CHAPTER XIII. 
PASTEURIZATION. 
Definition.—The word pasteurization has its derivation from 
Pasteur, a French scientist. Pasteurization consists in heat- 
ing milk somewhere between 140° F. and 212° F. This kills 
practically all germs in a vegetative state. Since most of them 
are in a vegetative condition, the process kills almost all the 
organisms. The heating is followed by rapid cooling. ‘‘Sterili- 
zation” is a word which is some times used incorrectly in con- 
nection with pasteurization. Sterilization means that milk or 
any other substance has been heated so often or to such a high 
temperature as to entirely destroy every living micro-organism 
present. In order to get a substance thoroughly sterilized 
without heating under pressure, it is essential that it be heated 
about thirty minutes on each of three or more successive days. 
Pasteurization in the dairy industry was introduced by Pro- 
fessor Storch of the Royal Experiment Station, Copenhagen, 
Denmark. 
Methods of Pasteurization.— 
(1) Intermittent. 
(2) Continuous. 
1. Intermittent pasteurization is usually accomplished in 
vats or cans. It is used nearly exclusively when pasteurization 
is practiced on a small scale, such as preparation of starters 
in creameries, pasteurizing cream and milk on the farm, ete. 
Intermittent pasteurization is as efficient, and undoubtedly more 
so, than the continuous method. The substance pasteurized 
is usually exposed to the high temperature a longer time than 
it would be by the intermittent system. In the continuous 
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