THE CREAMING ABILITY OF MARKET MILK 
Table 2. — Effect of heating milk to various temperatures without holding at 
pasteurization plants 
Tempera- 
ture to 
Percentage of in- 
crease (+) or de- 
crease (— ) 
Tempera- 
ture to 
which 
heated 
Percentage of in- 
crease (+) or de- 
crease (— ) 
1 Tempera- 
ture to 
which 
heated 
Percentage of in- 
crease (+) or de- 
crease ( — ) 
which 
heated 
Cream 
vol- 
ume 
Butterfat 
in under 
layer 
Cream Butterfat 
vol- j in under 
ume ' layer 
Cream 
vol- 
ume 
Butterfat 
in under 
layer 
F. 
138 
+6.6 

+4 
+3.3 
+13.6 
+7-4 
-3.7 
-8.7 
+4.2 
+3.5 
-50 
+12.5 
-50 
-50 
Not tested. 
-45. 4 
-22.7 
Not tested. 
-50 
-45. 4 
1 
° F. 
144.5 
145 
-4.3 
-6.6 
+9.1 
+83.3 
-3.7 
+8 
+13.6 
+31.8 
+6.1 

Not tested. 
Not tested. 
Not tested. 
-52. 1 
-22.7 
-38.4 
Not tested. 
-57.9 
-74 
Not tested. 
° F. 
146 
+7.1 
+55.6 
-3.7 

+8.3 
+8.7 
-6.6 
+8.3 
—36.6 
142 . 
146 
-76.5 
142 
145 
146 
-22.7 
143 
145 
| 146... 
—27. 5 
143.. 
145... . . . 
146 
-62. 5 
143 
145 
145.5 
145.5 
145.5 
146.5 
147 
-30.8 
143 
+33. 3 
143.5 
14? 
-62.5 
143.5 
144.5 
145.5 
Aii examination of Table 2 shows the following facts : 
In the 11 tests at temperatures from 138 c to 144.5 D F., 7 sam- 
ples show increases in the cream volume ranging from 3.3 to 13.6 
per cent. 1 sample shows the same depth of cream volume, and 3 
show decreases ranging from 3.7 t© 8.7 per cent. 
In the 9 tests at temperatures from 145° to 1+5.5" F.. 6 show 
increases ranging from 6.1 to 83.3 per cent, 1 shows the same depth 
of cream volume, and 2 show decreases ranging from 3.7 to 6.6 per 
cent. 
In the 8 tests at temperatures from 146 r to 148° F., 5 show 
increases ranging from 7.1 to 55.6 per cent. 1 shows the same depth 
of cream volume, and 2 show decreases ranging from 3.7 to 6.6 per 
cent. 
Twenty-one tests of the butterfat percentage in the under layers 
are contained in this table. In all but two samples there is a 
decrease in the butterfat percentage in the under layer of milk 
ranging from 22.7 to 76.5 per cent. 
The decrease in the butterfat percentage of the under layer of 
milk in practically all of the samples seems to indicate that heating 
milk to temperatures of from 138 c to 145 c F. causes an increased 
separation of the butterfat. 
In several instances where the cream depth had been seriously 
lessened as a result of previous steps in the processing, momentary 
heating apparently restored the creaming ability equal to that of 
the raw, unprocessed milk. Some of the apparently large increases 
found upon heating the milk were without doubt due to the fact 
that the raw milk did not show a normal cream volume. 
EFFECT OF HEATING AND HOLDING MILK FOR 30 MINUTES AT 
VARIOUS TEMPERATURES AT PASTEURIZATION PLANTS 
Table 3 is a summary of the results of pasteurization tests at 
commercial milk plants. The table indicates the temperature to 
which the milk was heated and held, the temperature of the heating 
medium, the amount of agitation during heating and holding, and 
