BACTERIAL INHIBITION 



I. GERMICIDAL ACTION IN MILK 



WILLIAM H. CHAMBERS 1 



From the Division of Dairy Bacteriology, University of Illinois 



Received for publication April 5, 1920 



Improvement of our milk supply and the evolution of better 

 methods for its handling will be aided by a more detailed knowl- 

 edge of the growth of bacteria in milk. The growth of bacteria 

 in bouillon, as shown by Buchanan and others, follows a rather 

 definite curve, a period of delayed multiplication or latency pre- 

 ceding the period of most rapid growth or logarithmic increase. 

 In milk, however, plate counts have, in many cases, demonstrated 

 a decrease of bacteria before the period of logarithmic increase. 

 Whether or not this is a true germicidal action has been the sub- 

 ject of intermittent controversy ever since Nuttall and Buchner 

 first reported a germicidal action in blood in 1888. Later work- 

 ers, such as Rosenau, have given very complete historical reviews 

 of the early literature, so that only a few points of conflict in 

 ideas are mentioned below. 



The earlier workers were sharply divided. Freudenreich, 

 Heim, Hesse, Weigmann, and Kolle found that Vibrio cholerae 

 was killed in raw milk, but Honigmann and Basenau observed 

 no germicidal action on this organism. Schottelius reports a bet- 

 ter growth of Corynebact. diphtheriae in raw milk than in sterilized 

 milk or bouillon. Hunziker in 1901 is apparently the first and 

 only investigator seriously to take account of the possible vari- 

 ation in germicidal power in the milk from different cows. He 

 showed a marked decrease in bacteria in the milk of some cows 

 and none in others, but observed only the action of the milk of 

 individual cows on their own milk flora and used no pure cul- 



1 Research Fellow, Missouri Botanical Garden. 



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THE JOURNAL OF BACTF.R'OLOnY, VOL. V, NO. 6 



