THE PASTEURIZATION OF MILK 



been somewhat extensively studied by the United 

 States Government experts, and it has been found 

 that as the temperature rises above 160 F., these 

 changes take place to an increasing extent, and at 

 the boiling point quite extensive changes are ob- 

 served. At this temperature, the milk sugar be- 

 comes scorched, the casein and the albumin are 

 somewhat hardened, the calcium, magnesium and 

 phosphoric salts are partially precipitated, all of 

 which renders the milk less easily digested. It 

 therefore follows that the lowest temperature 

 which is consistent with the destruction of the 

 pathogenic bacteria is the most desirable. 



It is also true that milk which contains an ex- 

 cessive number of bacteria carries with it, as a re- 

 sult of their growth, certain by-products, such as 

 acids and other undesirable substances, and may 

 also contain dangerous poisons. Rosenau states 

 that the known poisons which are produced by the 

 growth of bacteria in milk are very few, but that 

 such poisons may possibly exist and produce harm- 

 ful effects upon the persons using the milk. These 

 by-products of bacterial growth in milk are not 

 entirely destroyed by heating, even when the boil- 

 ing temperature is attained. For this reason it is 

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