Ferrous sulfate efficiently kills Vibrio parahaemolyticus and protects salmon sashimi from its contamination

The primary seafood-borne pathogen Vibrio parahaemolyticus seriously threats the health of consumers preferring raw-fish products, becoming a global concern in food safety. In the present study, we found ferrous sulfate (FeSO4), a nutritional iron supplement, could efficiently induce the death of V. parahaemolyticus. Further, the bactericidal mechanisms of FeSO4 were explored. With a fluorescent probe of Fe2+, a significant influx of Fe2+ was determined in V. parahaemolyticus exposed to FeSO4, and the addition of an intracellular Fe2+ chelator was able to block the cell death. This suggested that cell death in V. parahaemolyticus induced by FeSO4 was dependent on the influx of Fe2+. It was intriguing that we did not observe the eruption of reactive oxygen species (ROS) and lipid hydroperoxides by Fe2+, but the application of liproxstatin-1 (a ferroptosis inhibitor) significantly modified the occurrence of cell death in V. parahaemolyticus. These results suggested FeSO4-induced cell death in V. parahaemolyticus be a ferroptosis differing from that in mammalian cells. Through transcriptome analysis, it was discovered that the exposure of FeSO4 disturbed considerable amounts of gene expression in V. parahaemolyticus including those involved in protein metabolism, amide biosynthesis, two-component system, amino acid degradation, carbon metabolism, citrate cycle, pyruvate metabolism, oxidative phosphorylation, and so on. These data suggested that FeSO4 was a pleiotropic antimicrobial agent against V. parahaemolyticus. Notably, FeSO4 was able to eliminate V. parahaemolyticus in salmon sashimi as well, without affecting the color, texture, shearing force, and sensory characteristics of salmon sashimi. Taken together, our results deciphered a unique ferroptosis in V. parahaemolyticus by FeSO4, and highlighted its potential in raw-fish products to control V. parahaemolyticus.