MODERN DAIRY PRACTICE. 



The question of how often the new starter should be 

 prepared from the pure culture cannot as a matter of 

 course be answered so as to apply to all conditions, as these 

 vary greatly at different creameries. The only rule that can 

 be given on this point is to use it as often as it proves 

 necessary. The new starter is propagated in the usual 

 way, separated and pasteurized skim-milk obtained from 

 new milk drawn and treated throughout with the most 

 minute care being always used. 



The new starter must be watched to prevent the fer- 

 mentation from proceeding too far, lest the acidity grow too 

 strong for the lactic-acid bacteria, thereby offering other bac- 

 teria e.g., the butyric-acid starters favorable conditions 

 of life. According to my experiments this stage will occur 

 when the cream contains about .85 per cent of lactic acid 

 a degree of acidity which but slightly exceeds that usually 



and my hands were also washed with sublimate solution and wiped. 

 The milk was drawn directly into a sterile flask provided with a 

 cotton plug, through which a piece of glass tubing about one half 

 inch wide and three to four inches long was placed ; the latter was 

 also closed with a small cotton plug. This plug was removed in 

 milking, and the narrow tube was after the milking again closed with 

 the plug. As a still further precaution this milk was heated in the 

 flask up to 158 F. (70 0.) for ten minutes and rapidly cooled to 

 about 77 F. (25 C.). The seeding with the lactic-acid bacteria was 

 done by introducing a recently-ignited capillary glass tube into the 

 agar-agar culture and placing it in the milk through the glass tube in 

 the cotton plug. Treated with sufficient care the milk was never con- 

 taminated, which fact was always directly ascertained. The inocu- 

 lated milk was left standing at 77 F. (25 C.), and always soured 

 evenly in the course of 16-20 hours. From this soured milk agar- 

 gelatine cultures were made, which in their turn were used the next 

 day for preparing the new starter. 



