SIGNIFICANCE OF COLON COUNT IN MILK. 
23 
Table 12. — Growth and frequency of organisms of colon-aerogenes group at 60° F. 
(15.6° C). 
Num- 
ber of 
Conditions. 
Average 
total 
count. 
Average colon count. 
sam- 
ples. 
Fresh. 
24 hours. 
20 
Barn clean, cows clean, 
utensils sterilized 
(A). 
Per c. c. 
4,245 
Per c. c. 
100 per cent — In L/100 c. c. 
Per c. c. 
66.6 per cent — . 
33.4 percent +. 
Range, 400 to 76,000. 
Average colon count, 14,083.! 
34 
Barn dirty, cleaned 
once a week, cows 
dirty, utensils ster- 
ilized (B). 
38, 262 
94.1 percent — . 
5.9 percent + . 
Range, 100 to 300. 
Average colon count, 200. 
31 per cent — . 
69 per cent + .* 
Range, 1,000 to 510.000. 
Average colon count, 79,175. 
23 
Same as B, but uten- 
sils not sterilized. 
161,083 
95.6 per cent — . 
4.4 per cent +. 
Average colon count, 400. 
33.3 percent — . 
66.7 percent +. 
Range, 6,100 to 710,000. 
Average colon count, 156,450. 
Num- 
ber of 
Conditions. 
Average 
total 
count. 
Average colon count. 
sam- 
ples. 
48 hours. 
72 hours. 
96 hours. 
20 
Barn clean, cows 
clean. utensils 
sterihzed (A). 
Per c. c. 
4,245 
Per c. c. 
50 per cent — . 
50 per cent -f- . 
Range, 1,000 to 
840,000. 
Average colon count, 
318,333. 
Per c. c. 
35.3 per cent — . 
64.7 per cent +. 
Range, 1,700 to 
25,500,000. 
Average colon count, 
5,506,518. 
Per c. c. 
37.5 per cent — . 
62.5 percent +. 
Range, 4,000 to 
152,000,000. 
Average colon count, 
27,288,900. 
34 
Barn dirty, cleaned 
once a week, cows 
dirty, utensils 
sterilized (B). 
38, 262 
4.0 per cent — . 
96.0 per cent + . 
Range, 98,000 to 
21,600,000. 
Average colon count, 
3,285,750. 
8.3 per cent — . 
91.7 percent +. 
Range, 900,000 to 
68,000,000. 
Average colon count, 
18,786,364. 
100 per cent + . 
Range, 1,000,000, to 
66,000,000. 
Average colon count, 
23,008,333. 
23 
Same as B, but 
utensils not ster- 
ilized. 
161,083 
26.3 percent — . 
73.7 per cent +. 
Range, 84,000 to 
4,300,000. 
Average colon count, 
882,929. 
5.5 per cent — . 
94.5 per cent +. 
Range, 64,000 to 
42,000,000. 
Average colon count, 
4,579,117. 
100 per cent +. 
Range, 115,000 to 
168,000,000. 
Average colon count, 
15,600,611. 
1 Average colon count per cubic centimeter in samples showing them in 1/100 of a cubic centimeter and 
over. 
When milk is held at higher temperatures the growth of organisms 
of the colon-aerogenes group increases in rapidity, which is shown by 
the results given in Table 13. Twenty samples of milk produced 
under dirty conditions with unsterilized utensils were held at 50° F. 
(10° C.) and 70° F. (21° C.) and the colon count determined in the 
fresh milk and after holding for 24 hours. Although this milk was 
produced under extremely filthy conditions, only 3 of the samples 
when fresh showed organisms of the colon-aerogenes group in 1/100 
of a cubic centimeter. This series contained the only sample of 
fresh milk produced under normal conditions which showed a colon 
count of over 2,000 per cubic centimeter. The results in this table 
