MANUAL OF GENERAL AGRICULTURE. 113 



If sulphuric acid alone is used it is likely to char the 

 sugar in the ice cream, thus giving difficulty in reading 

 the results. 



Ice cream should contain not less than twelve per cent 

 of milk fat. 



Fruit ice cream and nut ice cream should contain not 

 less than ten per cent of milk fat. 



86. STANDARDIZATION OF MILK AND OF CREAM. 



Materials: Half gallon of milk testing 4% or over, 

 1% quarts of skim milk, Babcock tester and accompany- 

 ing materials. 



Milk or cream is " standardized" or brought to any 

 required test by the addition of skim milk, milk, or cream, 

 according to the conditions. Standardization is perhaps 

 most often a lowering of the butter fat test to just meet 

 the requirements imposed by law. 



The ordinance of the city of Los Angeles requires at 

 least 3.5 per cent butter fat. Probably most of the milk 

 produced for Los Angeles consumption will test 4% or 

 more. 



Example. Standardize 300 pounds of 4% milk to 

 3.5%, using skim milk testing .1%. 



300 Ibs. of 4 ~~ 3.4* 300 : 3.4 



Then 



as 



Xlbs. of .1 .5 X : .5 



Solving, 300:3.4::X:.5 



3.4X=150 



X=44.1 



*The 3.4 and .5 are obtained by subtracting diagonally. 



Therefore to get the standard of 3.5% we must add 

 44.1 Ibs. of skim milk. 

 Proof: 300 Ibs. of 4% milk=12 Ibs. of fat. 



44.1 Ibs. of .1% skim milk=.Q4 Ibs. of fat. 

 344.1 Ibs. of 3.5% milk=12.04 Ibs. of fat. 

 Obtain a half gallon of milk testing 4% or over and 

 a half gallon of skim milk. Test each for butter fat. 



