514 BACTERIA IN BUTTER AND CHEESE-MAKING 



becomes separated as buttermilk. The latter generally has the 

 following composition : Water, over 90 per cent. ; fat, about J per cent. ; 

 nitrogenous compounds, 3.4 per cent.; lactose, 4.7 per cent.; ash, 

 0.7 per cent. 



The artificial starters used in the souring of cream as employed 

 in this country are either in the form of a powder or in the form of 

 a liquid culture. They are first increased before being added to the 

 cream, a procedure called the "building up of the starter." This is 

 done by adding a freshly opened package or bottle of the starter to a 

 quart of skim milk, whole milk, or cream which has been sterilized or 

 pasteurized and cooled down to 60 F., and stirring and mixing it 

 thoroughly with the milk. The latter is then kept at 65 F., protected 

 against dirt and other contamination. When quite sour, but before 

 coagulation has occurred, the increased or built-up starter is added 

 to the cream which is to be soured or ripened. If the cream used 

 has been pasteurized or has come from pasteurized milk, more of the 

 starter is needed than if this is not the case, and thus, according to 

 varying circumstances from 4 to 10 per cent, of the starter are added. 

 The use of pasteurized cream for butter making is very prevalent 

 in some European countries, because the butter so obtained, owing 

 to the non-development of certain undesirable bacteria, is more 

 uniform in character and less liable to show objectionable features. 

 In the United States artificially prepared starters are often used on 

 unpasteurized cream. In such cases the bacteria of the starter act in 

 combination with the bacteria already present in the cream and the 

 results are not as satisfactory as when pasteurized cream is used. 



Conn (Agricultural Bacteriology}, in discussing the use of starters 

 in our country, says : "The fact that starters, with or without pasteur- 

 ization have become almost universally used among the better class 

 of creameries is in itself sufficient proof that they are of practical 

 value. Their advantage lies in four directions : 



"1. They enable the buttermaker to handle his cream more easily 

 and uniformly. He can regulate the ripening in such a way that 

 his cream will always be of a certain grade of ripeness at a certain 

 time of the day; for a little experience tells him how much of his 

 culture, under proper conditions, should be added to the cream to 

 produce the proper grade of ripening at the particular time when he 

 desires to churn. 



"2 The use of starters has produced a greater uniformity in the 

 grade of butter. The buttermaker can depend more certainly 

 upon producing butter of a high grade, month after month, than he 

 can without the starter. There is a general belief also among those 

 who have tested the butter in countries where starters are widely 

 used that there is an improvement in the average quality of the 

 butter as well as in its uniformity. 



"3. It has become pretty definitely agreed that the flavor of butter 

 is improved by the use of such cultures. It is somewhat difficult 



