696 
Journal of Agricultural Research voi. xxxi, No. 7 
the separator. The average bacterial count of 100 samples of whole 
milk was 435,240 per cubic centimeter. The cream and skim milk 
resulting from the separation of the milk gave average bacterial 
counts of 500,830 and 312,740 per cubic centimeter, respectively. 
The average per cent butterfat of the whole milk was 3.905, and 
that of the cream 34.64. The per cent fat in the skim milk was 
0 .02. The average increase of the bacterial count of all the cream 
samples over the milk from which it was obtained was 14.84 per 
cent. Twenty-three of the 100 samples of cream showed a lower 
count than the whole milk. The per cent decrease for these samples 
was 14.06. Seven samples gave the same count for the cream as for 
the whole milk. The increase in 70 samples of cream showing an 
increase over whole milk was 23.87 per cent. (See Table I.) 
Table I. — Increase and decrease of bacteria per cubic centimeter in cream as 
compared with whole milk 
Per cent 
Increase in bacteria per cubic centimeter of 100 samples of cream over * 
the whole milk from which the cream was separated_ 14. 84 
Increase in bacteria per cubic centimeter of the 70 samples of cream 
showing increase_ : _23.87 
Decrease in bacteria per cubic centimeter of the 23 samples of cream 
showing decrease___ 14. 06 
Seven samples gave same count as whole milk. 
Both high and low count milk was used. The percentage of fat 
varied from 3.4 per cent to 5.0 per cent. The bulk of the samples 
gave a bacterial count between 25,000 and 100,000 bacteria per cubic 
centimeter. (See Tables II and III.) 
Table II. — Range and average of bacterial counts and butterfat determinations in 
100 samples of whole milk and in the cream and skim milk separated from it 
by centrifuge 
Bacteria per cubic centi¬ 
meter 
Percentage of 
butterfat 
Range 
Average 
Range 
Average 
Whole milk__ 
9,000-14,410,000 
7,000-18,600,000 
9,000- 7,500,000 
i 
435,240 
500,830 
312,740 
3.4-5 
17.5-54 
is 
Cream... 
Skim milk..... 
Table III. — Samples grouped according to bacterial counts 
Bacteria per cubic centimeter 
10,000 
and 
lower 
10,001 
to 
25,000 
25,001 
to 
50,000 
50,001 
to 
100,000 
100,001 
to 
500,000 
500,001 
to 
1 ,000,000 
1 ,000,001 
and 
higher 
Number of samples: 
Whole milk. 
4 
13 
38 
20 
8 
7 
9 
Cream.. 
2 
16 
33 
22 
11 
7 
9 
Skim milk... 
4 
29 
27 
13 
8 
4 
i 
9 
) 
When the same samples are grouped according to their bacterial 
count, it appears that the greatest per cent of increase in the cream 
