3 o THE BUTTER INDUSTRY IN UNITED STATES [254 



Ever since the hand separator came into general use the 

 creameries have tried to improve the quality of the cream. 

 There are some obstacles in the way. In the first place, the 

 hand separator must be thoroughly washed and sterilized 

 every time it is used in order to prevent the growth of per- 

 nicious bacteria and their transmission into the newly-sep- 

 arated cream. The importance of sterilization is, of course, 

 not always appreciated, and this causes a great deal of 

 mischief. In the second place, there is frequently keen 

 competition among producers, and in the effort to secure all 

 the cream available, terms that encourage laxity in the care 

 of the cream are sometimes made with farmers. Attempts 

 are being made, however, to remedy the evil by paying for 

 cream according to quality. In general, the plan is to pay 

 more for sweet cream than for sour cream. This, of course, 

 presupposes cooperation among the creameries in a given 

 section of the country. 



RECENT CHANGES IN METHODS OF PRODUCTION 



Nature has provided a special bacterium, called the lactic 

 acid bacillus, to sour milk or cream. When cream is al- 

 lowed to ripen naturally preparatory to churning, it is due 

 to the development of these bacilli that always manage to 

 get into milk. It takes considerable time, however, for the 

 cream to ripen naturally, and in order to' avoid this delay 

 creameries now generally use home-made or commercial 

 " starters ". The commercial " starter " is prepared by 

 isolating the lactic acid bacilli and cultivating them in a 

 suitable medium. By the use of the " starter " the time of 

 ripening can not only be controlled, but the flavor of the 

 butter can be improved, since good flavor is believed to be 

 largely dependent upon the predominance of lactic acid 

 bacteria over other bacteria in the cream. Too much acid- 

 ity in the cream, however, produces a " fishy flavor " in 



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