1 88 BACTERIA IN BUTTER. 



however, the cream is churned without ripening, the butter 

 will contain various bacteria which can grow in the butter, 

 inasmuch as the lactic bacteria do not check them. The lactic 

 bacteria do not gro.w so readily in the butter as in the cream, 

 and the result is that other forms of fermentative bacteria 

 which may injure butter have a greater chance of developing 

 in butter made from unripened cream than in that made from 

 ripened cream. 



Effect of Ripening upon Flavor. The most important 

 effect of the ripening process is upon the flavor. The growth 

 of bacteria produces a variety of new chemical products. 

 Some of these may be excretions, and some of them by-pro- 

 ducts of chemical decomposition. Of these products, some 

 are known and others are as yet not understood by chem- 

 ists. Prominent among them, of course, is lactic acid, but 

 there is a long series of others. The products of fer- 

 mentative decomposition always have very strong tastes and 

 smells. These new chemical products which are developed 

 rapidly in the ripening cream, as the result of the wonderful 

 gro.wth of bacteria, will give to the cream a variety of new 

 flavors and odors. The butter made therefrom will show a 

 flavor not found in butter which is made from crearn before 

 such decompositions have taken place. The butter flavor is 

 that of incipient decomposition. 



While this is certain, the problem of what kind of bacteria 

 produces the typical flavors is one that has not yet been satis- 

 factorily settled. We have noticed that two prominent types 

 of milk bacteria are those producing lactic acid and those pro- 

 ducing albuminoid decomposition. Since these are the chief 

 types in ripening cream there can be little question that to one 

 of them must be attributed the butter flavors. But which is 

 primarily concerned ? It has been generally assumed by bac- 

 teriologists that it is the lactic bacteria which are responsible 

 both for the flavors and the acid. This conclusion is a natural 

 one, since the lactic bacteria greatly predominate in milk 



