THE PASTEURIZATION OF MILK 



rise of temperture at the outlet will be compara- 

 tively gradual in its rise and will not reach its 

 highest point for a considerable time. It will also 

 be found that the proportional rise in temperature 

 at the outlet will not be as great as at the inlet 

 of the holder. When the temperature of the inlet 

 is dropped instead of being raised, it will be found 

 that the change of temperature at the outlet occurs 

 in a much shorter space of time. 



In choosing between the color test and the tem- 

 perature test, it can safely be said that for the 

 Park holder the color test is the more accurate. 

 When the tubular holder is used, which will be de- 

 scribed later, it is probable that the two tests are 

 nearly equal in accuracy. 



When two or more tanks are employed in series, 

 it is desirable that the piping be so arranged that 

 the lowest tank can be filled with milk first when 

 the process of pasteurizing is commenced for the 

 day, and then when the lower tank is full the up- 

 per tanks should be filled and the process contin- 

 ued in this manner. The milk will then flow 

 through all the tanks in succession from the high- 

 est to the lowest. The reason for filling the lower 

 tank first is as follows: When each tank is first 

 118 



