In this study we evaluated the ability of the UV-A-LED to eliminate bacteria in a colored beverage. Ten edible pigments were used to make a colored solution at concentrations of 1.0%, 0.1%, 0.01% and 0.001%. We used a colony-forming assay to monitor the bactericidal action against the bacteria. The bactericidal effect of UV-A-LED against Escherichia coli DH5 alpha decreased with the increasing concentration of almost all of the edible pigments.
Although less effective in colored solutions and commercially available orange juice than in the positive control PBS, it holds potential for further development and use to ensure food and water safety.