Magnetic Bead-Based Immunoassay Coupled with Tyramide Signal Amplification for Detection of Salmonella in Foods

摘要

Salmonella is the leading cause of bacteria-associated foodborne illnesses in the United States. Early detection of this pathogen by a rapid and sensitive assay is important to prevent salmonellosis. In this study, we describe a magnetic bead-based immunoassay for detection of Salmonella consisting of immunomagnetic separation for simple target concentration with tyramide signal amplification to increase the assay sensitivity. The developed immunoassay was able to detect Salmonella Typhimurium in culture with the detection limit of 280 CFU/mL in less than 3 h without any enrichment and further decreased to 70 CFU/mL with 3 h enrichment. When tested with ground beef and poultry samples artificially contaminated with S. Typhimurium and Enteritidis, the assay showed increased detection limits with 800 and 200 CFU/mL, respectively, due to the effect of complex food matrices. However, when 12 h enrichment was added, the detection limits in both food matrices decreased to 1 CFU.