Tuesday, July 30, 2013
Exhibit Hall (Charlotte Convention Center)
Erin Crowley, Q Laboratories, Inc., Cincinnati, OH
Morgan Wallace, DuPont Nutrition and Health, Wilmington, DE
Patrick Bird, Q Laboratories, Inc., Cincinnati, OH
Kiel Fisher, Q Laboratories, Inc., Cincinnati, OH
Travis Huffman, Q Laboratories, Inc., Cincinnati, OH
M. Joseph Benzinger, Q Laboratories, Inc., Cincinnati, OH
James Agin, Q Laboratories, Inc., Cincinnati, OH
David Goins, Q Laboratories, Inc., Cincinnati, OH
Introduction: The BAX
® System Real-Time PCR Assay for
Salmonella and BAX System PCR Assay for
Salmonella 2 utilize Polymerase Chain Reaction (PCR) to amplify a specific fragment of bacterial DNA, which is stable and unaffected by growth environment and detected using the system software. These new methods simplify the PCR process by combining the requisite primers, polymerase and nucleotides into a stable, dry, manufactured tablet already packaged inside the PCR tubes. After amplification, these tubes remain sealed for the detection phase, thus significantly reducing the potential for contamination with one or more molecules of amplified PCR product. The Real-time
Salmonella assay provides results in real-time reducing the time to final detection. The system
Salmonella 2 assay utilizes a proprietary “hot-start” technology to help reduce the effects of human error.
Purpose: The purpose of the evaluation was to compare the BAX System methods to the FDA BAM for the detection of Salmonella Enteritidis in shell eggs.
Methods: For each new method, 20 replicates of approximately 1,000 g each (20-egg pool) were analyzed at one inoculum level: 0.2-2 CFU/test portion. Five control replicates were analyzed at 0 CFU/test portion. For each PCR Assay for Salmonella, aliquots of each enriched sample were analyzed with and without a 3 hour re-growth step in BHI.
Results: The results of a Mantel-Haenszel Chi-square analysis indicated no statistically significant difference observed between the two new methods and the FDA BAM reference method (χ2 < 3.84). For both the BAX System methods a χ2 value of 1.21 was obtained. No false negatives or false positives were reported.
Significance: For the method comparison, these new methods demonstrated high specificity in the identification of Salmonella Enteritidis in shell eggs reducing the time of detection from 7 days to 2 days.
