FROM THE PRACTICAL VIEWPOINT 



mixing of the milk due to various causes, which 

 will be discussed later. 



Schores and Rosenau found that pathogenic bac- ^ 

 teria were not all killed when the factors of tem- 

 perature and time were attempted which had been 

 found effective in laboratory tests. They there- 

 fore recommended, in order to provide a sufficient 

 margin of safety, that all milk he heated to a 

 temperature of at least 145, and there held for 

 no less than twenty-five minutes. This opinion is 

 shared by most persons who have made a study 

 of the subject. The New York City Department 

 of Health, in 1Q14, so modified its regulations as 

 to require that pasteurized milk be heated to from 

 142 to 145 F. for at least thirty minutes. 



While the destruction of all pathogenic bac- 

 teria in milk is the primary concern of health au- 

 thorities, there are certain other considerations 

 which have weight with them, and among these 

 is the effect which heat has upon the chemical 

 characteristics of the milk. It has been found that 

 when milk is heated to say 160 F. or over, some 

 of the constituent parts of the milk are changed in 

 such a way as to make it somewhat inferior as a 

 food, especially for infants. These changes have 



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