Aberdeen herald. [volume] (Aberdeen, Chehalis County, W.T.) 1886-1917, 1904-05-09
WHAT MAKES MILK SOUR.
Science Blames Ii Upon Everlasting
and EverPresent Microbe.

Science BIames 1t Upon Everlasting
and EverPresent Microbe.
1t has been discovered by scientific
investigation that the cause of milk
turning sour is the presence i'll the
fluid of bug. imperceptible to the
naked eye. which initiates the process
of decay or fermentation. At least the
Connecticut Agricultural College ana
station has just published bulletin
thus declaring. The following extracts
from the bulletin are we'll worth study
ing by all who handle milk and cream
Dairymen at the present time under
stand that milk is sure to contain bac-
terra In greater or less numbers ana
that these bacteria are the cause of the
various changes characterzing the
spelling of milk. 1t is the type OF bac-
terra known as the Tactic bacteria that
is responsible for the Souring o; milk
and all of the other changes " hich are
liable to prove troublesome to the
dairyman. Shiny milk. bitter milk. etc,
are to-day well known TO be due also
to the bacteria in the milk. 1t Is not
simply the presence of the bacteria III
the milk that produces these changes.
but rather their growth and muitlpii-
cation. If they did not multiply at all
the milk would not sour; the mere rap
idly they multiply the quicker the
changes of the milk take place: the
longer the growth may be delayed and
the slower it is. the longer the milk
may be retained in its fresh condition.
These facts are fundamental phe-
norena associated with the keeping OF
milk and every milkman should there
fore understand as a foundation of
dairy practice that the keeping of milk
is dependent upon preventing or check
ing the multiplication of bacteria rath-
er than upon simply preventing their
presence in milk.
A second fact which is not so thor
oughly appreciated. but Is equally true.
is that the rapidity of growth of all
species of bacteria is dependent upon
temperature. At a temperature OF
freezing bacteria do not grow at all
and milk. therefore, if frozen. may be
kept indefinitely without any changes
taking place therein. II the milk Is
kept at few degrees above freezing
the growth of bacteria begins, but at
low temperatures this growth is ex
tremcly slow. AS the temperature rises
the rapidity of bacterial growth in
creases. When the temperature reaches
20 degrees bacteria grow very rapidly;
at temperature of 80 to 90 degrees
they grow more rapidly still, and Mt a
temperature of about 100 degrees the
growth of some species of bacteria is
II ost rapid of all.
The temperature of 30 degrees is to
be emphatcnlly recommended to the
dairyman for the purpose of keeping
his milk sweet and in proper condition
for market but he must especially be
on his guard against the feeling that
milk which is several days old is pro-
per for market. even though il is still
sweet and has not curdled. Quite the
reverse Is the case. Old milk Is never
wholesome. even though it has been
kept in a temperature of 80 degrees
and still remains sweet and uncurdled
This very considerably modifies some
of our previous ideas concerning milk,
for it has been generally believed that
so long as the milk remains sweet it
is i'm good condition for use. Quite the
contrary is the ease. if it has been kept
at a temperature of 80 degrees or in
this vicinity. 1t is not unlikely that
ii is this fact that leads to some OF
the eases of ice cream poisoning so
common in summer. The cream is
kept at a low temperature for several
days until considerable quantity has
accumulated or Il demand has come
for ice cream, and when made into
cream ii is filled with bacteria in great
numbers and of ii suspicious character.