Application of magnetic immuno-polymerase chain reaction assay for detection of Salmonella spp. in chicken meats

Abstract

Since contaminated chicken meats have been the principal foodborne source of the contamination of Salmonella to human beings and cultural detection methods are labor-intensive and time-consuming, a study evaluating the performance of the combination of two techniques that are immunomagnetic separation (IMS) and polymerase chain reaction (PCR) for the detection of Salmonella in chicken meats was conducted. The IMS and PCR assay combines selective extraction of Salmonella by specific antibodies with primer-specific (primer pair based on the sequence of invA gene) PCR amplification. Initially chicken meat samples, in which no Salmonella contamination had been determined by using ISO 6579 reference method, were inoculated with Salmonella Enteritidis culture and subsequently the shortest non-selective pre-enrichment time, that had been needed for the detection of approximately 1 or 10 CFU/mL chicken meat levels of target bacteria by magnetic immuno-PCR assay, was found by using 14, 12, 10 and 8-h periods. In conclusion, it was found that magnetic immuno-PCR assay was able to detect 1–10 CFU Salmonella/25 g chicken meat, after only incorporating a non-selective pre-enrichment period of 12 h. Therefore, an overall 16-h (magnetic immuno-PCR assay in conjunction with 12-h non-selective pre-enrichment) magnetic immuno-PCR assay statistically evaluated as sufficient (p = 0.182 > 0.05) for rapid and sensitive detection of approximately 1–10 CFU Salmonella from 25 g chicken meat samples. Accordingly, 16-h magnetic immuno-PCR assay can be promising for routine use in the detection of Salmonella in chicken meat samples, and it consequently may prevent the risk of Salmonella infections in regard to chicken meats.