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 sterihzed. . 



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. 



31 



