CARE OF MILK AND CREAM 



49 



the growth of bacteria. They develop more slowly, as 

 has been stated, as the temperature of the milk decreases. 

 In each experiment recorded in Table XI all the milk in 

 can 4, which was stirred continuously, was cooled very 

 rapidly, and the largest drops in temperature occurred 

 near the beginning of the period ; while in can 3, which was 

 not stirred at all, the temperature of the milk ranged as 

 high as 72° F. at the end of the hour. The point is 

 further illustrated in Table XIII, according to which, at 

 the end of twenty minutes, the difference in temperature 

 due to stirring the milk varied from 3° to 17° F., and the 

 average difference in temperature between the milk stirred 

 and not stirred was 9.7° F. This average drop in tem- 

 perature, 9.7° F., in twenty minutes due to stirring means 

 an effective check on the development of bacteria. For 

 all practical purposes it seems that stirring the contents 

 of the can once every ten minutes for an hour is sufficient. 



'Table XII — Comparison of Temperature of Milk in 

 Center op Can at End of Cooling Period Before 

 Stirring and After Stirring 



