CHAPTER VI 



Methods of Testing Skim-Milk, Buttermilk, 



Whey, Ice-cream, Condensed Milk 



and Powdered Milk 



Dairy products such as ice-cream, condensed milk 

 and powdered milk can be tested for fat by the Bab- 

 cock method, and also by-products, such as skim-milk, 

 buttermilk and whey ; but in general, some special mo- 

 difications are necessary. 



METHOD OF TESTING SKIM-MILK, WHEY, ETC. 



In testing materials containing only .2 or .3 per cent, 

 of fat, two difficulties are experienced: (i) In the 

 ordinary test-bottle, the reading of so small amounts 

 of fat can not be easily done with accuracy. (2) Some 

 fat is necessarily left in the mixture of acid and milk- 

 serum, which may constitute an important factor when 

 the total fat content is small. 



Special forms of test-bottles used in testing whey, 

 etc. To enable one to make readings of small amounts 

 of fat with increased accuracy, special forms of double- 

 necked test-bottles have been devised, which are so 

 graduated as to enable readings to be made as low 

 as .01 per cent. (Figs. 34 and 34a). In using these 

 bottles, the milk and acid are delivered into the larger 

 neck, the fat being driven up into the small neck by 

 the hot water added toward the end of the test. 



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