Photodegradation of riboflavin in milks exposed to fluorescent light

Photodegradation of riboflavin in 50-ml samples of fluid milks exposed to fluorescent light (2690 lux) followed first-order reaction kinetics, and the reaction rate (s-1) averaged 1.86 x 10(-5) in skim milk and 1.47 x 10(-5) in whole milk. Additional evidence led us to conclude that photodegradation of riboflavin proceeds prior to the appearance of a light-induced off-flavor.