Rural Hygiene Part 15

In recent years, due to the advocacy of the eminent scientist, Metchnikoff, who a.s.serts that researches in the Pasteur Inst.i.tute have shown that certain diseases of advanced age are due to auto-intoxication from the larger intestine and that the consumption of fermented milk acts as an antiseptic, neutralizing this bacterial intoxication, the consumption of fermented milk, or b.u.t.termilk, or koumiss, has very largely increased. It is, in fact, rather remarkable to find that in large cities, business men whose digestions have been ruined are devoting themselves to unlimited quant.i.ties of b.u.t.termilk in the hope that their former excesses and absurdities in the way of food may be counteracted and health restored.

Between these two extremes--the use of milk for the very young and for the aged and infirm--milk plays an important part as food. The consumption of milk in New York State, according to statistics, amounts to about a pint a day for each person for that part of the country. As an article of food, milk has the advantage already referred to, namely, that besides its nutritive power it has a curative effect greatly augmented by fermentation, the modification so vigorously advocated by Metchnikoff. Another advantage which milk possesses as an article of food is that, by sterilization and storage in closed vessels, it may be kept for days and even months in good condition. At the time of the Paris Exposition, milk was sent from America and exhibited alongside of French milk with no preservatives except heat used for removing the bacteria in the milk and then cold storage for keeping others out, and two weeks after the original bottling the milk was in good condition. To meet the need of ailing babies, advantage was taken of this valuable property of milk, by which it could be shipped from dairies near New York to the Isthmus of Panama, and used continually with good results although more than a week old.

_Bacteria in milk._

The great disadvantage which milk sustains as an article of food is that the same composition that makes it so useful as a diet for man, also renders it a most admirable culture medium for the rapid development of all kinds of bacteria. Some of these bacteria are, without doubt, benign in their effect upon man; as, for example, the particular species used to produce koumiss and other varieties of fermented milk now recommended by physicians. But there are many other kinds of bacteria that find life in milk congenial, whose effect upon the human system is not salutary, and, if milk infected with those varieties is used for feeding infants, the result is quite likely to be a disturbance of their digestive system, producing diarrhea and cholera infantum and possibly death.

It was at one time common to add to milk certain antiseptics for the purpose of preventing the growth of bacteria, and, except that the preservatives acted quite as injuriously upon man as upon the bacteria, the results, so far as merely keeping the milk went, were all that could be desired. The chemicals added were borax, boracic acid, salicilic acid, sodium carbonate, and other similar disinfectants. Gradually, however, it has come to be known that, inasmuch as the milk when first drawn from the cow's udder is sterile, that is, contains no bacteria, and since it is quite possible to prevent the introduction of bacteria into milk during the processes of milking, straining, and bottling, there is no need of the addition of preservatives, provided particular care is exercised in handling the milk.

_Effects of bacteria._

Since this care involves the expenditure of both additional time and money, questions at once arise whether such expenditure is necessary, whether the introduction of a few bacteria into the milk is objectionable, and what the results are upon the persons drinking milk containing bacteria. For our present purpose, the kinds of bacteria which find their way into milk may be divided into two cla.s.ses, namely, those that are normally in milk and which tend to produce souring, and those which accidentally enter and are able to produce disease in persons drinking the milk. The first kind probably enter the milk from the air or from the surface of the milk-pail, and in the milk increase in numbers very rapidly and have the same effect in the milk and on persons drinking the milk as any large amount of organic matter.

The second kind of bacteria are known as pathogenic; that is, are the direct cause of disease when taken into the human system. Under ordinary circ.u.mstances, this latter cla.s.s will not be found in milk, since these kinds of bacteria must come from some infected person, and if no such person is in contact with the milk at any stage, then it is impossible for the milk to become so polluted. However, those interested in preventing the spread of disease through polluted milk argue that if the conditions in a stable and dairy are so unclean that large numbers of the normal milk bacteria can enter the milk and increase in numbers there, then conditions would be favorable for the introduction of pathogenic bacteria whenever the milker or bottle-washer or the strainer or any of the helpers became sick.

