



280 ‘Beronr OF one QuEMIst OF THE 
ammonium butyrate, ammonium caproate, etc. Also calcium 
salts of these acids are formed. - 
6. The casein, so far as it is not decomposed, slowly passes 
into a soluble condition. 
CAUSE OF CHEMICAL CHANGES IN THE RIPENING OF CHEESE. 
The chemical changes that take place when cheese ripens are. 
due to the action of bacteria. These bacteria get into the cheese 
by way of the milk, and they get into the milk from the air, the — 
bodies of cows, the hands of milkers, and all unclean utensils 
used in storing the milk —in fact, they may come from anything 
and everything with which the milk chances to come into contact 
from the time it leaves the cow’s udder up to the time it is put into 
the cheese-press. The nitrogen-compounds of the cheese, as well 
as the other constituents, furnish an extremely favorable medium 
for.the development of bacteria, other conditions being favorable. 
The bacteria in some way cause the casein, the albumen, the fat, 
and the sugar to undergo certain changes, producing new chemi- 
cal compounds and these new chemical compounds give to the 
cheese the characteristic taste due to what we call ripening. If 
the bacteria act more rapidly or for a longer period of time, these 
products of bacterial action become greater in quantity and the 
cheese acquires a stronger flavor. 
Different bacteria produce different changes, and even the same 
kind of bacteria, under different conditions, are believed to pyro- 
duce different changes. Hence in the ripening of cheese, we 
have different results produced, according as certain kinds of bac- 
teria develop more abundantly. Certain bacteria, whether one 
particular kind or more we can not yet say positively, produce 
the flavor which the market demands and which may be said to 
be the result of the natural ripening process. Either these same 
bacteria under other conditions or other bacteria under conditions 
suited best to their development often give rise to products that 
are offensive and that render the cheese worthless. In the present 
method of ripening cheese, the process is difficult to control, 
because we do not, at the outset, know what kinds of bacteria we 
have to deal with in our cheese. It is not improbable that in the 
near future we shall greatly modify our methods of cheese-making 
by sterilizing the milk to start with; that is, by destroying all ay 

