Presentation Abstract

Abstract Title: Pathogen Detection in Food Microbiology Laboratories: An Analysis of Proficiency Test Performance
Author Block: C. C. Snabes1, D. C. Edson1, S. Empson1, L. D. Massey2;
1American Proficiency Inst., Traverse City, MI, 2N/A, Pomona, MO.
Presentation Number: 1148
Poster Board Number: 1148
Keywords: proficiency testing,food pathogens,pathogen detection
Abstract: Background: For U.S. clinical laboratories, proficiency testing (PT) has evolved into an essential component of quality assurance programs. These laboratories are regulated by CLIA 1988, which requires participation in an approved PT program. Food laboratories may soon be subject to similar requirements with the passage of the Food Safety Modernization Act into law on January 4, 2011, which may mandate food laboratory accreditation for foods regulated by the FDA. American Proficiency Institute, a federally approved PT provider serving the clinical laboratory market, and an A2LA Accredited Food Microbiology PT provider, offers PT programs for the food industry. This study includes data from 1999 to 2012. Our objective was to assess whether laboratories have improved in their ability to detect or rule out contamination over a 14 year period with 4 common food pathogens: E. coli O157:H7, Salmonella spp., Listeria monocytogenes, and Campylobacter spp. Methods: False (+) and false (-) rates for selected food microbiology pathogens were recorded from cumulative proficiency testing results submitted in 3 test events per year over 14 years. Results: Performance accuracy for food pathogens remains problematic although the recent trend shows a decrease in both false positive and false negative results. The average percentage of false (+) results over the past 14 years has averaged 2.5 % for E. coli O157:H7, 3.9 % for Salmonella spp.; 2.5 % for L. monocytogenes; and 3.6 % for Campylobacter spp. The average percentage of false (-) results over the past 14 years has averaged 6.6 % for E. coli O157:H7; 4.9 % for Salmonella spp.; 5.7 % for L. monocytogenes; and 9.1 % for Campylobacter spp. Conclusions: In this retrospective study involving more than 39,500 results, food laboratories continue to routinely fail to detect pathogens in food samples more than 5% of the time. The data suggest that: 1) laboratories are more proficient at ruling out than detecting the presence of pathogens, and 2) cumulative performance is showing an encouraging trend downward in false positive and false negative rates over a 14 year period.