Modified Most Probable Number Assay to Quantify Salmonella in Raw and Ready-to-Cook Chicken Products.

Abstract

Salmonella is a leading cause of foodborne illness in the United States, particularly in poultry products. Traditional methods for detecting Salmonella focus on prevalence rather than quantification, which limits their utility in assessing contamination levels and risks. This study introduces a novel most probable number (MPN) assay designed to quantify Salmonella in ready-to-cook poultry products, such as chicken cordon bleu. The method involves washing the poultry sample, concentrating the rinse through centrifugation, and serially diluting it in a 48-well block. The MPN assay is integrated with the loop-mediated isothermal amplification (LAMP) method to provide a sensitive, accurate, and rapid quantification of Salmonella contamination within the same timeframe as existing Food Safety and Inspection Service (FSIS) protocols. Results show a strong linear correlation between the MPN-LAMP measurements and theoretical inoculation levels (R² = 0.933). However, variability at lower concentrations highlights challenges in accurately detecting Salmonella at these levels, with the practical lower limit of detection estimated at approximately 300 CFU/g. Potential refinements to improve the protocol's applicability include increasing the quantity sampled to further improve the limit of detection, optimizing enrichment media formulations, and expanding molecular detection to target multiple Salmonella serovars. Overall, this study presents a practical tool for the food industry, enabling reliable quantification of Salmonella contamination in poultry products, contributing to improved food safety and public health.