TREATMENT OF CREAM PREVIOUS TO THE CHURNING. 231 



have thus shown that cream can be ripened by means 

 of carefully-prepared pure cultures in such a manner that 

 pure and well-keeping butter is made from it, but that 

 there seem special difficulties in obtaining a distinct flavor 

 in the butter. Bacteriologists have gone to a great deal of 

 trouble in searching for a bacteria which would produce 

 not only a strong fresh acid taste, but a good flavor, with 

 but little success; so that Spallanzani finally says in de- 

 spair that fine flavor and keeping quality are character- 

 istics which only to a certain extent go hand in hand, and 

 Weigmann doubts that there is any single bacterium possess- 

 ing the faculty of bringing about this double end. Jensen 

 makes the following demands to a lactic-acid bacterium to 

 be used in creameries : (1) that it will sour the cream rather 

 strongly in comparatively short time, so that it can com- 

 pete with other bacteria present; (2) that it will thrive at 

 a relatively low temperature (60-72 F.); (3) that it will 

 coagulate the cream and milk to a uniform homogeneous 

 mixture, and give it a slightly sour taste and odor; (4) that 

 it will produce an agreeable aromatic taste and flavor. 

 But, he adds, we know at the present no acid bacterium 

 that fills all these conditions. 



In my experiments along this line I have not, among 

 the numerous bacteria examined, been able to show any one 

 bacterium possessing all the valuable qualities desired; but 

 by cultivating two different organisms, and mixing them 

 at the same time in the milk used for a starter, I have suc- 

 ceeded in obtaining a starter which produced both good 

 acid and an excellent flavor in the cream. I have either 



1890, to " Die Milch " by H. Scholl, 1891, and to nay book on " Sap- 

 rophytic Micro-organisms in Cow's Milk " (in Swedish), published 

 1889. G.G. 



