222 BACTERIA AND OTHER MICROORGANISMS IN CHEESE 
material. This layer grows deeper and deeper as it encroaches 
upon the curd. The enzyme produces a profound change in the 
casein, converting it first into peptones and similar bodies; later 
these break down into simpler bodies, or end-products, among 
which ammonia may always be detected. These latter end-prod- 
ucts give the flavor, and appear to be produced by bacteria rather 
than by the action of the enzymes secreted by the mold. During 
the ripening the cheese will be found to have a core of a sour, acid 
curd in the center, surrounded by a layer of soft, digested material. 
The cheese ripens thus, from thesurface inward, 
and is not completely ripened until the soft 
layer reaches the center. 
The flavors are not due to the enzyme 
digestion, but to the end-products of decom- 
position. In the case of this cheese, as in 
the hard cheeses, no positive knowledge is at 
hand as to the exact source of the flavor. 
That it is not due to the mold alone is certain, 
‘ from the fact that the softened cheese may be 
nearly tasteless, if a pure culture of mold has 
completed theripening. ‘The peculiar Camem- 
Fic. 44.—Pemcil- bert flavor is, beyond doubt, associated with 
ute pide oes some of the microérganisms growing in or on 
Roquefort cheese the cheese, but at present no more is known 
(Thom). 
about the matter. 
Roquefort Cheese—This represents a type of cheese that, like 
Camembert, is ripened by both bacteria and molds. Closely 
allied to it are the Sizlion and Gorgonzola cheeses. The mold is a 
blue instead of a white one, and it grows through the cheese and 
not alone on its surface. To bring about the growth in the 
center of the cheese special means are devised in its manufacture. 
The cheese-maker begins by cultivating the necessary mold on 
bread. After the mold on the bread has produced a great quantity 
of spores, the mass is dried and ground into powder (Fig. 44). 
