Popular Science Monthly/Volume 45/August 1894/Milk for Babes

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IN the natural advance made in the study of the subject of infant foods—methods of preparation, administration, etc.—the process of sterilization of milk, as ordinarily and formerly understood, is now replaced by "Pasteurization," which is, practically speaking, the low-temperature process of the earlier method, and specialists who comprehended the serious changes produced in milk by high and prolonged temperature advised from the first the lower method.

It is easy enough, by prolonged and repeated application of a high temperature, to keep milk apparently unchanged, but the point aimed at all along has been to devise a way by which it might be made sterile with the least possible interference with its nutritive qualities. Investigation has demonstrated that milk subjected to lengthy boiling under pressure is in many ways unsuited to the digestion of an infant. Chemical analyses have proved what experience has shown to be the case namely, that milk sterilized by the higher and prolonged temperature is not fit for administration to an infant. Dr. Henry Chapin, of New York, has been making a study of infant feeding and of children in the Post-graduate Hospital of that city, to which he is attached, and he says, in an article recently published in the New York Medical Journal, that partial sterilization or Pasteurization, to the point of killing the germs only, is necessary and desirable, as a high and continuous temperature produces unfavorable changes in the milk; the fat collects in masses, the albuminoids are changed, the casein is altered, and the digestive action on the casein of sterilized milk is incomplete. Simply

PSM V45 D510 Pasturizing and sterilizing milk.jpg

sufficient heat must be applied to the milk to keep it sweet until the next supply can be procured. Herein lay one of the most frequent sources of trouble in the earlier days of sterilization, caused by lack of exact knowledge in this direction; and in. addition to this, when sterilized milk was first introduced, many mothers reasoned that, being sterile, it was a perfect food, and consequently used it without any further preparation, with the natural result of indigestion and all its resultant ailments. It is quite true that milk to be a perfect food must first be sterile, but it must also be assimilable; and to reach this point great care must be given as well to its preparation and administration. Notwithstanding the care exercised by boards of health, it is impossible at any time to be sure of the purity of the milk supply; hence the need is urgent that it be made safe by Pasteurization, which is, in reality, simply subjecting the milk to the lower temperature of 150º to 160º F., instead of 212º F., as was formerly done, and is called thus in deference to Pasteur, who long ago found that the ordinary germs of fermentation and bacteria would be destroyed by this temperature, and recommended such, a process for their destruction and for the preservation of foods. Thirty years ago Liebig said that by scalding milk once a day it could be kept indefinitely, and many a housewife, before and since, has put the same fact into practice. The process is new only in name—the discovery lies principally in its application—experiment having shown that the application of 150º F. for thirty minutes will destroy the Bacillus tuberculosis with certainty, and many germs that are likely to be found in reasonably pure milk, which, with ordinary precaution, will remain sweet for several days.

There is a good deal in a name, and it is to be hoped that "Pasteurized" milk will receive as cordial a welcome as was given to "sterilized" milk.

Generally, new ideas are received with some conservatism and are subjected to tests in expert hands before being adopted by the public; but the need was great, and it is seldom indeed that anything has had the benefit of so wide a trial and so immediate an acceptance as this idea of sterilization of milk. Benevolent persons opened dispensaries to give it to the poor, who, jumping to the conclusion that it was "exactly like mothers' milk" and had wondrously valuable qualities, failed frequently to see the true purpose of the work. Few stopped to inquire what sterilized milk really was, and directions given for its use were rarely followed.

The fact that milk, when subjected sufficiently to a high temperature, can be kept unchanged for an indefinite length of time, while of interest from a scientific standpoint, is of no practical interest to consumers, except upon long journeys, as it has been conclusively shown that for ordinary usage Pasteurization should be done daily. It is generally conceded that pure milk will save much infant mortality. The fact that thousands of children especially infants die every year from want of care in the preparation of their food is underestimated by many. At one of the meetings of the Philadelphia Board of Health, Dr. Shakespeare said, in his report, that milk of poor and unwholesome quality is originally and directly responsible for thousands of deaths annually in that city alone, not to speak of the sickness from this origin which is not fatal. To this category, he declares, certainly belong most deaths from cholera infantum, infantile tuberculosis, many of the deaths from acute diarrhœa, from typhoid fever, and some of the deaths from diphtheria and scarlet fever.

