168 Dairy Bacteriology. 



and Schweitzer Hauskase, a soft variety. Of the nln3 

 species of bacilli and cocci found in mature Emmenthaler, 

 eight of them were also present in ripened Hauskase. 



Different investigators have studied the bacterial flora of 

 various kinds of cheese, but as yet little comparative sys- 

 tematic work has been done. Freudenreich * has determined 

 the character and number of bacteria in Emmenhtaler 

 cheese, and Russell 2 the same for cheddar cheese. The same 

 general law has also been noted in Canadian 8 and Eng- 

 lish 4 cheese. At first there is found a marked decrease in 

 numbers, lasting for a day or two. This is followed by an 

 enormous increase, caused by the rapid growth of the 

 lactic-acid type. The development may reach scores oi 

 millions and often over a hundred million organisms per 

 gram. Synchronous with this increase, the peptonizing 

 and gas-producing bacteria gradually disappear. This rapid 

 development, which lasts only for a few weeks, is followed 

 by a general decline. 



In the ripening of cheese a question arises as to whether 

 the process goes on throughout the entire mass of cheese, 

 or whether it is more active at or near the surface. In the 

 case of many of the soft cheese, such as Brie and limburger, 

 bacterial and mold development is exceedingly active on the 

 exterior, and the enzyms secreted by these organisms dif- 

 fuse toward the interior. That such a condition occurs in 

 the hard type of cheese made with rennet is extremely im- 

 probable. Most observers agree that in this type of cheese 

 the ripening progresses throughout the entire mass, al- 

 though Adametz opposes this view and considers that in 



1 Freudenreich, Landw. Jahr. d. Schweiz, 4: 17; 5: 16. 



'Russell, 13 Kept. Wis. Expt. Stat., 18%, p. 95. 



8 Harrison, Unpublished Data. 



* Lloyd, Bath ajd West of Eng. Soc. Kept., 1892, 2: 180. 



