292 DAIRYING. 



bottles), and should be thoroughly chilled in a refrigerator 

 for several hours (better over night) before being delivered 

 lo the consumer. This chilling process should succeed the 

 heating operation as quickly as possible, as the sudden 

 transition in temperature from 155° F. to 55° F. or less has 

 a paralyzing effect on the development of those organisms 

 (spores) that are not killed by the heat. The machines that 

 have been put on the market have for the most part been 

 designed primarily from the dairyman's standpoint, and 

 while they fulfill their requirements as to capacity, cheap- 

 ness, etc., yet they cannot in general be relied upon to treat 

 the milk in a way so as to free it with certainty from all pos- 

 sible disease-producing bacteria. The Potts' Pasteurizer, 

 which has been sold quite extensively in this country during 

 late years, may, however, be considered an entirely satis- 

 factory and practical machine. 



Pasteurization in this country is applied with great suc- 

 cess to milk and cream where these products are used in 

 the liquid form. It is used to some extent in this country, 

 but much more widely in continental Europe, in the prepara- 

 tion of cream for the manufacture of butter by the use of a 

 pure culture-starter. It can also be used advantageously 

 in the hot months for increasing the length of time that 

 by-products of the factory like skim-milk and whey may be 

 preserved. 



Pasteurization, as well as sterilization, reduces the body, 

 consistency, of milk and cream, and these products therefor 

 seem thinner after having been subjected to the process of 

 heating than before. To obviate this. Dr. Babcock and 

 the writer in 1S96 recommended the addition of a smaU 

 quantity of a solution of sucrate of lime ('* viscogen ") ta 

 the milk or cream, which will restore the consistency of the 

 products, and in case of cream, greatly increase its whip- 

 ping quality. (See Bull. No. 54 or thirteenth report ol 

 Wisconsin Experiment Station.) 



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