING THE PRODUCTION
AND CARE OF MILK

A. THE HEALTH OF THE HERDS

1. The producer must agree to permit the veterinarian
of the company to examine his herd as often as may be con-
sidered by the company to be necessary and he must vive
the veterinarian such information as he may desire in reeard
to the herd, the feeding and the milk.

The producer must agree to observe the instructions of the
veterinarian.

2. The eattle that are designated by the veterinarian as
tuberenlous are to be removed from the herd at once, and, as
goon as possible, they are to be sold or killed. Cattle that for
any other cause are picked out by the veterinarian are, as he
directs, to be removed from the stable or placed apart at one
end; the milk may not be used and the cows may not be
restored to their places with the herd until permission is given.

3. In ease disease oceurs between the visits of the veter-
inarian. and especially any of the following.—tuberculosis, in-
flammation of the udder, inflammation of the uterus. severe
diarrheea,—the affected animal or animals are to be isolated

16

242 MILK HYGIENE

and their milk must not be used. The company will con-
tinue to pay for this milk until the veterinarian makes an in-
spection. If a number of cows become diseased in such a
way as to suggest the outbreak of an epizootic or poisoning
the veterinarian and the business manager of the company
are 10 be notified at once by telegraph or telephone.

4. The milk of newly purchased cows may not be used until
these cows have been examined by the veterinarian and ap-
proved.

5. The producers of nursery milk are obligated to add no
cows to their herds until they have been tested with tuberculin
and are declared by the veterinarian for the company to be
healthy.

All of the cows of the herd are to be tagged by the veter-
inarian.

The producer is required to have his herd tested with
tuberculin at least once a year. The records of test are to be
submitted by the veterinarian of the company to the com-
mittee.

Tf there is maintained on a farm a herd of reacting cows, -
the producer is required to dispose of these gradually and to
take care that there is no contact between the healthy and the
reacting cattle.

B. THE HEALTH OF THE PERSONNEL

1. The producer is required to observe the following rules
in relation to the health of the persons who work in the stable
or with the milk:

a. No one may be employed who is affected with tubereu-
losis or syphilis.

b. Persons who have discharging or suppurating sores or
wounds on the face, hands or arms, or a disease of the skin of
these regions, or that have severe diarrhoea are not under any
circumstances to be permitted to come in contact with the milk.

c. Persons who live in a house where there is typhoid
fever, gastric fever, diphtheria, scarlet fever or any other
virulent infectious diseases are, likewise, positively prohibited
from coming in contact with the milk until the local physician

COMPANY REGULATIONS 243

certifies that they are no longer infectious. If, nevertheless,
such persons should by accident come in contact with the milk,
it is to be held back (not shipped) and the company will pay
the usual price for it, unless the contamination was the result
of connivance on the part cf the producers.

d. The producer is required to use all possible care in
keeping informed as to the condition of health of his employees
so that every case of infectious disease may be discovered and
isolated as soon as possible.

¢. Once a year—soon after the ‘‘movine days’'—a_ state-
ment is to be submitted from the local physician to show the
state of health of the persons on the farm and all cases of in-
fFeetious diseases that he treated [on the farm] during the pre-
ceding half year.

2. If a ease of typhoid fever, gastrie fever, diphtheria,
searlet fever or any other virulent infectious disease occurs
amone the people living at the farmstead or among the people
employed on the farm, the producer is obligated immediately
to notify the manager of the company by telegraph or tele-
phone. The milk shall be held back and shipments may not
be resumed until the committee of control has given pernmis-
sion.

For all milk that is held baek under these circumstances
the company will pay full price.

C. FEEDING AND CARE OF THE COWS

1. All food must be quite fresh [friseh —not deteriorated].
Mouldy or otherwise damaged food must not be in the stable,
or in the immediate vicinity. The veterinarian of the com-
pany has the right to inspect the food.

> In summer, so far as possible, the cows are to be fed
in the pasture. If it is necessary to feed them in the stable,
the company is to be notified and then the producer is re-
quired to use eare that the stable and the cows are kept as
clean as possible.

The company reserves the right to forbid, if it is considered
necessary, the stable feeding of cows that produce nursery
milk.

244 MILK HYGIENE

3. The veterinarian shall be advised as to the composition
of the feed. The following rules apply:

a. No roots may be fed to cows producing nursery milk
except carrots and sugar beets, and of these not more than 20
kilos [40 lbs.] per day.

b. Cows producing regular milk may receive as much as
30 kilos [60 lbs.] per day, provided this amount does not
cause diarrhea.

c. Beet tops, beet trimmings, cabbage, distillers’ slops,
malt, ete., may not be fed.

d. For cows producing nursery milk, the following foods
are prohibited: molasses, cotton-seed meal, green or dry buck-
wheat and mustard. These feeds may be given to other cows,
but only in small quantities. Molasses must not be used if it
produces any undesirable effect.

e. If rape seed is used, it must not contain any consider-
able quantity of oil of mustard, and before it is used it must
be shown to the official veterinarian.

4. The producer is required, so far as possible, to forbid
frequent and sudden changes of food.

5. Before the cows are stabled in the fall, the hair is to be
clipped from the udder, tail and thighs.

6. The use of beast milk is forbidden until ten days after
ealving. The milk shall not be used from cows that have daily
less than 3 kilos [3 quarts].

D. THE CARE OF THE MILK

1. Milking must be conducted with the highest degree of
cleanliness and care. The following specifie rules shall apply:

a. Kach milker must always wear a milking suit and must
be supplied with a towel. Clean water must be supplied in
ample amount, so that the hands may be washed as often as
necessary.

b. The stable must be so well lighted, and especially behind
the cows, that those who do the work can see clearly enough to
perform their work in an orderly and clean manner.

c. Immediately after milking, the milk is to be passed

COMPANY REGULATIONS 245

through a fine metal strainer, which must be cleaned fre-
quently.

d. The milk is to be cooled before it is shipped, at all sea-
sons, and just after milking, by the use of a cooler, to at least
8° C. (46.4° F.),

«. Mucking out shall not take place until after the morn-
ing milking, and in the afternoon it must be completed at
least one hour before milking.

f. Fresh cows [those giving beast milk], cows which give
less than 3 kilos [3 quarts] a day, and cows that have been
separated from the herd by the veterinarian shall have places
in the end of the stable, so that it will not be possible for the
milkers to mix their milk with that of the cows producing milk
for the use of the company.

