14 
BULLETIN" 240, TJ. S. DEPARTMENT OF AGRICULTURE. 
in order to eliminate this factor of possible infection. The result of 
these experiments are shown in Table 3. 
Table 3. — Comparison of bacterial reductions in milk pasteurized in steamed 
dottles and in pasteurized milk bottled tvhile hot. 
Raw milk. 
Milk pasteurized at 145° F. for 30 minutes. 
Sample No. 
Hot pasteurized milk in 
hot steamed bottles. 
Milk pasteurized in 
steamed bottles. 1 
Bacteria 
per c.c. 
Bacteria 
per c.c. 
Percentage 
reduction. 
Bacteria 
per c.c. 
Percentage 
reduction. 
24 
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 
380 
860 
21,800 
5,400 
2,200 
5,900 
6,300 
920 
4,200 
4,320 
11, 800 
7,500 
98.47 
99.08 
92.85 
97.70 
98.75 
93.91- 
97.26 
99.26 
97.47 
99.89 
98.80 
96.06 
570 
2,200 
55, 800 
7,600 
11,400 
8,350 
5,500 
1,500 
11,400 
3,520 
18, 400 
9,300 
97.71 
25 - 
26. . 
97.66 
81.70 
27 
96.76 
28 
93.52 
29 
30 
91.39 
97.61 
31 
32 
33 
98.79 
97.46 
99.91 
34 
98.13 
35 
95.10 
Average 
571, 766 
5,965 
97. 46 " 
11,295 
95.48 
1 Bottles were steamed two minutes, and cooled before they were filled with raw milk. 
It will be seen that the results again were in favor of the milk 
pasteurized in bulk and bottled while hot. Of the 12 samples in the 
experiment 10 showed lower counts than when the milk was pasteur- 
ized in the bottles. 
The average count of the raw milk was 571,766 bacteria per cubic 
centimeter. After pasteurization in bulk, followed by bottling hot, 
the count was 5,965, and a portion of the same milk pasteurized in 
bottles averaged 11,295 bacteria per cubic centimeter. In several of 
the samples the count in the milk pasteurized in bottles was very 
much higher than in the same milk pasteurized in bulk and bottled 
hot. The explanation of these marked differences is not known. 
While minor differences are always within the limits of the errors 
of bacteriological methods, the great differences found in many. cases 
can not be explained in this manner. 
PREVENTION OF BOTTLE INFECTION BY BOTTLING HOT MILK AND 
BY PASTEURIZATION IN BOTTLES. 
Since the process of pasteurizing milk in bulk and bottling while 
hot enables the use of hot, steamed bottles which can be directly 
filled with hot milk, it should be expected that there would be no 
contamination added to the milk during bottling. 
To determine this point eight samples of milk were pasteurized 
in bulk and bottled hot in hot, steamed bottles. The bacteriological 
results are shown in Table 4, column A. Two steamed and cooled 
