The Republican journal., 1874-01-22
VOLUME Il.
Influence of Light on Milk and Cream.

influence OF A1EUG Oh MILK ana OTeam.
While some organisms Of peculiar
nature flourish better in the dark than il
the light, the general effect of light upon
living organisms, both animal and vege-
table, is to encourage growth and perfect
development. Milk is full of organic
germs, and it is found that light hastens
the changes required for their develop
ment and multiplication. Direct sunlight
Very soon spoils milk or cream by pre-
mature souring and decomposition. The
effect of indirect or reflected hight has
been but little observed. 1t nevertheless
eNerts an active influence not only upon
milk and cream but upon butter and
cheese while curing. The general effect
of light upon milk and cream is to hasten
the action Of the Tactic yeast, and then the
formation of alcohol and after that to
hurry up putrefaction and these changes
are occasioned by the influence of reflected
light the same rs direct sunlight, only in
Il teebler degree,
The first effect, however, of Il small
would Just enable one with good eyes to
color of cream during an exposure of
thirty-six to torty-eight hours Whether
the increase of color would continue for
an indefinite length of time. | am unable
to say, but probably not
As soon as the quantity Of light allowed
to tall upon milk is increased beyond the
small amount named, its influence is soon
manifested upon the cream; causing it to
become sour and stale, lose color and fla
Vor. and if the light is strong its surface
Al,
where the same milk standing in a more
shaded position will be all right The
quantity of light winch can be safely ad-
mitted into 4 milk room, even from a
northern exposure, is very small, as a few
examples will Illustrate. In the Speeds
vile creamery, Tioga County, n Y, q
streak of light was admitted from 4 Win
dow having a northern exposure, but To-
Gated under a porch so that its effect was
diminished by its indirect course, and fell
obliquely across two of the pools in which
the coolers We're standing full Of milk
The rest of the room where the other
coolers stood was SO shaded as to appear
quite dusky upon first entering it. The
milk in all the coolers was kept at fifty
eight to sixty degrees alike. and stood
from forty-eight to sixty hours. The cream
in all the coolers standing in that streak of
light was observed to lose color and grow
stale, and at length become covered with
pimples and mould, and finally tiecky.
The pimples with which the top was bis
tered became watery, giving indications
Of vinous fermentation and premature de-
cay The top of the cream soon became
sour and shortly reached through to the
milk, while the cream and milk standing
IN the more shaded part of the room was
sweet and sound.
When the window was shaded all the
phenomena at once disappeared, but if the
shade was removed they re-appearcd. 1t
was changed several times. and always
with the same results.
In a recent visit to some of the butter
factories in Franklin County, n. Y, a
similar experience was related by Mr.. &.
l.. Donaldson, manufacturer in the SO.
Bangor factory The milk in that, as in
all the other Franklin county butter fac
tories, is set in twelve large .Jewett pans
ten feet long by four wide and seven
inches deep; these are placed six on each
side Of the room, with one end butting
against the wall, and the other reaching
toward the middle of the room. While
there are six pans butting against a side
Of The room, there are but three windows
on a side, so that onc-half the pans stand
squarely against a window and the other
half against a wall. The pans standing
before the windows, and especially the end
next to the light, We're noticed to have the
cream on them paler than the rest. ~
though the milk was the same and stood at
the same temperature, and it sooner be
came stale and sour The effect in the
Bangor factory was not 50 great as that in
the SpeedSvllie factory, rs the milk only
stood in the pans thirty-siN to torty-cight
hours, Had it stood as long, it would no
doubt have been the same. The quantity
of light was gradually diminished till it
was found that the best effect was pro-
duced when all the windows on the sunny
side Of the room We're closely shaded, and
light only admitted through three l0Xl2
panes i'll each window on the opposite
side
Finding too much light injurious, DR.. ID.
tried the opposite extreme lie put Il
screen over some of the pans, SO that one
end was exposed to moderate light and
the other entirely dark, and found the dark
ends paler than the others, but otherwise
sound. A similar experience has occurred
III OllItl ldclollcS III lc llclSllDOlHOOu, dlltl
the practice has there become general Of
shading down the light in their milk rooms
to the same standard as above indicated.
Too much light is doubtless often the
cause Of faulty butter; and even after it is
manufactured, butter, like cream, will
soon fade it exposed to the light, even
though it may be covered with brine. l..
b. Arnold, in Live Stock journal.