106 Testing Milk and Its Products. 



The extent of the adulteration is determined as given 

 below. 



124. Calculation of extent of adulteration. 1 In the fol- 

 lowing formulas, per cents, found in the control-samples, 

 if such are at hand, are always substituted for the legal 

 standards. 



a. Skimming. 1. If a sample of milk has been skim- 

 med, the following formula will give the number of 

 pounds of fat abstracted from 100 Ibs. of milk : 



Fat abstracted = (x)=legal standard for fat f, . (I) 

 f being the per cent, of fat in the suspected sample. 



2. The following formula will give the per cent, of fat 

 abstracted, calculated on the total quantity of fat origi- 

 nally found in the milk: 



x = 10 o fXl (II) 



legal standard for fat 



b. Watering. 1. If a sample is watered, the calcula- 

 tions are most conveniently based on the percentage of 

 solids not fat in the milk: 



Per cent, of foreign (extraneous) water in adulterated 



milk - 100 S X 100 an , 



legal standard for solids not fat 



S being the per cent, of solids not fat in the suspected 

 sample. 



Example: A sample of milk contains 7.5 per cent, solids not 

 fat; if the legal standard for solids not fat is 9 per cent., 



100 =16.7, shows the per cent, of extraneous water 



y 



in the milk. 



2. Watering of milk may also be expressed in per cent, 

 of water added to the original milk, by formula IV: 



1 Woll, Handbook for Farmers and Dairymen, New York, 1897, pp. 207-8. 



