72 Dairy Bacteriology. 



be confined to the treatment of surroundings, rather than 

 used in the milk itself. 



70. Overcoming 1 taints by use of starters. An- 

 other method that is often fruitful, is that which rests 

 upon the inability of one kind of bacteria to grow in the 

 same medium in competition with other species. 



Some of the undesirable taints in factories can be in 

 large part controlled by the introduction of starters made 

 from certain organisms that are able to obtain the as- 

 cendency over the taint-producing germ. Such a method 

 is commonly followed when a lactic ferment, either a 

 commercial pure culture, or a home-made starter, is added 

 to milk to overcome the effect of gas- generating bacteria. 



A similar illustration is seen in the case of the "lange 

 wei" (slimy whey), that is used in the manufacture of 

 Edam cheese to control the character of the fermentation 

 of the milk. 



This same method is sometimes applied in dealing with 

 certain abnormal fermentations that are apt to occur on 

 the farm. It is particularly useful with those tainted 

 milks known as "sweet curdling. n The ferment organ- 

 isms concerned in this change are unable to develop 

 in the presence of lactic acid bacteria, so the addition of 

 a clean sour milk as a starter restores the normal condi- 

 tions by giving the ordinary milk bacteria the ascend- 

 ency. 



71. Chemical disinfection. In only exceptional in- 

 stances will it be necessary to employ chemical disinfect- 

 ants to restore the normal conditions. Of course with 

 such diseases as tuberculosis, very stringent measures are 

 required, as they are such a direct menace to human life, 

 but with these abnormal or taint- producing fermenta- 

 tions, care and cleanliness, well directed, will usually 

 overcome the trouble. 



