The ever-growing needs of civilized communities constantly demand new
methods. At the time when the streets of Boston may have been the
actual cow paths which we are sometimes told they represent, the milk
problem did not exist. Every farmer owned his cows, and if some of the
people in the small communities did not happen to own a cow there were
plenty of these animals in their neighborhood to furnish them with
milk. But as our cities have grown the farmer has been pushed back
farther and farther into the country, while the demand for milk in the
cities has been constantly increasing. The man of the city can no
longer call upon his neighbor for milk, but must depend upon some
unknown farmer living perhaps many miles away. In England the farmer
still lives somewhat close to the city, and as soon as one passes the
city limits he begins to find the fields and meadows covered with
cows. London and Berlin draw their immense milk supply chiefly from a
radius of seventy-five miles. In the United States, however, the
farmer does not live so close to the cities, and the demand for milk
is even greater than in Europe. Our cities must therefore depend upon
a wider range of territory. New York draws its milk from a radius of
some three hundred miles. It is easy to see that with such conditions
many new problems have arisen. These problems, so far as they concern
the obtaining of a sufficient quantity and the transportation and
preservation of the milk, have, from a business standpoint, been
pretty satisfactorily solved. The milk-supply companies succeed in
obtaining a sufficient supply at all seasons of the year, and get it
into the city in such a manner that when delivered to the consumer,
even though it be forty-eight hours old, it is in tolerably good
condition. But it is beginning to appear that the problem, as concerns
the consumer, is a somewhat serious one, and that this problem has not
yet been solved, nor is it likely to be solved unless the consumer
himself takes a direct interest in it.
The problem of the milk supply in the smaller cities is quite
different from that of our larger cities. In the smaller cities, even
those with populations of one hundred thousand, there may be commonly
found a number of milkmen who bring into the city the milk from their
own farms and personally distribute it. Such a business is a small
one, and the dealer and the producer may be held directly responsible
for the quality of the milk. In large cities, however, the business is
very different. The individual milk dealer who brings in milk from his
own farm has almost disappeared, and his place is supplied by the
milk-supply companies that control the product from hundreds of farms
and regulate the large part of the milk which the city consumes. These
companies send milk trains into the country in all directions, and
collect milk from thousands of farms. The milk is brought into the
city in cars in which it is cooled by ice. It may be already many
hours old when it reaches the city. It is taken from the cars, and the
milk from many different sources is mixed in large mixers to insure
greater uniformity. It is again packed in ice, and remains thus until
the individual dealer is ready to put it into his cart and distribute
it through the city to the customer.
As a result of this the customer no longer knows whence his milk
comes. If he is a citizen of New York, he may receive milk from his
own State, or Connecticut, or Pennsylvania, or New Jersey. It may come
from a thrifty farmer, or from a slovenly, filthy farm, or, for all
that the consumer knows, it may come in part from a farm where there
is a contagious epidemic. There is no method of tracing
responsibility, no method of even knowing the source of any lot of
milk. One morning we may receive milk from northern New York, and the
next from New Jersey. One morning, for all he knows, it may come from
a model dairy farm, and the next from the most unhygienic surroundings
imaginable.
But this is to a certain extent true of other foods. We can not tell
where our flour or meat comes from, or our apples or sugar. Why should
we be more disturbed over milk than other foods? Indeed, until
recently we have had no especial interest in the milk problem, and
have taken milk as it has been offered without question, except as to
its being pure milk unadulterated with water. But the rapid
discoveries of bacteriology, which have shown milk to be such a good
locality for bacterial growth, have been raising some very significant
questions. We have been told of the countless millions of bacteria
which we have been drinking daily. This has somewhat disturbed us, and
no sooner have we become reconciled to this idea than we are told of
the great amount of filth that finds its way into milk--two hundred
pounds of cow dung being the daily ration of New York city, some one
tells us. The matter appears more serious still when we are told by
the public press that there are more bacteria in city milk than in
city sewage, and are informed of the epidemics of typhoid which are
distributed by milk, or of the prevalence of tubercle bacteria in this
food product. We become suspicious of the milk supply and hesitate to
use this food product or to give it to our children.
