ARTIFICIAL CULTURES IN CHEESE MAKING. 249 



cheeses (American cheeses) have been learning that the use 

 of lactic cultures enables them to control the character of the 

 ripening far better than in previous years. The growth of 

 lactic bacteria checks the growth of other species in all milk 

 products, and thus protects them from undesired fermenta- 

 tions. A pure culture of lactic bacteria added to the rnilk to 

 be made into cheese proves to have a valuable influence in 

 preventing abnormal ripening of the cheese. The cultures 

 used are prepared by practically the same method as in mak- 

 ing starters for cream ripening. Both pure cultures and 

 natural starters are used, and they are sometimes propagated 

 in a cheese factory from day to day for months without the 

 necessity of renewal by a fresh culture. Here, as in cream 

 ripening, the pure cultures appear more reliable than the 

 natural starters. The use of these lactic cultures has come to 

 be adopted almost universally in some qf the large cheese- 

 making districts in America, and is making a rapid change 

 in the method of cheese-making. 



The future development of the use of bacteria in cheese- 

 making cannot be predicted. It is probable that the problems 

 will be solved slowly and that, little by little, as the different 

 types of cheeses are studied, one factor after another will be 

 brought under control. The next few years will probably 

 see the gradual solution of many of the problems connected 

 with cheese-making, and whereas it will not be likely that any 

 one great discovery will be made which will apply to all types 

 of cheeses or which can be used widely throughout the 

 cheese-making sections, it seems very likely that, in different 

 localities, through the agency of bacteriological discoveries, 

 the whole industry will be slowly but completely changed. 

 We may probably look forward to the time when the process 

 of cheese ripening will be much more completely under the 

 control of the cheese-maker than at the present time. This, 

 ho.wever, is not likely to come by the wholesale use of pure 

 cultures, but rather by a combination of the use of pure cul- 



