FUNGI IN CHEESE RIPENING. 97 
Two of the very common green species of Penicillium grew 
richly. Oidium lactis grows abundantly in the Brie and Isigny 
cellars visited. In these the temperature was 50° to 55° F. 
(11° to 12° C.). Numerous experiments in the ripening cellar 
show that the Camembert Penicillium does not grow at its best 
in a room cooler than 60° F. (15° C.) and that to obtain rapid 
development the room should be slightly warmer. Until this 
mold is well established, therefore, it is distinctly an advantage 
to grow it at a temperature of 65° to 70° F. Repeated experi- 
ments have shown that lowering the temperature to 52° to 55° F. 
checks the rate of ripening very materially. A difference of 
less than ten degrees between two rooms will often make as 
much as two weeks difference in the ripening period of cheeses 
from the same lot in the two rooms. <A temperature as low as 
54° to 55° F. as given in an article in the Creamery Journal 
referred to above appears to prolong the ripening period with- 
out contributing any compensating advantages. A half-ripened 
cheese was cut, the progress of the softening of the curd was 
noted, and the cheese put in a refrigerator where it was held 
for four weeks at 48° F. It was then found to be completely 
ripened and perhaps a little old in one place, but the changes 
noted at the end of this period would have been produced 
within a single week at 60° F. The cold storage possibilities 
suggested by this experiment will be further studied. 
Some experiments were made to show the resistance of spores 
to heat. The spores of the Camembert and Roquefort Peni- 
cillia were inoculated into gelatine and placed in an incubator. 
Heating for an hour and fifteen minutes at 56° C. killed all 
spores of the Camembert species. Only a few spores of this 
mold grew after one hour at the same temperature, while some 
spores of the Roquefort Penicillium grew after two and a half 
hours. 
HUMIDITY. 
The use of very moist cellars and caves in the ripening of ‘this 
class of cheeses is practically universal. The richest develop- 
ment of mold is seen in rooms where the atmosphere is saturated 
or nearly so. ‘This appears to be exceptionally true for species 
like Camembert Penicillium which is purely a milk fungus, 
and in which there is a large development of thin-walled 
