CHAPTER VIII 



Method of Testing the Bacterial Condition of 

 Milk 



A thorongli bacteriological examination of milk re- 

 quires somewhat extended special training, but there 

 are methods for ascertaining- the general bacterial con- 

 dition of milk which arc available in the hands of any 

 careful worker, and which afford most valuable sug- 

 gestions in regard to the cleanliness of milk. The 

 methods of studying the bacterial condition of milk 

 which we shall notice are ( i ) determining the acidity, 

 (2) the fermentation method known in its most avail- 

 able form as the "Wisconsin Curd-Test," and (3) test- 

 ing for dirt in suspension. 



THE RELATION OF ACIDITY TO THE BACTE- 

 RIAL CONDITION OF MILK 



The details of the method of determining acidity in 

 milk have been given in Chapter VII. We need say 

 here only a few words in regard to the interpretation 

 of the results as they relate to the cleanly character 

 of milk and its fitness for use. The amount of acid in 

 milk is generally an indication of the care given to the 

 milk after being drawn from the cow ; to some extent, 

 it indicates the age of the milk, especially if the tem- 

 perature at which it has been kept, is known ; and, if 

 the age of the milk is known, the acidity indicates, to 

 some extent, the temperature at which the milk has 



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