The modern milk problem in sanitation, economics, and agriculture

Front matter

Book H^S

JO

COPYRIGHT DEPOSm

Preface

Notwithstanding the fact that the milk problem is constantly growing more acute in many parts of the United States, no book has thus far appeared treating, in a brief space, its main aspects and stressing the practical and economic as well as the sanitary factors involved. The present volume is designed to fill this obvious need by providing a convenient survey of a perplexing subject, — not merely for health officials and milk inspectors, but also for dairymen and city milk dealers, agricultural authorities, legislators charged with the framing of milk laws, inquiring consumers and members of organizations engaged in efforts to secure better milk supplies, physicians, and all others who are interested in the understanding and solution of the milk problem.

ACKNOWLEDGMENT

The author desires to thank collectively the many correspondents who have assisted him in the collection of material, and particularly Mr. Franz Schneider, Jr., Sanitarian in the Department of Surveys and Exhibits of the Russell Sage Foundation, for his valuable criticism of the manuscript.

Vll

Contents

Chapter Page I. Why There Is a Milk Problem 1

Nature and Importance of the Problem. Milk: A Cheap and Universal Food. Milk: A Sanitary Danger. The "Invisible Cloak" of Contamination: Dirt; Bacteria. Bad Milk and Infant Mortality. Milk as a Vehicle of Disease. Summary. A Practical Definition of " Pure Milk."

II. The Case To-day 31

Chapter I

That there exists to-day a large and, in many instances, acute milk problem is being increasingly recognized. Most persons, however, appreciate the nature of the matter no further than that it involves a '^campaign for pure milk" which appears to them similar to the movements for other municipal improvements. Even to the well-informed citizen the factors and persons involved — the dairy farmer, the middleman dealer, the municipal official — appear in no distinct perspective; he is only vaguely aware of the contentions of these different parties, except as newspaper publicity may occasionally bring one or another of them to the fore; his interest usually goes no further than a jealous watchfulness of the price of the daily family supply; he entertains, therefore, no particular ideas as to improvements and readjustments and the ways of bringing them about. And this is no wonder when the officials and legislators to whom the public looks for remedies are themselves frequently puzzled for an answer to this much-debated question.

At the outset, therefore, the prime underlying considerations must be well borne in mind.

Among all food products milk gives rise to a peculiar question. One hears nothing, in any general and continuous sense, of a beef or a bread problem. Why, then, a milk problem?

That such exists is briefly explained by the conjunction of two conditions:

Milk is one of the most valuable and most largely used of all foods.

It is the food which is most apt, by far, to be dangerous to health.

This second condition depends very largely upon the fact that, in this country at least, milk has customarily been consumed raw, without the cooking, or halfcooking, which has always protected civihzed man against infection in animal food.

'^Milk," wrote Professor William T, Sedgwick, years before the problem reached its present acute form, ^'has always been one of the most trusted of human foods. Clothed in a veil of white; associated with the innocence of infancy; of high repute for easy digestibility; believed to represent in perfection a natural dietary, popular and cheap, — milk has always deservedly held a high place in public esteem. Of late years, however, while maintaining its reputation in respect to cheapness, food value, blandness and digestibility, it has, in the eyes of physicians and sanitarians at least, come to be regarded, while in the uncooked condition, with general suspicion. '^ ^ *

This well-founded suspicion has developed with the rise of three branches of sanitary science : bacteriology, which has demonstrated the readiness with which milk may be contaminated and act as a medium for the

* Note numbers refer to list of references at end of Chapter V.

growth of germ life; epidemiology, which has searched out countless instances in which it was the vehicle of disease; and vital statistics, which, in conjunction with clinical observation, has indicated the part played by bad milk in the preventable disease and mortality of infancy. The subject of safe, wholesome milk is therefore directly related to the two principal fields of modern public hygiene, — prevention of communicable disease and conservation of child life.

