Effect of Nitrite Treatment and Ultraviolet Irradiation on Natural Food Colors

Thirteen natural food colors were treated with nitrite and they were subjected to mutagenicity assay against Salmonella typhimuium TA98 and TA100 with rat-liver microsomal activation system. Only one color showed a increase of His+ revertant colonies and others showed slight increases in TA98. Conversely, in TA100, four colors showed more than 150 of His+ revertant colonies. Studies were also carried out to test the changes of the numbers of revertant colonies caused by ultraviolet irradiation to the natural colors. In both strains, however, all the natural colors showed less than 150 of His+ revertant colonies