A Biochemical Study of Irradiated Milk

Abstract

Recently O'Brien, Davis and Armstrong 1 have described a method for irradiating milk with ultraviolet light. Their source of light is an arc from carbon electrodes vf special composition and has an energy emission, in the wave length region from 2,800 to 3,100 ngstrom units, 1,260 times that of bright sunlight. There is very little energy emitted at Wave lengths shorter than 2,800 A. They point out that radiation of wave lengths between 2,800 to 3,100 A. is very effective in producing anti-rachitic potency, while radiation of wave lengths less than 2,800 A. is destructive to vitamin A, causes protein coagulation and produces a bad odor and taste in the milk. The apparatus in which the milk is irradiated is essentially a glass cylinder. The carbon arc is in the center of this cylinder and the milk flows down the inside of the cylinder in a thin fihn in such a way that each particle of milk receives a uniform dosage of light. Feeding experiments which they have conducted show that the vitamin D potency of irratiated milk is increased 16 times, while the vitamin A potency is 86 per cent. of that in the original milk. They also report bacteriological studies showing a decided reduction in the bacterial count after irradiation.