PURE CULTURES VS. NATURAL STARTERS. 2OJ 



nated with bacteria that produce undesirable results. In 

 some dairies the lactic bacteria which are present are gas- 

 producing organisms, and these do not produce so satisfactory 

 a natural starter as the type of lactic bacteria that does not 

 produce gas. Consequently, in the preparation of a natural 

 starter the butter-maker cannot be absolutely confident that 

 the starter will be satisfactory. When it is satisfactory it 

 is probably equal, if not slightly superior to, an artificial 

 starter ; but it is not always of a character that can be used. 



The question which kind of starter is most practical for 

 use in ordinary butter-making will be answered in each 

 case, to a large extent, according to convenience. In large 

 creameries it will, perhaps, be found less expensive and more 

 satisfactory to use commercial cultures ; in small ones, where 

 the dairies are more directly under the control of the butter- 

 maker and close at hand, the use of natural starters will 

 probably continue, and it is doubtful whether commer- 

 cial cultures will ever be introduced. At all events, in 

 this country natural starters have hitherto proved to be more 

 practical than the commercial cultures. Natural starters are 

 used very widely by butter-makers ; commercial cultures are 

 used, as yet, only in a comparatively few isolated cases, 

 although their use is increasing. What the future will be 

 would be rash to predict. 



The facts above given indicate that the commercial cul- 

 tures are never quite equal to the best type of natural starter, 

 and that the butter made by the use of pure cultures is never 

 quite of the high grade of flavor that is found in the best 

 kind of spontaneous ripening. This apparently indicates that 

 the bacteriologists have not, as yet, succeeded in putting into 

 their cultures the proper kind of organisms. If the explana- 

 tion of cream ripening given above is correct, it is easy 

 to understand why this is true. If the ripening of 

 the cream is a twofold process, involving first the growth 

 of miscellaneous bacteria with a production of flavor and, 



