28 



A Handbook for Dairymen 



Pasteurization. 



There are two general methods of pasteurization, 

 — the Holding and the Flash methods. A more 

 recent development is the pasteurization of the milk 

 after it has been bottled. However, this method is 

 not used so generally as the first two. 



The Flash Method: The milk or cream is heated 

 to a temperature of 170° to 180° F. for an instant, 

 and then cooled. Unless great care is exercised the 

 high temperature is likely to impart a cooked flavor 

 to the product. 



The Holding Method: The milk is heated to a 

 temperature of 142° to 145° F. and held at this 

 temperature for thirty minutes. 



Bottle Method: 

 After the milk is 

 packaged, it is placed in a large 

 container and heated by live 

 steam. Although the application 

 is different, the principle of pas- 

 teurization is the same as has been 

 described above. The bottles are 

 cooled by running cold water into 

 the container. It is claimed that 

 this method of pasteurization is 

 more efficient because there is little 

 or no chance for the milk to be 

 contaminated. 



Pasteurization is the critical 

 stage in the handling of market 

 milk. Temperatures in the pas- 

 teurizer should be known and care- 

 fully regulated at all times. EVen the most experi- 

 enced operator cannot be so efficient or so vigilant 

 as a recording thermometer or a temperature con- 



Special Foxboro 

 bulb and fitting for 

 the Bottle Method 

 of Pasteurizing. 



