FoodNet

Foods, their selection and preparation

1935

Page 110

Presented as published in 1935. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
In infant feeding there is usually no dif¬ ficulty in the digestion of fat, provided the milk is so modified that the amount of fat present is not greater than in average mother’s milk. Holstein milk is recom¬ mended for infant feeding in preference to Jersey milk, because it has lower fat content, and because the smaller fat globules are more easily digested by infants. SANITARY CARE OF MILK Milk furnishes an excellent medium for the growth of bacteria, and the method by which milk is collected offers many oppor¬ tunities for contamination. The air of the stable, the cow herself, the pails, the hands of the milker all may carry bacteria. Bacteria in Milk. Many different types of bacteria are found in milk. Some are harm¬ less or useful under controlled conditions; others are harmful under all conditions. Lactic-acid-forming bacteria are the pre¬ dominating type. When raw milk is allowed to stand, these bacteria change some of the lactose to lactic acid and the milk curdles, since the acid precipitates the casein. The time required for this change depends upon the number of bacteria present and the temperature at which the milk is held. About one-fourth of the lactose in the milk is used in the formation of this acid. The presence of lactic acid holds in check the development of certain other types of bacteria. In areas where refrigeration is not available, use is made of natural souring as a means of extending the time during which fluid milk is usable. Koumiss and kephur, forms of fermented milk used in eastern Asia and North Africa, probably had their origin as a means of preservation. Putrefactive bacteria also are found in nearly all samples of milk. These organisms, if allowed to persist, decompose the proteins in milk and produce disagreeable odors and flavors. The development of these bacteria is retarded by the acid formed when lactic- acid bacteria are present. Disease-producing bacteria may be pres¬ ent. Diseased cows produce infected milk. Tuberculosis and undulant fever are trans¬ mitted in the milk from infected animals. Other sources of disease-producing bacteria are the hands of the milker, and utensils or containers which have been washed with water from a contaminated source. A single organism entering the milk may multiply sufficiently before the milk is used as food to cause infection of the whole supply. The diseases most frequently transmitted by milk are tuberculosis, undulant fever, typhoid fever, and occasionally diphtheria and scarlet fever. All disease-producing bacteria are destroyed by the pasteurization of the milk. Tuberculosis, and especially undulant fever, are so likely to appear, even in the best herds, that health authorities recommend the pasteurization of all milk to be used for food in any form.