2. A sufficient supply of iee shall be available. For cool-
ing, an apparatus is to be used that is set up in a light, clean
room, that is used for no other purpose, and each time, before
used, it is to be rinsed off with clean water.

3. The producer agrees to follow the instruetions recard-
ing cleanliness in the stable and the care of the milk that may
he viven him by the company or by their veterinarian.

E, DELIVERY

1. In the summer the transport wagons must be supplied
with a cover to protect the milk cans from the sun.

Feed, fertilizer, ete., must not be earried on the same
wagon with milk or with the cleaned milk containers.

2. The company furnishes the cans used for transporting
the milk. Those used for nursery milk must not be used for
other milk. Under no eireumstances shall the cans be used
for any purpose other than to send milk to the milk station.
The cans are cleaned by the company before they are returned.

3. The producers are to rinse the cans in clean, cold water,
and, if soiled during transportation, they are to be cleaned.

4. The producer is required to furnish a supply of good
water for the cows and for cleaning the vessels and utensils
that come in contact with the milk. Any suspected defect of

246 MILK HYGIENE

the water supply is to be reported at once to the committee on
control.
F, OTHER PROVISIONS

1. The producer agrees to answer truthfully and honestly
all questions from the company in regard to the milk supply.

2. It is agreed that the herds and premises where the milk
is handled and eared for shall be open at all times to the mem-
bers of the committee on control.

IV. INSTRUCTIONS TO THE VETERINARIANS

The veterinarians are appointed and can only be dismissed
by the committee on control, and all instructions come from
this committee.

A report is to be rendered to the committee on every visit
to a herd, and this shall contain information in regard to:
the total number of cows, the cows in milk, all cases of disease,
whether cows have been sold or killed that were isolated as
suspicious or diseased, the condition of the whole establish-
ment in respect to cleanliness, the method of feeding and re-
marks on any pertinent subject.

[It is especially to be noted, in respect to the above regula-
tions, that they are planned not for the purpose of measuring,
by means of a laboratory examination, the extent to which milk
has become contaminated, but for the purpose of preventing
contamination.

The most injurious bacteria in milk are the pathogenic
forms that come from diseased persons or cattle and the putre-
factive organisms that come from diseased cows, dirty prem-
ises or utensils or faulty methods of milking or handling milk.
The most important pathogenic forms cannot be detected in
milk by the usual routine methods in use in milk laboratories,
if at all. And if these organisms are detected by laboratory
examination it is not until long after the milk has been con-
sumed. Nor can the injurious saprophytes be identified in
the laboratory until too late to prevent the use of milk con-

COMPANY REGULATIONS 247

taining them. Tence, it must be clear that the truest protec-
tion to the consumer consists in guarding the source of the
milk and the milk itself, from conditions that are known to be
accompanied by danger of injurious contamination.

The value of laboratory examinations as to the number and
kind of bacteria, pus cells ard solid dirt is not under-esti-
muted; it is very great as a measure of the thoroughness of
the precautions taken on the dairy farm, and during shipping.
But the value of this examination should not be exaggerated,
as appears to he the tendency in some quarters, and it should
not be thoueht that any laboratory examination can, with
safety, be permitted to take the place of regular, expert veter-
inary inspections of the cattle, methods and premises.

The bacteriologice and microscopic eraminations of milk that
are made in public health laboratories keep contaminated milk
from entering the market only in so far as they point out the
necessity for the veterinary and sanitary control of dairy
farms. (See quotation from Freeman on page 168.) L. P.]

APPENDIX II.

The following instructions in regard to the production of
nursery milk are taken from a circular letter of May 27th,
1899, from the central government of Germany to the local
governments.

NURSERY MILK

““The special establishments for producing and selling
nursery milk, which have greatly increased in number in re-
cent times, and which use special designations, as sanitary
dairy, health milk, children’s milk, superior milk, ete., are to
be looked after with special care by the sanitary authorities.
The general methods, the cleanliness of the stable. the store-
room, the utensils, the condition of health of the cows and their
feeding and care are to be placed under veterinary oversizht

‘The stables shall be roomy, light and airy, and they shall
have impervious floors and mangers of such description that
they can be easily cleaned. Running water shall be provided
for cleansing and the drainage shall be good. Only cows for
the production of nursery milk shall be kept in such special
stables and these cows shall be marked in some permanent
way.

‘“ Tt is not necessary to lay down special regulations for feed-
ing such cows, but attention should be called to the known
facts as to injurious effects of certain eattle foods on milk
used for infant feeding.

‘“ In general, the feeding of creamery refuse should be for-
bidden on account of the danger of spreading tuberculosis.

“‘ The condition of health of cows designed for producing
nursery milk is to be determined before they are placed in the
empire. This examination is to be repeated at intervals of
three months.

“© 4 eareful book record is to be kept of these examinations.
The official who is charged with this oversight shall make an
appropriate entry for each visit.

249

250 MILK HYGIENE

“« The occurrence of any one of the following named diseases
among the cows is to be reported at once to the official veter-
inarian: anthrax, contagious pleuro-pneumonia, foot-and-
mouth disease, black quarter, rabies, cowpox, icterus, dysentery,
inflammations of the udder, blood poisonings, especially
pyemia and septicemia, putrid inflammation of the uterus or
other febrile conditions, retention of the after-birth and con-
ditions that result in the occurrence of discolored milk.

“* Cows which show evidence of disturbance of digestion, of
diarrheea or pica, or cows that are suspected of being afflicted
with tuberculosis shall at once be removed from the stable,
until the animal is examined and the condition determined by
the official veterinarian.

““Tt is not permitted to use as bedding soiled or refuse
straw or other waste material.

‘* Cows for producing nursery milk shall be kept particularly
clean. Before milking, the udder is to be carefullv cleaned.
The milkers must keep themselves thoroughly clean. They
must wash their hands and arms with soap before milking, and
wear a clean frock. Any person suffering with a contagious
or eruptive disease must not be permitted to milk.’’

APPENDIX III.

Certified milk in Philadelphia is produced under the con-
trol of a commission organized in 1899 under the following
plan:

1. There shall be a Milk Commission of the Philadelphia
Pediatrie Society, whose duty it shall be to have examined
milk submitted to them by dairymen and certify as to the
result. of such examination.

2. The actions of the Commission shall be reported from
time to time to the Society and shall be subject to its approval.

3. The Commission shall consist of four members besides the
President of the Society, who shall be a member er officio. The
members shall be appointed yearly by the President as soon
as possible after his election. he Commission shall eleet a
chairman and a secretary from their number.

