THE CREAMING ABILITY OF MARKET MILK 
11 
The importance of cooling the pasteurized milk to a low tempera- 
ture before placing in storage is clearly illustrated in this table. 
There was no difference in the cream volume in the sample cooled 
to 107° F. as compared with those cooled to 63° and 73°, but the 
samples cooled below 55° showed an increase. The samples cooled 
to 54° showed a cream volume of 10.5, and each sample cooled below 
this temperature showed a consistently greater cream volume, the 
largest, 11.5, being on the sample cooled to 41° F. 
The milk that was cooled in the can to 52° F. in one and one-half 
hours showed a cream volume of only 7. This illustrates the fact, 
elsewhere shown, that the cream layer is injured by slow cooling 
through certain temperatures, and is comparable to vat cooling to a 
temperature below 50°. 
There was no difference between the cream volume of the raw 
samples that were cooled and those that were set in storage room at 
a temperature of 70° F., the temperature of cooling apparently 
having less effect on the raw milk. 
In Table 8 are shown results otf cooling pasteurized milk imme- 
diately to various temperatures, and of cooling to various tempera- 
tures slowly in the can and then cooling immediately to 45° F. over 
a separate cooler. 
Table 8. — Effect of cooling pasteurized milk to various temperatures at once, 
and of partially cooling in tank 
Sample 
No. 
Description 
Temper- 
ature to 
which 
cooled 
Cream 
volume 
1 
Raw 
o F 
45 
45 
47 
52 
58 
45 
45 
45 
45 
17.5 
2 
16.0 
3 
do .. 
15.0 
4 
do 
11.0 
5 
do 
12.0 
6 
Pasteurized, cooled in tank to 90° F. then cooled at once 
16.0 
7 
16.0 
8 
15.0 
9 
13.5 
These results also show the advantage of cooling milk quickly 
after pasteurization to a low temperature. The cooling in the tank 
to 80° F. did not seem to injure the cream layer. This cooling was 
done more quickly, however, and with less agitation than is the case 
with commercial vat pasteurizers. (See Table 6 in regard to cooling 
in vat.) 
EFFECT OF STORAGE TEMPERATURE 
The temperature at which the milk is stored has an important 
bearing on the creaming ability. Duplicate samples of both raw 
and pasteurized milk were stored at two different temperatures, one 
at a low temperature of 38° to 48° F. and the other at a compara- 
tively high temperature of 50° to 60° F. The results are shown in 
Tables 9 and 10. With nine tests on raw milk, the difference in 
cream layer between the samples of milk stored at the two tempera- 
tures was 28.6 per cent. 
In the pasteurized milk there was not so great a . difference in 
cream volume for the two temperatures. The average difference in 
