MILK. 267 



ADULTERATION OF MILK? 



The legal standards adopted in the different States of the 

 Union determine the limits for fat or solids, below which 

 the milk offered for sale must not fall. Where no control 

 sample can be taken of a suspected sample of milk, calcula- 

 tions of the extent of the adulteration practised are made 

 on basis of the legal standard in each State. Whenever 

 possible, a control sample should be secured on the prem- 

 ises of the suspected party, and subjected to analysis. If 

 the control sample contains appreciably less fat or solids 

 not fat than did the suspected sample, the latter was 

 skimmed or watered, or both skimmed and watered.* 



Skimming. — I. If a sample is skimmed, the following for- 

 mula will give the number of pounds of fat abstracted from 

 loo lbs. of milk : 



Fat abstracted ~ x = legal standard for fat —/, . (I) 



/"being the per cent of fat in the suspected sample. 



In this and following formulas the percentages found in 

 the control samples, if such are at hand, are always to be 

 substituted for the legal standards. 



II. The following formula will give the per ce.it of fat 



abstracted, calculated on the total quantity of fat originally 



found in the milk: 



/X lOO 



:r = ICO — , — — - — -— -— (II) 



leg. stand, for fat 



Watering. — I. If a sample is watered, the calculations 



are most conveniently based on the percentage of solids 



not fat in the milk: 



Per cent extraneous water in milk 



J Xioo 



= ;r. = 100-- -r—: rr-, —T^l^ ' ^^^^' 



leg, stand, for solids not fat 



s being ine per cent of solids not fat in the suspected 

 sample. 



Example. — A sample contains 8.5 per cent of solids not 

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



8.5 X 100 ^ .,, • i_ r 



100 = 5.6, will give the per cent of extraneous 



q 



water in the suspected sample of milk. 



* ^"ce Farringlon-Wull, Testing Milk and its Products, 22d Ed., 

 pp. 111-117. 



