Milk and Cream 31 



one day and to deliver it the next, it is necessary to 

 refrigerate the milk for several hours. The refrig- 

 erator temperature should be held uniformly at 

 40° F. and the milk should not be allowed to freeze. 

 Here, too, the only practical precaution for the 

 dairyman is a recording thermometer. With the 

 recording elements on the outside of the refrigerator, 

 the temperature may be observed and maintained 

 uniformly without the loss otherwise incurred by 

 frequent opening of the door for temperature 

 observation. 



Standardizing Milk and Cream. 



To satisfy the consumer, cream or milk containing 

 the same percentage of fat should be sold every day. 

 Because a separator will not deliver cream testing 

 the same percentage of fat every day the cream must 

 be standardized. 



Standardizing milk or cream consists of raising 

 or lowering the fat content to a fixed standard. 



In standardization, there are two classes of prob- 

 lems involved: first, a certain fixed amount of milk 

 is to be made up or a certain amount of standardized 

 milk is desired. Second, a certain amount of milk or 

 cream is to be used and enough of another product 

 added to make the mixture test a certain percentage 

 of fat. In the latter case the amount of the mixture 

 is indefinite. 



The original method of computing problems in 

 standardization is long and difficult, but a scheme 

 has been devised that is simple. The method is as 

 follows : 



Draw a rectangle and place in the center of it the 

 percentage of fat desired. Place at the left-hand 

 corners of the rectangle the percentage of fat in 