The milk problem, as we shall find in the course of these pages, is characterized by complication and confusion. Its complications are due partly to the peculiar sanitary and economic conditions of the milk industry, and partly to the difficulties of harmonizing the several human interests involved. Milk is produced in quantities enormous in the aggregate, comes from animals liable to disease, and is handled by persons liable to diseases transferable by milk. It is, for the most part, under the care (or lack of it) of men whose education and experience know not the delicate science of bacteriology. It reaches the city consumer by a journey which is interrupted at frequent intervals for transference or handling, and at each stage there are chances of contamination and improper treatment. Finally, the consumer has no direct knowledge of its source, its history, and its sanitary quality when it reaches him. Even in the home, its final destination, it may, and frequently does, suffer impairment. Sanitary measures must be carefully devised and correlated, and even with an adequate force of officials — frequently not available — regulations are not easy to enforce. When strictly enforced they may arouse the antagonism of farmers and dealers who assert that they are entitled to additional recompense for the sanitary precautions they are obliged to take. The price of milk, which then comes into question, is notoriously a subject of jealousy on the part of all concerned. Those who deal with the question find, therefore, that they face not only a sanitary problem, hut also an econoinic problem complicated by various human factors.

While the necessity of a safe, wholesome milk supply is the same for all communities, the difficulties of obtaining it are immensely increased in the case of the cities. The larger the community becomes, the farther it gets from the individual farmer and the nearer to the domination of the wholesale dealer and the complications incident to supplies drawn from many and distant sources. The milk problem is thus characteristically urban, but may exist in the smaller communities in greater or less degree.

Some of the reasons for the title of this volume have now been suggested. Under the conditions of modern, urbanized life a complicated milk problem has arisen, involving such questions as:

What is '^pure milk"?

Is pure milk — or clean milk — or safe milk — or wholesome milk — practically possible? — and how can it be got?

Will the public pay for it? .

The importance of the practical question is shown by the fact that it has invaded politics and has figured in a number of States and cities as a political issue.

This development brings out the fact that the several interests concerned are often in conflict with regulation or with each other. The appearance of milk in the political forum is perhaps a sign hopeful rather than otherwise, as indicating that this greatest of food problems has become the subject of a public discussion which may lead to justice to all concerned.

MILK: A CHEAP AND UNIVERSAL FOOD

Whole milk contains all the elements of nutriment and combines them in readily digestible form in the proportions of a balanced ration. Hence its use as a substitute for mother's milk for infants, as an important component in the diet of children, as a special diet for invalids, and as a considerable portion, directly or indirectly, of the diet of all adults. Its value in these respects is such that it must be considered a necessity of civilization, being in this sense a universal food.

We need not here go into the details of the chemistry and dietetics of milk. Cow's milk varies in composition, but on the average good, unadulterated milk contains about 87 per cent water and 13 per cent solids. About one-fourth of these solids consists of protein compounds, i. e., tissue-forming and waste-repairing substances. Fats, in the form of butter fats, form one-third of the total solids. Butter fat occurs in globules throughout the milk, and it is upon the size and number of them that the creaminess of the milk consists. Carbohydrates, which, like the fats, are energy-producing or fuel elements, make up somewhat more than another third of the solids, the most important of them being

Fat J

Total ^ Solids

SOLJOS NOT FAT

Water lactose, or milk sugar.

The remaining 5 per cent of the solids consists of mineral matter. Upon assumed allowable minima of these various com^ponents official requirements for '^fats'^ and ^Hotal solids'^ are based.

The greatest variations are observed in the case of the fat content, which is most commonly taken as an index of the food value of any given milk.

Consideration of the uses of milk leads to the broad conclusion that it is a great staple, the lessened use of which, either through popular fear of its possible dangers or through a much increased cost of production, would be a grave disadvantage.

Pecuniary Economy of Milk as Compared with other

Foods

More important than purely abstract laboratory figures of food values is the question as to how milk compares with other foods in relative economy. Facts

Fig. 1. Composition of Cow's Milk, Showing Variations

(Report on milk investigation, Boston Chamber of Commerce, 1915.)

