The record-union., 1894-07-13
BAoTFRIoLoGY AGAIN.
Conclusion of Paper on Its Relation to
Dairyiug.

DAlryIuE.
breeder and Sportsman.
In order to make plain why bacteria
increase in milk we need only repeat that
"a basin Of warm milk is almost the best
OF all feeding grounds for BACTERIA aud
If we add this further statement that this
feeding ground more nearly approaches
the ideal according as its temperature
approaches certain point, we also make
plain why milk at one time will Keep tor
week, at another scarcely for half
day. The temperature most favorable TO
bacteria is probably somewhere between
80 and 100 fahr., just about the temper
ature at which milk is drawn from the
cow, and if we wish to grow an extraor-
binary crop of bacteria-if we wish 10
have the milk soured quickly-we ought
to keep the temperature OF the milk as
near this as we can. On the other hand,
ii we wish the milk to keep for a longer
time its temperature Ought to be at once
very much reduced to below co. at least,
because if it be reduced only a short dis
tance the bacteria increase less rapidly at
first but In halt day or so quite rs rap
idly as if it had not been reduced a5 all.
In support of this statement Freuden-
reich quotes some data.
l. Milk containing 5000 bacteria per
cubic centffneter was set at 81. In seven
hours it contained $4,000; in nine hours
10000, and in twenty-five 100000.
2. Milk containing $4,000 bacteria per
cubic centImeter was set at II. In six hours
il contained $1,000; in nine hours 2, I5U,-
600, and in twenty-four SOC, 600 900.
j. Milk containing $4,000 bacteria per
cubic centimeter was set at 99o. In six
hours it contained 2,700,0D0; in nine
hours 3, 400, 0U0, and in twenty-four SI2,-
500, 900.
In what has already been said indica-
tons have been given OF means by which
milk could be kept more free from bac-
terra, in the first instance, or by which
the effects of bacteria, that had already
got in the milk, could be reduced. These
means might be summed up thus: Have
a rational sytem OF drainage and ventila-
ton. Keep everything and every body
connected with the milk clean, and keep
the milk itself cool. But as this is an abb
solute impossibility to keep all bacteria at
a distance. we are compelled to deal with
them after they have got into the milk.
The ends that are aimed at may be said
to be:
/. Destruction of pathogenic or dis
producing germs.
2. Temporary preservation of the
milk.
3. Complete sterilization.
OF course the most desirable Of these is
complete sterilization, because ii we sue
ceed in this we obtain the other ends that
are aimed at; but complete sterilization is
very difficult TO obtain, and moreover it
is very seldom an absolute necessity.
The chief agents that have hitherto been
in use are the two carbonates of soda,
boracic acid, salicylic acid, borax, lime,
great heat and great cold. Others have
been proposed, @. G. electricity and ILL
tration, but, as yet, little has resulted.
Taking these agents in order, we hnd
that
l. The two carbonates of soda are in
tended merely to neutralize acidity, and
therefore to hinder coagulation of the
milk; but. on unsteriliZed, that is, ordi-
nary milk, they have no effect, nor have
they any action upon pathogenic bac-
terra.
2. Salicylic acid most of all hinders
coagulation. In fairly clean milk, in
summer, it may hinder it for two or even
era germs within twenty-four hours, but
doctors say that its continued use is dan
gerous to the health Of the consumers.
3. Boracic acid has very feeble action
against coagulation, and against patho-
genie bacteria it has none.
4. Borax prevents coagulation for
about day, but it has very feeble
action on pathogenic germs.
3. Lime is absolutely inactive.
6. Great cold may preserve the milk,
but it has this disadvantage that it does
not kill all pathogenic bacteria, besides,
it raises the cream, which is very difficult
to mix with milk again.
Z. Great heat, say boiling heat, will
certainly bring about absolute steriliza-
ton, If it be continued long enough; but
it has these two 0isad vantages, the flavor
of the milk is so much altered that to
those unaccuStomed to its use it is yery
unpalatable. and the heating has to be
done in vessels of a strength almost ap-
preaching that of a steam boiler. Besides
if the heating be not continued long
enough, although the pathogenic bac-
terra are destroyed. the spores of the
milk bacteria are untouched and the de-
sired preservation Of the milk is not OBJ
tanned.
1t viii be seen that none of all these is
q thoroughly satisfactory method of deal
ing with milk, whether we desire COM
pete sterilization or merely the destruc-
tion Of pathogenic germs along with the
suppression Tor reasonable time of the
ordinary milk bacteria. OF the methods
already mentioned. that of using a high
temperature is the one that most nearly
approaches perfection; and the method
that is now becoming general on the con-
tinent, and which is favored by Freuden-
reich is really the same method, with one
or two important notifications. This
method is called PdSteHrlSdtgon It has
been known that the majority of bacteria
are killed by exposure for short time to
a temperature OF 1917 Fahrenheit, and
processes were invented for heating milk
To this temperature, but they failed in
this, that they still made the milk un-
palatable. Experiments were afterward
started, and it was discovered that the
changes that made milk unpalatable be-
gin at about 1590, and that majority of
bacteria are killed if they be kept for
from twenty to thirty minutes at tenn
perature of 1867. From these discoveries
the process now in vogue at once suggests
ITSELF the milk is kept for nearly half an
hour at temperature of 1862, and at the
end of that time is cooled as quickly as
possible to temperature OF, at most, 60o.
Thus the bacteria are killed, the milk is
still palatable, and if the milk be well
cooled the spores that are left (which are
spores OF milk bacteria only will find
themselves unable to do much damage
during the time left for the milk to get to
its final destination.
photography. = DIR. Freudenreich's
Bacterlology of the Milk Industry article
by u. W." in n. B. Agriculturist.-Prot
Thomas Bowhill, T. II. G. V. S., +. Il. 2.
S. Edin.
Mother-Miss Smithers, your school
mistress. tells me she's always being
Obliged to scold you, Johnnie. / am sorry
to hear that. Johnnie Considerably
oh, never mind. mother, it doesn't mat
ter. Pm not one of those sensitive chill