120 



Dairy Bacteriology. 



of the serum, and they remain distributed throughout 

 the milk. In such cases, no cream rises, and even the 

 cream separator is unable to remove the fat from such 

 milk. 



In selling bottled milk, it is highly desirable that the 

 cream line should show distinctly. In normal milk, this 

 line forms in a few hours, but where milk is heated to a 

 high temperature, and agitated at the same time, the 

 clusters of fat globules are broken apart and the cream- 



FIG. 25. FAT GLOBULFS IN RAW MILK. 



In raw milk the fat globules are in masses of varying sizes. 

 These 'rise to the surface quickly in gravity creaming. 



ing power injured. This physical change is dependent 

 not only on the temperature, but also on the time of 

 exposure. A momentary exposure at 160' F., ar for 

 20 minutes at 145 F., is about the maximum limit which 

 can be applied to milk without material injury to the 

 creaming property. 



The body or consistency of pasteurized cream may be 

 restored by allowing the cream to stand for several days 



