THE PASTEURIZATION OF MILK 



three minutes, at which time the temperature was 

 found to be 14 2 y^ F. This sample, upon being 

 set, showed 12 per cent, of cream in the cream 

 gauge and contained 3.8 per cent, of butter fat. 

 The fourth sample was taken from the same tank 

 of milk, but when the tank was nearly empty. 

 The milk had been standing in this tank for one 

 hour and twenty minutes. It had been, however, 

 cooled to a temperature of 60 F. by means of 

 cold water pumped through the revolving coil. 

 A sample of this milk, upon setting, showed 15 

 per cent, of cream in the cream gauge and con- 

 tained 3.8 per cent, of butter fat. 



It was thought possible that the speed of cool- 

 ing of milk might have an effect upon the cream 

 line. Therefore two samples of milk were taken, 

 one of which had a temperature of 135 F. This 

 sample was allowed to stand un-iced until cooled 

 by air contact to a temperature of about 40 F. 

 The second sample of milk was taken from the 

 same batch of heated milk, but this sample was 

 taken after the milk had been quickly cooled in 

 the cooling apparatus to a temperature of 32 F. 

 After setting, these two samples showed no appre- 

 ciable difference in the cream content. This indi- 

 216 



