CHEESE 
Cheese is the curd of milk which has been 
separated from it, pressed, and undergone some 
fermentation. The precipitation is produced 
either by allowing the milk to become sour 
—when the lactic acid is the agent—or by rennet. 
The first-named method is mainly applied to the 
manufacture of so-called Dutch or sour-milk 
cheese, green Swiss cheese, and cottage cheese. 
More commonly cheese is obtained by means of 
rennet derived from the fourth stomach of the 
calf. The action is due to an enzym which 
acts directly on the proteins and does not pro- 
duce its affect through the intervention of acids. 
The curd (cheese) undergoes, by keeping, various 
decompositions, some essentially putrefactive, 
and due to the action of microbes. The de- 
composition of the cheese is termed ‘‘ripening.”’ 
In the sour milk cheeses, ripening is restricted 
intentionally, since there is liability to an irregular 
and miscellaneous bacterial growth by which the 
fermentations may be carried too far, undesirable 
and even harmful products being formed. Such 
cheeses are intended for prompt use. 
Cheese contains no casein, if by this term 
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