Evaluation of methods for identifying poultry wing rinses with Salmonella concentrations greater than or equal to 10 CFU/mL

Authors: Schmidt, John; CARLSON, ANNA - Cargill, Incorporated; Bosilevac, Joseph; Harhay, Dayna; Arthur, Terrance; BROWN, TED - Cargill, Incorporated; Wheeler, Tommy; VIPHAM, JESSIE - Kansas State University

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/2024
Publication Date: 11/1/2024
Citation: Schmidt, J.W., Carlson, A., Bosilevac, J.M., Harhay, D., Arthur, T.M., Brown, T., Wheeler, T.L., Vipham, J.L. 2024. Evaluation of methods for identifying poultry wing rinses with Salmonella concentrations greater than or equal to 10 CFU/mL. Journal of Food Protection. 87(11). Article 100362. https://doi.org/10.1016/j.jfp.2024.100362.
DOI: https://doi.org/10.1016/j.jfp.2024.100362

Interpretive Summary: It has become consensus that presence/absence testing in poultry is not providing adequate protection against the risk of Salmonella in final products. Regulatory requirements may soon include testing whether samples exceed a certain level of Salmonella. To prepare for this eventuality and to improve process control the poultry processing industry requires feasible, rapid methods to identify wing rinses exceeding a certain level of Salmonella. The currently available laboratory and commercial Salmonella quantification methods ranged in accuracy from 91.1% to 58.1%, but none provided both adequate accuracy and feasibility of implementation. We developed a series of simple threshold tests that could be calibrated to different threshold levels that ranged in accuracy from 83.9% to 91.1%. This threshold test concept provides a better combination of cost, speed, ease of use, and accuracy than currently available Salmonella quantification methods and could be adapted to many food production sample types to ensure pathogen levels are low.

Technical Abstract: In the United States, the Proposed Regulatory Framework to Reduce Salmonella Illnesses Attributable to Poultry published by the Food Safety and Inspection Service (FSIS) has highlighted the need for simple, rapid methods that identify poultry wing rinse samples harboring Salmonella concentrations =10 CFU/mL. One of eight cold-stressed and nutrient-starved Salmonella strains was inoculated into post-chill two-joint poultry wing rinses (48 turkey and 72 chicken) at levels from 0.22 to 3.79 log CFU/mL, and then measured by 3-tube Most Probable Number (MPN), BioMerieux GENE-UP QUANT, Hygiena BAX SalQuant, and novel threshold methods. The MPN lower limit of quantification (LLQ) for Salmonella was -0.96 log CFU/mL. MPN overestimated the inoculated Salmonella level by 0.05 ± 0.35 log CFU/mL. The GENE-UP QUANT Salmonella method (LLQ = 1.00 log CFU/mL) underestimated the inoculated Salmonella level by 0.05 ± 0.51 log CFU/mL. The BAX SalQuant method (LLQ = 0.00 log CFU/mL) underestimated the inoculated Salmonella level by 1.21 ± 0.78 log CFU/mL. Threshold test methods with Poisson probabilities of 0.95 (PiLOT-95), 0.86 (PiLOT-86), 0.63 (PiLOT-63), and 0.50 (PiLOT-50) were developed to identify poultry wing rinses harboring Salmonella levels =10 CFU. MPN was 93.1%, accurate for determining if Salmonella levels in poultry wing rinses were =10 CFU/mL, but MPN costs and time requirements can be prohibitive for most laboratories. GENE-UP quantification was 86.1% accurate, but the GENE-UP method requires equipment and technical expertise that some food safety laboratories may not possess. BAX quantification had the lowest accuracy; 58.4%. PiLOT threshold test accuracies ranged from 83.2% for PiLOT-50 to 93.1% for PiLOT-86. The PiLOT threshold tests are simple and can be adapted to identify many environmental or food samples containing Salmonella exceeding any user-defined concentration threshold.