June 15, 1914 
Flavor of Cheddar Cheese 
183 
One variety of the Streptococcus group was isolated once, and two 
varieties of the Micrococcus were isolated, each only once, in small 
percentages. The small percentages of cocci were isolated from cheese- 
agar plates in the same manner as was followed in the analysis of the 
raw-milk cheese presented in Table IX. Cheese No. 20 was quite 
badly contaminated with a liquefying coccus which infected each of 
the three vats of milk made up separately into cheese. The contam¬ 
ination is given in a separate column. The data from the dilution cul¬ 
tures show Bacterium lactis acidi, b, as the predominating organism of 
the cheese at every examination. The B. casei group developed 
slowly in this cheese. It was present in exceedingly small percentage 
during the first few days. Unfortunately the dilutions were made too 
high, so that this group did not appear in the dilution cultures in the 
analyses made between the sixth and forty-seventh days. At the 
forty-seventh and seventy-second days there were present 1,000,000 
bacteria of this group per gram of cheese. 
Table XIV .—Bacterial content of pasteurized-milk cheese No. 21 to which was added 
°'75 P er cen t °f a culture of Bacterium lactis acidi , d 
Age. 
Plate cultures. 
Dilution cultures. 
Bacteria 
content. 
Variety 
of B. 
lactis 
acidi, d. 
Variety of 
micrococci. 
Bacterial 
content. 
Vari¬ 
ety of 
B. lactis 
Variety of 
Bact. casei. 
a 
b 
acidi, 
d. 
a 
b 
Days or state. 
Milk. 
Per cent. 
Per ct. 
Per ct. 
10,000,000 
100,000,000 
xoo, 000.000 
1,000,000,000 
1,000, 000,000 
Per ct. 
too- 00 
Per ct. 
Per ct. 
Curd. 
250,000,000 
270,000,000 
X,120,000,000 
X,200,000,000 
250,000,000 
X,400, 000,000 
X, 200,000,000 
1,000,000,000 
1,480,000,000 
100.00 
100.00 
100.00 
100.00 
100.00 
99- 99 
99.99 
99.94 
100.00 
5. 
99.999 
100.00 
0. oox 
. 
21. 
29 .. . . 
1,000, 000,000 
1,000,000,000 
1,000,000,000 
100.00 
37. 
0.01 
. 01 
.02 
46... 
99.90 
. 100 
57.. 
0.04 
71. 
1,000,000, 000 
99.90 
0.1 
Cheese No. 21 (see Table XIV) received three-fourths per cent of 
Bacterium lactis acidi y d, as a starter. A study of the pure cultures 
isolated from this cheese shows that this variety composed practically 
100 per cent of the cheese organisms, as determined by plate cultures. 
No other variety of Bacterium lactis acidi and no variety of the Strep¬ 
tococcus group appeared. Small percentages of micrococci were isola¬ 
ted on the thirty-seventh, forty-sixth, and fifty-seventh days. The 
pure cultures isolated from the dilution flasks showed only B . lactis 
acidi , d, and a slowly increasing number of B . casei , which reached 
1,000,000 of these bacteria per gram of cheese on the forty-sixth day. 
The data in Tables XIII and XIV illustrate well the facts which are 
demonstrated by a study of the results of many analyses of 14 pas- 
teurized-milk cheeses. In some of these cheeses a mixture of several 
43841 14- 2 
