Validation of a New and Innovative Rapid Assay for the Detection of Salmonella in Food and Environmental Samples

Introduction: Salmonella is omnipresent in nature and comprises over 2,500 identified serotypes. It can be found in intestinal tract of vertebrates including livestock, domestic pets and human as well as in the environment. Based on this ubiquity, it is not surprising to find food contaminated with Salmonella. Among them, eggs and egg derivatives are commonly identified as being contaminated with Salmonella. An effective way to reduce the prevalence is to monitor its presence in the final product and in the environment of the food processing and apply the appropriate corrective measures when necessary.

Purpose: The aim of the study was to develop and validate an immunomagnetic lateral flow assay for the rapid detection (in less than 24h) of the most frequently isolated Salmonella (group B to E) in eggs and egg derivative products and in environmental samples.

Methods: The performance was evaluated according to the Guidelines of the AOAC for the Performance Tested Methods^SM. Method comparison study was carried out using 600 samples (egg products and environmental surfaces). Half of the samples were analyzed using the new assay and the other half using reference methods.

Results: During the comparison study, the new developed assay correctly identified 299/300 of the samples tested. Difference of probability of detection was used as statistical model to confirm no significant difference between both methods. Ninety-nine percent (102/103) of the Salmonella strains tested belonging to serogroups B to E were detected. None of the 31 non-target strains tested shows cross-reactivity in the assay enrichment conditions. In addition, this new detection method shows strong robustness, good stability, consistency and good reproducibility.

Significance: The new FoodChek™ Salmonella assay is an effective tool for the rapid detection of Salmonella spp. in whole liquid eggs, liquid egg white, shell eggs, dried whole eggs, dried egg yolks and on environmental surfaces.