424 SCIENCE AND PRACTICE OF CHEESE-MAKING 



cock test finds occasion for use in connection with 

 cheese-making in the following ways : ( i ) Testing 

 milk of individual patrons when dividends are made 

 on the basis of the milk- fat; (2) testing milk to 

 ascertain if its fat content has been seriously affected 

 by skimming; (3) testing milk to use as a basis for 

 estimating the yield of cheese and regulating the 

 amount of salt used (p. 38) ; (4) testing whey 

 and press-drippings to ascertain if the loss of fat 

 is excessive, and (5) testing cheese for percentage 

 of fat. 



Apparatus and materials used. The following list 

 includes the apparatus and materials used in making 

 this test: (i) Test-bottles, graduated from o to 10 

 per cent, so that each smallest division represents 0.20 

 per cent when 17.5 cubic centimeters (18 grams) of 

 milk are used; (2) pipette for measuring milk, hold- 

 ing 17.6 cubic centimeters to mark; (3) measure 

 for acid, holding 17.5 cubic centimeters to mark; 

 (4) centrifugal machine, having a wheel 12 to 20 

 inches in diameter, easily capable of being run at a 

 speed of 700 to 1,200 revolutions a minute; and (5) 

 commercial sulphuric acid having a specific gravity 

 between 1.82 and 1.83, preferably just 1.825 (Test- 

 ing Milk, etc., pp. 32-52). 



Sampling milk for testing. Milk that has curdled, 

 or on the surface of which cream has risen and dried, 

 or milk the fat of which has partially churned, is 1 dif- 

 ficult to sample. These difficulties should not be com- 

 mon in cheese-factory work, but, when they arise, 

 careful attention should be given to the details pre- 

 scribed for such cases (Testing Milk, etc., pp. 22- 

 24). The samples to be tested must be thoroughly 

 mixed. 



