A highly sensitive multiplex lateral flow immunoassay for simultaneous detection of Listeria monocytogenes, Salmonella Typhimurium and Escherichia coli O157:H7

Foodborne pathogens Listeria monocytogenes, Salmonella Typhimurium and Escherichia coli O157:H7 continue to be leading causes of foodborne illness. Herein, we describe a sensitive and reliable lateral flow immunoassay for the simultaneous detection of these three bacteria via multiplex PCR and test strip by using gold nanoparticles (AuNPs) as label. Biotin, FITC and digoxin were used as tags for Listeria monocytogenes, Salmonella Typhimurium and Escherichia coli O157:H7, respectively. AuNPs were conjugated with thiolated probes and detected by multiplex lateral flow strip with three test lines corresponding to the three bacteria. The proposed method exhibited excellent specificity (no cross-reactivity with other tested foodborne bacteria were observed), good precision with the coefficient of variation less than 8.73%, and satisfactory recoveries (82.34–98.34%). The limits of detection were from 0.3 × 101 to 3.5 × 102 CFU mL−1 for the three bacteria in chicken breast sample, without culture enrichment, revealing the feasible and reliable of this method. The developed process, including sample preparation, PCR amplification, AuNPs conjugation and test strip detection, can be completed within 4 h. In light of the high level of targets specificity and sensitivity, this method provides a novel application potential for the simultaneous detection of foodborne pathogenic microorganisms.