Isolation and Identification of Dominant Spoilage Biogenic Amine Producing Bacteria from Refrigerated Skipjack Tuna and Analysis of Their Production Ability

In order to explore the types of dominant spoilage biogenic amine-producing bacteria in skipjack tuna, three dominant bacteria were screened from refrigerated skipjack tuna. The strains were identified by 16S rDNA molecular identification technology, which were Pseudomonas fluorescens, Citrobacter freundii and Aeromonas hydrophila. The dominant spoilage biogenic amine-producing bacteria were inoculated onto sterile fish and stored at 4 ℃. By measuring the total number of colonies and the value of volatile base nitrogen (TVB-N), we used the yield factor (Y_TVB-N/CFU) of spoilage metabolites to analyze the spoilage ability of the three dominant spoilage biogenic amine-producing bacteria. The production ability of bacteria was compared by detecting the content of biogenic amines in the samples. The results showed that the total number of colonies in the groups inoculated with P. fluorescens, C. freundii and A. hydrophila were 8.36, 8.27 and 8.13 lg CFU/g at the end of storage, respectively. The TVB-N values reached 28.21, 30.30 and 31.29 mg/100 g, respectively. The spoilage ability of the three dominant spoilage amine-producing bacteria were A. hydrophila>C. freundii>P. fluorescence. On the 8th day of storage, the histamine contents of the P. fluorescens, C. freundii and A. hydrophila groups reached 196.23, 83.43 and 261.22 mg/kg, respectively. The total biogenic amine contents of the three groups of samples at the end of storage were A. hydrophila>P. fluorescens>C. freundii. The combined comparison concluded that A. hydrophila had the highest spoilage biogenic amine-producing ability in skipjack tuna. This study increased the knowledge and provided a partial theoretical basis for the dominant spoilage biogenic amine producing species in refrigerated skipjack tuna.