RELATION OF BACTERIA TO DAIRY INDUSTRY. 91 



ing normal ripening. These experiments consist 

 of making cheese out of milk that has been de- 

 prived of its bacteria, and which has been inocu- 

 lated with large quantities of the species in ques- 

 tion. Hitherto these experiments have not been 

 very satisfactory. In some cases the cheese ap- 

 pears to ripen scarcely at all ; in other cases the 

 ripening occurs, but the resulting cheese is of a 

 peculiar character, entirely unlike the cheese that 

 it is desired to imitate. There have been one or 

 two experiments in recent times that give a little 

 more promise of success than the earlier ones, for 

 a few species of bacteria have been used in ripen- 

 ing with what the authors have thought to be 

 promising success. The cheese made from the 

 milk artificially inoculated with these species 

 ripens in a satisfactory manner and gives some 

 of the character desired, though up to the pres- 

 ent time in no case has the typical normal ripen- 

 ing been produced in any of these experiments. 



But these experiments have demonstrated be- 

 yond question that the abnormal ripening which 

 is common in cheese factories is due to^the pres- 

 ence of undesirable species of bacteria in the milk. 

 Many of the experiments in making cheeses by 

 means of artificial cultures of bacteria have re- 

 sulted in decidedly abnormal cheeses. Many of 

 the cheeses thus manufactured have shown imper- 

 fections in ripening which are identical with those 

 actually occurring in the cheese factory. Sev- 

 eral different species of bacteria have been found 

 which, when artificially used thus for ripening 

 cheese, will give rise to the porosity and the ab- 

 normal swelling of the cheese already referred to 

 (Fig. 24). Others produced bad tastes and fla- 

 vours, and enough has been done in this line to 



