RECEIVING AND GRADING OF MILK AND CREAM 97 



adhered to. A small portion of the sample to be tested is put 

 into a tin cup, and the cup is put into hot water or over a jet of 

 steam. When the milk is hot its characteristics are noticed. 



5. Use of Babcock Test and Lactometer. These tests are 

 of special value in detecting watered or skimmed milk. When- 

 ever a sample of milk appears watery or blue, it is fair to presume 

 that water has been added. The test for specific gravity and the 

 test for fat can then be applied to such samples of milk. As a rule 

 composite samples are taken daily at creameries,, and the patrons 



,- 



FIG. 20. Acid carboy trunnion. 



FIG. 21. Acid hydrometer. 



paid according to the fat delivered. For this reason water adul- 

 teration is not very common at creameries, but is practiced to a 

 greater extent in the milk-supplies of cities. The use of the lac- 

 tometer in connection with the Babcock test has already been 

 referred to under the heading of " Specific Gravity of Milk." 



The Babcock test is now in such general use in America for 

 determining the per cent of fat in milk and cream that no other 

 will be dealt with here. At one time the Oil-test Churn was used 

 quite exclusively for testing cream, but it has gone almost entirely 

 out of use. 



