CREAM-RIPENING 217 



or the first part of June, cover it with salt and hold it until the 

 winter months, keeping it in the cellar or some other cool place 

 until it was used up. As dairying advanced and butter-began 

 to be made on a large scale in creameries, in various countries, 

 the bacteriologist resorted to the method of isolating certain 

 species of bacteria for the purpose of ripening cream and pro- 

 ducing the desired flavor. 



It has not yet been proved that any particular species of 

 bacteria is responsible for the production of fine flavor in butter. 

 It is generally agreed that the flavoring substances developed 

 during the ripening of cream are decomposition products of bac- 



FIG. 72. Wizard vat pasteurizer and cream-rlpencr. (Creamery Package 



Mfg. Co.) 



terial growth, and it has been generally recognized that the types 

 producing the lactic acid are the most desirable ones to have 

 present in cream. There are a great many bacteria in milk and 

 cream which produce acid, over one hundred species have been 

 studied and described. It is apparent, however, that only a 

 comparatively few of these produce the best results in cream- 

 ripening. Hence, in the preparation of a natural starter, great 

 care should be exercised in selecting milk that will sour with a 

 pleasant acid taste. 



At the Iowa Experiment Station, McKay and Eckles con- 

 ducted a series of tests on fermentation by taking milk from 

 different patrons' herds, placing it in sterile glass bottles and 

 allowing it to sour naturally. It was found that milk which 



