126 



Dairy Bacteriology. 



3. Heafc water in pail until the temperature of same 

 reaches 155 to 160 F. ; then remove from source of direct 

 heat, cover with a cloth or tin cover, and allow the whole 



FIG. 26. A home-made pasteurizer. 



to stand for half an hour. In the preparation of milk for 

 children, it is not advisable to use the low-temperature 

 treatment (140 F.) that is recommended for commercial 

 city delivery. 



4. Remove bottles of milk and cool them as rapidly as 

 possible without danger to bottles and store in a refriger- 

 ator. 



Commercial pasteurizers. As noted before, the object 

 in commercial pasteurization depends upon whether it is 

 desired to treat milk for general milk supply or to make 

 into butter. The ends to be attained are so widely different 

 that it naturally follows that the apparatus best suited for 

 the respective purposes must vary considerably. In pas- 

 teurizing milk in butter-making, capacity is one of the 



