Abstract:

A real-time fluorescent PCR array using the optimal combination of primer and Taqman MGB probe designed from the fimY conserved sequence of Salmonella was developed for the rapid and quantitative detection of Salmonella in seafood. Totally 24 strains of 14 serotypes of Salmonella and its 17 close relatives as well as common foodborne pathogenic bacteria coexisting in a sample were subjected to detection using the method. Results were positive for all Salmonella strains and negative for all other species tested with a specificity of 100%. The sensitivity of the method was sufficient to detect 13 CFU/ml of Salmonella in pure cultures, 130 CFU/ml of S.enteritidis spiked in shell ligament or shigimi meat, and 1300 CFU/ml of S.enteritidis spiked in moon snail meat. This method exhibited a quantification regression equation of y = －3.381418ln(x)＋45.115715, R2 = 0.964878, and could be completed within 2 h, thereby providing a useful approach for the rapid detection of Salmonella in seafood without prior isolation and characterization of strains which are needed in traditional microbiological methods.

Key words: real-time fluorescent PCR, quantification, Salmonella, fimY sequence, Taqman MGB probe, seafood