THE RELATION OF MICROORGANISMS TO BUTTER 409 



colonies, and in America. It may be said to be the standard butter 

 of the world since it is the type made in all the great dairy countries. 

 Sweet-cream butter is made especially in southern Europe, and in 

 Umited amounts in other countries. 



The intensity and kind of flavor of butter is thus dependent on 

 the acid fermentation of the milk or cream. It is not believed that 

 the fat undergoes any changes during the acid fermentation of the milk 

 which could produce the flavor of sour-cream butter, but rather that 

 the increase in flavor is due to the absorption by the butter fat of certain 

 of the compounds formed in the acid fermentation. It is not essential 

 that the fat be present during the acid fermentation in order to impart 

 flavor to the butter. If sweet cream is mixed with sour milk and 

 chm-ned at once, the flavoring compounds are absorbed by the fat from 

 the fermented milk, and the butter will have much the same flavor, 

 both as to intensity and kind, as though the fat had been present 

 during the fermentation. The churning of a mixture of sweet cream 

 and sour milk is used commercially and is identical with the methods 

 employed by the manufacturers of oleomargarine and renovated 

 butter to impart flavor to the flavorless fats they employ. It is 

 impossible to 'recognize these substitutes for butter by their flavor 

 since it is identical with and derived from the same source as the flavor 

 of butter. 



In the past many ideas have been expressed as to the source of 

 the flavor of butter; some have asserted that it is due, in part, to the 

 decomposition of the proteins of milk by proteolytic bacteria. Both 

 practical experience and experimental work have demonstrated the 

 connection between the acid fermentation of milk and the flavor of 

 butter, and it is certain that what is now considered the finest type of 

 butter can be made from cream in which only acid-forming bacteria 

 (see Chap. I) have grown. 



Flavor of Butter 



Control of Butter Flavor. — ^The commercial value of any 

 sample of butter is largely determined by its flavor. If it is lacking 

 in flavor and aroma, or if it has a poor flavor, it brings a low price. The 

 importance of being able to control the flavor, both as to degree and 

 kind, in the manufacture of butter has increased greatly in recent 



