4 BULLETIN 240, U. S. DEPARTMENT OF AGRICULTURE. 
Table 1. — Bacterial reductions during the process of pasteurization in oottles. 
Sample No. 
Raw milk. 
After pas- 
teurization 
in the 
bottle for 
30 minutes 
at 145° F. 
Percentage 
reduction. 
Sample No. 
Raw milk. 
After pas- 
teurization 
in th6 
bottle for 
30 minutes 
at 145° F. 
Percentage 
reduction. 

Bacteria 
per c. c. 
58,000 
63,000 
5,100,000 
580,000 
5,900,000 
99,000 
7, 400, 000 
191,000 
14,100,000 
24,700 
75,000 
126, 000 
4, 100, 000 
76,000 
8, 100, 000 
18, 900 
24,000 
28, 300 
Bacteria 
per'c. c. 
1,630 
1,070 
11,800 
8,000 
15, 600 
980 
7,100 
7,600 
14,200 
5,780 
28,000 
1,720 
2,410 
3,550 
1,660 
710 
10, 900 
23,300 
97.18 
98.30 
99.76 
98.62 
99.74 
99.01 
99.90 
96.02 
99.89 
75.59 
62.66 
98.63 
99.94 
95.32 
99.98 
96.24 
50.41 
17.67 
20 
Bacteria 
per c. c. 
80,000 
160, 000 
151,000 
81,000 
24, 900 
94,000 
305, 000 
235,000 
176,000 
97, 000 
230,000 
124,000 
450,000 
3, 950, 000 
985,000 
190, 000 
Bacteria 
per c. c. 
2,010 
29,500 
12,500 
9,800 
570 
2,200 
55, 800 
7,600 
11,400 
8,350 
5,500 
1,500 
11,400 
3,520 
18,400 
9,300 
97.48 
3 
21 
81.56 
4 
22 
91.72 
5 
23 
87.90 
6 
24 
97.71 
7 
25 
97.66 
8 
26 
81.70 
9 
27 
96.76 
10 
28 
93.52 
11 
29 
91.39 
12 
30 
97.61 
13 
31 
98.79 
14 
32 
33 
34 
35 
Average. 
97.46 
15 
99.91 
16 
98.13 
17 
95.10 
18 
19 .. 
1,570,493 
9,863 
90.86 
As may be seen from the table, the bacterial reductions were high 
as a rule, but there were exceptions. The average total count of the 
samples of raw milk was 1,570,493 and after pasteurization 9,863 bac- 
teria per cubic centimeter. It is interesting to note that the percent- 
age reductions averaged 90.86 per cent and ranged from 17.67 per 
cent to 99.98 per cent. When the latter reduction was obtained the 
raw milk contained 8,100,000 bacteria per cubic centimeter ; when the 
minimum reduction was obtained the raw milk contained 28,300 bac- 
teria per cubic centimeter. These results further substantiate the con- 
clusion expressed in Bulletin 161, page 58 (3) ,that percentage bacterial 
reduction has no special meaning, since it is influenced by the number 
and kinds of bacteria in the milk when pasteurized. Considering 
the results as a whole, it is evident that low counts may be obtained 
by pasteurization in bottles. 
While carrying on these experiments the following points were 
noted which are worthy of attention : 
TEMPERATURE OF THE MILK DURING HEATING. 
In the process of pasteurization it was found that the temperature 
of the milk in different parts of the bottle was quite different during 
the time the milk was being heated. Several experiments were made, 
heating water in sealed bottles to determine the differences in the top, 
middle, and bottom of the bottles. Three thermometers were inserted 
through a rubber stopper into a bottle so that the stems were at the 
top, middle, and bottom of the bottle, respectively. The bottles were 
then submerged in hot water at a temperature of from 145° to 146° 
F. and the temperatures of the water in the bottles were recorded. 
