
THE CAMEMBERT TYPE OF SOFT CHEESE. 59 
Camembert mold (Culture No. 128); 2, the related species iso- 
lated from Roquefort cheese which we may call the Roquefort 
mold; 3, one species of Mucor; 4, Oidium lactis, and sometimes 
other species of the same genus Penicillium. In’some studies 
the list has been extended to a dozen species in each experi- 
ment, because with the larger numbers, comparison of charac- 
ters gives a better judgment of the real nature of the processes 
studied. 
The souring of the curd as a consequence of the presence of 
lactic bacteria has already been described as the first change 
after the cheese is made; also the fact that in Camembert cheese 
the lactic acid so produced later largely disappears, so that when 
fully ripe such a cheese commonly has an alkaline reaction to 
litmus. This disappearance of acid together with the well- 
known ability of many molds to reduce acidity, has been re- 
garded as the main, if not the only, function of the mold in 
ripening cheese. This view has been widely quoted. Compara- 
tive cultures of a large number of species shows that a very 
large proportion of the common molds are able to neutralize, if 
not decompose, lactic acid, but they do this in different degrees 
and at very different rates. The Camembert mold increases 
the acidity of the medium during its first few days of growth, 
then changes and reduces acidity for the remainder of the period 
of activity. Some other forms reduce acidity from the first and 
do itmuch more rapidly than this one. If this were the only 
function of the mold in cheese ripening, many other species 
should be equally valuable, or by working more rapidly, would 
probably be far more effective. This part of the ripening then 
might be accomplished by any one of a large number of forms. 
We then turned our attention to determining whether any or 
all of these fungi acting in pure cultures possessed the power to 
change the hard curd to the semi-liquid or viscous condition of 
the ripened Camembert cheese. A long series of cultures upon 
sterilized milk, milk agar, and sterilized curd were prepared. 
Careful bacterial determinations were made to show that the 
cultures were pure. From these the following facts appeared: 
Sterile milk is slowly but almost completely digested by nearly 
every species of fungus tried. Flakes of curd in milk agar 
plates disappear as a result of the action of the fungi selected 
