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TOLMAN. The Chemist in Food Control as Relating to the Enforcement

of the Law. Journal of Industrial and Engineering Chemistry, Vol. 8, pages 926–928 (1916).

Work of the Chemist in the Food Industries. Chemical Age (New York), Vol. 27, pages 241-245 (1919). UNITED STATES DEPARTMENT OF AGRICULTURE. Food Inspection Decisions;

Notices of Judgment; Service and Regulatory Announcements. WESTERVELT. Pure Food and Drug Laws, Federal and State. WILEY. Foods and Their Adulterations. Wisconsin Dairy and Food Laws and Decisions of Courts. Issued by the

Dairy and Food Commissioner, Madison, Wisconsin, August, 1923.

CHAPTER III

MILK

MILK is the one article of diet whose sole function in nature is to serve as food. It is also the one food for which there seems to be no satisfactory substitute. Each species of mammal produces a milk especially adapted to the nutritive requirements of its own young, but it was early learned that the milk of other species is also an excellent food for man, and several different species are used for dairy purposes in various parts of the world. In general only cows' milk is of much commercial importance, and the statements which follow refer always to cows' milk unless otherwise explained.

It is estimated by the United States Department of Agriculture (Yearbook for 1922, page 291) that 98,862,276,000 pounds of milk were produced in this country in 1921 and that 45.66 per cent of this was used for household purposes, chiefly for direct consumption as milk or cream; while 47.03 per cent was used in the manufacture of butter, cheese, condensed and evaporated milk, and ice cream; and 7.31 per cent was either fed to calves, lost or wasted, or devoted to unspecified uses.

The present chapter will be devoted to milk as such, its products being treated in subsequent chapters.

The Department of Agriculture estimates the farm value of dairy products produced in the United States in 1921 at $2,410,000,000. The proportionate valuation of the milk consumed as such would be about $1,100,000,000, so that the milk industry is one of the few whose annual product reaches a value of a billion dollars a year.

The real importance of the milk industry to the community is much greater than can be expressed in terms of money value, because of the supreme importance to public health of an adequate milk supply. It has long been recognized that milk occupies a unique place in the dietaries of most children and many invalids, while at the same time the fluidity and opacity of milk offer unusual opportunity for adulteration unless the supply is properly safeguarded. It is largely for these reasons that in many states laws designed to protect the milk supply antedated general food legislation. It is perhaps less commonly realized that not only the quality but also the quantity of the milk supply is an extremely important factor in public health, partly because the reduction of infant mortality depends upon the abundance as well as the excellence of the milk available for infant feeding, and also because a liberal consumption of milk, even by healthy adults, tends to a higher degree of health and vigor and greater ability to resist disease. Thus not only is a good milk supply directly essential to public health, but confidence in the milk supply leads to better health by inducing a more liberal use of milk.

In the present chapter the production and handling of milk will first be outlined, then its composition and standards of purity will be discussed, and finally its nutritive value, pecuniary economy, and place in the diet will be considered.

Production and Handling of Milk The cows. A milch cow should produce an average of over two gallons of milk per day for eight months of each year with a smaller yield for about two months longer, making a total of at least 600 gallons or 5000 pounds of milk for the year.

Many high-grade cows produce three or four times this quantity, and more than one cow has produced over 30,000 pounds of milk in a year; but the average for all the milch cows in the United States at the present time is only about 4000 pounds per year (United States Department of Agriculture, Yearbook for 1922). In Great Britain and in Denmark the average production of milk per cow is half as large again as in the United States, and in the Netherlands it is about twice as large. The production of milk in the United States can be greatly increased without increasing the number of dairy cattle.

Increased yield of milk per cow may be obtained both by breeding and selection and by superior care and feeding. According to official estimates the annual yield of milk per cow in Denmark, where the dairy industry is well developed and highly systematized, was increased from 4480 pounds in 1898 to 4884 pounds in 1901, 5335 pounds in 1904, and 5874 pounds in 1908.

Since the fat of the milk is commercially its most valuable constituent, the productiveness of a milch cow is perhaps as often expressed in terms of fat or butter yield as in terms of weight of milk. Those races of cattle which have been developed with special reference to milk or butter production are called the dairy breeds, and those which are chiefly useful for meat production are known as beef breeds. An investigation in Wisconsin showed a higher food consumption on the part of the more productive dairy cows, but the value of the milk produced increased much more rapidly than the cost of feed, so that the more productive cows proved very much more profitable.

The United States Department of Agriculture reports that cows averaging a production of 400 pounds of butter fat per year showed over twice the profit, after deducting cost of feed, as was shown by cows producing only half as much milk and butter; and states that “all studies that have been made of dairy cattle indicate that where other things are equal the economical producers are always comparatively high producers."

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1 Studies in Dairy Production, based on the Records Secured in the Wisconsin Dairy Cow Competition, 1909-1911. Wisconsin Agricultural Experiment Station, Research Bulletin 26 (October, 1912).

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The same authority summarizes as follows the characteristics of the dairy cow as a producer of human food :

“The dairy cow economically converts pasture grasses, dry and succulent roughage, and the by-products of many different kinds of grain into milk, that most excellent food for man. The dairy cow does well when a large proportion of her ration comes from these products. Only through the agency of animals can roughage be converted into human food. The great purpose of agricultural production is an adequate food supply. For feed eaten the dairy cow returns more than three times as much digestible protein as the steer and more than twice as much energy in edible products.

Good health of the cow is of great importance and should be insured by systematic veterinary inspection. Annual or semiannual testing with tuberculin, with elimination or segregation of all cows which show any indication of tuberculosis, serves to protect the herd from the ravages of the disease as well as to remove one source of possible danger to the consumer of the milk. Dairy farmers can now arrange with the United States Department of Agriculture to have their herds tested and" accredited ” by the Federal authorities.

It is important also that the cows be kept clean, and especially that the udder and adjacent parts of the body be thoroughly clean at the time of milking.

The stable should be free from contaminating surroundings, well drained, well lighted and ventilated, as clean and comfortable as possible. It should be used for no other purpose than the keeping of cows, and if there is a loft overhead, the ceiling should be tight to prevent the falling of dust. The feeding of the cows should be so planned that there will be no dust from hay or other feed in the air of the stable at milking time. The floor should be tight, constructed preferably of cement, and properly guttered; walls and ceiling should be whitewashed twice a year.

1 Yearbook of the United States Department of Agriculture, for 1922, pages 281-282.

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