PROPERTIES OF MILK 39 



(4) It imparts a cooked taste (especially if not heated and 

 cooled properly). 



(5) It precipitates some of the albuminoids and ash con- 

 stituents. 



(6) It destroys the properties of enzymes present in milk. 



(7) It divides or spUts up the fat globules. 



(8) It caramelizes some of the sugar. 



1. Destroys Nearly All Germs.— Heating milk to a tem- 

 perature of about 180° F. for ten minutes destroys most of 

 the germs present in milk. This is the temperature used 

 chiefly in creameries for pasteurization. The details concern- 

 ing the different effects of temperature upon growth of germs 

 properly comes under the heading of bacteriology, and will 

 be referred to more in detail in the chapter on " Bacteria in 

 Milk." 



2. Diminishes the Viscosity, or Body. — Heating milk or 

 cream diminishes the viscosity of these substances; that is, 

 the body or consistency is lessened; and in cities where milk 

 or cream is sold directly to consumers, heated milk appears 

 as if it had been adulterated. This diminution in the body 

 is claimed to be due to a breaking up of the fat-globules and 

 the caseous matter. The chemical union of some of the cal- 

 cium salts and the casein is altered or destroyed. 



The consistency of milk or cream can be restored by adding 

 a substance named viscogen. Russell and Babcock* advise 

 this method of overcoming the apparent defect caused by 

 heating. It consists of making a strong solution of cane-sugar 

 and mixing it with freshly slacked lime. This mixture is 

 allowed to stand, and the clear solution coming to the top 

 is the viscogen, which, when drawn off and used in the pro- 

 portion of one part of viscogen to from 100 to 150 parts of 

 cream, restores the body of cream or milk. This is due to 

 the fact that viscogen causes the fat-globules to cluster together 

 again, and the lime in the viscogen may combine with the 



* Bulletin No, 54, Wisconsin. 



