Practical Dairy Problems 1531 



computing percentage of fat, pounds of product, or pounds of 

 fat, having any two of these quantities given 



Problem 5 : 



How many pounds of milk testing 4.5 per cent fat would be required 

 to furnish 157.5 pounds of fat? 



? lbs. milk X .045 = 157.5 



Therefore, 157.5 -^ .045=^3,500, number of pounds of 4.5% milk. 

 Answer. 



Problem 6: 



250 pounds of cream contained 75 pounds of fat. What did the cream 

 test? 



2 50 X ? = 7 5 lbs. fat 



Therefore, 75 -^ 2 50 = .30 



.30 X 100 = 30%, fat test. Answer. 



Problem 7: 



How many pounds of 22-per cent cream can be obtained from 3,500 

 pounds of 4-per cent milk? 



In 3,500 lbs. of 4% milk there are 140 lbs. of fat (3,500 X .04 = 140). 



This amount of fat will be contained in the 22% cream. We then have 

 a certain number of pounds of cream testing 22%, to find the number of 

 pounds of cream. 



? lbs. cream X .22 = 140 



Therefore, 140 -f- .22 = 636.36, number of pounds of cream. Answer. 



STANDARDIZING MILK AND CREAM 



Standardizing milk or cream consists in raising or lowering the fat 

 content to a fixed standard. This is done by adding to the material to 

 be standardized, milk or cream of a higher or lower percentage of fat. In 

 standardization there are two classes of problems involved: first, one in 

 which a certain fixed amount of milk is to be made up or a certain amount 

 of standardized milk is desired; and second, one in which 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 which is comparatively 

 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 comers of the rectangle the percentages 



* By R. A. Pearson, at that time Professor of Dairy Industry, Cornell University. 



