Anaerobic and aerobic regulation of H2S formation and spoilage mechanism of Shewanella putrefaciens via integrated multi-approaches.

Shewanella putrefaciens is a specific spoilage organism, yet the spoilage mechanism and its correlation with hydrogen sulfide (H2S) formation under anaerobic and aerobic conditions are still largely unknown. The study found that H₂S content and spoilage potential of the anaerobic group were significantly lower than those of the aerobic group at 30 °C and 4 °C. Aerobic conditions increased the H₂S content, intensified the degree of protein degradation, and caused significant changes in quality indicators such as pH and water-holding capacity in the fish meat inoculated with S. putrefaciens. Spatial metabolomics identified 9 significantly differential metabolites involved in the H₂S formation pathway between the anaerobic group and the aerobic group. L-methionine and taurine showed a high correlation with 13 spoilage indicators (r > 0.6) and thus could be used as potential spoilage markers. This study clarified the effects of anaerobic and aerobic conditions on H2S metabolism and spoilage potential of S. putrefaciens, and provided a theoretical basis and key targets for the quality control of aquatic products.