Evaluation of a rapid detection method of Salmonella in comparison with the culture method and microbiological quality in fish from the Brazilian Amazon

Abstract Microbiological safety of fish is a concern of consumers, industries and regulatory agencies worldwide. Among the pathogenic microorganisms, Salmonella spp. is one of the main agents of foodborne diseases and should be absent in animal products. Rapid and accurate identification of pathogens in the supply chain is important for both quality assurance and tracking infectious agents within the chain. In this context, this study aimed to evaluate the equivalence of two rapid detection tests, as alternative methods to the conventional Salmonella detection method, as well as to verify the microbiological quality parameters of two commercially important fish species in the Amazon biome. The plate count of aerobic bacteria ranged from 7.76 x 104 to 8.71 x 107 CFU.g-1 for mesophiles and 1.70 x 106 to 4.27 x 108 CFU.g-1 for psychrotrophic whereas the maximum for this group of microorganisms in fresh fish is 106 CFU.g-1. Regarding the Staphylococcus count, the two species presented variations between 1.35 x 104 to 1.51 x 105 CFU.g-1. This represents unsatisfactory conditions of handling, storage and conservation of fish species. The immunoenzymatic and molecular methods have been shown to be reliable, fast and effective in the detection of Salmonella and for its high index of agreement with the conventional detection method. We also emphasize the convenience of multiplex PCR application due to the high sensitivity, specificity, speed and accuracy of Salmonella detection.