The Analysis Of Microbial Community Diversity In Dried-salted Fish During Process And The Control Technology Of Biogenic Amine-forming Bacteria

Dried-salted fish has a long history in our sourthern food culture, It’s very popular among people due to its easy processing, unique flavor and long-storage. Dried-salted fish processing was dominated by a variety of microorganisms, Microbial species and quantity was closely related to the quality, flavor and nutrition of dried-salted fish. Dried-salted fish was rich in a variety of microbes that formed the unique microbial community structure in the processing system, How the microorganism of dried-salted fish processing growed in the fermentation system and the relationship with population of lactic acid bacteria and the effects of their interaction on dried-salted fish processing were so far no system and further research both at home and abroad. The microbes inevitablely producted biogenic amine in the processing and storage of dried-salted fish. However, the problem of biogenic amine content in the dried-salted fish exceed standard is the important problem limited aquatic product industry. Therefore, this chapter researched community change during processing of dried-salted fish and microbiological assay related biogenic amine, also analyzed the inhibition effect of three kinds of additives(food additives, plant extracts and microbial agents) on biogenic amine-forming bacteria and biogenic amines for providing theoretical basis that is dried-salted fish fermentation mechanism, the quality control and establishing low biogenic amine content process.1 、 Microbial community diversity during different processing of dried-salted fish was analyzed by means of metagenomics technology, The results indicated that the processing system contained high diverse of bacteria and mainly divided into three categories: Bacteroidetes, Firmicutes and Proteobacteria. Enterbacteriaceae, Enterococcactae, Pseudomonadaceae and Shewanellaceae were dominant microorganism in the initial stage of Brown-striped mackerel scad. Microbial community was single during traditional cured processing, The dominant microorganism were Vibrionaceae, Staphylococcaceae, Pseudomonadaceae and Planococcaceae;Added into lactic acid bacteria, The microbial diversity during the processing showed a trend of increase, and the lactic acid bacteria became dominant bacteria and promoted the bacteria breeding of Exiguobacteracea and Staphylococcus. And Aeromonadaceae and Lactobacillaceae that did not appear during traditional processing were detected. Microbial community diversity during processing of Sea bass were significantly higher than Brown-striped mackerel scad, Aeromonadaceae, Bacillaceae, Staphylococcaceae, Comamonadaceae, Enterbacteriaceae, Enterococcaceae, Moraganellaceae and Streptococcaceae were dominant microorganism in the initial stage, Added into lactic acid bacteria, Microbial community diversity also increased slightly.2、To confirm the species of biogenic amine-forming bacteria during processing of dried-salted fish, Bacteria were isolated and identified by primary step with biogenic amine-forming bacteria isolation agar and high performance liquid chromatography analysis, and its biogenic amine producing ability was studied. The results showed Aeromonas hydrophila, Pasteurella canis and Vibrio alginolyticus were dominant biogenic amine-forming bacteria during processing of Brown-striped mackerel scad. Salmonella group had the strongest putrescine, cadaverine and tyramine producing ability(P<0.05), Aeromonas hydrophila had the strongest histamine producing ability(P<0.05); Added into lactic acid bacteria, Vibrio alginolyticus, Aeromonas hydrophila and Sphingomonas paucimobilis became the dominant biogenic amine-forming bacteria. Aeromonas salmonicida had the strongest putrescine and histamine producing ability(P<0.05), Salmonella group had the strongest cadaverine and tyramine producing ability(P<0.05). Vibrio alginolyticus, Lactococcus garvieae and Staphylococcus haemolyticus were dominant biogenic amine-forming bacteria of Sea bass. Lactococcus garvieae had the strongest putrescine and cadaverine producing ability(P<0.05), Staphylococcus warneri had the strongest histamine producing ability(P<0.05), Staphylococcus haemolyticus had the strongest tyramine producing ability(P<0.05). Added into lactic acid bacteria, Aeromonas hydrophila, Enterobacter cloacae and Staphylococcus sciuri became the dominant biogenic amine-forming bacteria. Enterobacter cloacae had the strongest putrescine producing ability(P<0.05), Aeromonas hydrophila had the strongest cadaverine and histamine producing ability(P<0.05), Citrobacter freundii had the strongest tyramine producing ability(P<0.05).3、Effects of temperature, p H and salt concentration during curing processing on growth and biogenic amine production of biogenic amine-forming bacteria strains. The results showed the change of temperature and salt concentration had a great influence on growth and biogenic amine production of strains, Low temperature can inhibit effectivitely the formation of biogenic amine. 100~200 g/L salt concentration could inhibit the growth of biogenic amine-forming bacteria, 100 g/Lsalt concentration could inhibit the production of histamine, However, 200 g/Lsalt concentration could inhibit the production of putrescine, cadaverine, tyramine. So appropriate low temperature and high salt concentration can inhibit biogenic amine content.4、Inhibition effect of three additives(potassium sorbate, gingerol, lactic acid bacteria)to biogenic amine-forming bacteria and biogenic amine were compared, The results showed potassium sorbate had the strongest inhibition effect on biogenic amine-forming bacteria. 5% Potassium sorbate had the strongest inhibition effect on putrescine and cadaverine, the reduced rates were 65.30%, 69.77% respectively, The inhibition rate of histamine was 66.15%, 300mg/kg gingerol had the strongest inhibition effect on histamine, the reduced rate was 76.75%, However, The inhibition rate of putrescine and cadaverine were only 21.78%,35.93% respectively. The inhibition effect of lactic acid bacteria was not as good as potassium sorbate and gingerol; Three additives all had a weak inhibition effect on tyramine. Therefore, comprehensive considering 5% potassium sorbate applied to the production and processing of dried-salted fish.