CHAPTER II 



COMPOSITION OF MILK AND CREAM AND 

 THEIR PRODUCTS 



MILK is a white, opaque fluid, when seen in bulk, but ap- 

 pears transparent in thin layers. It has a peculiar, pleas- 

 ant odor and taste which cannot be described. They can 

 best be appreciated — by comparison — when they are ab- 

 sent. Thus, milk which has been heated in open vessels or passed 

 through a separator loses some of its finest flavor. This flavor 

 resides in a volatile substance which escapes in either process. 



Milk has been called a vital or living fluid. This because of 

 its semblance to other fluids in the living body and since it pos- 

 sesses some of the constituents and properties of these other fluids 

 of the body. Like blood, milk contains cells — as fat and leucocytes 

 — and opsonins, alexins, and various ferments. After 24 hours 

 from its leaving the body milk becomes dead, — that is, the action of 

 the ferments and germicidal properties are lost. 



Chemically, milk is composed of all the essentials of a com- 

 plete food. That is, it is a single substance which contains all the 

 food-elements necessary to indefinitely support life. These food- 

 elements are known technically as Protcids, Fat, Sugar and Mineral 

 Matters. In reaction cow's milk is amphoteric, i. e., it turns red 

 litmus paper blue, and blue litmus red. 



Proteids in milk have the same food value as flesh or eggs* 

 Water is, of course, the largest constituent of milk, forming about 

 87 per cent, of it. 



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