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MANUAL OF MILK PRODUCTS 



FIG. 80. A convenient equipment for 

 pasteurizing milk or making starter. 



One very easy method of pasteurizing milk, when one of the 



especially constructed machines is not available and only a 



small quantity of milk is to 

 be pasteurized, is to cut off 

 the upper part of a barrel 

 and insert a steam pipe in 

 the barrel (Fig. 80). The 

 can of milk to be pasteur- 

 ized is put into the barrel 

 and the steam is turned on. 

 Care should be taken that 

 the milk is not heated to 

 too high a temperature, and 

 it should be stirred fre- 

 quently in order to insure 

 even temperature and to 



prevent a cooked flavor in the product. The stirring may be 



done with either a dipper or an especially constructed stirrer ; 



in either case the implement should be left in the can and the 



can kept covered as much as possible 



while the milk is being heated and 



cooled, as otherwise contamination is 



likely to occur. The improved pas- 

 teurizers have a mechanical stirrer. 

 An arrangement by which the milk 



may be stirred without removing the 



cover is shown in Fig. 81, but in order 



to take the temperature which should 



be taken with a sterile thermometer 



it is necessary to remove the cover. 



This apparatus also makes a very good 



outfit for the preparation of starter. 



By whatever method pasteurization is accomplished, the 



milk should be heated to a temperature not above 140 F. for 



FIG. 81. Pasteurizer with 

 mechanical agitator. 