4. No statement for publication or information to any
dairyman shall be given by or in the name of any individual
member, but only after consideration by the Commission and
in the name of ‘‘The Milk Commission of the Philadelphia
Pediatrie Sovicty.”’

5. The Commission will hold itself in readiness to examine
milk from dairies desiring this examination, and to certify to
the good quality of milk which comes up to the standards fixed
by it. It is understood that only the milk of dairies, and not
that of milkmen who merely serve milk bought by them, will
be examined by the Commission.

6. The method of examination and certification to which
the dairyman or his agent shall agree to submit shall be as
follows:

7. The Commission shall select a bacteriologist, a chemist,
and a veterinary inspector. The bacteriologist shall procure
a specimen of milk from the dairy, or, preferably, from de-
livery wagons, at intervals to be arranged between the Com-
mission and the dairy, but in no ease at a longer interval than

251

202 MILK HYGIENE

one month. The exact time of the procuring shall be with-
out previous notice to the dairy. He shall test this milk for
the number and nature of bacteria present in it, to the extent
which the needs of safe milk demand. He shall also make a
microscopic examination of the milk for pus cells. Milk free
from pus and injurious germs and having not more than
10,000 germs of any kind or kinds to the cubic centimeter,
shall be considered to be up to the required standard of purity.

8. The chemist shall in a similar manner procure and ex-
amine the milk for the percentages of proteids, fat, sugar,
mineral matter, and water present. He shall also test its
chemical reaction and specific gravity, and shall examine it
for the presence of foreign coloring or other matters or chem-
icals added as preservatives. Standard milk shall range from
1.029 to 1.034 specific gravity, be neutral or very faintly acid
in reaction, contain not less than from 3.5 per cent. to 4.5 per
cent. proteid; from 4 per cent. to 5 per cent. sugar, and not
less than 3.5 per cent. to 4.5 per cent. fat in the case of 4 per
cent. fat milk, and shall be free from all contaminating foreign
matter and from all addition of chemical substances or color-
ing matters. Richness of cream in fat shall be specified and
shall vary not more than 1 per cent. above or below the figure
named in selling. Neither milk nor cream shall have been
subjected to heat before the examination has been made, nor
at any time, unless so announced to the consumer.

9. The veterinary inspector shall, at intervals equal to
those of the bacteriologist and chemist, and without previous
warning to the dairy, inspect the cleanliness of the dairy in
general, the care and cleanliness observed in milking, the care
of the various utensils employed, the nature and quality of the
food used, and all other matters of a hygienic nature bearing
upon the health of the cows and the cleanliness of the milk,
including also as far as possible the inquiry into the health of
the employees on their farms. He shall also see that the cows
are free from tuberculosis or other disease.

10. The charges made by the experts shall be—for the
veterinarian $10.00, and $5.00 for each of the others for each
examination; this amount to be paid by the dairy at the time

PLAN FOR COMMISSION 233

of the examination and without regard to whether the report
is favorable or unfavorable. The experts shall make their
examinations when, and only when, notified to do so by the
Commission. Any dairy the milk of which shall be found by
the examiners to be up to the standard of the Commission
shall receive a certificate from the Commission, which shall
read as follows:

MILK COMMISSION OF THE PHILADELPHIA
PEDIATRIC SOCIETY

Date... ......
The Veterinary Inspector of the Commission has examined
the dairy of Mr. ......... and reports it to be well kept and

elean, and the cows to be in a healthy eondition.

The Bacteriologist reports that the milk does not contain
germs beyond the limits of the standards of the Commission.

The Chemist reports that the milk is of standard richness,
and that he has discovered in it no impurities, coloring mat-
ters, chemical preservatives, or harmful substances.

The Commission certifies to these statements of the
examiners. It is understood and agreed to by the said

DFS uh isd that this certifieate is vood for not more
than ........ from date, when another examination is to be
made.

[Signed by the Commission. ]

11. In ease an examination shows the milk not to be up to
the standard the dairy may have a re-examination made within
a week or within a short time, at the discretion of the Commis-
sion.

12. Milk furnished by the dealers to whom certificates
have been issued shall be furnished to consumers in glass
bottles hermetically sealed in a manner satisfactory to the Com-
mission. In addition to the sealing, and as a guarantee to the
consumer that the examination has been regularly conducted,
there shall be pasted over the mouth of the jar, or handed to
the eonsumer with every jar, according to the discretion of
the Commission, a certifieate slip which shall read as follows:

254 MILK HYGIENE

PHILADELPHIA PEDIATRIC SOCIETY.
MILK COMMISSION CERTIFICATE,

Milk from the dairy of Myre... .ccccccccccceccccceccescescescesceceeseseneceeeceseneeasens has been recently

examined by the experts of the Milk Commission and found to be up to the required
standards. Another examination is to be made within a month, and, if satisfactory,
new labels for the bottles will be issued, dated

NOTICE THE DATES,

The blanks used by the experts of the Commission in re-
porting to the secretary are as follows:

REPORT OF VETERINARIAN.

Pliladelphia, <3 gc.cs ce eseactst abeeees 190...
Secretary of the Commission,
Dear Sir:—I have examined, as requested by the Commission,
the dairy” Of} sccscadecsne mans Chu er eee aes Bt cna peer aah yom ee gS
and find the following conditions :—

dy: seve derees milking cows.
s25ceea vis hospital cows.
Sein Rercer cows sick since last report.
a cae Gul Susie dry cows.
work ich ic Ba cows recently calved.
20h Sp eases Bee cows added since last report.
Did they pass veterinary inspection and the tuberculin test before

Shek Seay < cows now in quarantine.
Total number of cows in herd.......... of which..........
have been tested with tuberculin in the past year.

II. Food employed.

IV. Condition of Stables:

Ventilation. .......... BAG widsica aes echaaen
Cleanliness, ete. 2.0... 0. cee eens
if} (ota): ree ee ane ee Troughs..........

Condition of other buildings...................
V. Health of employees and their families, as far as ascertained,

VI. The general precautions of cleanliness in milking and the care
of the milk are ................

I therefore recommend that. milk from this dairy be submitted to the
Bacteriologist and Chemist of the Commission for their examinations.
MOUTS tH ceacacais ane oieda ween ele a cae we Veterinarian.

ESTIMATION OF QUALITY 259
REPORT OF BACTERIOLOGIST.