To show the difference in the effect of a clean stable and dairy as compared with an ordinary one, it is only necessary to say that in investigating the quality of the milk supply of a certain city recently, the writer found one stable where the milk a.n.a.lyses showed from half a million to a million bacteria per c.c.,[2]--that is, per half-teaspoonful,--and this was occurring in the dairy regularly from month to month as the a.n.a.lyses were made. Another stable in the same city showed just as regularly a bacterial count in the milk of from 1000 to 5000 per c.c., the difference being due solely to the way in which the stables and dairies were kept,--in the one case with no regard to cleanliness and in the other with the very best attention paid thereto.

Certainly, if dirt is so much in evidence that a million bacteria can enter the milk in every c.c., no particular pains can be taken in such a stable to keep out disease germs; while in the clean stable, where so few germs enter, disease germs could hardly find any opportunity for lodgment.

[Footnote 2: c.c. = cubic centimeter, or centister. A centimeter is about 2/5 of an inch (.3937). 1 cubic inch is about 16-1/2 c.c.]

The following example may be given to indicate the effect of impure milk upon a community. The vital statistics of the city of Rochester, including the deaths of children under five years, show that from 1889 to 1896, during the summer, infants died at the rate of 109 per 100,000 population. The health officer of the city undertook to improve the quality of the milk, and from 1896 to 1905, statistics show that the number of children dying, under five years, was only at the rate of 54 per 100,000,--a manifest saving due, without doubt, to the improvement in the quality of the milk. By repeated examinations of the dairies, by rigid enforcement of certain rules governing the distribution of milk, and by detailed lessons to mothers in the tenement-house districts on the care of milk, the quality of the milk was so improved as to make the reduction in the death-rate already pointed out.

The Honorable Nathan Strauss, of New York City, has taken up the same idea, and, by supplying the poor with milk properly heated so as to destroy the bacteria which may have been introduced by careless handling, has also saved hundreds of thousands of children from premature death.

_Diseases caused by milk._

Many infectious diseases are propagated by milk, not only among children, whose chief food is found in this supply, but also among those of more mature age who, though drinking only a small quant.i.ty, are apparently more easily affected. Four diseases are particularly to be noted in connection with the consumption of milk, namely, typhoid fever, scarlet fever, diphtheria, and tuberculosis.

_Typhoid fever from milk._

One of the most striking ill.u.s.trations of the spread of typhoid fever through milk occurred this last year in the city of Ithaca, New York.

The city proper lies in a valley between two hills, the milkmen having their farms on both sides of the valley to the east and west, on the hill slopes. One milkman on the west, with a large route, delivered his own milk only in part and bought an additional supply from a farmer on the east. In the family of the latter occurred a case of typhoid fever in September, p.r.o.nounced by the local physician to be sunstroke, but evidently typhoid fever, since other cases of secondary infection developed in the same family and were then p.r.o.nounced typhoid. The milk from this east-side farm was taken down the hillside and turned over to the west-side farmer, who distributed his own milk in his trip from his farm across the valley, his route being so timed as to allow him thus to dispose of all his own milk. Having then loaded up with the east-side supply, he started back across the valley, distributing the milk which was evidently polluted, since on his return route house after house developed typhoid fever, with no cases on the first part of the route and with no other cases in town except those on this milk route.

Forty-four cases developed in all, with two deaths.

The Reports of the Ma.s.sachusetts State Board of Health give a number of cases of the same sort, all showing that milk is easily infected by persons suffering from even mild attacks of typhoid fever, attacks so slight as perhaps not to be recognized or to be worth submitting to a physician, but which are responsible for bacteria pa.s.sing from the hands or mouth to a can cover or ladle, and so to the milk.

_Diphtheria._

Diphtheria seems to be well established as a disease transmissible by milk, although its occurrence is not so frequent as that of typhoid fever. Not long since, the writer was much interested in an epidemic of this sort described by a physician who was convinced that the bacteria responsible for the mild form of the disease occurred largely in the nose and throat pa.s.sages. He noted that as the result of these growths a constant exudation from both pa.s.sages was present, and that a man with this disease, working over the milk, might easily allow the milk to be polluted by this exudate dropping from his nose.

The result was a general distribution of a mild form of diphtheria among those using the milk.

_Scarlet fever._

Many examples have also been given of the distribution of scarlet fever through the agency of milk, the specific contagion probably being discharged by the patient from his nostrils, mouth, or from the dry particles of skin so characteristic of this disease. Unfortunately, mild cases of scarlatina are very apt to occur, so mild that a physician is not called in, and the only positive proof of the disease consists in the subsequent "peeling," although the nasal pa.s.sages may have been alive with germs.

