PASTEURIZATION. 185 
much by pasteurization. The flavor of the butter made from 
such pasteurized cream is usually not improved very much. 
However, the keeping quality of butter made from poor cream 
pasteurized is usually better than if no pasteurization had been 
employed. If the inferior quality of cream and milk can be 
pasteurized, neutralized with an alkali, such as powdered chalk 
or bicarbonate of soda, then inoculated with a desirable species 
of bacteria and re-ripened, the quality of butter can be im- 
proved several points. But experiments carried on at the 
Towa Experiment Station indicate that the improvement in the 
quality of butter is not very permanent. Immediately after it 
has been made there is a very distinct improvement in the 
quality of the butter from such cream, sometimes as much as 
five points. But for some reason butter from cream that has 
been neutralized in such a way does not seem to keep well. 
Some days after its manufacture it begins to lose decidedly in 
flavor and to assume a very rank condition. For this reason 
this method of treating poor cream has not been generally 
advocated. The deterioration that takes place in such butter 
after standing seems to be due to chemical changes rather 
than to biological changes. The butter referred to was kept 
in a refrigerator at a temperature of about 50° F.; if the rancid 
flavors were due to the growth of micro-organisms, they should 
not reveal themselves in so short a time. 
(5) Pasteurization increases the keeping quality of butter. 
This is one of the greatest advantages of employing pasteuriza- 
tion in butter-making. The advantage of keeping butter from 
the time of large supply and small prices to the time of small 
supply and higher prices, makes pasteurization in butter-making 
of vital importance in improving the keeping qualities of butter. 
Butter made from good pasteurized cream and washed in pas- 
teurized water will keep about twice as long as butter made 
from the same kind of cream not pasteurized and washed in 
unpasteurized water. 
(6) If milk is pasteurized previous to skimming, closer 
skimming can be obtained than if the milk were heated to a 
