44 THE BOOK OF CHEESE 



size. The contents may be either the culture medium 

 upon which the organisms grew or inert substance designed 

 merely to hold the bacteria in inactive form. In either 

 solid or liquid form, the producer of the culture should 

 guarantee its activity up to a plainly stated date. 



It is the problem 1 of the cheese-maker or butter-maker 

 to increase this small amount of lactic acid-forming or- 

 ganisms to such numbers and in such active condition 

 that it may be used in the factory; while being built 

 up, these organisms must be kept pure. The usual prac- 

 tice is to allow them to develop in some material, usually 

 whole milk or skimmed-milk ; dissolved milk powder may 

 be used in the place of milk. 



60. Manufacturer's directions. The manufacturer 

 usually sends directions with his starter preparation, 

 telling how it should be used to secure the best result. 

 These directions apply to average conditions and must be 

 varied to suit the individual instances so that a good 

 starter will be the result. The directions usually state 

 the amount of milk necessary for the first inoculation. 

 It is usually a small amount, one or two quarts. After 

 the specific amount has been selected, this milk should 

 be pasteurized. 



61. Selecting milk. The milk for use in starter- 

 making should be selected with very much care. Only 

 clean-flavored sweet milk, free from undesirable micro- 



1 Bushnell, L. D., and W. R. Wright, Preparation and use of 

 butter starter, Mich. Exp. Sta. Bui. 246, 1907. 



Hastings, E. G., Preparation and use of starter, Wis. Exp. 

 Sta. Bui. 181, 1909. 



Larsen, C., and W. White, Preparation and use of starter, 

 S. D. Exp. Sta. Bui. 123, 1910. 



Guthrie, E. S., and W. W. Fisk, Propagation of starter for 

 butter-making and cheese-making, N. Y. (Cornell) Exp. Sta. 

 Circ. 13, 1912. 



