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

Authors: Schmidt, John; CAROLSON, ANNA - Cargill, Incorporated; Bosilevac, Joseph - Mick; 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: N/A
Citation: N/A

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. Post-chill two-joint poultry wing rinses (60 turkey and 72 chicken) were inoculated with one of eight cold-stressed and nutrient starved Salmonella strains. Inoculated poultry wing rinse Salmonella levels ranged from –0.71 to 3.79 log CFU/mL. The Most Probable Number (MPN) quantification method had a lower limit of quantification (LLQ) = –0.96 log CFU/mL. MPN quantification underestimated the inoculated Salmonella level by 0.03 ' 0.35 log CFU/mL. The Biomerieux GENE-UP QUANT Salmonella method (LLQ = 1.00 log CFU/mL) underestimated the inoculated Salmonella level by 0.16 ' 0.44 log CFU/mL. The Hygiena 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 identifying poultry wing rinses harboring Salmonella levels = 10 CFU of 0.95 (PiLOT-95), 0.86 (PiLOT-86), 0.63 (PiLOT-63), and 0.50 (PiLOT-50) were developed. MPN quantification was the most accurate method for determining if Salmonella levels in poultry wing rinses were = 10 CFU/mL. MPN quantification accuracy was 91.1%, but MPN costs and time requirements would be prohibitive for most laboratories. GENE-UP quantification was 88.2% accurate, but the GENE-UP method but requires equipment and technical expertise that some food safety laboratories may not possess. BAX quantification had the lowest accuracy, 58.1%. PiLOT threshold test accuracies ranged from 83.9% for PiLOT-50 to 91.1% for PiLOT-95. The PiLOT threshold test can be performed in nearly any food safety laboratory. The PiLOT threshold test concept can be adapted to facilitate the identification many environmental or food samples containing Salmonella exceeding any user defined threshold concentration.