WHY THERE 7^ A MILK PROBLEM 7

in this connection have been worked out and the following conclusions drawn from them by the United States Department of Agriculture: —

Bearing these things in mind, we see that milk at all but the highest prices assumed is a cheaper source of protein than any of the animal foods except cheese, very cheap meat, and salt fish. At usual prices skim milk furnishes protein more cheaply than any common animal food except salt fish. The protein of vegetable foods is less expensive, but, on the other hand, as prepared for the table is less thoroughly digested. Moreover, it is accompanied by such large amounts of carbohydrates that to secure much vegetable protein in the diet usually means an excess of the carbohydrates. Under ordinary market conditions milk, and even skim milk, is a cheaper source of body fuel than any of the usual animal foods except cheese and salt pork, but is a dearer one than the usual vegetable foods. Here again, however, the milk furnishes the ingredients in a form more readily and thoroughly digested than the vegetable foods as ordinarily served. Milk, then, is fully as economical a source of nutrients as most animal foods, but is dearer than most vegetable foods. It has the decided advantage of having no waste, requiring no time for preparation, and being more digestible than the vegetable foods. . . . Both whole and skim milk at moderate prices are therefore to be ranked among the most economical of foods not only when taken as beverages, but also when used in preparing other foods. ^

Attention must be drawn, however, to the fact that with each cent's increase in price milk may lose, or seem to lose, its pecuniary advantage over some other article or articles (unless they also have risen), which then tend so far as possible to take its place. Sometimes the rival is a milk product, such as skim milk

Cost of Living

In the JDast year 5 leading food jiroducts have risen in cost at an average of

64%

Potatoes advanced. .... .114%

Beans advanced ..... 67%'

MILK

Codfish advanced 50%

Eggs advanced 58%>

Butter advanced 307o

\ has only I advanced

) 11%

The answer is use more 1

's

Milk

A Complete Food. |

Clean — Pure —

Safe

^Reduce the Cost of Living:

or evaporated milk.

Substances of less dietetic value are likely to be substituted in cookery, and its use as a table article may be stinted.

At the same time a certain increase in price may be inevitable, especially when prices are going up all around, as they are at present writing. This question will be further considered in later chapters.

Science and Experience

The scientific deductions from the figures for food values

Fig. 2. Commercial Appeal on Eco- and prices are COn-

NOMic Grounds firmed in the ordi-

This, if accurate, is a legitimate and nary widespread USe useful kind of advertising based on the r -jy,;]]^ About oneimportance of milk as a food. • i 7 i

Sixth 01 the total lood of the average American family is furnished by milk and its products.^ The average per capita use of milk (as such) in the United States is estimated by the Deequals in food value either

% LB.

STEAK.

1 QUARr

Milk

A Safe Food A Pure Food A Cheap Food

Drink tl Youself — Feed it to the Children partment of Agriculture at six-tenths of a pint daily, or a quart and one-half for each family of five. (See statistics, Appendix A.) This means that an enormous capital and an extensively ramifying system of equipment and operation are necessary to furnish the total supply. Besides the above amount of milk consumed as such (either drunk or used in cookery) must also be considered that large amount (about three times as much) which is made into butter, cheese, condensed milk, etc. Many of the considerations applying to milk as such apply also to these derived products.

The following reasons for the use of milk, adapted from a leaflet issued by the Massachusetts Dairy Bureau, summarize the matter in a general way: —

It is cheap.

It is nutritious.

It is easily digestible.

It is the best food for babies (mother's milk excepted).

It should enter liberally into the diet of children.

Many adults would be benefited by the use of more milk and less meat.

More milk used in cooking would add the cheapest nutrition of its kind.

Proper nutrition conduces to efficiency and long life, — ^in other words, to good health.

MILK: A SANITARY DANGER

The widespread use of milk has, however, another and an unfavorable aspect. While this universal food affords vast benefit, it is also, to a certain degree, the agent of disease. Of all foods it has in this respect the greatest potentiality.

