CHAPTER XII. 



SANITARY EXAMINATION OF MILK. 



Seveeal cities have adopted bacterial standards for milk. 

 Rochester, N. Y., requires that the bacterial content of 

 their city milk be kept below 100,000 per cubic centimeter. 

 Boston permits 500.000 per cubic centimeter, and other 

 cities have different requirements for different grades of 

 milk. 



The number of bacteria in milk cannot be determined 

 until 24 to 48 hours after the sample was taken, by which 

 time the milk has been consumed. A milk dealer demands 

 a quicker test for the quality of the milk. Since the age 

 of milk is indicated somev/hat by the degree of acidity, 

 the acid test is used to some extent to determine the 

 quality of the milk. 



Acidity Test. — The simplest method of determining 

 roughly the acidity of milk is by the use of Farrington's 

 Alkaline Tablets, using a solution made of one tablet to one 

 ounce of hot water. Using the same unit for the measure- 

 ment of both, the milk and the alkaline solution, one volume 

 of alkaline solution added to one volume of milk will neu- 

 tralize acid equivalent to one-tenth of one per cent. If the 

 addition of two volumes of alkaline solution to one of cream 

 does not neutralize all the acid (turn the milk pink), then 

 that milk contains more than two-tenths of one per cent 

 acid, and is not a first-grade product. 



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