Dr. Chapin says that of six hundred infants whose cases were studied, nearly all the troubles were acquired and not hereditary. "While a tendency to constitutional disease may be inherited, it is the bad surroundings and faulty conditions of life that powerfully predispose to illness"—poverty and ignorance being the chief sources of difficulty. He says the waste of child life in densely populated centers, especially in New York, is enormous. Last year the bodies of three thousand and forty-two children under five years of age were received at the morgue and nearly all were buried in Potter's Field, killed by poverty and ignorance, want of proper diet and care. In France, out of two hundred and fifty thousand infants dying annually, M. Rouchard, President of the Society for the Protection of Children, says one hundred thousand might be saved by careful nursing. This knowledge caused the passage of the bill forbidding the use of solid food for infants under one year of age, unless advised by a physician.

In the effort to guard against the tuberculosis germ our own Government is taking action, and the United States Department of Agriculture, in connection with work upon the forthcoming report upon tuberculosis, has issued a circular giving simple directions for the sterilization of milk. Dr. Salmon, in his report, comments upon the danger of contagion, and says the sterilization of milk can be satisfactorily accomplished by a very simple apparatus, which he describes at length. Any suitable utensil—whether a bottle plugged with cotton or a Soxhlet stopper, a fruit jar loosely covered, or whatever vessel may be used—is to be placed inside of a larger one of metal containing water, the requirements being that the interior vessel shall be raised above the bottom of the other, and that the water shall reach nearly or quite as high as the milk. The apparatus is then heated until the water reaches 155º F., when it is removed from the heat and kept tightly covered for half an hour. The cooling after this should be rapid, and the bottles kept in a low temperature. A hole may be punched in the cover of the pail, a cork inserted, and a chemical thermometer put through the cork, so that the bulb dips into the water, or a dairy thermometer may be used by removing the lid from time to time.

An ordinary double boiler will be found to meet all the requirements, using the dairy thermometer. If preferred, the Arnold steamer or the Freeman Pasteurizer will be found convenient. Dr. Chapin says that fifteen minutes' heating will be found sufficient, as a rule.

The problem seems to be, in infant dietetics, to approximate such milk to the composition of human milk. That this can be done has been demonstrated by expert analyses, results showing that the value of this care is not overestimated by those who thoroughly comprehend its purpose. The casein of the milk, being the objectionable feature for infant diet, must be treated in such a manner as to make it digestible, supplying at the same time the constituents required as a consequence of this treatment, by the addition of sugar and fat.

Clinical results point to barley water as the best diluent, as it produces the finest curd. As a result of Dr. Chapin's study and experiments made by Dr. Arnold Eiloart, a receipt has been devised by which a mixture of barley or wheat flour is treated with maltine, the effect of malt upon milk being to favor its digestion and assimilation. Dr. Judson C. Smith, who is a district visitor for the hospital mentioned, says he has used the extract of malt to peptonize milk for about a year, both for infants and adults, with very satisfactory results. His method has the advantage of simplicity. One tablespoonful of malt is added to a pint of milk, which is heated from twenty to thirty minutes and then brought to the boiling point, which practically Pasteurizes the milk. It is to be diluted for administration according to the age of the infant. Top milk should be used with the proportion of cream sufficient to give at least four per cent after dilution; thus, twelve per cent of cream would be required to allow for two parts of water to one of milk, which is the dilution advised by Dr. L. Emmett Holt in order to reduce the proteids to their normal proportion. By careful experiment he has found that one quart of ordinary cow's milk, allowed to stand for six hours in a common fruit or milk jar, will give about five ounces of top milk of this strength.

The underlying truth of all the past and present agitation concerning the purity of the milk supply and the artificial feeding of infants is that both have been sadly neglected for many years, with the pitiful result of a vast amount of suffering and many useless deaths of children from one to five years of age, especially during the hot summer months, when it is so difficult not only to secure but also to protect the milk upon which these little ones depend. Comparatively few people stop to consider how quickly dangerous changes take place in this important article of food and how readily it becomes contaminated by absorption of various volatile substances. This is particularly true of those who have the immediate charge of milk. It is appalling to any one understanding the subject and its bearings to see the carelessness that is frequently displayed by the milkmen, maids, and nurses, all of whom play so important a part in infant dietetics. Is it any wonder that philanthropists, scientists, and physicians have combined in solicitous effort to wake up mothers to the crying need for a pure supply of milk and for its proper administration to save helpless and suffering infants? The subject is of infinite importance, and should be kept constantly to the front. The truths concerning it should be iterated and reiterated until satisfactory evidence has been given that persistence in a cause like this has been of some avail in changing existing conditions that are a reproach to our people and a menace to our health as a nation.