THE ''INVISIBLE CLOAK'' OF CONTAMINATION

Dirt and Milk

Though it is not fanciful to speak of milk as a symbol of beneficence, it must not be forgotten that its veil of innocence may hide possible dangers. Most white things readily show soiling; milk, as someone has remarked, stands almost alone in absorbing without obvious sign all but the grossest contamination. The amount of dirt — to use the mildest term — which can be added to a bottle of milk without visibly affecting its virgin whiteness is almost unbelievable. Of each dose of such contamination some is dissolved, some halffloats in suspension among multitudinous obscuring fat-globules, and some settles to the bottom, where least likely to be observed: only a fraction remains on the top or otherwise visible. The ordinary milk bottle tells no tales.

That the opportunities for such contamination under present-day conditions in the dairy industry are many is well recognized by all who are familiar with milk sanitation. In Fig. 3 is shown the long and broken route which may be required for country milk to reach the city consumer. At each stage of the journey is the possibility of contamination or deterioration of the product. Dirt and manure particles from the flanks and udder of the cow, hair and dandruff from her hide, the manurial dust of the stable, the questionable hands of the milker, the unclean milk pail contaminated with the decomposed dregs of the previous milking, or rinsed with polluted water, the unsavory straining cloth, imperfectly cleansed pans, further handling in process of bottling, bottles and other utensils of doubtful cleanliness, — these, together with lack of proper cooling and frequently many hours of transportation, are some of the details which demand the attention of the milk sanitarian. If, as Sedgwick suggests, drinking water were derived in the same manner and passed through the same processes as milk — drawn from the body of an animal standing in a stable, by the hands of workmen of questionable cleanness, and subsequently handled as milk frequently is — few would care to drink it. ''It is clear," he adds, ''that milk requires and deserves even more careful treatment than water, for it is more valuable, more trusted and more readily falsified or decomposed," and also, as we shall note presently — the most important consideration of all — • it is a readier agent of infection.

The dairy cow herself [as Dr. Charles E. North says] contributes a peculiar form of contamination. The udder is constructed like a sponge. There is a constant shedding of waste tissue from the lining of the udder. This udder waste often includes the products of udder inflammation. Such inflammations are so common they are present in some form in practically every dairy herd. Even when there is no external evidence there is often internal inflammation discharging its products with the miik.^

Now what is the sanitary significance of all this?

In the first place, no one wishes to eat or drink dirt, even that of the proverbial "peck of dirt." The various kinds of ordinary dirt may or may not be directly injurious to health. At the present time the tendency in sanitary science is to distinguish between the varieties that are, or may be, accompanied by infection, and those that ordinarily are not. Nevertheless dirt of any kind is in itself undesirable.

The instinct of decency is not without meaning. It is a protective instinct, and it is supported by the general fact that dirt is suspicious. There are places where dirt is naturally to be found, but when it is ^'matter out of place" it is a sign that something is wrong. We are not surprised to see muck in the gutter; we do not shudder at manure in a manure bin; but when we perceive foreign matter in a milk bottle we are rightly disquieted. The soiled hands of the daylaborer are the result of honest toil; the unwashed but milk-wet hands of the dairy worker excite revulsion.

This instinct has applications which are without sanitary significance. But in the matter of food it is truly protective. We have spoken above of ''dirt" in a general sense. But ordinary dirt shades into filth, such as the manure of the cow stable : from contamination it is but a step to pollution, and pollution may mean infection.

It is possible to make theoretical distinctions between various forms of contamination, and it is possible to devise practical measures which lay stress upon the more dangerous. But both decency and experience aver that we should avoid all forms of contamination. Decency is, in short, a rough (though, as we shall see later, an incomplete) insurance of safety. But even though we are able to secure complete safety by other means, we should still desire the greatest degree of decency that we can obtain. Decency, as North points out, '^distinguishes humans from animals. Decency adds pleasure and appetite to food. Cleanliness contributes most to decency. Milk may be safe because it is boiled but may be indecent because it is filthy." *

Bacteria and Milk

Dirt (using the word to include all forms of contaminating matter) in considerable quantities may be, in itself, more or less deleterious to health. But it is the associated bacteria which constitute the real objection or danger. Various forms of contamination are accompanied by various forms of bacteria, which may be more or less deleterious or dangerous. In the case of milk, they exert their effect upon the consumer either through their action upon the milk or through their infectious character.

