PURDUE UNIVERSITY
Agricultural Experiment Station
Circular No. 42
LaFayette, Ind., January, 1914
TESTING MILK AND CREAM FOR BUTTER FAT
O. F. Hunziker, Chief Department of Dairy Husbandry
PURPOSE
The purpose of this circular is to furnish to the milk and cream producers and the manufacturers of dairy products of the State accurate, concise and understandable directions for testing milk and cream in accordance with the most approved and practical methods of using the Babcock test.
These directions are especially intended also for the information of applicants for testers’ licenses, and supplementary to the instruction offered in Purdue University Agricultural Experiment Station Circular No. 41.
MILK TESTING
Sampling the Milk
The sampling is the most important operation of the test. Unless the sample is representative of the milk from which it is taken the result of the test can not be correct. The fundamental cause of non-representative samples lies in the fact that the butter fat is lighter than the remainder of the milk constituents. When the milk is allowed to lie in the cans undisturbed, the butter fat rises to the surface. Unless the milk is thoroughly mixed before sampling, a representative sample cannot be taken.
Single Samples oe Milk.—The most accurate and reliable method of sampling is to take single samples of each patron and test them daily. In order to minimize the work, the sample may he