PHYSICAL AND CHEMICAL EXAMINATION OF MILK 



139 



taken. It is not infrequently desirable to take samples in the 

 stable in order to find at what stage of handling the milk has been 

 tampered with, or to locate the source of a particular abnormal 

 milk. Sampling milk in the stable requires greater circumspec- 

 tion than sampling the milk from vendors. The samples should 

 be taken from each cow after milking has been completed. The 

 mixed milk from each cow may then be examined separately or 

 an equal amount from each cow's milk mixed and the mixed sam- 

 ple examined. Which one of these procedures is to be selected 

 depends upon the object of the examination. Sometimes samples 



Fig. 32.— Tin sampler. Fig. 33.— Milk thieves. 



Fig. 34. — Equity miUc 

 sampler. 



must be taken from each quarter of the udder. Small samples 

 in such cases are usually sufficient. 



Sampling cream is a difficult process and particular care is 

 necessary to obtain a representative sample. When cream stands 

 for some time the surface layer becomes tough from evaporation. 

 Heating to 40° to 45° C. is necessary to overcome this difficulty. 

 What has been said in regard to violent shaking of milk samples 

 applies in even greater measure to sampling cream, as cream is 

 more viscous than milk. Very rich cream should always be 

 warmed to 30° to 32° C. before a sample is taken. 



Samples from sour and loppered milk are always unreliable. 



