THE PASTEURIZATION OF MILK 



tendency which there was to create foam, espe- 

 cially if the milk were cold. This foaming is due, 

 of course, to the entrance of air into the milk dur- 

 ing the process. Milk which has been previously 

 pumped seems more likely to foam than when 

 pumps have not been used. Machines are now 

 made by which the air is excluded, and no foam, 

 or almost none, is produced when they are oper- 

 ated, even when the milk is cold. It is generally 

 held that the clarification of milk by a centrifugal 

 machine is a good thing. It is claimed that the 

 pus cells, leucocytes, etc., which are in the milk, 

 tend to form a covering for the bacteria contained 

 in the milk, to such an extent that they are some- 

 what protected and are not so readily destroyed 

 by heat. It is claimed that the removal of this 

 covering by means of the clarifier therefore assists 

 in the complete destruction of the bacteria. This 

 claim has not been fully demonstrated to the knowl- 

 edge of the writer. 



It is the practice of some dealers to strain the 

 pasteuried milk as it enters the bottling machine. 

 This is to be condemned unless the strainer is 

 completely covered and is sterilized at the same 

 time that the final sterilizing of the bottler occurs. 

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