Improvement of the quality and safety of low-salt fish sauce by reconstruction of microbial community through cooperative fermentation of starters.

Low-salt fermentation can speed up the fish sauce production, but it will lead to bad flavor and biogenic amine increase due to the metabolisms of spoilage microorganisms. In this work, cooperative fermentation of Tetragenococcus muriaticus, Bacillus subtilis, and Staphylococcus edaphicus that were isolated from traditional fish sauce were used to improve the quality and safety of low-salt fish sauce. The high-throughput sequencing found that these starters could significantly inhibited the spoilage microorganisms and reconstructed the microbial community with the total abundance over 99 % during fermentation. The amino acid nitrogen concentrations after cooperative fermentation were much higher than the natural fermentation, while the concentrations of biogenic amines were significantly inhibited. The headspace solid-phase microextraction gas chromatography-mass spectrometry identified 33 core volatile compounds (odor activity value ≥ 1), most of which with pleasant flavors were obviously improved by starters while those with unpleasant flavors were inhibited. The group-dimension correlation after genus influence calculation suggested that the starters contributed the most to the improvement of quality and safety due to their good fish sauce environment adaptability, spoilage microorganism inhibition, and protein and lipid metabolisms, with the influence ranking of T. muriaticus > S. edaphicus > B. subtilis. These strains are expected to be developed as special starters for the industrial production of low-salt fish sauce.