24 Testing Milk and Its Products. 



30. Partially churned milk. A second difficulty some 

 times met with in sampling whole milk arises from the 

 fact that a part of the butter fat may be separated in the 

 form of small butter granules, by too zealous mixing or 

 by reckless shaking in preparing the sample for testing. 

 This will happen most readily in case of milk from fresh 

 cows or with milk containing exceptionally large fat 

 globules. When some of the butter granules are thus 

 churned out, they quickly rise to the surface of the 

 milk after pouring and cannot again be incorporated in 

 the milk by simple mixing; it is, therefore, impossible 

 to obtain a fair sample of such milk for testing without 

 taking special measures which will be explained in the 

 following. The granules of butter may be so small as to 

 pass into the pipette with the milk and the quantity 

 measured thus contain a fair proportion of them, but 

 they will be found sticking to the inside of the pipette 

 when this is emptied, and thus fail to be carried into the 

 test bottle with the milk. 



A similar partial churning of the milk will sometimes 

 take place in the transportation cans. When such milk 

 is received at the factory, the butter granules are caught 

 by the strainer cloth through which the milk is poured, 

 and are thus lost both to the factory and to the farmer. 

 This separated fat cannot be put into the cream or added 

 to the granular butter, without running the risk of mak- 

 ing mottled butter, and it will not enter into the sample 

 of milk taken for testing purposes. 



When milk samples are sent by mail or express in 

 sni all* bottles, or carried to the place of testing, they 

 often arrive with lumps of butter floating in the milk or 



