METHODS OF REDUCING THE GERM CONTENT 



523 



with hot and then with cold water. By another process water of 

 increasing temperature is sprayed on the bottles. The feasability 

 of pasteurizing in bottles has been demonstrated by brewers, who 

 have applied a similar process to beer for years. The writer 

 called attention to the possibility of applying the principles of 

 beer pasteurization to milk in 1908. Two types of bottle pas- 

 teurizers are shown in Figs. 212-214. 



There are three objections to pasteurization in the final pack- 

 age, but these can be overcome in time. The first objection arises 

 from the fact that odors are retained in the milk thus pasteurized. 

 Since most milk contains an appreciable amount of manurial 



H P MOTOR 



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PRE-HEATING 



Fig. 212. — The Barry-Wehmiller national milk pasteurizer. 



pollution which imparts a "cowy" odor, the gases producing this 

 odor have no outlet for escape if sealed in bottles. Milk pasteur- 

 ized by the flash or holding process is freed from disagreeable 

 odors, as they can escape during the operation. For pasteuriza- 

 tion in the final package, therefore, a relatively clean milk must be 

 available. The second objection, one that can also be overcome, 

 comes from the necessity of discarding the present costly ma- 

 chinery and replacing it with new and equally expensive machin- 

 ery. Finally, air- and water-tight caps are considerably more 

 expensive than pulp caps, and unless air-tight caps are used there 

 IS danger that the water used for cooling the bottles may leak 

 through the caps, and as this water is not guaranteed to be germ- 



