i8o 
Journal of Agricultural Research 
Vol. II, No. 3 
circumstances, for the ripening of Cheddar cheese must be regarded as a 
spontaneous fermentation, limited to certain groups of bacteria by the 
conditions obtaining in the cheese mass and subject to variation within 
the groups by accident of inoculation before or during the cheese mak¬ 
ing, or by slight variations in the raw material or in the method of manu¬ 
facture, which enable one variety or the other to gain an ascendancy. 
SYMBIOTIC RELATION OF CHEESE ORGANISMS 
The complex chemical changes taking place in a mixed culture of bac¬ 
teria have usually been regarded as the result of the combined activity of 
the individual properties of each of the several species when grown alone, 
with these properties accelerated in some cases by the associated action. 
Among the many cultures of cheese organisms inoculated into the car¬ 
bohydrate media, it was observed that when by accident the culture 
was contaminated with other cheese organisms through failure of a pure 
isolation, there appeared to be a high ability to attack the more complex 
substances. Accordingly many inoculations of cheese cultures were 
made into the test media in various combinations, to determine whether 
associative action would give new properties to the cultures concerned. 
In this experiment the test for acid production was the reddening of litmus 
paper. In many cases acid was produced from a given substance by the 
associated action, when neither culture working alone would give such a 
reaction. A few examples are given in Table XI to show the results of 
these inoculations. 
Table; XI.— The effect of the associative action of cheese organisms in breaking down 
test substances 
Organism. 
Production of acid in broth containing— 
Lactose. 
Salicin. 
Sucrose. 
Glycerin. 
Mannit. 
Inulin. 
Bacterium lactis acidi, a. 
+ 
Bacterium casei, a. 
_ 
_ 
_ 
Bacterium casei, b. 
Streptococcus, b. 
+ 
+ 
+ 
+ i 
+ 
+ 
- 
+ 
- 
Streptococcus, c. 
+ 
+ 
Micrococcus, b. 
_ 
_ 
Bacterium lactis acidi, a; Bac¬ 
terium casei, a. 
Bacterium lactis acidi, a; Bac¬ 
terium casei, b. 
+ 
! 
! 
+ 
+ 
+ 
j _ 
+ 
_ 
Bacterium lactis acidi, a; Strep¬ 
tococcus, b. 
+ ■ 
+ 
+ 
_ 
i 
_ 
Bacterium lactis acidi, a; Strep¬ 
tococcus, c. 
Bacterium casei, a; Bacterium 
casei, b. 
+ 
+ 
+ 
+ 
_ 
+ 
+ 
~r 
_ 
+ ! 
_ 
Bacterium casei, a; Strepto¬ 
coccus, b. 
+ 
_ 
+ 
_ 
| 
_ 
Bacterium casei, a; Strepto¬ 
coccus, c.. 
+ 
+ 
+ 
+ 
+ 
_ 
Bacterium casei, a; Micrococ¬ 
cus, b. 
+ 
+ 
+ 
- 
- 
- 
