STANDARDIZATION OF MII^K AND CREAM 589 



CHAPTER XXII. 



STANDARDIZATION, TESTS AND CHEMICAL 



ANALYSES OF MILK, CREAM, SKIM MILK, 



BUTTERMILK AND BUTTER 



Standardization of Milk and Cream for Butterfat 



In commercial creamery operation as well as in experimental 

 work it frequently becomes desirable, and sometimes necessary, to 

 standardize milk or cream of any richness to a definite per cent of 

 fat. 



In case the milk is richer than desired, it may be reduced to the 

 desired per cent of fat either (a) by simply adding skim milk, or 

 milk of a per cent of fat lower than that desired, to the milk to be 

 standardized, or (b) by skimming a certain portion of it and return- 

 ing the skim milk to that portion which was not skimmed. If cream 

 is to be standardized to a lower per cent of fat, the same method as 

 given under (a) for standardizing milk is used, except that in addi- 

 tion to skim milk and milk, cream of a lower per cent fat than that 

 desired may also be used. It is never advisable, and under certain 

 conditions it is unlawful, to reduce the per cent of fat in milk or 

 cream by adding water. 



In the case the milk is lower in fat than desired, its fat content 

 can be increased to the desired standard, either (c) by adding to 

 the milk or cream, a sufficient quantity of milk or cream that is 

 richer in fat than that of the standard desired, or (d) by skimming 

 a portion of the milk to be standardized and returning the cream so 

 produced to the portion of milk that was not skimmed. 



For the correct determination of the amount of skim milk, milk 

 or cream to be added or the portion of milk to be skimmed, so as to 

 utilize all of the milk or cream which is to be standardized, or of the 

 correct amount of the milk or cream to be standardized and of the 

 skim milk, milk, or cream to be added for standardization in order 

 to obtain the desired volume of standardized mixture, it is necessary 

 to apply a simple and accurate method of calculation. Such a method 

 has been devised by Dr. A. R. Pearson. 1 The following directions 

 for standardization of milk and cream are based on Pearson's 

 method : 



1 A. R. Pearson, formerly Professor of Dairying, Cornell University, and 

 now President Iowa State College, Ames, Iowa. 



