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

Abstract

Approx. 70% of all retail milk deliveries are removed from the doorstep or protected from light within 5 min. after retail delivery; 3.3% of consumers leave milk exposed for > 2.5 hrs. When milk is exposed to light, the loss of riboflavin varies, depending upon the intensity of the light, the size of glass container, the temp. of the milk, and the time of exposure. Under av. summer conditions the losses in quart size bottles range from approx. 12% for 1/2 hr. to approx. 40% for 21/2 hrs. Ascorbic acid in milk is usually destroyed after 30 min. exposure to sunlight. The photolysis of riboflavin stops when milk is removed from light; ascorbic acid losses continue at a somewhat slower rate. A flavor described as the "sunlight" flavor develops quickly when milk is exposed to light. This problem appears to be much more critical than the loss of a small part of the riboflavin.