Foods, their selection and preparation

Methods of Control. So many epidemics have been directly traceable to the milk supply that public health and dairy officials have made every effort to safeguard the sanitary character of this important food. Herds are inspected regularly to detect any diseased animals. In addition, every precaution must be taken to prevent contamination during milking. This requires sanitary stables, cleaned before milking, and clean milkers with sanitary clothing and sanitary milk pails. The milk must be cooled as soon as it has been drawn and stored in suitable containers to prevent subsequent contamination. It must be held at a low temperature to retard the development of any bacteria present. By such precautions, "certified raw milk” is produced with a minimum bacterial count at a cost consider- ably above that of milk produced with reasonably good care. In view of the fact that individual cows from herds producing certified milk may be found infected during required inspections, public-health officials recommend that reasonable precautions be required in the col¬ lection of market milk, and that all supplies be pasteurized before distribution. The wis¬ dom of this recommendation is borne out by the frequent cases of undulant fever in areas where pasteurization is not required. Heating the milk lowers the bacterial count. Boiling the milk will kill any disease-producing forms of bacteria and decrease markedly the number of the other forms present in milk. Boiling is definite and easily controlled but brings about a decided flavor change in milk which is objectionable to many persons. For this reason pasteurization, in which the heating is done at a lower temperature, is generally used. Heating milk to controlled temperatures below boiling is called pasteurization. There are two methods: in one, the milk is held at a temperature no lower than 143° F. for not less than 30 minutes; in. the other, known as the flash method, the milk is brought to 160° F. and held there for not less than 15 seconds. In both cases the milk is cooled quickly to 50° F. or below. Pasteurization, like boiling, destroys all the disease-producing bacteria and greatly reduces the counts of the other types without having the adverse effect on flavor that boiling has. Sanitary Grades. As a part of the effort to improve the sanitary quality of milk by the regulation of conditions of production and methods of handling, grades and stand¬ ards based on sanitary care have been estab¬ lished in most communities where milk flows into commercial channels. These regulations are not uniform from community to com¬ munity. To encourage uniformity in stand¬ ards, a model milk ordinance has been drawn up and jointly approved by the U. S. Public Health Service and the Bureau of Dairy Industry of the U. S. Department of Agri¬ culture.1 These requirements for producing milk of the various sanitary designations and the standards for each are listed below. The sanitary grade of bottled milk is indicated on the bottle cap, and when the milk is dis¬ tributed in cartons this information is placed on the carton.