PASTEURIZATION 



385 



whose temperature at the moment of injection was below 39.5 C. 

 (103 F.) is to be regarded as a positive reaction. 



"Any rise in temperature between 39.5 C. (103 F.) and 40 C. 

 (104 F.) must be regarded as of doubtful significance; animals 

 exhibiting such require special study." 



Milk-conveyed typhoid fever can be handled nearly as effectively 

 as can tuberculosis by excluding typhoid carriers as producers and 

 handlers of milk. This can be very easily and efficiently done by 

 requiring the blood test for all dairymen and their workers. 



. 

 Milk 



Acid 



Coagulating j 



Group 



Acid 

 Group 



Inert 

 Group 



Alkali 

 Group 



Feptonizingf 

 Group 



Milk Pasteurized fbr,30 Minutes at 



(H5F.) (160 F.) 



7(5 .7' C. 



82.2C. 

 (180F.) 



87.8C. 

 (190"F.) 



03.3C> 

 (200 F.) 



FIG. 46. The hypothetical relation of the bacterial groups in raw and pasteurized 

 milk. (Tanner, after Ayers and Johnson.) 



Pasteurization. There are two methods of pasteurization the 



"flash" and "continuous" processes. In the flash method the milk 



is heated to 80 or 90 C. for from one to five minutes and then 



cooled to 50 C. or below. This method is rapid, cheap, and much 



25 