Naturally, the people in small communities feel somewhat more at ease
in the matter since they know their milk producer and can hold him
responsible. But it is questionable whether the milk supply of the
large city is not more reliable. The milk supply in the city is
handled by organizations, and these, on the whole, are rather more
likely to exercise care in the treatment of the milk than are the
small dealers. The advantage of handling the matter through companies
is well shown in many European cities. In the large cities of England
and the continent the milk business is commonly handled by concerns
that distribute great quantities daily. Now, many of these companies
deal with the subject in a very intelligent manner. They exercise a
very considerable control over the individual dairy farms. Some of
them keep inspectors traveling constantly among the farms, spending
$10,000 to $15,000 yearly in such inspections. They will receive no
milk from a farm until after an inspector has visited it and looked
into the hygienic conditions of the dairy, even sometimes going so far
as to make an analysis of the water used in the dairy. Only after such
inspection has been declared favorable is the milk received in the
city. These inspections are repeated monthly. The appearance of a
contagious disease on the farm is noted at once and the milk no longer
received, although still paid for. These companies employ chemists and
bacteriologists to study the character of the milk received. They
educate their men into their business, and consequently employ more
intelligent help than small concerns can. They can furnish a more
uniform product than can be expected of smaller dealers. They soon
acquire a reputation for their milk, which they are very careful to
preserve. Such firms can exercise a much more satisfactory control
over the individual farmer than can even public statute, since, with
their systems of inspection, it is possible to have an accurate
knowledge of the actual conditions under which the milk is produced.
It is plainly within the power of firms dealing in large quantities to
control the character of its milk more accurately than can small
dealers.
Results, too, appear on the whole in favor of the large dealers. In
the cities where there is a system of rigid milk inspection it is
comparatively seldom that the milk furnished by such companies is
found below the standard. This milk is kept up to the standard, and
the companies having a chemical laboratory and having milk from many
sources can keep the quality of the milk much more uniform than can a
dealer whose supply comes from a single farm. The milk inspectors
usually find that it is the small dealers that fail to meet the
standard. Moreover, it is a fact that where epidemics have been traced
to milk it has always been in communities where individual milkmen
bring in milk from one or two dairies and distribute it personally.
All the epidemics of typhoid that have been definitely traced to milk
have been in small communities, and none traced to the milk of large
dealers. It is true that it would be difficult or impossible to trace
to the milk a typhoid epidemic which might occur in a large city. No
one is likely to receive the milk from the same source for two days in
succession, and the mixing which the milk receives in the receiving
station entirely obliterates the individual source. If there should be
some milk brought to the city which contained typhoid bacteria it
would be impossible to determine the fact, for such milk, after
mixing, would be thoroughly scattered beyond any possibility of
following it. We may, then, question somewhat the significance of the
fact, but it certainly is true that while serious epidemics have been
caused by milk in smaller cities no such instance has occurred in the
large cities, or been traced to the milk furnished by companies that
handle it in considerable amounts. It would seem that if milk has ever
been the cause of such diseases in large cities there ought to have
been some evidence of the fact obtained.
It is probable, therefore, that the small community can hardly feel
itself any better off in regard to the milk supply than the larger
city. It is, of course, easier to trace responsibility for bad milk if
we know where it comes from, but it is less likely to be very bad if
it comes from a large number of sources and is thoroughly mixed. The
milk in the large city is perhaps forty-eight hours old when it is
received by the consumer. But it has been kept on ice, has perhaps
been filtered, and many of its bacteria may have been killed by the
long-continued cold temperature. So far as concerns the bacteria
question, our milk which is thus two days old, appears to be actually
superior to milk delivered in European cities, which is only a few
hours old. The free use of ice in our milk car produces a more
favorable result than the more rapid handling which the milk receives
in Europe. The milk company controlling a large territory, with great
resources at its command, can put into practice rules which even
public statute can not enforce, and which the individual farmer will
rarely do by himself. One who is acquainted with the methods of
handling milk in our cities finds that the companies are each year
improving their methods, and that the milk is in most places becoming
more reliable. The proper solution of the milk supply for our
communities is in the formation of large companies, provided they are
managed partly for the benefit of the public and not wholly for
money-making.