Philadel phiai.:cces'se ca veeeese ses ses¥ 190...
Secretary of the Commission,
DEar Sir:

At the request of the Commission, received on..........

milk
Sie tt 7190.2, cream from “the dairy’ Of #2 045 cece nee an sees esse. &
labéledhsccuse0 ats ieee ie deden ealok was obtained by me on............
DOO 2g ES a soit hagning wine Dread aah se Rr ae Street, at ...... o'clock,
....M., and examined at ...... o’clock, ....M., with the following results—

milk

Number of bacteria per c.c. of cream..............--.

I have been unable to detect any pathogenic organisms or evidence
of purulent inflammation of the udder.

milk

I therefore recommend the cream as coming up to the bacteriologic
standards adopted by the Commission.

I find the bottles to be sealed in the manner prescribed by the
Commission.

Yours truly,

elaidind Ieceleth aet ba @Bbd SU dawg eran uBaClerulug¢se.
REPORT OF CHEMIST.
Philudelphity 54 03 23 25 feet a tesa ee a 190... .

Secretary of the Commission,
DEAR Sir:

At the request of the Commission, received on. .......
milk
.« cream from the dairy of. a .ccec cakes ese cee ws
labeled ics gute see Geechee eee ee Rays was obtained by meon.........
190. , and examined with the following results:
Fat, (Leffman-Beam method,) nn
Total proteids, (Xjeldahl-Gunning method, factor 6.25), 00 ......
Preservatives, added color and heat, none.
NGILIEY a ea
Speeifte gravity,
milk
I therefore recommend the cream as coming up to the chemical
standards adopted by the Commission.
I find the bottles to be sealed in the manner prescribed by the Com-
mission.

Yours truly,
Chemist.

APPENDIX IV.

The following plan for estimating the quality of dairy
farm conditions, and for making it possible to compare farms.
Was originated and arranged by R. A. Pearson, Professor of
Dairy Industry at Cornell University.

The score card idea has been extensively employed in
judging animals, plants, seeds, ete.. but this is the first adapta-
tion of this principle to the judging of such a complex object
as a dairy farm, ineluding all of the factors that enter into
the production of sanitary milk. A special feature of this
scheme is the division into groups: a low seore in any group
renders the whole inferior, no matter how excellent the other
groups nay be.

The eveneral idea is an excellent one: it enables the in-
speetor to record in convenient form a summary of the result
of his inspection and, by this means, a comparison can readily
be made between the conditions of a farm at different times.
Some practice is required to obtain the best results from the
use of this method.

to
ue
a

258 MILK HYGIENE

Department of Dairy Industry, College of Agriculture,
Cornell University.

Score Card for Production of Sanitary Milk.

DATs Hi stinwince cawaen sev nesa DBI ry IOP a icawistarerantecouniniidaare wiidoirevaiuls eitiaieres eats
| perfect Score
|
, Health and comfort of the cows and their isola-

I. Health of the tion when sick or at calving time............. 45

herd and its pro- Location, lighting and ventilation of the stable..| 35

tection | Poodiand waters icsicases: seascies vender “nomanuaiaas 20
i TOCA siisitsirsh acegeeciiw eormiaing se she on ap Merete de 100

COWSlne sh wesieng canes xqlteriey viaiiving Ve tha cinewh feb Bee 30
FTI, Cleanliness of =| Stable... 00.0... cece ec eee eee cec eee eeeeeewes 20
the cows and their | Barnyard and pasture..............0. cece eee ees 20
surroundings Stable air (freedom from dust and odors) ........ 30
Lota] yi s:s siieuauctees va slam anscisids Seamlensals hapa 100
Construction of utensils and their cleaning and
ITT. Construction 3 erased rege settee eeee : rs nena Berbice 40
ater supply for cleaning and location and pro-
and care of the tection of its source.... 00.0... cece cece cee e eee 25
utensils Care of utensils after cleaning............2....00% 20
Use of small-top milking pail..................... 15
Total aensxs “schemes news xe ancenes vee tees 100
Health of employees..............ccceccecececeees 45
ITV. Health of em-| Clean over-all milking suits and milking with
ployees and Clean ry NANdS a. ciccayscecceicdad cases sesteee 30
“m.| Quiet milking, attention to cleanliness of the
manner of milk udder and discarding fore milk............... 25
ing ———
TOtalosictin jis seianteinaan. os eangtes eerie He Sais 100
Prompt and efficient cooling...................05- 35
V. Handling the Handling milk in a sanitary room and holding it
milk at alow temperature.......... 6... cee eee eee ee 35
Protection during transportation to market...... 30
Total icirsaniniie ae vintariwoceninen aieaems weenie 100
TOTAL OF ALL SCORES................. 500
If the total of all scores is And each division is The sanitary conditions are
480-OF ADOVE. cscs seer ceebeaasennes 90 OM ADONC wis s caienieainsncieg:s name sale EXCELLENT

450.08 BDOVEsiiciic ners eseiies s cece 80 OF BDOVE. 62 )n0s ti remind a asia 4 GOOD

400-OF ADOVE, iiccicc cs crewwiewes canon G0. OF BDOVE: sscanaewa ee asaeiiias on MEDIUM

Below 400..... ..........05 Or any division is below 60............... POOR

The sanitary

conditions are.............0..0008 SCOPE DY kas ve.00 cosine va Suaees o5 is deeaeaS Nees VARe ES

APPENDIX V.

On account of its historic value, the following agreement,
which was the first provision for the production of ‘certified
mull’ in America, is reproduced. The plan of the agreement
originated with Dr. Henry L. Coit, of Newark, N. J., and the
“party of the first party,’’ of the contract is the Medical Milk
Commission of Essex County, New Jersey. The date of this
agreement was May 9th, 1893. It is still in force.

1. The party of the second part doth hereby agree to con-
duct such parts of his dairy as may be hereafter named, collect
and handle its products in conformity with the following code
of requirements, for and in consideration of the promised
endorsement of the parties of the first part, as hereinafter
mdicated. The milk thus produced shall be known as certified
milk; shall be designed especially for clinical purposes, and
when at any time the demand shall be greater than the supply,
and it is required by a physician, either for infant feeding or
the diet of the sick, it is hereby agreed that such shall be the
preferred purchaser.

2. The party of the second part further agrees to pay for
chemical and bacteriological examinations of the aforesaid
certified milk, at such time as in the judgment of the party of
the first part is desirable.

3. Ile also agrees to defray the cost of a bi-monthly in-
spection of his dairy stock, or oftener. if necessary, by a
competent and approved veterinarian, all of which persons,
namely: the chemist, the bacteriologist, the veterinary surgeon,
shall be chosen by the parties of the first part. to whom they
shall render their reports in writing.

