Exploring Microbiota and Metabolome Dynamics During the Production of Dried Salted Mackerel (Pneumatophorus japonicus)

Dried-salted fish is a traditional aquatic product known for its sensory qualities, distinct flavor, unique taste, and nutritional value. However, its nutrient accumulation and flavor development during the drying and salting process remains largely unexplored. This study aims to investigate the influence of the production process on the microbiota and metabolites of dried-salted fish over four distinct periods. We identified an average of 63,380 taxon tags and 309 Operational Taxonomic Units (OTUs) per sample. Predominant pathogens included Neisseria, Streptococcus, Pseudomonas, and Arcobacter, while Bacteroidetes were identified as potentially beneficial microorganisms. LC-MS-based analyses of metabolomes revealed a significant increase in compounds mainly associated with amino acid metabolism, lipid metabolism and several organismal systems which contributed to nutrient accumulation. Finally, Spearman correlation analyses demonstrated that Myroides, Gordonia, and Rhodococcus may enhance the flavor, textural qualities, and sensory attributes by regulating amino acids and free fatty acid (FFA) levels. This comprehensive investigation elucidated the theoretical foundation and provided insights into the dynamic changes in the microbiota and metabolites of dried-salted fish during different drying-salting periods. These findings can contribute to refining the fermentation process and improving the safety of fish products.