According
to Morse and Talbot[33] the temperature of the pasteurization should
be as low as possible. Pasteurization at 140 deg. F. for 20 minutes is
sufficient; lower temperatures are not. "At this temperature there is
no change in the taste, odor, or color of the milk, no noteworthy
changes in the chemical composition are produced, the ferments and
bactericidal action are unaffected and bacterial toxins and
non-spore-bearing microorganisms are destroyed."[34]
Rosenau[35] states that the bacillus of typhoid, diphtheria, and
dysentery, as well as the cholera vibrio and other pathogenic
non-spore-bearing bacteria which are often found in milk, are
destroyed at a temperature of 140 deg. F. for twenty minutes, and at
higher temperatures for shorter lengths of time.
Sommerfield's[36] investigations prove that butyric acid bacilli are
destroyed at a temperature of 212 deg. F. for from 1 to 2 minutes.
It must be understood that no matter what method is used to insure
purity in milk, nothing does away with the necessity for keeping the
milk both clean and cold. The receptacles in which the milk is allowed
to stand, the vessels in which it is measured, and the person who
handles it must be absolutely clean, and the nurse must keep in mind
the fact that pasteurization does not completely destroy the bacterial
growth in milk, that it merely diminishes it, and she must see that
the milk which has undergone the pasteurizing process is kept cold,
otherwise the microoerganisms which are present, even if to a less
extent than in raw milk, will undoubtedly multiply.
~Adulteration of Milk.~--There is not nearly so much adulteration of
milk to-day as there was a few years ago. The stringent laws governing
the care and composition of the milk make it unprofitable for the
dairymen to practise it. However, there are times when such things are
done and care must be taken to prevent it. Milk is, as has already
been stated, very susceptible to contamination, and that which is
infected with putrefactive bacteria is not fit for food even if the
dealer has doctored it with formaldehyde. However, the danger to-day
is not so much from drugs as from lack of care in the handling of the
milk. It is well to remember, however, that water is an adulteration
just the same as formaldehyde and perhaps more pernicious, since the
quantities of the latter are so small in an ordinary quantity of milk
as not to make a great deal of difference except in t
|