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P1-40 Detection of Salmonella species by the DuPont™ BAX® System Real-time PCR Assay for Salmonella: Collaborative Study

Monday, August 4, 2014
Exhibit Hall D (Indiana Convention Center)
Morgan Wallace, DuPont Nutrition & Health, Wilmington, DE
Bridget Andaloro, DuPont Nutrition & Health, Wilmington, DE
Dawn Fallon, DuPont Nutrition & Health, Wilmington, DE
Nisha Corrigan, DuPont Nutrition & Health, Wilmington, DE
Stephen Varkey, DuPont Nutrition & Health, Wilmington, DE
Daniel DeMarco, DuPont Nutrition & Health, Wilmington, DE
Steven Hoelzer, DuPont Nutrition & Health, Wilmington, DE
Julie Weller, DuPont Nutrition & Health, Wilmington, DE
George Tice, DuPont Nutrition & Health, Wilmington, DE
Patrick Bird, Q Laboratories, Inc., Cincinnati, OH
Erin Crowley, Q Laboratories, Inc., Cincinnati, OH
Jonathan Flannery, Q Laboratories, Inc., Cincinnati, OH
Kiel Fisher, Q Laboratories, Inc., Cincinnati, OH
Travis Huffman, Q Laboratories, Inc., Cincinnati, OH
Megan Boyle, Q Laboratories, Inc., Cincinnati, OH
M. Joseph Benzinger, Q Laboratories, Inc., Cincinnati, OH
Paige Bedinghaus, Q Laboratories, Inc., Cincinnati, OH
Katherine Goetz, Q Laboratories, Inc., Cincinnati, OH
William Judd, Q Laboratories, Inc., Cincinnati, OH
James Agin, Q Laboratories, Inc., Cincinnati, OH
David Goins, Q Laboratories, Inc., Cincinnati, OH
Andrew Farnum, DuPont Nutrition & Health, Wilmington, DE
Jeffrey Rohrbeck, DuPont Nutrition & Health, Wilmington, DE
Eugene Davis, DuPont Nutrition & Health, Wilmington, DE
Introduction: Salmonella is found in many food and environmental sources and can cause serious illness. Since isolation by culture is long and difficult, especially in the presence of competing flora, rapid methods for its detection are needed.

Purpose: Internal validation studies were previously performed by DuPont Nutrition & Health on 24 matrices to demonstrate the reliability of the test method among a wide variety of sample types. Two of these matrices –frankfurters and orange juice– were each evaluated in 14 independent laboratories as part of a collaborative study to demonstrate repeatability of the method independent of the end user.

Methods: Samples were prepared at three inoculation levels - unspiked, low (<2.0 MPN/test portion) and high (~5 MPN/test portion) – then blind-coded and sent to each participating site. Frankfurters were compared to the USDA FSIS reference method in a paired study design, and orange juice was compared to the FDA BAM reference method in an unpaired study with enrichment in proprietary BAX® System MP media.

Results: For low-spike samples, the BAX® System method returned presumptive positive results for 186 of the 336 samples tested, and the reference method confirmed 182 positive results. For high-spike samples, the BAX® System method returned positive results for all 336 samples tested, and the reference method confirmed all 336 positive results. Also, all negative control samples (n = 336 samples total) were presumptively and culturally negative. At each inoculation level and for each matrix, results from the BAX® System method and the reference method were statistically indistinguishable when analyzed using the Probability of Detection (POD) statistical treatment as required by AOAC.

Significance: This study indicates that PCR detection of Salmonella using the BAX® System method is rapid and sensitive.  Test kit results demonstrated no significant difference when compared with the reference culture methods.

Back to: Poster Session - Applied Laboratory Methods, Produce, Low-water Activity, Beverages and Water
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