Research Of Dominant Spoilage Bacteria During Storage Of Semi-dried Grass Carp Slices

China has been a big country in aquaculture and trade. Fresh fish is easy tocorrupt. Microbial activity is the main cause of the corruption of aquatic products. Intermediate moisture food technology has been more and more used in food processing. This study selected semi-dry grass carp fillets as the research object, the changes of physical and chemical properties under different storage conditions were studied, and the spoilage ability of the dominant microorganisms was analyzed, dominant spoilage bacteria was identified and its growth characteristics was studied.In this study, the changes of the physical and chemical indexes of the semi-dry grass carp fillets at storage temperature 5℃,15℃ and 28℃ were obtained:at different storage temperature, the overall test indicators of the semi-dry grass carp fillets showed an upward trend. The change trends of pH, TVB-N, TBA and TMA were consistent with the changes of the total number of colonies. At storage temperature 5℃,15℃,28 ℃, the semi-dry grass carp fillets’ shelf life was 2d,15d, 30d or so.This study was based on the analysis of the bacteria in the end of the shelf of the semi-dry grass carp fillets, and the spoilage ability of these dominant strains were analyzed at 28℃:the sterile fish block with C1, C2, C3, C4, C5, C6 were corrupted, and the detection indicators increased significantly, C7 and C8 was not. The cluster analysis of these dominant strains showed that C1, C2, C3, C4, C5, C6 was spoilage bacteria of the semi-dry grass carp fillets at 28℃. The spoilage ability of C1 was the strongest, and its YTVBN/CFU was 2.12x10-7, YTMA/CFU was 9.51x10-8This study was based on the analysis of the bacteria in the end of the shelf of the semi-dry grass carp fillets, and the spoilage ability of these dominant strains were analyzed at 5℃:the sterile fish block with L1, L2, L3, L4, L5, L8 were corrupted, and the detection indicators increased significantly, L6 and L7 was not. The cluster analysis of these dominant strains showed that L1, L2, L3, L4, L5, L8 was spoilage bacteria of the semi-dry grass carp fillets at 5 ℃. The spoilage ability of L3 is the strongest, and its YTVBN/CFU is 2.27×10-7, YTMA/CFU is 8.87×10-8.In this study,12 dominant spoilage bacteria were identified. All strains were gram positive bacteria, globular. The homology of C1, C3, C6, L4 with Macrococcus caseolyticus reached more than 99%. The homology of C2 with Staphylococcus kloosii reached more than 98%. The homology of C4, C5 with Staphylococcus sciuri subsp AF508104 reached 100.00%. The homology of L1, L2, L3, L5, L8 with known strain Staphylococcus vitulinus reached more than 98.00%. Temperature (5℃-30℃) did not had much effect on the growth of Staphylococcus vitulinus, and had great influence on kloosii Staphylococcus. The salt tolerance (0%-10%) of each strain was good. Staphylococcus sciuri had the protease activity.