178 
Journal of Agricultural Research 
Vol. II, No. 3 
A more comprehensive study was made of raw-milk cheese No. 17 R. 
Analyses were made during the making and at intervals throughout the 
ripening period until the cheese was 8 months old. The results of this 
study are given in Table IX. 
Table IX .—Bacterial content of raw-milk cheese No. IJ R 
Age. 
Bacteria 
per gram 
(plate 
cultures). 
Variety of 
Bacterium 
lactis acidi. 
Variety 
of Bac¬ 
terium 
casei. 
Variety of 
streptococci. 
Variety 
of micro¬ 
cocci. 
Bacteria 
per gram 
(dilution 
cultures). 
Variety of 
Bacterium 
lactis acidi. 
Variety 
of Bac¬ 
terium 
casei. 
a 
b 
c 
d 
a 
b 
b 
c 
d 
a 
b 
a 
b 
d 
i 
a 1 
b 
Days. 
Curd. 
4. 
too, OOO, OOO 
70,OOO,OOO 
900,OOO, OOO 
120,OOO. OOO 
240, OOO, OOO 
280,000,000 
400, OOO, OOO 
160, OOO, OOO 
2CO, OOO, OOO 
IOO, OOO, OOO 
80, OOO, OOO 
IOO,OOO, OOO 
32,000,000 
7,000,000 
12,000,000 
P.c. 
P.c. 
30.0 
P.c. 
P.c. 
70.0 
40.0 
P.c. 
P.c. 
P.c. 
P.c. 
P.c. 
P.c. 
P.c. 
100,000,000 
100,000,000 
P.c. 
P.c. 
P. c. 
99- 999 
P.c . 
P. c. 
0.001 
10.0 
50.0 
8. 
88.8 
II. 2 
1,000,000,000 
1,000,000,000 
9.99 
* 01 
is.... 
22.. .. 
29 - 
36. 
43-.«. 
50.. .. 
57.. .. 
90.0 
10 
99.0 
1.00 
66. 3 
87.*5 
10.0 
22.2 
80.0 
12.5 
j 
r;; 
11.2 
0.3 
10.0 
TOO, OOO, OOO 
1,000,000, OOO 
IOO,OOO, OOO 
99.0 
99.0 
90. 90 
1. 0 
1.0 
9.1 
43-o 
56.3 
17*5 
. 1 
. 2 
. 1 
12. s 
°* 3 
100,000,OOO 
IOO,OOO, OOO 
.... 
90.9 
90.9 
.... 
9- 1 
9.1 
. 
76.5 
20.0 
3. 5 
64.. .. 
71.. .. 
89.. .. 
172.. . 
2 45••* 
88.8 
10.0 
j. 2 
IOO, OOO, OOO 
go. 9 
9, I 
35-1 
86.9 
41. 7120. 0 
67. oi. . . . 
3* 2 
IOO,OOO, OOO 
90.9 
9* 1 
22.0 
10.0 
3-i 
11.0 
100,000,000 
IOO, OOO,OOO 
99.0 
90.9 
50. 0 
I. 0 
9* 1 
■ 20. O 
1 
’ So 
:::: 
100,000,000 
50. 0 
! 
!' ! 
r 
Where very small percentages appear in the columns of the coccus 
groups the figures were obtained by plating upon an agar made with 
cheese extract. Upon this medium the lactic-acid groups of organisms 
form very small colonies, but the cocci, particularly the micrococci, 
develop large colonies and can be easily differentiated and isolated from 
plates which are very thickly seeded. 
Cheese No. 17 R was a good Cheddar cheese, with the characteristic 
flavor well developed when 1 month old. The cheese remained in good 
condition until the last analysis, with an increasing sharpness of taste 
which is common to well-matured cheese. The flora is considered typical 
of a good Cheddar cheese. The data confirm those presented in Table 
VIII. Twelve of the fifteen varieties of cheese organisms representing the 
four groups were isolated from this cheese. The data presented in Tables 
VIII and IX show that besides the Bacterium lactis acidi group, which 
has long been known to be important in cheese ripening, and the B. casei 
group, which was shown (Hastings, Evans, and Hart, 1912) to be con¬ 
stantly present in cheese in numbers almost as great as the former group. 
Coccus forms are also constantly present, and although they are fewer 
in number than the lactic-acid-forming groups they occur in sufficient 
numbers to affect flavor development. 
Other evidence of the constant presence of several varieties of bacteria 
in the cheese flora is found in the gradual decline in acid production, as 
the dilutions increase, in milk inoculated with the cheese emulsion. In 
the present study of cheese flora, several hundreds of series of titrations 
