282 Microbes and You 



disease. Before the advent of antibiotics, treatment for brucel- 

 losis was decidedly limited, but good results have been reported 

 with the administration of selected antibiotics. 



While notable progress has been made in the control and in 

 the eradication of brucellosis in animals through vaccination and 

 slaughtering programs, the fact remains that the danger of human 

 beings contracting undulant fever, tuberculosis, and other diseases 

 through the agency of raw milk, is a constant threat. Proper 

 pasteurization, however, can destroy these pathogens and make 

 milk safe for human consumption. This heat treatment originated 

 with Louis Pasteur, after whom the process is named, when he 

 employed the technic with French wines in an efiFort to prevent 

 spoilage. Present-day pasteurization, as applied to the dairy in- 

 dustry, is aimed primarily at making the food safe for human 

 consumption, with improving the keeping quality a secondary 

 consideration. 



Two general heating technics are employed in pasteurization of 

 milk today. The first is the holding method, in which the milk 

 is heated to between 142° and 145° F. (61.7° and 62.8° C), held 

 at that temperature for at least thirty minutes, followed by rapid 

 cooling to a temperature below 50° F. (10° C). A more recent 

 process is the short time high temperature pasteurization in 

 which the milk is heated to a temperature of 160° F. (71.1° C.) for 

 a period of from fifteen to seventeen seconds. Both of these 

 methods are based upon the time and temperature relationship 

 necessary to insure the killing of the tuberculosis organism, which 

 is the most resistant pathogen one might expect to encounter in 

 milk. 



Pasteurization ranks with chlorination of water supplies as far 

 as reduction of the spread of disease is concerned, but educating 

 the public to accept pasteurization has not been, and still is not, 

 a simple matter. A small but vociferous minority objects to man 

 tampering with nature's food. But if we consider that man has 

 raised and developed animals for milk production beyond the 

 normal requirements of the young calves for whom the milk was 

 intended, considerations other than those of nature's intent must 



