CREAM-KIPi;Xl\G 



217 



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

 winter months, keeping it in the cellar or some other C(jol place 

 until it was used up. As (kur}-ing ach'anced and Ijutter began 

 to be made on a large scale in creameries, in various ci.iuntries, 

 the bacteriologist resorted t(j the method of isolating certain 

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

 ducing the desired flavor. 



It has not )et been piroved that an}- particular species of 

 bacteria i,, responsible for the production of fine f^a^•or in butter. 

 It is generalh' agreed that the tla\-oring substances developed 

 during the rii)ening of cream are decomposition products of bac- 



r'lc. 72. — \\ izarij \at pasteurizer ami crcani-r.pcner. (CreaniLTy Package 



terial growth, and it has been general!)- recognized that the t\-l>es 

 producing the lactic acid are the n-ost desirable ones to ha^-e 

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

 cream which produce acid, over one hundred species ha\-e been 

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

 comparatiN'eh- 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 n-^ilk that will sour with a 

 pleasant acid taste. 



At the Iowa Experiment Station, i\IcKay 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 naturallv. It was found that milk which 