_Tuberculosis._

So far as tuberculosis is concerned, nothing seems to be definitely proved. There is little fear of milk becoming infected from tuberculous patients or of the disease being transmitted through milk from one person to another, as with the three other diseases mentioned. The possibility of infection here lies in the fact that a cow, like man, is susceptible to tuberculosis as a disease, and undergoes the same course of prolonged suffering and death. The interesting question is whether the disease may be transmitted from a cow to a man through the cow's milk. With all the refinements suggested by science as to the virulence of the disease thus transmitted, with a study of the comparative symptoms of the two diseases, of the progress of the disease in the cow when the germs are found in the milk, and of the possibility of eliminating these germs by heating or otherwise, the danger from diseased cows is still unsettled.

So far as present knowledge goes, it is probably conservative to say that although tests made on cows by inoculation with tuberculin show that a large proportion of the animals in the various dairy herds are more or less affected by tuberculosis, yet only a small proportion of the milk from such cows shows the presence of the tuberculosis bacillus.

So far as statistics can be given on this subject, it seems probable that not more than ten per cent of the cows reacting under the tuberculin test would show tubercular bacilli in the milk, or would develop tubercular reactions if the milk were used in inoculations. The reason for this is probably that the tubercular growth in the cow does not naturally attack the milk glands until the disease is well advanced, and when the general appearance of the cow indicates severe illness, so that any careful milkman would not use the particular milk, even if the milk flow did not cease. It is not reasonable to a.s.sume that all milk from tubercular cows is itself infected, nor yet that all children drinking milk so infected will contract the disease. But the mere possibility of demonstrating that a small percentage of tubercular cows will cause human tuberculosis is sufficient to justify all possible precautions against tubercular animals and against the distribution of tubercular milk. In this connection it is worth while noting that the cows most affected by tuberculosis are those confined in small crowded stables, with no fresh air, with no exercise, and with insufficient or improper food. Unfortunately it is not possible to trace the connection between the particular animal responsible for the disease in a human being, since the period required for the development of the disease is so great that the possible time of onset is forgotten and the cause of the disease entirely out of mind.

It can only be said, therefore, that laboratory experiments have demonstrated the presence of the tuberculosis bacillus in milk from tubercular cows, and that this bacillus is known to produce tubercular lesions in man. It is wise, therefore, to eliminate the milk of tubercular cows if healthy milk is to be provided.

_Methods of obtaining clean milk._

Aside from the infection of milk by specific disease-producing bacteria, the milkman of to-day must be very careful to avoid a milk which shall contain large numbers of bacteria of any type which, while not producing any specific disease, nevertheless causes changes in the chemical composition of the milk, which make it at the same time unfit as an article of food for individuals and shows the possibility of other kinds of infection.

There are two axioms to be followed if good clean milk is to be produced, and those are that the milking and straining shall be done in clean stables, from clean cows, by clean persons; and the other that the milk shall be cooled to a temperature of fifty degrees or less as soon as received from the cow. Neither of these requirements is difficult to attain, but they const.i.tute the sole reason why some milk contains a million or more bacteria and other milk less than a thousand; and it is quite possible by enforcing these two requirements to change the number of bacteria in milk from the large figure to the small one.

Probably it is in the stable where the cows are milked that the most important factor in producing large numbers of bacteria is to be found.

Not long ago the writer saw a number of stables, the ceilings of which were poles on which the winter supply of hay was stored and the atmosphere was noticeably dust-laden. A good milk could not be furnished from such a stable, and therefore it may be set down as the first requirement that the ceiling of the stable should be entirely dust-tight. Some of the best stables in the country for this reason have no loft of any sort above the cattle, but if the ceiling is tight,--that is, made with tongue-and-groove boards and then painted,--there can be no objection to the storage of hay in the loft. Hay should not be taken from the loft or fed to the cows just before milking, because the very moving of a forkful of hay through the air of the stable stirs up so large a number of bacteria in the air that quant.i.ties of them will later fall into the milk-pail.

_Light and air_ in a stable are both important, not so much for the quality of the milk as for the health of the cows that furnish the milk.

Ventilation and sunlight are both excellent antiseptics. The ordinary rule for the amount of window area per cow as given by the United States Department of Agriculture is four square feet of window surface. But it is not easy to definitely state any fixed amount of window area, since the value of the window is in its disinfecting power on the bacterial life of the stable, and this is greater or less as the windows receive the direct sunlight or are hidden under eaves where no sunlight reaches them.

