The Herd and the Dairy 



265 



If the above direc- 

 tions are carried out, 

 the milk is fit to be 

 graded as " certified " ; 

 but if any precautions 

 are omitted, it is then 

 best to pasteurize the 

 milk. This is done by 

 heating it for twenty 

 minutes at a tempera- 

 ture of one hundred 

 and fifty degrees Fah- 

 renheit, and then cool- 

 ing it quickly. This 

 process is sufficient to 

 kill any bacteria that 

 might cause disease, 

 and if the temperature 

 does not go above one 

 hundred and fifty de- 



When pas- 

 teurization 

 is neces- 

 sary; its 

 effects 



.W. T. Shilling 



FIG. 211. An effective milk-cooling de- 

 vice. The milk from the tank at the top 

 grees the taste Of the is spread over the cold pipes. From the 



pipes it runs through the trough and into 

 the can. 



milk is not affected and 

 it is quite as digestible 



as raw milk.' Moreover, pasteurized milk will keep 

 for a long time without souring, and therefore in cases 

 where milk has to be transported for long distances 

 pasteurization is almost a necessity. (Exp. 4.) Health 

 boards recommend that all milk be pasteurized unless 

 it is produced under very favorable conditions. Pas- 

 teurization does not remove dirt from unclean milk, but 

 it destroys germs that might cause disease. 



