Synergistic effect of citric acid and xenon light for inactivating foodborne pathogens on spinach leaves

Photodynamic inactivation (PDI) is an emerging new antimicrobial technology, which uses a combination of photosensitizers and light. This study demonstrated that the synergistic antimicrobial effect of citric acid and xenon light combination against foodborne pathogens on spinach leaves. [Display omitted] •A new photodynamic inactivation based on citric acid was investigated.•Xenon light-citric acid combination exhibited a synergistic lethal effect.•The potential mechanisms for this synergistic interaction were elucidated.•Treatment with XL-CA combination did not adversely affect the spinach quality. The aim of this study was to evaluate the synergistic antimicrobial effect of xenon light (XL) and citric acid (CA) combination against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes on spinach leaves and determine the effect of XL-CA combination on quality of spinach leaves. The XL-CA combined treatment for 8 min synergistically decreased the cell counts of E. coli O157:H7 and S. Typhimurium by 5.25 and 5.05 log CFU/cm2, respectively, and additively decreased the L. monocytogenes cells by 5.02 log unit on spinach. The mechanisms underlying synergistic lethal effect of the XL-CA combination were investigated. Qualitative and quantitative analyses revealed that the bacterial cell membrane damage was strongly associated with the synergistic antimicrobial effect of the XL-CA combination. Additionally, treatment with XL-CA combination for 8 min did not affect the quality attributes (color, total phenol contents, and texture) of spinach leaves. These results suggest that the XL-CA combination treatment can be effectively used to control major pathogens on fresh produce.