MILK 17 



THE EXAMINATION OF MILK. 

 A. SAMPLING. 



In the taking of a sample of milk for the purposes of analysis 

 or investigation, certain precautions must be observed owing to 

 the fact that the larger fat globules immediately begin to rise 

 to the surface even when the milk has only stood for a short 

 time. The chief point in taking an average sample which shall 

 faithfully represent the bulk of the milk is to subject the latter 

 to a thorough stirring immediately before drawing the sample. 

 The way in which such a stirring can best be performed will 

 depend upon the amount of milk and the shape and size of the 



FIG. 4. " Rouser " for Mixing Milk. 



vessel in which it is contained. If the milk is in an ordinary 

 railway can or churn, it is most satisfactory to use a so-called 

 " rouser," which consists of a round sheet of tin-plate in which 

 a number of holes, about three-quarters of an inch in diameter, 

 are punched. 



This circular piece of tin, which must be somewhat smaller 

 than the neck of the churn, is fastened to a long iron shaft, 

 and by slowly raising and lowering the " rouser " through the 

 milk a thorough mixing is assured. Immediately after the 

 milk has been mixed a sample must be taken, and the way in 

 which this is done depends upon the vessels in which the milk 

 is contained. If the milk is in several churns of different sizes, 

 and a collective sample has to be taken, then the samples 

 drawn from the various churns must bear some relation to the 

 size of these vessels. For example, from a can containing 50 



c 