The next factor in the production of good milk is the condition of the _walls of the stable_. Like the ceiling, they should be absolutely free from dust, and should be smooth, so that they may be brushed or even washed clean. For this reason, walls with ledges are objectionable, and all horizontal surfaces in a stable are undesirable. Tongue-and-groove sheeting should never be laid horizontally, but rather vertically, and a smooth brick or concrete wall is better than wood in any case. The same care must be taken to have the floor clean and dry. A floor of saturated wood, containing millions of bacteria which are stirred up by the milker moving around, causes many of those millions to be deposited in the milk-pail. A concrete floor for the stalls and drains is the ideal construction, and both should be thoroughly cleaned morning and night, so that no dried refuse may remain as the living place for bacteria. Nor should the manure thrown from the stalls be left in the vicinity of the barn, but carried away at least 200 feet, in order that the barnyard may be kept dry and clean, that no smell from the manure may reach the milk, and that the flies which come from manure piles may be kept at least that distance from the cows.

The next factor in the production of clean milk is the _condition of the cow herself_, not in the matter of her actual health, but in the matter of the cleanliness of her skin at the time the milking is done. If the udder and sides of the cow have been coated with manure, it is certain that more or less will fall into the milk-pail at the time of milking, and the "cowy taste" of the milk is easily accounted for in this way. In a modern stable, the milkman is careful to clean the cow ten or fifteen minutes before the milking is done by sponging or washing her belly, sides, and udder with a damp cloth or with a cloth moistened with a disinfecting solution. In one set of experiments, for instance, 20,000 bacteria per c.c. were found in the milk when the cow was rubbed off before the milking and 170,000 when the preliminary cleaning was omitted. In another case, milk from four dirty cows gave an average of 90,000 bacteria, while other cows of the same herd, milked by the same man, but carefully cleaned before milking, gave only 2000 per c.c. The care involved brings its own reward, and it is in most cases a lack of knowledge or an indifference to results which causes the malign effects above noted.

Only a few weeks ago, the writer watched the hired man start the milking and was disgusted to see the old-fashioned practice followed of squeezing a little milk onto the man's filthy hands and then the handful of milk rubbed around on the cow's teats to drip filthy and bacteria-laden into the milk-pail along with the milk itself.

One other factor is involved which, while scoffed at by some of the old-time farmers, has nevertheless proved its value, and that is the use of the _narrow-topped milk-pail_. It is startling when tested by bacterial growths under the two conditions to see how many more bacteria will be found in the wide open pail than in the narrow-topped one, and while, of course, some milkers may not be able to use a pail the top of which is only six inches in diameter, it is quite worth while for milkers who do not know how to use a narrow-topped pail to learn.

The size of the opening is not the whole consideration in the matter of the milk-pail. The way it is washed is even more important. If it is merely rinsed out in cold water and then washed in warm water, it is far from clean, and milk poured into such a pail and then poured out will by that process have gathered to itself thousands of bacteria. For example, some experiments have shown that milk in well-washed pails had, on the average, 28,600 bacteria per c.c., while that collected in pails of the same sort under identical conditions, except that the pails had been steamed, contained only 1300 bacteria per c.c.

Perhaps the most important factor in the care of these utensils is the necessity of killing the bacteria left in them by the milk itself.

Ordinary washing will not do this. Either the washing must be done with some sterilizing agent, like strong salsoda, which must then, of course, be thoroughly rinsed out, or else the inside of the pail must be filled with absolutely boiling water or with steam. The advantage of the latter is that no contamination is possible by the water itself, whereas in washing out the disinfectant the water, unless pure, contaminates the surface again. To show the effects of clean pails, an experiment was made in which milk was drawn from a cow and found to have 6000 bacteria per c.c. It was then poured rapidly from one to another of six other apparently clean pails. At the end of the sixth pouring, the milk was found to be so changed that the number of bacteria had increased to 98,000 per c.c.

The strainer for a milk-pail is preferably made of cheesecloth, since this can always be easily boiled between milkings, and so sterilized. A wire strainer through which the milk has to pa.s.s, and where the milk is often stirred by the finger of the milker to make it pa.s.s through more rapidly, is in no sense as satisfactory as cheesecloth.

