CHAPTER V 

 THE TESTING OF MILK AND CREAM 



THE value of milk either for direct consumption or for manu- 

 facture into various dairy products is largely dependent on its 

 chemical composition. Since normal milk varies widely in 

 composition, it is necessary to determine the relative amounts 

 of the more important constituents in order to know its market 

 value. A careful chemical analysis will give the most accurate 

 data, but this method is too expensive and too slow for use in 

 commercial work. The need for rapid methods for analysis 

 has led to the development of many tests both in this country 

 and in Europe. Many of these methods, while useful at the 

 time, have been superseded by later ones and are no longer 

 used. In commercial work, the constituents most commonly 

 considered are the fat and the solids not fat or the total solids. 

 In this country the percentage of fat is usually determined by 

 means of the Babcock test. In Europe either the Babcock or 

 Gerber method is used. The latter has not met with favor in 

 this country because two reagents are required instead of one 

 for the Babcock method. The percentage of solids is cal- 

 culated by using the percentage of fat and the specific gravity 

 as shown by the lactometer reading, in accordance with certain 

 well-established formulae. 



Specifications for standard apparatus for use in the Babcock 

 test have been worked out by the Official Dairy Instructors' 

 Association and have been approved by the United States 

 Bureau of Standards. They are as follows : 



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