104 



Dairy Bacteriology. 



Cultures of organisms that had been isolated from 

 pasteurized milk were inoculated into bouillon. One set 

 was left to grow at room temperature, another was pas- 

 teurized and allowed to stand at same temperature, 



FIG. 19. Diagram showing temperature changes in pasteurizing, and the re- 

 lation of same to bacterial growth. 



Shaded zone represents limits of bacterial growth, 10-43 C. (50-109 F.); the in- 

 tensity of shading indicating rapidity of development. The solid black line 

 shows temperature of milk during the process. The necessity for rapid cooling 

 is evident as the milk falls in temperature to that of growing zone. 



while another heated set was kept in a refrigerator. 

 The unheated cultures at room temperature showed evi- 

 dence of growth in thirty trials in an average of 26 