The straining should be performed as soon as each pail is filled with milk, and pails of milk should never be allowed to stand around in the barn back of the cows, but rather should be taken at once to the milk-room, where it can be strained before any further contamination takes place.

Then the milk should be cooled, and this, to be effective, must be done in such a way that the temperature of the milk shall at once fall to fifty degrees or less. It is well known that a forty-quart can of milk lowered into spring water cools slowly on the outside, but that hours will pa.s.s before the inside of the can has its temperature lowered appreciably. Meanwhile, bacterial growth has started, and that milk can never be as good as when cooled quickly throughout. Special apparatus is made in which the milk is spread out in very thin sheets over a surface cooled by ice or cold water to a low temperature. In this way all the milk is at once lowered in temperature and may then be kept in spring water until time for shipment. Many examples can be given of the value of this kind of cooling. A few years ago, the Cornell University Agricultural Experiment Station determined that a certain milk when fresh contained, about 4000 bacteria per c.c., and fifteen hours later at room temperature had 270,000, and twenty-seven hours later had soured with an innumerable number of bacteria. Another part of the same milk, however, kept at fifty degrees Fahrenheit, showed absolutely no increase in bacteria for twenty-seven hours, and was still sweet with only 12,000 bacteria at the end of three days.

_City milk._

The value of pure milk is not a matter of individual opinion on the part of the farmer, but it is a vital point with thousands and millions who are dependent upon the farmer for this life-giving food. Unfortunately, to-day the relation between the consumer and the milkman is so remote that it is almost lost sight of, and in place of the personal relationship which formerly existed, which made the milkman proud of his milk and the consumer proud of her milkman, there is to-day an absolute disregard of the interests of the other side in almost all cases. Even in the smaller cities, consolidated milk companies are being established by which the former independent milkmen are bringing milk to the central station in large cans, where it is dumped into vats along with the milk from a dozen other milkmen. Some may be good and some bad, but what is the use, each one says, of my taking particular pains when my neighbor produces milk of such poor quality? The result is that it is all far from good and likely to deteriorate rather than to improve. To be sure, at the central station it is bottled and distributed to the consumer in apparently clean gla.s.s jars, but this is not the same cleanliness that one gets when the bottling is done five minutes after the milk comes from the cow.

When the milk supplied to the larger cities is furnished as in New York, the impossibility of controlling the quality of the supply becomes apparent. The farmer brings to the shipping station his two or three large cans of milk, representing the night's and morning's milkings.

These are loaded on a train along with hundreds of others, a few chunks of ice are thrown on top, and the train is started for New York, from points as far as two hundred and fifty miles away, reaching the city in the early evening. There it is received and hauled to milk stations, where it is distributed in different-sized cans and bottles, and the next morning, thirty-six hours old, distributed to the babies of the city as fresh milk. Thanks to the energetic inspection practiced by the officers of the Department of Health of New York City, who have emptied hundreds of quarts of milk into the city gutters merely because the temperature of the milk was higher than that prescribed, the quality of the milk is not so bad as it might be. In fact, the writer has bought apparently good milk on Long Island, shipped down from New York City, because the local supply was deficient in quant.i.ty and inferior in quality, although the latter would naturally be supposed to be fresh and the other was certainly forty-eight hours old on its receipt.

Cleanliness and care are the two watchwords for good milk, and both practices ought to be observed faithfully by the milk producer, whether he has in mind the health of his own family or the health of the dwellers in the city hundreds of miles away.

_Dangers of diseased meat._

Next to milk, the product of the farm which has most to do with the health of those to whom farm products are sent is the meat which comes from the cows, sheep, and pigs, and makes a large part of the farmer's produce. To be sure, the amount of meat thus sent to market from the farm is by no means as great as in former years, since even the smallest village to-day has representatives of Swift and Co., Schwartzman and Sulzenberger, Jacob Dold, and others of the great western packing houses. There is still, however, a great deal of local butchering, and it is important that the farmer himself should know the characteristics of meat and should be so impressed with the dangers of diseased meat that the temptation to unload a bad carca.s.s on the unsuspecting public may be overcome. There is nothing more certain in sanitary science than that the application of heat destroys animal parasites and micro-organisms, so that, except for diminishing the nutritive value, there is comparatively little real danger in eating diseased meat when cooked, and the fearful ravages of bad ham have been largely due to occasions where the ham has been eaten raw or semi-raw.