260 



CITY MILK SUPPLY 



cocci, staphylococci, pneumococci, diphtheria and typhoid bacilli, because 

 of their greater weight, are more easily thrown out by centrifugal action 

 than are colon bacilli and other forms that occur in milk. 



Instead of using bouillon cultures, as Hinkelmann did, to study the 

 action of milk clarifiers in throwing out disease germs, McClintock 

 used milk cultures, with the results shown in Table 79. 



TABLE 79. ACTION OF MILK CLARIFIERS IN THROWING OUT DISEASE GERMS 



(McCLINTOCK) 



The percentage reduction of pathogenic forms including B. coli and 

 B. subtilis is remarkable, whereas the percentage reduction of the lactic 

 bacteria is comparatively slight. Thus it would appear that milk 

 clarifiers have a selective action in removing disease germs from milk. 

 In confirmation of this, McClintock made further tests using mixture 

 of disease germs and lactic bacteria in milk and found that 95.8 to 99 

 per cent, of the disease germs and only 15.3 to 16.1 per cent, of the 

 lactic bacteria were thrown out. 