4. It is expressly understood and agreed, that the party
of the second part shall not pay more than the sum of five
hundred dollars in anv one year, for the services of chemist,
bacteriologist and veterinary surgeon, and the party of the

259

260 MILK HYGIENE

first part shall hmit the expense of such service to that amount.
It is furthermore agreed that the party of the second part, on
receipt of a certified copy of the reports of the experts, shall
mail to the persons indicated by the parties of the first part,
and not to others, a duplicate printed copy of the aforesaid
reports, bearing the signatures of the experts and the names
of the physicians. The same to be issued at such intervals as
in the judgement of the parties of the first part is desirable;
also that the necessary expenditures for printing and cireula-
tion be met in the same wavy as herein provided for expert
examinations.
LOCATION OF LANDS

5. It is hereby understood and agreed, that the lands used
by the owners, agents or assigns of the dairy, conducted by
the party of the second part, and employed for pasturage, or
any lands that may hereafter be acquired for such purpose, or
such lands as may be used for the cultivation of hay or fodder,
shall be subject to the approval of the parties of the first part.

BUILDINGS

6. It is also understood and agreed, that the buildings, such
as stables, creamery, dairy house and spring house, shall be
constructed after the most approved style of architecture, in
so far as construction may affect the health of the dairy stock,
or the character and conditions of the milk.

7. The buildings, used for the housing of the animals, shall
be situated on elevated ground, and capable of being properly
drained.

8. Said buildings to be sheltered from cold winds, lighted
and ventilated according to approved hygienic methods. The
buildings shall be constructed so as to favor the prompt and
easy removal of waste products.

9. The apartments used for the storage of either feed or
fodder shall be removed from possible contamination by stable
waste or animal odors.

10. All buildings shall, in addition to healthy loeation, ap-
proved construction and proper ventilation, be kept free from
animal or vegetable matter in a state or process of decomposi-

FIRST AMERICAN AGREEMENT 261.

tion or decay, and always free from accumulations of dust or
mould.
THE WATER SUPPLY

11. The dairy shall be supplied with an abundance of pure
water.

12. No water from shallow wells or springs holding sur-
face drainage. shall be used for watering stock. cooling milk
or cleaning vessels.

13. Nor shall any well or spring be located within three
hundred feet of the stable.

SURROUNDINGS

14 sIt is further understood and agreed that the immedi-
ate surroundings of the buildings shall be kept in a condition
of eleanliness and order. There shall not be allowed to ac-
eumulate in the vicinity any loose dirt, rubbish or decayed
vegetable or animal matter, ov animal waste.

15. Nor shall there be within three hundred yards of any
building, any constantly wet or marshy ground, or stagnant
pools of water.

16. Nor shall there be kept within three hundred yards
of any building used for dairy purposes any fowls. hoxs,
horses or other live stock.

THE COWS

17. It is hereby understood and agreed that the following
unhealthy conditions shall be a sufficient reason to exclude any
animal from the herd used for any purpose in the aforesaid
dairy: Any animal that is judged by a competent observer to
suffer from tuberculosis, even thoueh the disease be loealized
in a part distant from the vital organs.

18. Any animal with fever. Any animal suffering from
septic absorption or other disease. following or associated with
parturition.

19. Any animal siffering from mammitis or mammary
abscess.

20, Any animal with persistent diarrhea or any other ab-
normal physieal condition, which could in any way be detri-
mental to the character of the milk.

262 MILK HYGIENE

21. It is furthermore agreed that when an animal shall be
found by a competent observer to be in a state of ill health,
prejudicial either to the other animals in the herd or to human
health, the same shall be removed immediately, and if neces-
sary. shall be killed.

22. It is also understood and agreed that the party of
the second part shall exelude from the herd used for produc-
ing certified milk, immediately after discovery, any animal
subject to the following conditions: Any animal that was
bred through consanguinity within a period of three gener-
ations.

23. And from this time forth, any animal of those bred by
the party of the second part, used for producing certified milk,
that was not, as a heifer, kept sterile during its first twenty-
seven months.

24. Any phenomenal milker, except that glandular disease
or tuberculosis has first been excluded for a competent ob-
server.

25. It is furthermore agreed that if at any time it is de-
sired by the parties of the first part, that a different breed of
milch cows should be substituted for the one in use, in order
that the standards of quality in the milk may be raised, the
party of the second part will endeavor to carry the same into
effect.

HOUSING AND CARE

26. It is furthermore agreed, that the dairy stock employed
in the production of certified milk, shall be properly sheltered
from the influences of weather and climate prejudicial to their
health; also that the animals shall be kept clean, groomed every
day. and treated kindly at all times.

27. The waste products of the stable shall be removed so
frequently, and the stable floor so thoroughly cleaned, that the
same shall be as free as possible from animal odors.

28. It is also agreed that no mileh cow shall be used for
dairy purposes while in a state of excitement, either as a result,
or during the period of estrux, or which has been made nervous
either by heating, whipping, kicking, prodding or running.

FIRST AMERICAN AGREEMENT 263

FEEDING

29. It is hereby understood and agreed that the methods
of feeding the cows furnishing the certified milk, shall be sub-
ject to the approval of the parties of the first part. The feed
and fodder shall consist only of nutritious and wholesome ma-
terials; such as vrass, clover and timothy hay, whole grain, or
the entire result of the grist. No materials shall be employed
which are or may become injurious to the health of the ani-
mals. There shall not be fed at any time, or in any quantity,
either alone or mixed with other feed or fodder, hulls, sereen-
ings, wet or dry brewers’ grains, oil cake, sour ensilage, the
refuse from distilleries, glucose or starch factories, any waste
by-product in the treatment of grain, low marsh grass. or any
of the questionable or exhausted feeds or fodders employed
either to increase the milking capacity of the animal, or that
will produce an impoverished milk, or that will impart to it
unnatural odors or flavors. Nor shall the cows he allowed to
eat green or worm-eaten fruit, poisonous weeds or to drink
poisonous or stagnant water.

COLLECTING AND HANDLING

30. It is furthermore understood and agreed, that the cows
from whieh is obtained certified milk shall be milked only in a
elean building, and not an illy-ventilated stable containing foul
odors and bad air.

31. No animal furnishing certified milk shall be milked
until the udder shall first have been cleaned in a manner ap-
proved hy the parties of the first part.

32. No person shall be allowed to draw the milk that has
not within fifteen minutes of the milking first washed his or
her hands, using soap and nail brush, and afterward thor-
oughly rinsing the hands in clean water.

