164 Dairy Bacteriology. 



stratum for their growth. In Brie cheese a blue coating 

 of mold develops on the surface. In the course of a few 

 weeks, a white felting appears which later changes to 

 red. This slimy coat below the mold layer is made up 

 of diverse species of bacteria and fungi that are able to 

 grow after the acid is consumed by the blue mold. The 

 red coating acts upon the casein, also producing an alka- 

 line reaction that is unfavorable for the growth of the 

 blue mold. Two sets of organisms are therefore, essen- 

 tial in the ripening process, one preparing the soil for the 

 ferment that later produces the requisite ripening 

 changes. The process as carried on is largely empirical 

 and if the red coat does not develop at the proper time, 

 the maker resorts to all sorts of devices to bring out the 

 desired ferment. The appearance of the right form is 

 dependent, however, upon the proper reaction of the 

 cheese, and if this is not suitable, the wished-for growth 

 will not appear. 



In those cases where the ripening change takes place 

 from outside toward the center, there is always an outer 

 layer that is changed to such an extent as to be unfit for 

 food. 



B. BACTERIA IN ABNORMAL CHEESE PROCESSES. 



173. Susceptibility of cheese to abnormal changes. 



Cheese more than butter is subject to detrimental fermen- 

 tations incited by bacteria, because it is so much better 

 adapted for germ growth on account of its better and 

 more available food- supply. Many abnormal ferments 

 that find their way into the milk before it is made up de- 

 velop these peculiarities, especially in cheese. Then too, 

 the method of curing is so often without control, es- 

 pecially with many of those methods that employ fungi 

 as agents in the curing process. Inability to check the 



