114 Testing Milk and Its Products. 



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

 fat abstracted, calculated on the total quantity of fat 

 originally found in the milk: 



x=100 fxioo n 



legal standard for fat 



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

 tions are mcst conveniently based on the percentage of 

 solids not fat in the milk. The percentage adulteration 

 may be expressed either on basis of the amount of 

 water present in the adulterated milk, or the amount of 

 water added to the original milk: 



1. Percent, of foreign (extraneous) water in the adul- 



, , , . ln , sxioo 



terated milk=10Q^ r ^ T~S ? T 3 , n . (Ill) 



legal standard tor solids not tat 



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

 sample. 



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

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

 100 7.5*1 ^-=16.7,' shows the per cent, of extraneous water 

 in the milk. 



2. Watering of milk may also be expressed in per 

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



Per cent, of water added to the o 



100 X leg. stand, for sol. dfi 

 =- -g- -^--100 (IV) 



%*" 

 In the example given above, l^? 100=20 percent. 



of water was added to the original milk. 



c. Watering and skimming. If a Cample has been 

 both watered f*nd skimmed, the extent of watering is 

 ascertained by means of formula (III) or (IV), and 

 the fat abstracted found according to the following 

 formula : 