33. The person or persons engaged in milking shall also be
dressed in clean over-clothes.

34. No person shall be allowed to draw the milk who has
been engaged with the care of horses in the same clothing or
without first washing his hands.

35. No milk shall be represented as certified milk that is not

264 MILK HYGIENE

received from the udder into vessels, and from these into cool-
ing cans, both of which are perfectly clean and dry, having been
cleansed and heated, at a temperature adequate to effect com-
plete sterilization, since the last milking; and have been kept
inverted in a clean, dry and odorless atmosphere.

36. No milk shall be represented as certified milk that has
not been passed through a sieve of wire or other cloth, either
while milking or immediately thereafter, having not less than
one hundred meshes to the linear inch.

37. No milk shall be represented as certified milk that does
not consist of the entire contents of the udder at each milking,
including the fore-milk, middlings and strippings.

38. No milk shall be represented as certified milk that has
been drawn from the animal at abnormal hours, such as mid-
night or noon; nor from any animal for a period of nine weeks
before calving, or that has not been separated for nine days
after parturition.

39. No milk shall be represented as certified milk, which
has been exposed to the emanation or infection of any form
of communicable disease, either in the person or persons hand-
ling the milk, or by accidental contamination in cleaning milk
containers, or by the association of any person engaged in
handling the milk, with person or persons sick of contagious
disease.

PREPARATION FOR SHIPMENT

40. It is hereby understood and agreed, that all milk repre-
sented as certified milk shall receive every known detail of
eare that will promote its keeping qualities, and favor its safe
transportation.

41. That the milk on being drawn from the cow, shall be
treated by ice, or clean, cold water in motion and proper aera-
tion, in order, first, to remove its animal heat, and second. to
reduce its temperature to a point not above fifty degrees, nor
below forty degrees Fahrenheit; said temperature to be ac-
quired within forty-five minutes after milking, and maintained
within the above limits while held for shipment, during its
transportation and until it is delivered to the purchaser.

FIRST AMERICAN AGREEMENT 265

42. That the cooling of the milk shall not be conducted in
the same building in which it is drawn, nor in an atmosphere
containing dust or tainted with animal odors.

43. That all the foregoing provisions coucerning the cleans-
ing and condition of vessels or utensils shall be complied with
in the said cooling process.

44. It is furthermore agreed, that no milk shall be repre-
sented as certified milk, that has been changed or reduced in
any way, by the addition of water or any solid or liquid sub-
stance, in or out of solution, or the subtraction or removal,
in any manner, of any part thereof.

45. It is hereby understood and avreed, that all milk to be
represented as certified milk, shall be packed in flint elass
quart jars luimediately after it is cooled.

46. Said jars to be of a pattern approved by the parties
of the first part.

47. It is furthermore agreed that the bottles or jars, before
being used, shall be cleaned by hand, separately, with the aid
of hot water, alkaline soaps, rotatine brush and steam, and
that they shall be rinsed in two separate baths of clean, hot
water and then thoroughly dried and kept inverted until used,
without covers, in a clean, dry atmosphere free from odors.

48. It is avreed that the jars shall be filled) by a method
approved by the parties of the first part.

49. That they shall be sealed after all air has been exeluded,
by the most approved device for closing them.

50. The bottles after beine filled, shall be labeled across the
eap, bearing the words ‘‘Certified Milk,’” with the name of the
dairyman, together with the date of milking.

51. It is furthermore agreed, that no milk shall be sold as
certified milk, that is more than three hours old when bottled,
nor more than twenty-four hours old when delivered.

TRANSPORTATION AND DELIVERY.

52, It is hereby understood and agreed, that the transporta-
tion and distribution of all milk represented as certified milk,
shall he eondueted hy the party of the second part, either in
person or by persons employed by him.

266 MILK HYGIENE

53. That in transit, the milk shall not be exposed to any
of the foregoing prohibitory conditions.

54. That it shall not be subjected to agitation.

55. That it shall not be exposed to the heat of the sun.

56. That the delivery wagons shall be so constructed that
the required temperature of the milk may be maintained dur-
ing transit.

57. That before the wagons are filled for shipment, the body,
the trays and compartments shall be flushed with boiling water.

58. It is furthermore agreed that the distributing agents
shall, during the transfer of the milk from the dairy to the
purchaser, be subject to the following restrictions, namely :

59. That they shall use no tobacco or intoxicating drinks.

60. That they shall not collect the empty containers, nor
receive money or milk checks from houses in which an infec-
tious or contagious disease 1s known to exist.

61. It is also hereby agreed that the collection of empty
bottles, from places where infectious or contagious disease is
known to exist, shall be made by other persons that those em-
ployed to deliver the milk.

62. That these collections be made with wagons not em-
ployed in the distribution of the milk.

63. That before these empty bottles shall be returned to the
dairy, they shall be carried to a separate building and first be
subjected to the process of cleaning bottles indicated in a
former clause of this contract.

64. It is hereby understood and agreed, that if any further
precautions or changes in method, calculated to improve the
quality of milk, or guard the same from impurities or dangers,
are desired, that the party of the second part will cheerfully be
governed by such additional rules and regulations as may
be laid down by the parties of the first part.

65. It is understood and agreed by the party of the second
part, the same binding the owners, agents or assigns of the
aforesaid dairy, that the product known as certified milk shall
be under the following restrictions in its sale, namely: That
until the amount required within the boundaries of Essex

FIRST AMERICAN AGREEMENT 267

county shall first be supplied, it shall not be sold beyond these
limits, except that the parties of the first part shall give their
consent.

66. It is furthermore agreed by the party of the second
part, the same binding the owners, agents or assigns of the
aforesaid dairy, that in the event of a failure to comply with
any or all of the requirements of the foregoing contract, the
party of the first part shall reserve the right to withdraw from
the contract, and publish the fact in such manner as they
deem best.

67. Finally, it is understood and agreed that nothing in
this contract shall prevent the obrogation of any of the pro-
visions of the same, by the parties of the first part, provided
that it shall be done for the purpose of substituting other
provisions, designed to promote the objects of their organiza-
tion.

68. It is further understood and agreed hy and between
the parties hereto, that the party of the seeond part shall be
at liberty to cancel this agreement by viving two months’
notice in writing, of his desire to do so, in case of inability for
any reason, to comply with the terms of the same.

APPENDIX VI.

The Second Interim Report of the Royal Commission on
Hunan and Animal Tuberculosis was issued in January, 1907.
It presents the conclusions of the commission after thorough
and extensive investigations covering more than five vears.

