CHAPTER XI 



PASTEURIZATION 



Pasteurization should be considered as one of the necessary 

 expenses in the modern factory of dairy products, for as long as 

 the inspection of individual dairies is impossible it will not be 

 safe to convert raw products obtained from such dairies into 

 finished products to be offered for sale unless they have been 

 subjected to pasteurization. Even though the dairy farm from 

 which the cream is delivered is under inspection, it is at times 

 possible that germs causing disease may also there gain entrance 

 into the milk unbeknown to the producer. It is therefore 

 generally recognized that if an absolutely safe product is pro- 

 duced it should be made from material which has been pasteur- 

 ized to a temperature of not less than 140° F. for twenty minutes 

 or longer or to a temperature of not less than 180° F. when ex- 

 posed to flash heat. Pasteurization also improves the immedi- 

 ate quality as well as the keeping quality of the butter and 

 causes a more uniform product to be produced. 



A. COST OF PASTEURIZATION 



The expenses incurred by pasteurization may conveniently 

 be divided into three groups: i, cost of steam required for 

 heating; 2, cost of cooling water; 3, cost of labor and equipment. 



I. Cost of Steam Required for Heating. — Theoretically the 

 amount of heat obtained from a pound of steam at a definite 

 gauge pressure is a known quantity, but in practice it is not 

 possible to obtain a hundred per cent of the theoretical efiS- 

 ciency. Losses sustained in transferring the heat to milk or 

 cream to be pasteurized are primarily due to radiation of heat 

 from the steam pipes and pasteurizer. It is therefore economy 

 to have the steam pipes leading from boiler to pasteurizer as 

 well as the pasteurizer itself properly insulated so as to reduce 

 such radiation to a minimum. 



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