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.