The pioneer express. [volume] (Pembina, Dakota [N.D.]) 1883-1928, 1908-09-11

Su1I "a OH AOOU6 W preserve anu nan.
die in a pure state. in that it is an.
ideal medium for the cultivation Of all
classes Of bacteria. The average milk
supplied to large cities is not safe
food. This is due to the ignorance
and indifference of those engaged in
the dairy business, to the unclean and
unhealthy cows used for producing
milk, to its insufficient cooling, to
long transportation, to unnecessary
and frequent handling, to- lack 4 Of
proper cleansing and sterilization of
containing vessels and to its frequent
association with infectious disease.
Bacteria enter milk Immediately 1t is
exposed to the atmosphere. At the
time of milking this exposure is great.
est. While perhaps 1t is impossible to
avoid wholly the introduction of bac.
terra during milking, If proper pre-
cautions be taken the number intro
duced may be relatively small. Bac.
terra reach the milk from the teat,
udder and body Of the COW, from the
hands. body and clothing of the milk.
er, with the dust from the atmosphere,
from particles Of excrement or litter
which enter the pail and from the
pail itself. The action of these BAG
terra may he considered broadly as Of
three types: (1) The large group of
'so-called Tactic bacteria produces lac.
tic acid from milk sugar. which acid
precipitates the principal protein of
milk, causing the well-known curdling
or souring. This always occurs when
milk is exposed to the air and kept at
temperature above ten degrees G..
These organisms as group. are harm
less, as are also the products Of their
growth. They, moreover, render good
service by inhibiting or crowding out
the very harmful sputrefactive bacteria
which so frequently reach milk from
excreta. These transporting organisms
are killed by most methods of pas
teurization, while the sporting putre-
factive organisms are not killed by
any method. 1t is obvious, therefore.
that a pasteurized milk containing
putrefactive bacteria such as the B.
aerogenes capsulatus or the B. putri.
ficus Of Bienstock, is in much less
protected condition than raw milk. (2)
Another group of organisms produce
butyric fermentation, also an acid
change. These grow best at tenn
perature approaching that of the hui.
man body. and produce spores which
resist the temperature of boiling wa
ter for some time. The products of
their growth produce serious disturb
ance in the intestinal tract of man.
more especially of children. The
spores of the germs of butyric fer
mentation are not killed by pasteuri.
cation. 90 Several micro-organisms,
including the two mentioned in ~,
produce putrefactive fermentations-
alkaline changes which proceed in
milk without indications visible to the
naked eye. These spore-bearing or.
ganisms are not destroyed by pasteuri.
cation. Too frequently milk comes in
contact with organisms of specific dis.
ease, 9. G.. tuberculosis. typhoid fever.
diphtheria, etc. Pasteurization for 20
minutes at 60 degrees to IS degrees G.
according 10 Rosenau, or 20 degrees
to 80 degrees G. for q shorter period
according TO Jensen, will effectually
destroy all such organisms.
The length of time during which
milk will keep-that is, the length Of
time which must elapse before sum.
cient numbers Of bacteria develop to
produce perceptible changes In its
function Of two factors. temperature
and the initial number of bacteria
present. Under ordinarily favorable
conditions, the number OF bacteria In
milk freshly drawn from healthy
COW will vary between 500 and 20, 900
per cubic centimeter. Milk can be-
produced BY commercial methods
which will contain less than 5000 bac-
terra per cubic centimeter. On tho
other hand, carelessly produced, the
number may reach 500, ZOO. 900.