There is little question that the public has become somewhat
suspicious of milk, and that many hesitate to drink it as freely as in
earlier years. This suspicion is more pronounced in Europe than in the
United States. Upon the continent of Europe the amount of milk which
is used raw is really very small, and apparently its use in this
condition is destined to cease. The younger generation of physicians
are now being taught that raw milk is a dangerous food, and in some
countries even the children in the schools are being taught that it is
not safe to drink raw milk. Such teaching can have only one result,
and that is the reduction in the amount of milk consumed. Much less
milk is used in Europe than in this country. It is used for tea or
coffee or for cooking, and of course for infant feeding, but for any
one to drink milk as we do in this country is certainly a rarity. The
suspicion under which milk has been placed has decreased its use.
The dangers which are feared in milk are of course connected with the
distribution of disease. Most persons who thus hesitate to use milk
have simply a vague fear, without knowing just what is to be feared.
When we put together all the facts in our possession we find that
there is good reason for believing that milk is sometimes concerned in
the distribution of the following well-known diseases and some obscure
ones: The first is _tuberculosis_, which is a disease attacking the
cow, and, if located in the mammary gland, may infect the milk with
tubercle bacilli, and may subsequently produce the disease in the
person who drinks the milk. It should be stated, however, that there
is good reason for believing that the danger from this source has been
overrated. Second, we have _diphtheria_, which apparently may also
attack the cow. The diphtheria germs may get into the milk from the
cow, and they certainly do get into the milk occasionally from
secondary sources. _Scarlet fever_ apparently is distributed by milk,
though whether this disease may come from the cow or only by secondary
contamination of the milk is not yet positively settled. _Typhoid
fever_ has in a large number of cases been traced to the milk supply.
This disease, however, does not occur in the cow, and the germs always
get into the milk from a secondary source, such as water or contact
with a person who has the disease. _Cholera_ may be distributed by
milk, but this is of course of little importance. Of these disease
bacteria, the tubercle bacillus probably never grows in milk, while
the typhoid and diphtheria germs do. The most common of all troubles
attributed to milk are those somewhat obscure _intestinal diseases_
which attack people especially in the summer months, and are
particularly common among children. Prominent among these stands
_cholera infantum_. These latter troubles, according to our present
knowledge, are not produced by distinct species of bacteria finding
entrance into the body and growing there, as are the other diseases
mentioned. They appear to be produced by bacterial poisons which are
in the milk. The bacteria--probably several different varieties--grow
in the milk and there give rise to certain poisonous products, and
these, when taken into the stomach, produce the diarrhoeal diseases
referred to.
The question of more importance is, however, as to the extent of the
danger from such causes. This question is much like the famous one of
how large is a piece of chalk. There is danger in everything, even in
drinking water and breathing air. Is the danger from milk so great as
to suggest that we should give up our habit of drinking milk as they
have largely done in Europe, or is this danger so slight that we can
well afford to neglect it? We can not avoid all sources of disease
even if we would. To do this we should need to shut ourselves up in a
box, breathe nothing but sterilized air, drink nothing but sterilized
water, and come in contact with no other person, to say nothing of
wearing sterilized clothes. Such a method will produce physical
weakness rather than vigor. We have learned in the last few years that
the proper way of avoiding disease is rather by preparing ourselves to
resist it rather than try to avoid all contact with possible disease
germs. The question is significant, then, whether the danger from milk
is so great that we should use every means of avoiding it; or is it
one of the slight dangers which we may best class with the everyday
incidents against which our proper guard should be simply vigorous
health?
It is impossible to say how great is the liability of contracting
disease from milk. Sometimes the subject looms up before us in
gigantic proportions. When our papers are describing the occurrence of
hundreds of cases of typhoid fever in a city, all traced to a milk
supply, the seriousness of the problem is very apparent, and very
likely we stop drinking milk for a season. But when, on the other
hand, we remember the millions of people that are drinking milk daily
without injury, and remember that our forefathers have done the same,
we grow graver and begin again our old custom. No one can, indeed,
pretend to say how great the danger is. That it is greater than that
from drinking water is pretty clear. That it is less than that of
riding in the cars is probably equally true. That it is greater in a
small community than a large one seems probable, and that there is a
greater likelihood of its being serious where the milk comes from a
single source than where it passes through the hands of a milk-supply
company appears to the author to be quite sure.
In his relation to this problem each person must decide for himself.
