THE MILK IN ITS RELATION TO CHEESE 25 



contamination of cheese milk is the use of the milk-cans 

 to return whey to the farms for pig feed. Frequently, 

 sour whey is left in the cans until ready to feed. These 

 cans are then not properly washed and scalded. The 

 practice of pasteurizing the whey at the cheese factory 

 is a great help in preventing this source of infection and 

 the spreading of disease. 



The use of a small-top milk pail 1 is to be especially 

 recommended in preventing bacterial contamination. 

 Because of the small opening, bacteria cannot easily fall 

 into the milk in as large numbers as when the whole top 

 of the pail is open. (See Fig. 3.) 



If a milking machine 2 is used, great care must be 

 exercised to see that all parts that come in contact 

 with the milk are cleaned after each milking, and then 

 put in a clean place until ready to use again. 



40. The factory. . Another source of contamination 

 is the cheese factory itself. The cheese-maker should 

 keep his factory in the cleanest condition possible, not 

 only because of the effect on the milk itself, but as a stim- 

 ulus for the producers to follow his example. All doors 

 and windows in the factory should be screened to keep 

 out flies. 



41. The control of bacteria. If, in spite of preven- 

 tive measures, bacteria get into the milk, their growth 

 can be retarded by controlling the temperature. If the 

 temperature of the milk, as soon as drawn, can be reduced 



1 Harding, H. A., J. K. Wilson and G. A. Smith, Tests of 

 covered milk pails, N. Y. Exp. Sta. Bui. 326, 1910. 



Stocking, W. A., Tests of covered milk pails, Conn. (Storrs) 

 Exp. Sta. Bui. 48, 1907. 



2 Wing, L. W., Milking machines ; their sterilization and their 

 efficiency in producing clean milk, N. Y. (Cornell) Exp. Sta. 

 Circ. 18, 1913. 



