82 MILK [vi 



(77 Fahr.) no less than the gigantic number of 

 577,500,000 bacteria per cubic centimetre have been 

 found (Freudenreich). 



Classification of Bacteria infesting Milk. 

 The bacteria infesting milk may be classified in 

 various ways. The classification adopted by 

 Grotenfelt l is the following : 



I. JBacteria whose Action is Indifferent. In the 

 first place, we have a large number of bacteria whose 

 action is quite indifferent; that is to say, which 

 exercise, so far as we know, neither a harmful nor a 

 beneficial action. 



II. Bacteria whose Action is of a Useful Nature. 

 Secondly, we have bacteria whose action in milk is 

 of an indifferent nature, but which are active in 

 milk-products cheese, etc. 



III. Bacteria whose Action is of an Indirectly 

 Injurious Nature. Thirdly, we have bacteria which 

 exert an indirectly injurious action on milk. Such 

 bacteria produce conditions which are favourable for 

 the development of bacteria whose action is directly 

 injurious. This class includes bacteria which cause 

 an alkaline reaction in milk a reaction favourable 

 to a large class, indeed the majority, of ferments. 

 Under this class also come certain bacteria which 

 exert a directly injurious action. For instance, the 



1 See Principles of Modern Dairying, by Grotenfelt, translated 

 by F. W. Woll (John Wiley and Sons), p. 94. 



