Preservation of Milk. 



131 



The accompanying table gives results that were ob- 

 tained in the testing of one of the continuous types of 

 machines. The machine in question required about three 

 hundred pounds of milk to fill it and was supposed to 

 handle 1,000 pounds per hour. Thus theoretically it 

 should require twenty minutes for any portion of the 

 milk to pass through the machine. As will be seen from 



the data, some of the milk passed through within seven 

 minutes after the water was shut off and the milk turned 

 on. The figures also show that not all of the water had 

 been replaced by the milk in even 45 minutes. In. actual 

 practice like results will be obtained, and a portion of 

 the milk will be heated to the temperature employed but 

 a short time. In this, the vegetating bacteria will not be 

 wholly destroyed. 



Pasteurization of small quantities of milk. It is 

 often desirable to treat a small quantity of milk for 

 home use, in which case the commercial types of pas- 

 teurizers are out of the question. This treatment can be 

 done in a number of ways, consideration always being 

 paid to the manner of heating which should be done un- 

 der such conditions, as have been shown to be necessary 

 for efficient pasteurization. Milk may be heated in tall, 



