Bacteria in Butter-Making. 131 



Conn has found a number of the organisms that are 

 favorable flavor- producers ; in fact they were much more 

 numerous than desirable aroma-yielding species. None 

 of the favorable aroma forms were lactic acid species l . 



131. Effect of bacteria on ripening". The majority 

 of bacteria in ripening cream do not seem to exert any 

 particular influence in butter. A considerable number 

 are positively beneficial, inasmuch as they produce a good 

 flavor and aroma, so far as these qualities are pronounced. 

 A more limited number are concerned in the production 

 of undesirable ripening changes 2 . A knowledge of the 

 conditions that control the development of these respect- 

 ive types of ripening is of greatest practical value to the 

 butter-maker. If it were possible to have these condi- 

 tions under exact control, then the butter industry would 

 be reduced to the terms of an exact science. 



132. Methods of cream-ripening". 1. Natural ri- 

 pening. The simplest and oldest method is where the 

 cream is allowed to ripen without any special control, the 

 only artificial aid being a regulation in a crude way of 

 the temperature. The whole process is a let-alone one. 

 The ripened product varies much in degree of ripeness ; 

 also in the kind of fermentation, depending upon the 

 various species of bacteria that have happened to gain 

 access to the milk. 



The results obtained by these cruder methods are 

 usually fair, but simply because the majority of the or- 

 ganisms normally present in ordinarily clean milk are 

 such as are unable to produce marked flavors of an un- 

 desirable character. 



2. Natural starters. In the above method the rate of 

 ripening is often irregular, and to overcome this, starters 



1 Weigmann has reached these same results (Milch Ztg., p. 793, 

 1891). 



2 Eckles. Cent. f. Bakt., II. Abt., 4: 730. 1898. 



