Volatile Flavor Improvement and Spoilage Microorganism Inhibition in Low-Salt Fish Sauce (Yulu) by Salt-Tolerant Bacillus subtilis

Use of low-salt fish sauce (Yulu) is limited due to its perishable property and rapid loss unique flavor. In this study, a salt-tolerant strain, Bacillus subtilis B-2, with high protease production was used as microbial starter for Yulu fermentation. A total 133 volatile compounds were detected through HS-SPME-GC-MS. Most aldehydes, alcohols, ketones, furans, hydrocarbons reached their maximum at 15 d, while most esters, aromatic compounds, acids, nitrogen sulfur peaked 45 d. The 16S rRNA gene high-throughput sequencing showed that remained in abundance during fermentation, reaching 93.63% characteristic flavor obviously improved the contamination significantly reduced fermented B. subtilis, compared those without starter. correlation network map suggested significant decrease Pseudomonas, Achromobacter, Stenotrophomonas, Cyanobium, Rhodococcus, Brucella, Tetragenococcus, Chloroplast contributed decreasing richness evenness community, only genus playing key role inhibition spoilage microorganisms improvement after addition. This study suggests potential use special industrial fermentation future.