Abstract:The purpose of this study was to investigate the antibacterial activity of single and compound bacteriostatic agents against specific spoilage organisms(Proteus vulgaris and Hafnia alvei) isolated from lightly salted large yellow croaker. In this study, the minimum inhibitory concentration of chitosan on specific spoilage organisms was detected, and then, the sub-inhibitory concentration of chitosan and the addition of different concentrations of nisin were used to treat the fish juice. And the two bacteria were respectively inoculated into the fish juice and stored at 5 ℃. The extracellular products and spoilage indexes were used to evaluate the inhibitory effect of different treatment groups on the two bacteria. The results showed that the minimum inhibitory concentration of chitosan against Proteus vulgaris and Hafnia alvei were 125 μg/mL. When the mass concentration of chitosan in fish juice was the sub-inhibitory mass concentration (62.5 μg/mL), the higher the mass concentration of composite nisin was the stronger the inhibition effect. According to the total number of colonies, the optimal synergistic combination for Proteus vulgaris and Hafnia alvei was chitosan 62.5 μg/mL and nisin 1 000 μg/mL. Compared with single chitosan, compound bacteriostatic agent had better effect(P<0.05), the combination of chitosan and nisin showed synergistic antibacterial effect. The results of this study provide basic research for targeted inhibition of bacteria and shelf life extension of lightly-salted large yellow croaker.