BACTERIA IN MILK 195 



consumer should strive to keep milk at the lowest 

 temperature practicable. Cities are now controlling 

 their milk supply by various regulations as to the 

 dairy management and shipping systems. The most 

 important domestic means of having clean milk consists 

 in receiving it in perfectly clean bottles and keeping 

 it on ice. 



Pasteurization. On account of the lack of perfect 

 municipal control of the milk supply, it is necessary 

 to resort to Pasteurization. This consists in heating 

 the milk to 60 or 70 C., 140 to 158 F., for ten to 

 twenty minutes, and then cooling rapidly. Various 

 methods are in use commercially, but this can be done 

 very easily in the home, using a double boiler and a 

 thermometer. Pasteurization kills all but the spores 

 of bacteria, which are of little danger if the milk be 

 kept on the ice or used shortly. Some persons object 

 to the use of this heating because the food value 

 of the milk is reduced by making certain chemical 

 constituents harder to digest. The casein curds of milk 

 become tougher after boiling. However, some German 

 pediatrists are now using boiled cows' milk for certain 

 intestinal disorders of children. If properly carried 

 out, Pasteurization does more good than harm, and 

 has proven its value by the reduction of the death 

 rate from infantile diarrhea in summer time. The 

 greatest objection anyone can raise to Pasteuriza- 

 tion is that it gives a false sense of security. It 

 cannot be too strongly emphasized that any natural 

 antibacterial power possessed by the raw milk is 

 destroyed by Pasteurization and that rigid precautions 

 should be observed that the heated milk is not allowed 