The report is signed by Sir Michael Foster, Prof. G. Sims
Woodhead, Prof. Sidney Martin, Sir John MeFadyean and
Prof. Rubert Boyer.

The following is au extract;

CONCLUSION

“We may briefly sum up the bearings of the results at
which we have already arrived as follows:

“There can be no doubt but that inca ecrtain number of
cases the tuberculosis occurring ino the human subject, es-
pecially tn children, is the direct result of the introduction into
the human body of the bacillus of bovine tuberculosis: and
fhere also can be no doubl that in the majority at least of
these cases the bacillus is introduced through cows’ milk.
Cows? milk contarning bovine tubercle bacilli is clearly a cause
of lubcreulosis and of fatal tuberculosis in man®

“OP the sixty eases of human tuberculosis investigated ly
us. fourteen of the viruses belonged toe Group IT, that is to say
contained the bovine bacillus. If, instead of taking all these
sixty eases, we confine ourselves to cases of tubereulosis in
which the bacilli were apparently introduced into the body by
way of the alimentary canal, the proportion of Group T beeomes
very much larger. Of the total sixty cases investigated by us.
twenty-eight possessed clinical histories indicating that in them
the bacillus was introduced through the alimentary eanal. Of
these, thirteen belong to Group T. Of the nine cases in which
cervical glands were studied by us three. and of the nineteen

* Original net italterzed.

270 MILK HYGIENE

cases in which the lesions of abdominal tuberculosis were
studied by us, ten belong to Group I.

‘« These facts indicate that a very large proportion of tuber-
culosis contracted by ingestion is due to tubercle bacilli of
bovine source.

“A very considerable amount of disease and loss of life,
especially among the young, must be attributed to the consump-
tion of cows’ milk containing tubercle bacilu. The presence
of tubercle bacilli in cows’ milk can be detected, though with
some difficulty, if the proper means be adopted, and such ought
never to be used as food. There is far less difficulty in recog-
nizing clinically that a cow is distinctly suffering from tuber-
culosis, in which case she may be yielding tuberculosis milk.
The milk coming from such a cow ought not to form part
of human food, and indeed ought not to be used as food at all.

“Our results clearly point to the necessity of measures
more stringent than those at present enforced being taken
to prevent the sale or the consumption of such milk.’’

INDEX

Abdominal tuberculosis, 78
Abnormal coloration, 56
odors and tastes, 55
Abortion, 41
Absorption of odors, 68, 69
Acid, benzoic, 64
boric, 62
eitrie, 150
lactic, 52
reaction, 227
salicylic, 63
Acid-fast bacteria, 81
Acidobutyrometer, Gerber’s, 209
Actinomyeosis, 92
and tumors, 48
Addition of Jactose or eane sugar,
221
Admixture of dirt, 126, 127
Advantages derived from pasteur-
izing market milk, 138
Adulteration, frequency of, 197
of cream, 225
partly skimmed and skimmed
milk, 225
Adulterations, effeets of, 224
Age of the cow, 20
Albumin, 14
Aleohol test, 229
Alkalies, 6S
Alkaline reaction, 227
Alkaloids, 49
Alpine eattle, milk of, 40
Amphoteric reaction, 227
Anthrax, 90
Antiseptics, 61-68
Appearance of milk, 226
Arnold's guaiae method, 192
Arsenic, 60
Asiatie cholera, 117

Ass’s milk, 24+

Attendants, health of, 178, 185

Automatie temperature-regulator, |
134

Babeock’s method, 214
Backhaus’s infants’ milk, 151
Bacteria, acid-fast, 81

in dung of cows, 127

market milk, 122
milk, 120

of putrefaction, 61, 229

pathogenic, 129
Bacteriological examinations, 231
Beast milk, 12
3eet taste, 40
Benzoie acid, 64
Biteh’s milk, 25
Blue milk, 56
Board of Health lactometer, 203
Boiled taste, 59
Borie acid, 62
Breed peculiarities, 27
Buffalo’s milk, 23
Burnt taste, 40
Buttermilk, 191

Calf cholera, 101, 125
Carbohydrates, 18
Carbolie odor, 69
Casein, 14, 16
Catarrh, mucous, 46
purulent, 46
Cat’s milk, 25
Cell protoplasm, 14
Cells, degenerated, 13
Certified milk in Ameriea, 259
Philadelphia, 251
Changes in milk, 31-58
at high temperatures, 38, 59
the secretion, 46-48
Cholera, Asiatie, 117
ealf, 101, 125
Citrie acid, 150
Cleanliness, 176

‘Colostrum, 12. 29, 30

bodies, 12
Composition of milk, 21-26
271

272

Constituents of milk, 15-21
Contamination with bacteria, 120-
126
organisms, 104-120
Control of milk in cities, 197
Contusions of the udder and teats,
45
Cooler, 135
Copenhagen Milk Supply Com-
pany, 159
Cow, disease of, 42
Cowpox, 89
Cow’s milk, 21
Cream, 191
adulteration of, 225
Curd fermentation, 230

Daily variations, 34

Dairy farm inspector, 167, 168

Degenerated cells, 13

Determination of fat content of
milk, 208

Digestion, 147

Dilution of whole milk with water,
219

Diphtheria, 112

bacilli, 114
Dirt, 127
Disease of the cow, 42

Effects of various adulterations,
224
Embolism and thrombosis, +5
Enteritis, 98
Examinations, bacteriological, 231
for dirt, 235
pus, 234
Exeretion of foreign matter,
48-50
of poisonous substances with
milk, 60, 61
Exereise and work, 42

Farm conditions, 257

Fats, 19

Fatty deyeneration, 14

Feeding the herd, 173

Fermentation, eurd, 230
test, 229

Feser’s lactoseope,.198

INDEX

Fjord pasteurizer, 132, 133

Food, influence of, 37

Foot-and-mouth disease, S7
virus of, &9

Foreign matter, excretion of, 48

Formaldehyde, 66

Formalin, 66

Formol, 66

Galactase, 20
Gangrenous mastitis, 47
Gartner’s fat milk, 151

Gases, 20

Gerber’s acidobutyrometer, 209
Globulin, 14

Goat’s milk, 23

Half milk, 190

skimmed milk, 190
Harmful properties of milk, 60
Health of the attendants, 178
Herd, attendants of, 178

feeding the, 173

health of, 169

sample, 201

sudden changes in food of, 176

Indigestion, 101
Individual peculiarities, 28
Infant mortality, 126
Infection by milk, 70-104
Infectious diseases, 103
Influence of food, 37
Inorganic salts, 20
Inspection of the milk, 10
Intestinal tuberculosis, 72
Todine, 60

