58 THE NORMAL COMPOSITION OF MILK 



have also been employed as counterfeits for non-fatty solids 

 reduced by the addition of water. 



Calculation of Adulteration 



Added Water. The probable amount of water added to 



milk may be calculated from the formula 



SNF 

 Added water = 100 7-XIOO in which SNF represents 



snf ^ 



the amount of solids-not-fat found, and snf the average amount 

 of solids-not-fat found in genuine milks during the same season. 

 If such records are not available a value of 8.8 may be assumed. 

 Where minimum standards are in force the value in the standard 

 is substituted in the above formula, whether it be for sohds- 

 not-fat or total solids. Thus 



Added water = 100 SNF found ^ 



minimum snf allowed 



100- .. ^VTIi . XlOO- 

 minimum T. S, allowed 



The added water calculated by this latter method is usually 



stated in the certificate of analysis as "at least . . . per cent." 



Another formula for calculating the added water is 



G-\-F 

 Added water =^ 100 — rj-^X 100 where G = degrees of gravity 



or lactometer reading, and F = the percentage of fat. The prob- 

 able amount added may be obtained by substituting 36.0 for 

 34.5. 



Fat Abstraction. The removal of cream is indicated by 

 an abnormally low fat content and the minimum amount of 

 fat abstraction may be calculated from the formula. 



Fat abstracted = 100— 1^X100 where /, and F, are the 



amounts of fat found in the sample and the minimum required 

 by the standard, respectively. The probable amount removed 

 may be obtained by substituting the average value for the 

 month in which the sample is taken. 



