194 PASTEURIZATION 



the pasteurizer. This will guard against excessive heating 

 and excessive steam pressure, which might jeopardize the 

 machine. 



At the beginning of the pasteurizing process some cream is 

 almost sure to pass through the pasteurizer at a temperature 

 lower than that required. If the system of pasteurization prac- 

 ticed, involves the running of the hot cream direct into the vat 

 where it is held for some time, before it is cooled, all the cream 

 has a chance to become heated to the proper temperature and no 

 material decline in the germ-killing efficiency of such pasteur- 

 ization is likely to occur, even if a small portion of the cream did 

 pass through the pasteurizer at too low a temperature. 



But if, as is usually the case, the cream passes from the 

 pasteurizer over an instantaneous cooler and reaches the vat 

 cool, then the escape from the pasteurizer of incompletely 

 heated cream becomes a serious menace to the quality of the 

 resulting butter. This danger can readily be avoided by instal- 

 ling, between the pasteurizer and the cooler, a by-pass, through 

 which the first cream pasteurized and any other portion of the 

 cream that fails to be heated to the desired temperature, can 

 be automatically returned to the pasteurizer and run through 

 again. When the pasteurizer is first started up, therefore, 

 all cream should be by-passed until the desired temperature 

 is reached and is permanently maintained. 



Automatic Temperature Recorders. The installation and 

 use of an automatic temperature recorder is of additional, 

 valuable help to insure reliable temperature control. By its 

 use a permanent record is produced which shows the exact 

 temperature of pasteurization during the entire process. The 

 superintendent in charge should examine these records daily, 

 and caution the operator when the records disclose irregular- 

 ities. The knowledge on the part of the operator that his 

 work is thus permanently recorded and the records checked 

 daily, exerts a good moral effect on the operator. He realizes, 

 that unless he performs his duty properly, the record is unsatis- 

 factory and that carelessness is thus immediately detected. 



Cooling Cream from Flash Pasteurizer. The hot cream 

 flowing from the pasteurizer is either passed over a surface 

 coil cooler, regenerative or otherwise, or through an internal 