1. Fermentation, Decomposition. — Many of these organisms thrive in milk, and in so doing alter its composition and excrete their waste products. The ordinary souring of milk is the usual form of fermentation. It may be argued that such a fermentation as this is not necessarily harmful, soured and fermented products being used as foods or even as remedies. The answer to this is that if such products are desired they should be obtained by known and controlled processes. The fermentation or decomposition of milk by miscellaneous, uncontrolled organisms is objectionable, and when the milk is to be used as food for infants and delicate persons it is dangerous. In every such process are produced greater or less amounts of substances

* Dr. North rates milks according to safety, decency, and price. (See p. 155.)

which tend to make the milk an unfit or deleterious food.

The extent of such bacterial changes in milk from the time that it is drawn from the cow to the time it reaches the consumer depends upon three things: (1) the kinds and amounts of contamination, (2) the temperature of the milk, and (3) the time in transit. The contamination can be reduced to a minimum, the temperature can be kept low, and, if these two conditions are right, a reasonable time in transit can be allowed. Under practical circumstances some latitude must be permitted in the endeavor to approach the ideal, — namely, that milk should be clean, fresh, and cold.

2. Infection. — A different case is that of infection. The germs of various diseases may gain access to milk, in which they live and frequently multiply. This is not merely a matter of contamination but of the transference of the secretions of already infected animals or persons. Relatively small contamination may in this case result in virulent and far-spreading specific infection. The unwashed hands of milker or milk-handler in an unrecognized stage of disease, infected manure from tuberculous cows, utensils which have been infected by washing in polluted water or in some other way: such are typical modes of infection. Polluted milk may at any time prove to be infected milk; it is, so to speak, a lottery of infection. Infection is possible even with a high degree of visible cleanliness, for infected individuals may be unrecognized and the transference of infectious matter undetected. Milk-borne disease, like other infection, ^^walketh in darkness."

Special reference must be made to carriers of communicable disease. Bacteriology has demonstrated the existence of many persons who harbor and emit germs of disease without themselves showing any symptoms. Such carriers have been demonstrated with respect to typhoid fever, diphtheria, septic sore throat, and a number of other diseases. While the percentage of carriers in the population is small, the evidence is that there are, in the aggregate, many such persons and many others who manifest only atypical, unrecognized symptoms of the disease of which they bear the infection. Such facts must greatly increase the sense of insecurity with respect to the sources of disease. It scarcely need be said that a proportionate number of carriers exists in the host of persons engaged in the handling of milk.*

There are two possible measures against infection in milk, to keep it out, or to destroy it if there. The difficulty or impossibility of keeping it out has just been indicated. There is immense importance, then, in being able to destroy it without material alteration of the milk. This, fortunately, can be accomplished by a form of insurance which will be discussed in another chapter — namely, pasteurization.

BAD MILK AND INFANT MORTALITY

Approximately one-fifth of the deaths occurring in the Registration Area of the United States are of in-

* It was estimated, for example, by Health Commissioner Lederle of New York City, in 1912, that about 127,000 persons were engaged in handling the milk supply of that city, and that there might be perhaps a hundred typhoid bacillus carriers alone in this army of persons. Rochester, N. Y,, in order to guard against infection, by typhoid carriers, of milk to be sold raw, has adopted the requirement of a blood test for dairymen and their workers.

fants under two years of age. The largest single cause of mortality among these infants is diarrhea and enteritis, to which one-quarter of the deaths is due. The latest available Census figures (1914) ascribe to this title in the Registration Area 43,532 deaths (under 2 years), which argues a total in the whole United States of some 65,000. It is in this figure that we must look for the effects of bad milk so far as they are reflected in mortality. Unfortunately it is impossible to determine just what proportion of these deaths may be put down to bad milk as compared with such factors as improper methods of feeding and improper hygiene in other respects. We may, however, turn to some intensive evidence.

