Validation of a high-throughput immunobead array technique for multiplex detection of three foodborne pathogens in...

This study rigorously evaluated a previously developed immunobead array method to simultaneously detect three important foodborne pathogens, Campylobacter jejuni, Listeria monocytogenes, and Salmonella spp., for its actual application in routine food testing. Due to the limitation of the detection limit of the developed method, an enrichment step was included in this study by using Campylobacter Enrichment Broth for C. jejuni and Universal Pre-enrichment Broth for L. monocytogenes and Salmonella spp.. The findings showed that the immunobead array method was capable of detecting as low as 1CFU of the pathogens spiked in the culture media after being cultured for 24h for all three pathogens. The immunobead array method was further evaluated for its pathogen detection capabilities in ready-to-eat (RTE) and ready-to-cook (RTC) chicken samples and proven to be able to detect as low as 1CFU of the pathogens spiked in the food samples after being cultured for 24h in the case of Salmonella spp., and L. monocytogenes and 48 h in the case of C. jejuni. The method was subsequently validated with three types of chicken products (RTE, n=30; RTC, n=20; raw chicken, n=20) and was found to give the same results as the conventional plating method. Our findings demonstrated that the previously developed immunobead array method could be used for actual food testing with minimal enrichment period of only 52 h, whereas the conventional ISO protocols for the same pathogens take 90-144 h. The immunobead array was therefore an inexpensive, rapid and simple method for the food testing.