Abstract: Sensory quality, the growth kinetic parameters of spoilage bacteria and the yield factor of metabolic products, YTVBN/CFU, were assayed on sterile Cyprinus carpio and Oreochromis niloticus tissue blocks inoculated with spoilage bacteria during chilled storage. The spoilage ability of two dominant spoilage bacteria, Pseudomonas spp. and Shewanella putrefaciens, were analyzed on Cyprinus carpio and Oreochromis niloticus stored aerobically under chilled conditions. The post-inoculation shelf-lives of sterile Cyprinus carpio tissue blocks inoculated with Shewanella putrefaciens and Pseudomonas putida were 132  h and 162 h, respectively, the TVBNs 27.12 mg/100 g and 22.51 mg/100 g, the bacterial counts 8.96 lg(CFU/g) and 9.07 lg(CFU/g) and the YTVBN/CFU values 9.28 × 10-9 mg TVBN/CFU and 1.81 × 10-8  mg TVBN/CFU. The post-inoculation shelf-lives of sterile Oreochromis niloticus tissue blocks inoculated with Pseudomonas fluorescens and Shewanella putrefaciens were 132 h and 144 h, respectively, the TVBNs 23.46 mg/100 g and 24.30 mg/100 g, the bacterial counts 8.83 lg(CFU/g) and 9.12 lg(CFU/g) and the YTVBN/CFU values 1.67 × 10-8 mg TVBN/CFU and 9.10 × 10-9 mg TVBN/CFU. Based on the microflora changes and the role of the spoilage bacteria during chilled storage of the two species of cultured fish, it can be preliminarily concluded that the special spoilage organisms of stored chilled Oreochromis niloticus and Cyprinus carpio was Pseudomonas spp and that the spoilage ability of Pseudomonas spp and Shewanella putrefaciens is strong.

Key words: spoilage ability, Pseudomonas spp., Shewanella putrefaciens, Cyprinus carpio, Oreochromis niloticus, Pseudosciaena crocea