FARM DAIRYING 



powder or liquid is emptied into a quart of pas- 

 teurized skim-milk and allowed to stand at a tem- 

 perature of 75° until coagulated. The can in 

 which the culture is made, and the stirring-ladle, 

 must always be sterilized, otherwise the culture 

 would soon become seeded with foreign germs. 

 The can must be kept covered. The first two or 

 three propagations may not have the desired 

 flavor, as it takes time for it to develop from the 

 commercial culture. 



In the ordinary making of a culture from time 

 to time, select good-flavored skim-milk, heat it to 

 a temperature of 185°, stirring it occasionally. 

 Allow it to stand at that temperature for twenty 

 minutes or longer, then quickly cool to a tempera- 

 ture of from 60° to 70°, according to conditions. 

 To this prepared milk add from one-half to two 

 per cent of the culture on hand; the amount should 

 depend on the vigor of the germs, the constancy 

 of the temperature, and the length of time before 

 the culture is required to be used. 



Before using, remove an inch or two from the 

 surface to guard against contamination from out- 

 side sources. Break up the remainder by stirring 

 it well, and fill a small sterilized glass jar for 

 propagating the next culture. With care, a cul- 

 ture may be propagated almost indefinitely. The 



[169] 



