Bacterial Community Succession during Long-Term Fermentation of Shrimp Paste and Its Effect on Formation of Biogenic Amines

Sensory characteristics, the succession of bacterial communities and the contents of six biogenic amines during long-term fermentation (1, 2, 3 and 8 years) of shrimp paste were investigated by sensory evaluation, high-throughput sequencing and high-performance liquid chromatography (HPLC), respectively. Results showed that the color of shrimp paste turned dark brown, the L* value declined and the b* value increased then declined, and the grainy mouthfeel disappeared along with the prolongation of fermentation time. Meanwhile, the shrimp-like and ammonia-like smell decreased, and umami taste reached the maximum after two years of fermentation. The bacterial flora detected in shrimp paste comprised 600 species belonging to 894 genera in 42 phyla, with the dominant phyla being Firmicutes and Proteobacteria, and the dominant genera being Tetragenococcus, Psychrobacter, Pseudomonas, Enterococcus, Lactobacillus and Roseovarius, and the bacterial diversity reached a peak after two years of fermentation. The types and contents of biogenic amines in shrimp paste gradually increased as fermentation progressed. Putrescine, cadaverine, histamine, tyramine, spermidine and spermidine were detected in all samples after eight years fermentation. Pearson correlation analysis showed that histamine had a significantly positive correlation with Devosia (P < 0.05), but a significantly negative correlation with Bacillus, Ralstonia, Photobacterium and Staphylococcus (P < 0.01). Putrescine had a significantly positive correlation with Ralstonia (P < 0.01), buta significantly positive correlation with Pseudomonas, Roseicyclus and Sulfitobacter (P < 0.05). Acinetobacter was positively correlated with cadaverine (P < 0.01). The study provides a theoretical basis for screening functional strains and controlling biogenic amines in shrimp paste.