The Effect of Route Delivery on the Flavor, Riboflavin, and Ascorbic Acid Content of Milk

It has been known for some time that riboflavin and ascorbic acid are readily destroyed by the sun's rays, but only recently has attention been called to this problem in milk The photolability of riboflavin in milk was demonstrated by Williams and Cheldelin (11), who observed as much as 64 per cent loss of this vitamin when milk was boiled in a light room for 45 minutes and only a 5 per cent loss when it was boiled in the dark. More recently Stamberg and Theophilus (9) found as much as 80 per cent loss of riboflavin when quart-size flint glass bottles were exposed to direct sunlight for six hours, while the same milk exposed in brown glass and paper bottles lost less than 10 per cent of its riboflavin. In a more recent paper, Stamberg and Theophilus (10) observed as much as 40 per cent loss after two hours exposure in quart-size bottles, while brown glass and paper containers gave good protection. Holmes and Jones (7) exposed one-half pint "bottles of milk to known intensities of sunlight and obtained losses of riboflavin up to 85 per cent in two hours. On a dark rainy day they found about 10 per cent loss in one hour. Their data, in general, show that the loss of riboflavin increases with the intensity of the sunshine. These workers further observed that little ascorbic acid remained after 30 minutes exposure to sunlight.