We do not cease to ride in the cars because there is danger here, nor
do the innumerable accidents from bicycling deter us from this
pleasure. Ought we to give up milk because of an occasional instance
of disease? It might be possible to give advice to use milk freely,
looking upon the danger as a slight one and one of the unavoidable
dangers of living, but if such advice is given some one will instantly
declare it bad advice. It might be possible to advise boiling all milk
before drinking, and again some authority would say that this is
unnecessary and bad. Personally, the author, though living in a small
community, uses raw milk with perfect freedom, but would regard it as
unwise to allow young children, especially infants, to use it in this
way.
As already stated, the agitation over the milk supply is greater in
Europe than in this country. While in England milk is used much as in
this country, on the continent really little milk is drunk raw, and
there is a growing demand for some means which shall deprive milk of
the suspicions attached to it. This demand has been rapidly growing in
recent years, and has resulted in the appearance of two new
industries. These are the preparation of _sterilized_ and
_Pasteurized_ milk. Neither of these industries has as yet developed
much in the United States, although in our larger cities beginnings
are being made along similar lines.
_Sterilized_ milk has been used for many years. Long ago our doctors
learned to recommend, for invalids, that milk should be boiled before
drinking. This was done before the matter of its relation to bacteria
was understood, and when physicians simply conceived that the boiling
rendered the milk more digestible. From being used by invalids it came
to be suggested in feeding infants, and then, after the relation of
milk to possible disease germs had been understood, the general
sterilization of milk was widely recommended. The process of
sterilization of milk has not taken much of a hold upon the people of
this country as yet, nor has it in England. In continental Europe,
especially in northern countries, where the amount of tuberculosis is
very large, it has made rapid headway, and now in most of the cities
sterilized milk can be bought on the streets just as easily as
ordinary milk.
In sterilizing milk as it is done in Europe the destruction of the
disease germs is not the only purpose. An object of perhaps equal
weight is to produce a milk that will keep. There are many
circumstances where it is desirable to carry milk for long distances,
and to lay in a supply to last many days or even weeks. Under these
circumstances sterilization is resorted to, since it preserves the
milk.
There are various methods of sterilizing milk. The simplest, and
doubtless the most common, is simply the boiling of the milk. This can
easily be done by any one at home, and is, beyond question, very
widely resorted to. But where the sterilization is to be performed by
a public-supply company, boiling is not satisfactory, since the milk,
although it will keep some time, is not indefinitely preserved. The
common method used is heating with superheated steam. The milk is
placed in bottles of special device, holding about a pint or a quart,
and are placed, hundreds at a time, in a large chamber which can be
hermetically sealed and then filled with steam under pressure. Here
the temperature rises to 102° to 106° C. (216° to 220° F.), and is
retained here for some little time. This high heat is supposed to kill
all the living bacteria that may be in the milk, even the resisting
spores being commonly destroyed. While the milk is still in this
apparatus, and before the chamber is opened, the bottles are sealed by
a mechanical contrivance and then allowed to cool. After this they are
taken out of the sterilizer, and are ready for distribution. The milk
thus treated is sometimes pure white, although frequently it has
acquired a brownish color, which is not enticing to one accustomed to
ordinary milk. Moreover, it has a taste of cooked milk, which is to
some people very unpleasant. But when the method is successful the
milk contains no living bacteria, and may now be kept indefinitely
without further change. It may be shipped to all parts of the world,
and whenever opened it will be found still sweet. The process is
evidently equivalent to the canning of fruit or meat, only more
difficult because the milk commonly contains many resisting spores.
Such sterilized milk can be bought almost anywhere in Europe, and
there is undoubtedly a growing demand for it. Where this or other
sterilized milk is used it is claimed that very favorable results
follow. Careful statistics have been collected as to the number of
deaths among infants from diarrhoeal diseases, and it is found that in
some cities the deaths from infants fed upon raw milk are nearly three
times as great as among those fed upon sterilized milk. Of course, no
typhoid epidemics can ever be traced to such milk, and in general its
use seems to meet with decided favor.
