192 



MODERN BUTTER MAKING. 



244. Variation in the per cent of fat in cow's mUk 

 during the entire period of lactation. 



TABLE XVIII. * 



^'uria^i(/n in the I'cr Cent of Fat in Cows' ilUk DurUxj the 

 Entire Period of Lactation. 



245. A standard temperature for pasteurization. 



The main question in pasteurization is: What is 

 the best temperature at which to pasteurize milk or 

 cream? Another important matter in connection 

 with this subject is the length of time the milk or 

 cream should be exposed to a given temperature in 

 order not to injure its quality, and yet destroy the 

 tubercle bacilli. When the tubercle bacilli are de- 

 stroyed we feel sure that all other harmful germs 

 are also destroyed. This can be accomplished in 

 either of two ways: First, by short exposure to a 

 temperature of 180° P. to 190° P. Second, by hold- 

 ing the milk or cream at a temperature of 140° P. to 

 160° P. for some length of time. I believe we are 

 safe in using the following temperature and time : 



* Table XVIII was translated by Leonard Pearson, (C, O. Jensen Milk 

 Hygiene.) 



