Refrigerated characteristics of Penaeus Vannamei and effects of biological preservatives against the spoilage bacteria

In order to evaluate the shelf life of Penaeus Vannamei, sensory evaluation, p H, total bacteria count ( TVC) and total volatile basic nitrogen ( TVB-N) were determined. Using the method of paper disc to determine the antibacterial activity of Fructus rhdomyrti, tea polyphenols, lysozyme and Nisin to the spoilage bacteria of Penaeus Vannamei.Then fold dilution method was used to determine different preservative's MIC of different spoilage bacteria.Results showed that the self life of shrimp was3 d under 4 ℃. Tea polyphenols can inhibit Pseudomonas putida, Shewanella putrefaciens, Micrococcus luteus, Acinetobacter lwoffii and Aeromonas hydrophilia. The MIC of tea polyphenols to these spoilage bacteria were 0.12, 016, 0.06, 0.18 and0.14 g·100 m L^-1. flavonoids extracts of Fructus rhdomyrti can inhibit Pseudomonas putida, Shewanella putrefaciens, Micrococcus luteus, Bacillus cereus and Acinetobacter lwoffii.The MIC of Fructus rhdomyrti to these spoilage bacteria were 0.40, 0.50, 0.20, 0.90 and 0.40 g·100 m L^-1. The MIC of lysozyme to Bacillus cereus, Columbia enterococcus and Micrococcus luteus were 0.18, 0.04 and 0.02 g·100 m L^-1. The MIC of Nisin to Acinetobacter lwoffii, Columbia enterococcus and Micrococcus luteus were 0.20, 0.05 and 0.04 g·100 m L^-1. To summarize, tea polyphenol and flavonoids extracts of Fructus rhdomyrti can inhibit part of G+and G-when Nisin and lysozyme mainly inhibit the G+.