There are, however, some serious objections to this method of treating
milk, which have been and probably will continue to be sufficient to
prevent its wide extension. The first is that such milk appears to be
slightly less digestible than raw milk. Over this matter, however,
there has been and still is a great diversity of opinion, and many
claim that there is really no difference in the digestibility. It is a
matter of comparatively little importance, however, at least for
adults and healthy children, for the sterilized milk can be digested,
and the slight difference in ease of digestion probably has little
significance unless it be for weakly individuals. Secondly, the taste
of the sterilized milk is that of boiled milk, and this is rather
unpleasant to most people. Probably a majority of our people, if
called upon to drink sterilized milk or none at all, would prefer to
give it up entirely. This is really an almost insurmountable obstacle
to the wide extension of the use of sterilized milk, at least for the
present generation. Those who have accustomed themselves to the taste
of raw milk will not drink sterilized milk, and, if they do not dare
to drink it raw, will not drink it at all. If infants are brought up
on sterilized milk the next generation may look upon the matter
differently, since the taste can be cultivated.
The third objection to sterilized milk is its cost, which pretty
effectually prevents its wide use. Here is probably the real reason
why the sterilized-milk industry has not extended more rapidly than it
has. The cost of the milk that has been subjected to the treatment
above described is considerably above that of ordinary milk, and the
size of the pocketbook is commonly a matter outweighing, with most
people, even matters of health. When raw milk can be purchased at half
the price of sterilized milk, or even for a cent or two less, it will
be purchased almost uniformly by the bulk of people, rather than the
more expensive sterilized milk. Thus it happens that, in spite of the
fact that sterilized milk can be purchased easily in most European
cities, the business is not a large one. Probably not one quart of
sterilized milk is sold to a hundred quarts of raw milk, even in
cities where the business is best developed.
There are some who think that this method of treating milk is soon to
be recognized as a necessity, and that it will be shortly regarded as
improper to drink raw milk as it is to eat raw pork. But the business
has grown rather slowly. Most people prefer to purchase their milk raw
at a cheaper price and then boil it themselves, if they do not forget
it. There is, moreover, one rather serious criticism that is made
against this sterilized milk. Even with the high temperature that is
used, it is impossible to be sure that all bacteria spores are
destroyed. In most cases they are killed, but occasionally, and indeed
not infrequently, a lot of milk will contain resisting spores that the
heat does not destroy. These few spores that are left may become
serious, far more so than the bacteria in raw milk. After
sterilization they begin to grow, and, since this milk is very
commonly kept for many days before it is used, these germs have a
chance to become very abundant in the milk and to produce profound
chemical changes therein, in some cases actually developing poisons.
The changes that thus occur may be such as to escape notice with the
eye, since they do not curdle the milk, and they may even fail to
affect the taste of the milk. Such milk is to all appearances good,
and would be given to infants without hesitation. If it did contain
the injurious products thus referred to the results would be serious.
Some bacteriologists are convinced that not a few cases of serious
sickness have been produced in this way. When the milk is used shortly
after the sterilization this matter is of no importance, since the
bacteria spores grow slowly. But sterilized milk is supposed to keep
indefinitely, and is therefore likely to be preserved some time before
using, giving abundant opportunity for these spores to grow.
For these several reasons there is developing a different method of
dealing with the problem. It is the well-known process of
_Pasteurization_. But although the process has been known for several
years, its application to the milk business on a large scale is quite
new. Pasteurization consists in heating the milk to a temperature of
only about 68° to 85° C. (165° to 185° F.), leaving it at this
temperature for a short time, and then rapidly cooling. The length of
time required depends upon the temperature used, being, of course,
shortest for the higher temperature, but it varies from some two
minutes to half an hour. This moderate heat does not necessarily
produce the cooked taste nor, as we shall see, does it involve an
expense which need raise the price. The temperature, however, is not
sufficient to destroy all bacteria, and for this reason is looked upon
with disfavor by those who feel that what is needed is an absolute
destruction of all bacteria. The Germans, who like to do things
thoroughly, do not take readily to Pasteurization, and there are
others besides Germans who insist that this treatment does not make
the milk safe. But if one is looking for practical possibilities
rather than theoretical success, there is perhaps at present more to
be said in favor of Pasteurization than sterilization.
