438 



MICROBIOLOGY OF MILK AND MILK PRODUCTS 



EXTERIOR OF Cow's BODY. The nature of the cow's coat and 

 the condition under which she is normally kept favor the accumulation 

 of dust and bacteria upon her body. Unless special care is taken to 

 keep the cow's body free from dirt, the organisms which fall into the 

 milk from this source at milking time will constitute one of the most 

 important sources of contamination. The importance of this source 



FIG. 140. Colonies developing from cow-hairs planted in agar plate. 



of contamination may be recognized when we see what large numbers 

 of microorganisms may be carried by small particles of dust or an 

 individual cow hair. The amount of this source of contamination is 

 indicated by the marked reduction in germ content resulting from the 

 use of a small top pail (page 442). 



The importance of this source of contamination depends very 

 largely upon the conditions under which the cows are kept and the care 

 exercised in cleaning just previous to milking. In many of the certified 

 milk dairies this source of contamination is reduced to a minimum and 

 has little effect upon the milk. 



