Now, researchers in Italy report development of a more reliable method for predicting shelf-life that accounts for light sensitivity for the first time and may help consumers choose fresher, tastier food products. Their study is scheduled for the June 25 issue of ACS' Journal of Agricultural and Food Chemistry, a bi-weekly publication.

In the new study, Lara Manzocco and colleagues note that the bright, intense light of retail displays is widely known to cause the formation of off-flavors, loss of nutrients, and color fading in food and beverages. But conventional methods to test the shelf-life of these products focus on the effect of heat and ignore the effect of light, leading to underestimations in shelf-life shown on product expiration labels. A more reliable test is needed, the researchers say.

The scientists exposed a soft drink containing saffron, which contains light-sensitive substances, to different levels of light at increasing temperatures. They found that the beverage grew lighter in color as light intensity increased, confirming that light can cause a dramatic decrease in beverage quality. Based on these observations, the scientists developed a new mathematical model that measures light-sensitivity as well as temperature to provide a more reliable method for predicting shelf-life. -American Chemical Society