28 



THE BOOK OF CHEESE 



43. The sediment test. The presence of solid material 

 or dirt in the milk is always accompanied by bacterial 

 contamination. By means of the sediment test, the 

 amount of solid material can be determined. The test 

 consists of filtering the milk through a layer of cotton ; 

 the foreign material is left on the cotton filter. Various 

 devices for filtering the milk have been 

 manufactured. (Figs. 4 and 5.) In 

 order to be able to compare the filters 

 from the different dairy-men's milk, the 

 same amount of each patron's milk is 

 filtered, usually about a pint. These 

 tests are usually made once or twice a 

 month at the factory and the filters 

 placed on a card where the dairy-men 

 can see them. Much improvement in 

 the quality of the milk has been accom- 

 plished by the use of the sediment test. 



FIG. 5. A single sedi- m, , . , , 



ment tester. * ne purpose oi this test may be and 



often is defeated by the use of effi- 

 cient strainers. Milk produced in an unclean way may be 

 rendered nearly free from sediment if carefully strained. 

 It must be remembered that the strainer takes out 

 only the undissolved substances and that bacteria and 

 soluble materials which constitute a very large part 

 of the filth pass through with the milk. 



