132 



Testing Milk and Its Products. 



solution ("Neutralize!*"), 9 cc. of milk, cream, etc., 

 being measured out for the test, and alkali solution 

 added from the combined burette and bottle, the former 

 being graduated to two-tenths of one cc. The burette 

 is filled by tipping the bottle and the surplus of the 

 ." neutralized' will flow back, leaving the solution at 



the zero mark. With 

 the quantity of milk 

 given, the readings ob- 

 tained represent per 

 cent of acidity direct. 

 147. Rapid estima- 

 tion of the acidity 

 of apparently sweet 

 milk or cream. a, 

 Milk. The alkaline 

 tablet method offers a 

 ready means of esti- 

 mating the acidity of 

 milk or cream that is 

 still sweet to the taste. 

 The selection of the 

 best kinds of milk 

 is especially important 

 in pasteurizing milk 

 or cream. As previously noted, milk which gives the 

 highest acid test contains, as a rule, a larger number of 

 bacteria and spores not destroyed by pasteurization 

 than does milk giving a low acid test (129) ; the acidity 

 test may therefore be used to advantage for the pur- 

 pose of selecting milk best adapted for pasteurization, 





FIG. 44. The Marschall acid test. 



