June is, 1914 
Flavor of Cheddar Cheese 
181 
Further inoculations were made into broth containing the test sub¬ 
stances to determine the quantitative effect of this associative action. 
The results of some of these inoculations are given in Table XII, in which 
the acidity is expressed as lactic acid. 
Table XII .—The effect of the associative action of cheese organisms in the production 
of acid 
Medium. 
Organism. 
Salicin. 
Sucrose. 
Mannit. 
Indi¬ 
vidual 
action. 
Asso¬ 
ciative 
action. 
Indi¬ 
vidual 
action. 
Asso¬ 
ciative 
action. 
Indi¬ 
vidual 
action. 
Asso¬ 
ciative 
action. 
Bacterium lactis acidi, a 
Bacterium casei, a. 
Bacterium lactis acidi, a, 
Streptococcus, b. 
Bacterium lactis acidi, b. 
Bacterium casei, a. 
Bacterium lactis acidi, b. 
Micrococcus, c. 
Bacterium lactis acidi, d. 
Bacterium casei, a.. 
Bacterium lactis acidi, d. 
Micrococcus, b. 
Per cent. 
o. 00 
. 00 
. 00 
. 00 
. 00 
• 30 
. 00 
•39 
. 00 
. 00 
. 00 
. 00 
Per cent . 
Per cent. 
o. 00 
. 00 
. 00 
. 00 
. 00 
. 00 
. 00 
•44 
. 00 
. 00 
. 00 
. 00 
Per cent. 
> o. OO 
} -j£, 
• 5 i 
■J1 
Per cent. 
( O. OO 
1 . OO 
f . OO 
\ . OO 
f . OO 
t . OO 
f . OO 
t . OO 
f . OO 
[ . OO 
f . OO 
l • 33 
Per cent. 
| O. OO 
| . OO 
| . OO 
} 
} 
} - 
The data show that considerable quantities of acid can be formed in 
mixed cultures even though the individual cultures are unable to ferment 
the substance in question. In the Bacterium lactis acidi group, 13 posi¬ 
tive reactions were obtained and determined by titration in cultures in 
which a member of this group was mixed with a representative of one 
of the other three groups of cheese organisms, while 23 cases were negative. 
In the entire 36 tests none of the organisms was able to ferment the 
substance used when working alone. The same symbiotic relations were 
exhibited by the B . casei group when a member of this group was grown 
together with a representative of one of the other groups of cheese 
organisms or with another variety of the same group. (See Table XI.) 
Thus, it appears not only that the influence upon each other of the 
cheese organisms is beneficial in enhancing the individual powers in many 
cases but also that the symbiosis enables the cheese organisms to attack 
other food substances than any one species working alone would be 
able to utilize. 
The fact that the normal flora of Cheddar cheese consists of a number 
of varieties of the four groups of cheese organisms and that these exert 
upon one another a decided influence in their chemical activities is most 
important in considering the cheese-ripening problem. 