Pasteurization is found to be sufficient to destroy all the strictly
pathogenic bacteria that are likely to be in milk. The germs of
diphtheria and typhoid are killed, and even the tubercle bacillus is
rendered innocuous by a few moments at a temperature of 75° C. The
resisting spores above mentioned are of course not destroyed, and many
other bacteria are left uninjured. But the bacteria which escape the
heat are not strictly pathogenic, and do not grow in the body. If they
produce any injury to the drinker it is because they grow in the milk
and produce injurious chemical products there. They are only
dangerous, therefore, after they have had an opportunity to grow in
the milk for some time. This opportunity they do have, as we have
seen, in sterilized milk, but they do not have the opportunity in
Pasteurized milk. Pasteurized milk is not designed for keeping, and
those who use it know that while the strictly pathogenic bacteria are
killed the milk will not keep. It will remain sweet a little longer
than raw milk, but it must be used at once. It must be treated just
like fresh milk. Under these conditions the bacteria do not commonly
have an opportunity of growing sufficiently to produce their poisonous
products before the milk is consumed. Practically, then, these
bacteria that resist the moderate heat of Pasteurization are of no
serious importance in connection with the healthfulness of milk.
Pasteurized milk has been deprived of all its strictly pathogenic
bacteria, and the germs still left will commonly have no opportunity
to grow very much before the milk is consumed. It is therefore the
confident belief of many that Pasteurization is actually a safer
method of treating milk than sterilization. Moreover, the results
appear to be equally favorable, for Pasteurization is claimed to
produce an effect upon diarrhoeal diseases equal to that of
sterilization.
But the most important argument for Pasteurization seems to be that it
is really practical, and can be introduced upon a scale vastly more
extended than can sterilized milk. The practice of Pasteurizing milk
has doubtless been followed not a little by private families, but from
the very outset it has appeared that the proper method of dealing with
the matter is to treat the milk at a general distributing center,
rather than to depend upon the consumer to do it. Not a few devices
have been suggested for accomplishing the purpose satisfactorily and
rapidly. The machines invented are planned upon two different
principles. In one plan the milk is placed in some large vessel
holding many gallons and is here heated, commonly by steam coils. It
is allowed to remain here at the desired temperature for twenty
minutes to half an hour, and is then cooled. This method is
necessarily slow--so slow, indeed, that it is impractical for use
where large amounts of milk must be treated rapidly for general
distribution. It probably could not be used for the milk supply of a
city. The other method is called that of continuous flow. Here the
milk is allowed to flow continuously over a heated surface, which
brings it quickly to the desired temperature. It is kept hot for only
a short time, however, and it then flows over a cooled surface, where
the temperature is brought down again and the milk is finally
delivered from the machine in a continuous stream of cooled milk.
Great objections have been urged against this process, from the fact
that it is not thorough. The milk is retained at the high temperature
for such a short time that many of the bacteria are not killed. The
Pasteurization is decidedly less thorough than by the other method.
But here, again, before condemning the process it is necessary to
consider its purpose. If it is to destroy all the bacteria, or as
large a number of them as is possible, it is of course unsatisfactory.
If, however, the purpose is to treat the milk cheaply and rapidly in
such a manner as to remove the danger of disease distribution
through, the milk supply, it would appear that such a method is
perhaps satisfactory.
So far as can be determined, this method is efficient in destroying
pathogenic bacteria. Its efficiency is of course dependent upon the
length of time that the milk is retained at the high temperature, and
this can be regulated by the rate of the flow of the milk through the
machine. All evidence we have seems to point to the conclusion that a
temperature of 75° C., continued for a few minutes only, so far
destroys or weakens the pathogenic bacteria which are liable to be
found in milk that they need not subsequently be feared as producing
disease. Of course, there are pathogenic bacteria that are not
destroyed by this temperature, but they are not likely to occur in
milk. The germs of typhoid, diphtheria, and tuberculosis are probably
rendered harmless by such treatment, and these are the chief
pathogenic bacteria of milk. Moreover, the other bacteria are very
greatly decreased in numbers, so that the dangers of intestinal
troubles are at least much reduced. In hospitals where Pasteurization
has been adopted the results are as favorable as with sterilization.
