MICRO-ORGANISMS IN MILK 



321 



Prucha, Harding, and Weeter determined in a series of experi- 

 ments that the germ content of the milk was increased by 57,077 

 bacteria per cubic centimeter when the pails were merely washed, 

 but not sterilized. 



Thorough cleaning and washing of pails seems to be indispen- 

 sable if the germ content of milk is to be kept low. Care ex- 

 pended on stables, animals, and milking pails may produce milk 

 with small numbers of bacteria, but good results from these prac- 

 tices are largely vitiated unless equal care is given to cans, cool- 

 ers, and bottles. The remnants of milk adhering to utensils should 

 be rinsed with cold or lukewarm water, then the utensils should* 



Fig. 149. Can rinser. 



Fig. 150. Sterilizer and cleanser. 



be scrubbed with some alkaline solution, wash powder, soap pow- 

 der, or some similar preparation. Finally, steam should be ap- 

 plied (Figs. 148-151). Steam under pressure is most effective, 

 and large autoclaves have been constructed to serve this purpose. 

 Cans and pails may be treated with a jet of pressure steam, or 

 may be held tightly by a special device while subjected to the action 

 of steam. Good results may be obtained by exposing utensils to 

 steam in a closed chamber for a considerable time, and even boil- 

 ing water destroys nearly all micro-organisms. A simple and inex- 

 pensive steam sterilizer for small dairies has been devised by Ayers 

 & Taylor and is described in Farmer's Bulletin No. 748. 



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