Effects of Feeding Different Milks

The normal and the best food, by far, for the baby is mother's milk. Such are the difficulties of artificial feeding under ordinary conditions that it is estimated that bottle-fed babies have only one-tenth the chance to live that breast-fed babies have.^ *

There are, however, cases in which artificial feeding is deemed necessary; besides which, cow's milk must always play a major part in the weaning of infants and the feeding of young children. Milk for infants should, if possible, be of the highest original sanitary quality. If the raw product is of a lower quality, it should be pasteurized. The evidence is that it should be pasteurized no matter what its quality.

* From a careful analysis of a three months' study, the New York City Health Department determined that almost two and a half (2.4) times as many infants were attacked by diarrhea among artificially fed as among breast-fed infants. (Weekly Bulletin, June 19, 1915.)

Fig. 3. The Long vs. The Short Haul This cartoon, from the Chicago Health Department, brings out the contrast between natural and artificial milk supply, and suggests some of the difficulties inherent in the latter.

An important series of observations was made some years ago by Park and Holt,^ illustrating the effects of feeding infants with several different grades of milk. The deleterious results of bad milk during the summer months are shown by the following table, summarizing the observations on six groups of babies. (The percentages have been computed by the present writer from the original table.) *

No. of Did Did Did

infants well fairly badly Died

Condensed milk 70 31 29 20 20

Good bottled mUk 98 38 23 30 9

Milk from Central Distributing

Best bottled milk 12 75 25 — —

Breast feeding 31 55 22 . 5 22 . 5 —

All cases excluding duplications 421 44% 25% 21% 10%

In the winter observations no appreciable difference among the different modes of feeding was noted; what might be considered good results were shown in 93 per cent of the cases as contrasted with the 69 per cent indicated by the above table.

* This study is open to criticism in certain respects. The small number of cases in the fifth group cannot be taken as a suflBcient basis for rating best bottled milk above breast feeding. The number in the breast-fed group is also rather smaU for the calculation of significant percentages. Nor is distinction between raw and heated milk made in this table. The element of care of the infant (as weU as other factors) in the different groups is discussed by the authors as a separate, important consideration taken into account in their conclusions, certain of which are quoted below. There is no doubt but that, were all other things equal, breast feeding would show decidedly the highest rating. The Park and Holt study, while not entirely satisfactory, is here quoted on account of its general illustrative character.

Special observations were made on the effect of pasteurized as opposed to raw milk, as summarized in the following table: —

Kind of milk S* S-^ ^- o.S os 5 m gj P a; >>

^ 3^3 ^"BcJcSSP cS.3 OS'S 43

Pasteurized milk, 1000 to 50,000

bacteria per c.c .41 31 10 3 4 oz. 3.9 1

The results set forth in the first of the above tables cannot, indeed, be taken as indicating exactly the effects of the different kinds of milk, for the elements of care of the infant in the different groups was also of influence. The following extracts from the conclusions of the authors, who endeavored to sum up all factors, must, however, be taken as indicative: — ■

During hot weather when the resistance of the children was lowered, the kind of milk taken influenced both the amount of illness and the mortality; those who took condensed milk and cheap store milk did the worst, and those who received breast milk, pure bottled milk, and modified milk did the best. The effect of bacterial contamination was very marked when the milk was taken without previous heating; but, unless the contamination was very excessive, only slight when heating was employed shortly before feeding.

* Thirteen of the 51 infants on raw milk were transferred before the end of the trial to pasteurized milk because of serious illness. If these infants had been left on raw milk, it is believed by the writers that the comparative results would have been even more unfavorable to raw milk.

When milk of average quality was fed sterilized * and raw, those infants who received milk previously heated did, on the average, much better in warm weather than those who received it raw. The difference was so quickly manifest and so marked that there could be no mistaking the meaning of the results. The bacterial content of the milk used in the test was somewhat less than in the average milk of the city.