The great value of this plan is, however, that it is practical on a
large scale. In Copenhagen it has been in practice for some three
years very extensively. In Denmark the amount of tuberculosis among
cows is very great, somewhat more than half the animals suffering from
this disease. As a result the public milk supply is regarded with more
suspicion than in countries where the disease is less. It is
everywhere recommended that the milk be always boiled before using,
but the bother of treating the milk thus daily makes people unwilling
to do it, and it is doubtful whether the practice is as common as the
physicians think necessary. Some three years ago a company was
organized to meet the public demand for safe milk, and it has adopted
plans by which it furnishes Pasteurized milk on a scale as extensive
as that of the ordinary milk-supply companies. The company has devised
and manufactured two large machines which receive the milk, Pasteurize
it, and cool it in a constant stream, and are capable of treating two
thousand quarts an hour. The milk received by the company is tested
chemically and filtered, and then allowed to pass through one of these
large machines. After this it is placed in glass bottles and sealed
with the company's seal. The heating is done by steam, and the cooling
by brine cooled by an ammonia cooling machine. The greatest care is
taken in cleaning and sterilizing the bottles, an enormous chamber
some twenty feet long and six feet in diameter being used for a
sterilizer. Into this the washed bottles are placed, the chamber
hermetically closed, and then superheated steam is turned in upon
them. Everything connected with the establishment is conducted with
the greatest attention to cleanliness, and upon a very large scale.
The bottled milk is subsequently distributed in ordinary milk carts. A
bacteriologist is constantly testing the efficiency of the machines by
bacteriological examinations of the Pasteurized milk.
The most important feature in this undertaking is that the company
furnishes the city with milk at the same price as that furnished by
the other companies without Pasteurization. It seems strange that this
can be done, for the Pasteurization of course costs something. But the
explanation is essentially that heat is cheaper than cold. Because of
the subsequent Pasteurization this company does not feel it necessary
to demand that the milk should reach them in as cool a condition as is
required by the other companies. While their business rivals insist
that they shall receive milk not warmer than 4° C., this Pasteurizing
company receives it as warm as 10° C., and this saving in the cooling
largely pays for the Pasteurization. The mechanical bottling enables
them to employ a cheaper grade of help than is necessary when the milk
is peddled in carts.
The results of this endeavor to furnish safe milk are in quite decided
contrast to those connected with sterilized milk. Sterilized milk has
now been on the market for quite a number of years, but, in spite of
the fact that it can be readily bought in most cities, the actual
business is small. The largest milk-supply company in Europe has a
demand for only a few hundred quarts per day. This company in
Copenhagen offers to the public a milk which has the taste of fresh
milk and which has been so treated as to have all pathogenic bacteria
within it destroyed, and at the same time the other bacteria greatly
reduced in number. This milk it sells at the same price as ordinary
milk. As a result its business has rapidly grown, and instead of
supplying a few hundred quarts it sells some thirty thousand daily,
and the amount of milk handled is increasing with great rapidity. It
probably sells more Pasteurized milk than all the sterilized milk sold
in Europe.
It would thus seem that we have here actually a practical method of
dealing with the new problem of the milk supply. That it is practical
is manifest from the actual results in this institution in Copenhagen.
Whether it is regarded as satisfactory will of course depend upon our
standpoint. Those that insist that the milk must be freed from all
danger, and hence deprived of all bacteria, will not regard this
method as satisfactory. But probably every one will recognize that
milk thus treated is very much safer than raw milk, and that dangers
from typhoid epidemics and tuberculosis are removed, even if they do
not admit that intestinal troubles are thus avoided.
There can be little doubt that the method would be successful in our
own cities, but its success would depend upon the price at which the
milk is sold. If the Pasteurized milk is sold for a price much higher
than ordinary milk it will not be a commercial success, for the vast
majority of people prefer to save the one or two cents per quart, and
run the rather slight risk of trouble from the milk. If it can be sold
in our cities, as in Copenhagen, for the same price or a price only
slightly higher than that of ordinary milk, it is hardly doubtful that
it would soon come into favor, for who would not prefer milk that is
safe from disease germs if the price is the same? Already there are a
few attempts in this direction in some of our cities, but as yet they
are only in the beginning stage. Whether they will develop to a wide
extent depends probably almost wholly upon the price at which the milk
can be sold.
It would appear, then, that this method of Pasteurization by a central
company offers the most hopeful solution of this feature of the
problem which is growing with the growth of cities. The milk companies
could probably arrange, without great expense, such a plan of
Pasteurizing large amounts of milk. This only emphasizes the
conclusion, already reached, that the most hopeful method of dealing
with the problem in our cities is through properly organized companies
that can handle milk on a large scale, and will do it conscientiously,
and not wholly from the standpoint of money-making.