BULLETIN 303, U. S. DEPARTMENT OF AGRICULTURE. 
THE NUMBER OF BACTERIA. 
Numerous samples of ice cream were purchased from various stores 
in Washington during the summer and winter season; they repre- 
sented 24 different manufacturers. 1 Samples representing 11 plants 
were examined during both seasons. The ice cream from 5 manu- 
facturers was examined during the summer season only, and from 7 
plants during the winter season only. In Table 2 are shown the total 
(average of the two kinds of samples) average counts of ice cream 
from each plant, together with the average of the samples collected 
during the summer and winter seasons. It will be seen that only 
two plants, K x and P, out of the 24 showed an average bacterial 
content of less than 1,000,000 per cubic centimeter. It is possible 
that if more than one sample had been examined from plant P the 
average count for that plant would have been more than 1,000,000. 
Table 2. — Average number of bacteria per cubic centimeter in ice cream from different 
manufacturers. 
Manufacturer. 
All samples. 
Summer series. 
Winter series. 
Total 
samples. 
Average 
bacteria per 
cubic centi- 
meter. 
Number 
of 
samples. 
Average 
bacteria per 
cubic centi- 
meter. 
Number 
of 
samples. 
Average 
bacteria per 
cubic centi- 
meter. 
A. 
32 
27 
19 
11 
9 
8 
12 
5 
8 
3 
4 
12 
4 
4 
3 
6 
1 
2 
1 
3 
4 
2 
3 
3 
2,986,187 
32,007,500 
27,779,631 
18,836,363 
44,783,333 
5,381,500 
2, 580, 250 
4,203,600 
15,487,500 
5,890,000 
265,750,000 
357,583 
32,225,000 
10,910,000 
5,723,333 
46,465,000 
920, 000 
19,750,000 
20,500,000 
2,463,333 
3,650,000 
28,500,000 
14,700,000 
17,566,666 
19 
10 
11 
8 
3 
3 
5 
4 
5 
1 
4 
4 
4 
4 
3 
6 
1 
5,008,333 
31,226,000 
47,909,090 
26,125,000 
118,000,000 
8,966,666 
6,192,500 
5,207,500 
18,360,000 
14,100,000 
265,750,000 
530,000 
32,225,000 
10,910,000 
5,723,333 
46,405,000 
920,000 
13 
17 
8 
3 
6 
5 
7 
1 
3 
2 
416,000 
47,763,529 
101,000 
6,066,666 
8,175,000 
3,230,400 
1,160,428 
188, 000 
10,700,000 
1,785,000 
B... 
c 
D 
E 
F... 
G 
H... 
I 
J . 
K 
Ki«... 
8 
271,375 
L 
M 
N 
. 
P 
Q - 
2 
1 
3 
4 
2 
3 
3 
19,750,000 
20,500,000 
2,463,333 
3,650,000 
28,500,000 
14,700,000 
17,560,666 
R.... 
s 
T 
U . 
w 
X. 
« Ki same plant as K, but there was probably a change in management. 
An interesting point is shown in the bacterial averages of ice cream 
from manufacturers K and ~K V The average bacterial content of 
ice cream from K was 265,750,000, and from K x 357,583 per cubic 
centimeter. These represent the same plant, but in all probability 
there was a change in management. We are not certain of this 
point, but after the four samples were taken from K the condition 
i Throughout this paper reference is made to samples from different manufacturers or plants, but it must 
be remembered that the samples were obtained from stores and not at the plants. 
