Erythrosine B (Red Dye No. 3): A potential photosensitizer for the photodynamic inactivation of foodborne pathogens in tomato juice

The objectives of this study were to evaluate the efficacy of erythrosine B (ERY, Red No. 3)-mediated photodynamic therapy (PDT) for inactivating Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes in tomato juice. The inoculated tomato juice was subjected to xenon light (E - L+), ERY (E + L-), or xenon light and ERY combination (E + L+) treatments. Treatment with E + L+ for 15 min decreased the cell counts of E. coli O157:H7, S. Typhimurium, and L. monocytogenes by 6.77, 2.74, and 6.43 log CFU/mL, respectively, without generating sublethally injured cells. The cell count reductions of E. coli O157:H7 and L. monocytogenes in the E + L+ treatment group were higher than the sum of cell count reductions in the E - L+ and E + L- treatment groups, which indicated the synergistic activity of the treatment combination. The T-3d and T-5d values calculated by the Weibull model indicated that S. Typhimurium exhibited higher resistance to the E + L+ treatment than the other two pathogens. Compared with control group, the E + L+ treatment group exhibited higher lycopene content and a* (red) value, whereas the pH value and sensory attributes were not significantly (p > .05) altered. These results suggest that ERY-mediated PDT can be potentially applied to control foodborne pathogens in tomato juice products without negatively affecting the product quality.