PASTEURIZING MILK. 
23 
THE CREAM LINE AND FLAVOR OF PASTEURIZED MILK COOLED 
BY VARIOUS METHODS. 
In the consideration of the process of bottling hot pasteurized 
milk followed by slow cooling it is of practical importance to know 
what effect such a process will have on the cream line and flavor of 
the milk. Several experiments were made to determine the effect on 
these points. Milk was pasteurized, and hot 500-cubic-centimeter 
graduated cylinders were filled with hot milk up to the 500-cubic- 
centimeter mark. Together with the cylinder of hot pasteurized 
milk one cylinder was filled with raw milk and one with pasteurized 
milk which had been cooled to 50° F. in 15 seconds' time by running 
through a coil immersed in brine. The method of cooling the hot 
cylinders of pasteurized milk was varied considerably, as may be seen 
from Table 8. After holding the milk for 24 hours at 45° F. the 
numbers of cubic centimeters of cream were read off directly from 
the graduations on the cylinder. This method, of course, gave a very 
accurate means of determining the effect of heating and cooling on 
the cream line; in fact it was too accurate, since considerable dif- 
ferences in the cream line by this method of measurement were not 
apparent in bottled milk. 
Table 8. — Cream-line experiments with raw milk and milk pasteurized at 145° F. 
for 30 minutes. 
Experi- 
ment 
No. 
Process. 
Cubic centimeters of 
cream in 500 c. c. 
cylinder after 24 
hours' refrigeration 
at 45° F. 
( Raw milk 
1 
Pasteurized milk: 
Cooled quickly in 15 seconds to 50° F. and held in refrigerator at 45° F. . 
Cooled slowly in air blast for 45 minutes and placed in refrigerator at 
45° F 
64.5 
65.0 
64 5 
Held above 105° F. for 3 hours, cooled in ice water, and placed in re- 
frigerator at 45° F 
[Raw milk 
65 
2 
Pasteurized milk: 
Cooled in 15 seconds to 50° F. and placed in refrigerator at 45° F 
Cooled slowly in air blast for 1J hours and placed in refrigerator at. 45° F . 
Hold above 100° F. for 1| hours and placed in refrigerator at 45° F 
[Raw milk lost 
62.5 
52.5 
52.5 
3 
Pasteurized milk: 
Cooled in 15 seconds to 50° F. and placed in refrigerator at 45° F 
Cooled slowly for 30 minutes in air blast, cooled quickly in brine, and 
placed in refrigerator at 45° F 
83 
85 
Held above 100° F. for 3 hours, cooled quickly in brine, and placed, in 
refrigerator at 45° F 
90 
Raw milk Lost 
4 
Pasteurized milk: 
Cooled in 15 seconds to 50° F. and placed in refrigerator at 45° F 
Cooled slowly in air blast for 2J hours, cooled in ice water, and placed in 
refrigerator at 45° F 
75 
69 
Held above 100° F. for 2h hours, cooled in ice water, and placed in refrig- 
erator at 45° F 
75 
Raw milk 
80 
5 
Pasteurized milk: 
Cooled in 15 seconds to 50° F. and placed in refrigerator at 45° F 
Cooled slowly in air blast for 2 hours and placed in refrigerator at 45° F . . 
After cooling in air blast for 2 hours the milk was cooled quickly in 
brine to 50° F. and placed in refrigerator at 45° F 
68 
55 
62 
Held above 100° F. for 5 hours and placed in refrigerator at 45° F 
After holding above 100° F. for 5 hours the milk was cooled quickly 
in brine to 50° F. and placed in refrigerator at 45° F 
55 
62 
