BACTERIA IN I'.U T TER-MAK IN(J. 24! 



is less uniform than when pasteurization is used. Third, the 

 butter-maker certainly has a better control over the ripening 

 process than by the method of spontaneous ripening ; for by 

 the addition of the starters he can, with very great accuracy, 

 determine beforehand the rapidity of the ripening and the time 

 of churning. 



Because of these results this method of making butter has 

 been very widely adopted. Ten years ago the use of special 

 "starters" was frequently resorted to, but they were reserved 

 practically for cold weather, when the ripening took place 

 slowly, and no very special attention was given toward obtain- 

 ing the proper starter. But to-day starters are used very ex- 

 tensively throughout the year, even in hot weather, and spe- 

 cial attention is given toward obtaining the proper kind of 

 starter. There are, however, two quite different methods of 

 preparing these starters, one by the use of pure cultures, and 

 the other by the use of natural starters. 



Use of Non-pasteurized Cream with Commercial Pure Cul- 

 tures. This method of preparing starters is by the use of 

 commercial cultures which are so easily purchased. These 

 can be obtained at regular intervals from different supply cen- 

 ters, and then, by the use of very simple methods already 

 described, they can be "built up" into proper cultures for 

 adding to the cream. Such a starter is practically uniform in 

 all cases. 



Use of Non-Pasteurized Cream with Natural Starters. A 

 far more common method of obtaining a starter for the pur- 

 pose, one that is now widely adopted in American dairies, 

 consists in using what is known as a natural starter. A natu- 

 ral starter is within the reach of any butter-maker, independ- 

 ent of commercial cultures, for it is something that can be 

 made in any dairy, entirely without the aid of a bacteriologist. 

 It does not involve the expense of purchasing a pure cul- 

 ture, and for this reason has been adopted in hundreds, per- 



