84 MODERN METHODS OF TESTING MILK * 



Sampling cheese for fat-test. Since different por- 

 tions of the same cheese vary in composition, special 

 means must be used to get a representative sample. 

 The sample for testing is prepared as follows : When 

 a cheese can be cut, a narrow, wedge-shaped seg- 

 ment is taken, reaching from the outer edge to the 

 center. This is cut into strips and passed through a 

 meat-grinding machine two or three times. This mass 

 is carefully mixed, and from this a 9-gram sample is 

 weighed into a cream-testing bottle, or a 4.5-gram 

 sample into an ordinary milk-testing bottle. 



When cheese can not be cut, samples are obtained 

 by a cheese-trier. If possible, three plugs should be 

 drawn, one at the center, one about an inch from the 

 outer edge, and one at a point half way between the 

 other two. If only one plug can be drawn, this should 

 be taken at a point about half way between the mar- 

 gin and center. The plugs should be taken perpen- 

 dicular to the end surface of the cheese and should 

 reach either entirely through the cheese or just half 

 way. The plugs should be made fine by grinding or 

 cutting and carefully mixed before weighing samples. 

 In preparing samples, they should not be exposed to 

 the air longer than necessary, since loss of moisture 

 should be prevented as much as possible before w^eigh- 

 ing. 



Testing sample of cheese. The sample is weighed 

 into the bottle. Then one adds about 15 cc. of hot 

 water in the test-bottle and agitates until the water 

 disintegrates the cheese ; this may be hastened by add- 

 ing a few cubic centimeters of acid, and keeping the 

 bottle in slightly warm water. When no more lumps 



