462 MICROBIOLOGY OF SPECIAL INDXTSTEIES 



The principle of pasteurization may be said to have originated in 

 the early work of Spallanzani and Scheele, already mentioned, and 

 was employed by Appert in his later investigations. The operation 

 as carried out by Appert does not, however, appear to have found 

 general appUcation until Pasteur revived the method, and as a result 

 of his activities in attempting to secure a general adoption of the 

 practice to prevent the spoiling of wine, the process was named from 

 him. 



Specific Application. Beer. — Pasteurization is of economic im- 

 portance particularly in the dairy and fermentation industries. In 

 brewing, "The process of pasteurization is in use with even the smallest 

 brewers in the United States, beer being pasteurized even for local 

 consumption." The beer, is pasteurized in bottles by being subjected 

 to a temperature of 58° to 63° for one-half hour. The entire process 

 as practised in the large breweries, requires less than an hour, and in- 

 cludes the warming of the cold bottles to pasteurizing temperature, the 

 pasteurizing proper, and the cooling to a little above room tempera- 

 ture. The process is a continuous one, the bottles being put into the 

 machine at one end and taken out at the other. Experiments have 

 been made in pasteurizing beer in large containers, steel, copper, 

 aluminum, and tin having been tried, but without complete success 

 as yet. 



Fruit Juices. — The essentials in the pasteurization of wine and fruit 

 juices are similar to those for beer. There is, however, no universal 

 rule of application. Details of the process must be arranged to suit 

 the character of the different liquids under treatment. 



Cream and Milk. — Pasteurization as employed in the dairy industry 

 varies in its method of application according to the purpose for which 

 it is used. In factory butter making, it must be employed to secure 

 the best results. Milk as ordinarily received at creameries contains 

 a widely variant microbial flora, many of the species exerting a greater 

 or lesser influence in determining the flavor of the finished product. 

 By pasteurization of the cream, the butter-maker destroys most of the 

 organisms present; and by the use of a culture starter of lactic acid 

 bacteria, he is able to control the fermentation, and is assured of a 

 uniform quality of product from day to day throughout a season. An 

 added value of pasteurization is that all pathogenic organisms are 

 destroyed, thus aiding in the prevention of such diseases as might be 



