The Caucasian

Influence of Light on Milk and Cream.

While some organisms of a peculiar nature flourish better in the dark than in the light, the general effect of light upon living organisms, both animal and vegetable, is to encourage growth and perfect development.

Milk is full of organic germs, and it is found that light hastens the change required for their development and multiplication. Direct sunlight very soon spoils milk or cream by premature souring and decomposition. The effect of indirect or reflected light has been but little observed. It nevertheless exerts 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 lactic 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 as direct sunlight, only in a feebler degree.

The first effect, however, of a small quantity of reflected light--a quantity that would just enable one with good eyes to read ordinary print--is to heighten the color of cream during an exposure of thirty-six to forty-eight hours. Whether the increase of color would continue for an indefinite length of time, I am unable to say, but probably not.

As soon as the quantity of light allowed to fall upon milk is increased beyond the small amount named, its influence is manifested upon the cream; causing it to become sour and stale, lose color and flavor, and if the light is strong its surface is soon covered with mould and pimples, where the same milk standing in a more shaded position will be all right.

The quantity of light which can be safely admitted into a milk room, even from a northern exposure, is very small, as a few examples will illustrate. In the Speedville creamery, Tioga county, N. Y., a streak of light was admitted from a window having a northern exposure, but located under a porch so its effect was diminished by its modified course, and fell obliquely across two of the stools in which the coolers were standing full of milk. The rest of the room where the coolers stood was so shaded as to appear quite dusky upon first entering. The milk in all the coolers was kept at fifty-eight to sixty degrees alike, and stood from forty-eight to seventy 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 flecky. The pimples with which the top was covered became water, giving indications of non-fermentation and premature decay. 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 were sweet and sound.

In a recent visit to some of the butter factories in Franklin county, N. Y., a similar experience was related by Mr. G. E. Dwinnel, manufacturer at the South Bergen factory. The milk in that, as in all the other Franklin county butter factories, is set in twelve large Howett pans, ten feet long by four wide and thirty inches deep; these are placed six on each side of the room, with one end butting against the wall and the other reaching towards the middle of the room. While there are six pans sitting against a side of the room, there are but three windows on a side, so that one half the pans stand squarely against a window and the other half against a wall. The pans standing before the windows, especially near end next to light, were noticed to have the foam on them rise faster than the rest although the milk was the same and stood at the same temperature, and sooner become flat and sour.

In the Eatonbrook factory I am not sure but that one of the Speedville factory, as the milk only stood on the pans thirty-six to forty-eight hours, and it would not have been the same.

The quantity of light was gradually heightened at last from that the by self was raucous when the windows on the sunny side of room were closely shaded, and light only admitted through three or four pans in each window on the opposite side.

Judging from much light injurious Mr. Deltheop's experiment.

He put a screen under one of the pans, so that one end was exposed in direct light and the other nearly dark, and found the dark end did better than the other as might be supposed. A similar experiment is urged in the factories in the neighborhood, and he prefers that they regulate down the light in their milk rooms to the same standard as above mentioned.

Too much light is doubtless often the chief fault; for an even better it is manufactured. Butter the cream all soon late if exposed to light, though it may be covered a brine. - L. B. Arnold, in Live Stock Journal.