1 90 BACTERIA IN BUTTER AND OLEOMARGARINE. 



mark butter is always made from pasteurized cream, and this 

 makes it necessary to use an artificial starter, since pasteurized 

 cream will not ripen of itself. The pasteurization destroys practi- 

 cally all of the acid bacteria, and, as we have learned, when the acid 

 bacteria are absent the putrefying bacteria are quite sure to develop. 

 Hence, pasteurized milk requires an acid starter to insure a proper 

 ripening. 



In Unpasteurized Cream. By this method the starter is 

 simply added to the ordinary cream. The use of starteis in this 

 way is open to a theoretical objection. The cream already con- 

 tains bacteria in large numbers and, ordinarily, in considerable 

 variety. These would themselves produce the ripening of cream, 

 even without any starter. The effect of the starter added to the 

 cream already filled with bacteria will, evidently, not always be 

 uniform. It might produce little or no effect, or, if the starter is 

 added in considerable quantity, it might overcome the effect of the 

 smaller number of bacteria originally in the cream. In practice it is 

 found that the use of starters does have this latter effect, and in most 

 cases, there is a noticeable improvement in butter made from cream 

 thus ripened. The results, however, are not absolutely uniform, 

 and even with the use of a large amount of starter it will sometimes 

 happen that the bacteria present in the cream will have more in- 

 fluence than those of the starter, and the butter will suffer. 



The use of cultures in unpasteurized cream was first begun in the 

 United States and has been more widely adopted here than any- 

 where else. Butter made from unpasteurized cream is not so 

 uniform as that made from pasteurized cream, but the butter made 

 in this way is, at least to the American taste, superior to butter made 

 with pasteurization, due probably to the fact that pasteurization 

 prevents the growth of miscellaneous bacteria that ordinarily 

 occurs before the lactic bacteria develop. Pasteurized cream butter 

 is somewhat milder in flavor than that made from unpasteurized 

 cream, and the American market demands a flavor somewhat 

 stronger than that which is popular in Europe. Hence, to the 

 American taste, up to the present time, the butter from pasteurized 

 cream is not superior to that made from unpasteurized cream. 



