Bacterial flora and identification of dominated spoilage organisms on cultured Pseudosciaena crocea at chilled storage

Bacterial flora and identification of dominated spoilage organisms on cultured Pseudosciaena crocea at the end of shelf life during storage at 0 ℃ and 5 ℃ were qualitatively and quantitatively investigated, based on the colony and cellular morphology, biochemical and physiological characteristics as well as whole-cell fatty acid composition, and applied with Sensititre，BioFosun，MIDI bacteria identification systems. The dominated bacteria of Shewanella putrefaciens were 75.5% and 59.6% at the end of shelf life at 0 ℃ and 5 ℃,and its colonies on nutrition agar and trypticase soy broth agar were global apophysis, trim side, smooth clarity, achromatism to pink. The cells were gram negative rod［(0.6-0.9) μm×(1.5-3.3) μm］ and motile by means of polar flagellum, the optimum growth occurred at 25-35 ℃ and pH 7-9. Strains were positive for oxidation，H2S，TMAO，gelatin and Tween 40. Strains utilized N-acetyl-D-glucosamine, ect. The dominant fatty acids were 16∶1ω8c, iso-15∶0，17∶1ω8c，16∶0, mean contents were 21.31%，13.63%，9. 82%，9.76%， respectively. Results from tested strains were compared with database values in the bacterial identification systems, indicating the dominated spoilage organisms were Shewanella putrefaciens.