The Oakes times. [volume] (Oakes, N.D.) 1906-current, 1911-09-14
When Milk sours.
BY G. L. MARTIN.

Office of Agricultural Editor, Ex-
tension Department, North Dakota
Agricultural College, Fargo, N. d.
The souring of milk is not unlike the
souring of fruit juice or vegetable mat
ter. It is due to the action of a par
ticular kind of micro-organlsm which
we call bacteria. These little organ
isms are good deal like other forms
of life in that they must have air,
moisture, warmth and food in order to
live, multiply and work. The partic-
ular food Of great many bacteria is
sugar and the product which they man.
ufacture is called acid. For instance,
when the juice is pressed from the
apple it is called sweet cider because of
the sugar it contains. But soon the
bacteria enter from the air, from un-
clean utensils, or from other surround
ings and at once begin work upon the
sugar which soon turns the cider hard
and finally it becomes vinegar unless
put into an air-tight keg and kept in a
cool place.
COMPOSITION OF MILK.
Among the constituents of milk are
water to the amount of 871 per cent,
fat 3.9 per cent, casin So per cent,
mineral matter .75per cent and sugar
ATS per cent. When the milk is first
drawn it tastes sweet because of the
milk sugar which it contains just the
same as cider tastes sweet when it is
first pressed from the apple. The aver
age milk as will be seen contains nearly
s per cent sugar which means about
five pounds for every one hundred
pounds of milk, which when changed
into acid by the bacteria produces
what we call souring.
CONDITIONS NECESSARY
To work best, these bacteria require
warm surroundings of about 70 de-
grees F. or room temperature, besides
they must have some air and enough
moisture to keep their food, the sugar,
in solution. The milk, the same as
cider, has all these conditions present
so just as soon as it is drawn the bac-
terra begin to work rapidly because
since the milk is warm all the conditions
necessary are exactly right. Then un-
less the milk is cooled they continue
rapid work until all the sugar is
changed to acid-the milk soured.
HOW TO PREVENT soUR1NG.
Since these little sorganisms must
first get into the milk then have a
warm temperature in which to work,
the way to prevent the milk from sour
ing is to keep the bacteria out as much
as possible then make the surroundings
so cold that they cannot work. To do
this have all surroundings as yard,
stable and stall in good sanitary con-
dition, then curry and brush the COW
at least with as much care and atten-
ton as is given the horses. Keep all
pals, strainers and other milk utensils
scrupulously clean and finally cool the
milk to SO degrees F. Immediately
after milking. Setting milk into an
ice box, q cave or a cellar to cool is
not q very good plan because of fire.
quent poor ventilation and bad odors.
A more satisfactory way is to make
either small vat large enough to hold
several shot gun milk cans, or cut a
barrel into halves and provide with a
well fitted cover to keep out all dust
and shield the heat from the sun. By
placing this between the pump and the
watering trough then run a spout from
the pump to the cooler and another
from the cooler to the trough, fresh,
cool water may be kept about the con-
tents of the cooler at all times. The
average temperature of well water is
about SO degrees F. so an arrangement
like this is simple, Inexpensive and
effective way to keep milk from sour
ing.