Laetalbumin, 18

Lactation period, 29

Lactie acid, 52
Lactodensimeter, Quevenne’s,
Lactoglobulin, 18
Lactometer, Board of Health,
Lactoscope, Feser’s, 198
Lactose, 14, 18, 221

Lecithin, 150

Leffmann-Beam method, 213
Leeal standards, 187, 188
Lung plague, 92

202

203

INDEX 273

Mare's milk, 23
Mastitis, 46, 93, 125
gangrenous, 47
parenchymatous, 47
Medicines, 43
Mereury, 60
Method, Arnold's euai 2
Babeock, 214 aoe
Leffmann-Beam, 213
Soxhlet’s, 208
Storch’s, 192
Metritis, 125
Milk, acidity of, 228
appearance of’, 226
ass’s, 24
Backhaus’s infants’, 151
bacteria in, 120
market, 122
beast, 12
bitch’s, 25
blue, 56
bottling of, 196
buffalo’s, 23
eare of, 180
certified, 251
changes in, 51-59
commission, 163
composition of, 21-26
constituents, 15-21
containers, 193
control, 9, 10
of in cities, 197
cow’s, 21
determination of fat content
of, 208
dilution of whole with water,
219
elephant’s, 26
epidemies, 104
fat, 19
for infants, 147
Gartner’s fat, 151
glands, 12-15
goat’s, 23
half, 190
skimmed, 190
harmful properties of, 60
infection by, 70-104
inspection of, 10

Milk, keeping and selling, 184
legal standards for, 188
mare’s, 23
modified, 152
nursery, 249, 250
odor of, 226
of the Alpine cattle, 40
of the eat, 25
packing of, 185
pasteurized, 191
pasteurizing market, 138
preparations, 193
preparing for delivery, 152
public control of, 157, 158
publie supervision of, 196, 226
putrid, 123
rabbit’s, 26
red, 56
regulation of production of,

164-181
regulation of sale of, 182-196
reindeer’s, 26
retailing in cities, 159
sale and delivery of, 182
secretion, 12-15
sheep’s, 23
sickness, 103
skimmed, 190
shmy, ]2+
specific gravity of, 197, 202
sterilization of, 142
sterilized, 192
sour, 123
sow’s, 25
taste of, 226
transpareney of, 197
tuberele baeilli in, 73

mixed, 81

unclean or dirty, 235
variations in, 24-26
Voltmer’s mother’s, 151
voluntary control of, 163
whole, 186
woman’s, 24
yellow, 57
zebu’s, 22

Milking, method of, 31
time of, 31

Miliary tuberculosis, 73

274

Modified milk, 152
Mortality among children, 154
Mucous catarrh, 46

Nitrate and nitrites, 221
Nursery milk, 249, 250
Nyniphomania, 41

Odor, carbolie, 69
of milk, 227
Odors, 69
abnormal, 55
absorption of, 68, 69, 70
(Estrum, 41
Oily taste, 56
Ovariotomy, +1

Paraecasein, 17
Parenchymatous mastitis, 47
Partial skimming, 218

Partly skimmed, adulteration of,

225

Pasteurization, 128-142

objections to, 139

quick, 131
Pasteurized milk, 191
Pasteurizer, Fjord, 131
Pastenrizing a fluid, 128

market milk, 138
Pathovenie bacteria, 129
Pepsin digestion, 17
Peptone, 123
Potassium bichromate, 65
Preparing for delivery, 182
Preservatives, 61-68
Preserving samples for analysis,

201

Proteids, 16
Pseudo-tubercle bacilli, S81
Publie supervision, 196, 226
Purulent eatarrh, 46
Putrid milk, 123

Quevenne’s lactodensimeter, 202

Rabbit’s milk, 26

Rabies, 91

Rapid method for determining
acidity of milk, 228

INDEX

Reaction, 227

acid, 227

alkaline, 227

amphoteric, 227
Red milk, 56
Regenerative heater, 144
Regulation of production, 164-

181
sale, 182-196

Reindeer’s milk, 26
Retailing milk in cities, 159

Sale and delivery, 182

Salicylic acid, 63

Salts, 20

Sample, herd, 201

Samples, preserving, 201

taking, 200

Searlet fever, 115

Sediment, 126

Septie metritis, 101

Sexual conditions, significance of,
40

Sheep’s milk, 23

Skimmed milk, 190

Skimmed milk, adulteration of,
225

Skimming of whole milk in con-
junction with addition of
water, 222

partial, 218

Shmy milk, 124

Soapy taste, 56

Sore throat, 119

Sour milk, 123

Sow’s milk, 25

Soxhlet’s method, 208

Specific gravity. 197
of milk and whey, 202
whey, 206

Stage of the lactation period, 29

Sterilization, 130, 142-146

Sterilized milk, 192

Storch’s method, 192

Sudden changes in food of herd,
176

Suppurative processes, 102

Tabes mesenterica, 78
Taking samples, 200

INDEX 275

Taste, beet, 40
boiled, 59
burnt, 40
of milk,
oily, 7
soapy, oF

Tastes, abnormal, 55

Temporary changes, 38

Test, aleohol, 229
fermentation, 220

Transpareney of milk, 197

Trifoltun Milk Supply Co.,

2PRO-RAT

Toxie substances, 60

Tubercle bacilli in milk, 72

mixed milk, S1
separation of, So
temperature af whieh killed,
SG

Tuberenlosis, 71-87
abdominal, 78
broncho-pneumonia, 72
in eattle, 71
intestinal, 72
miliary, 73
udder, 48, 71

Tumors, 48

Typhoid bacillus, 110
fever, 106

229

Unelean or dirty milk, 235
Udder and teats, contusion of, 45
iflammation of (mastitis), 93
cedema, 46
tuberculosis, +5, 71
Unsanitary practices in bottling.
195, 196

Variations in cow’s milk, 26-45
Viseoven, 226

Viscosity, OS

Volatile oils, 60

Voltimer’s mother’s milk, 151
Voluntary control of milk, 163

Water, 16
supply, 179
Whey proteid, 17
specifie eravity of,
Whole milk, TS6
dilution of with water, 219
skimming of in conjunetion
with water, 222
Woman's milk, 24

Do Eas

Yellow milk, 57

Zebu’s milk, 22

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