Roka Listeria Detection Method Using Transcription Mediated Amplification to Detect Listeria Species in Select Foods and Surfaces

• Published in: Journal of AOAC International 2012-11, Vol.95 (6), p.1672-1688
• Main Authors: DONNELLY, Catherine, RYSER, Elliot, YI CHEN
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Food industries; Food microbiology; Fundamental and applied biological sciences. Psychology; General aspects; Methods of analysis, processing and quality control, regulation, standards
• ISSN: 1060-3271; 1944-7922
• DOI: 10.5740/jaoacint.12-063

The Roka Listeria Detection Assay was compared to the reference culture methods for nine select foods and three select surfaces. The Roka method used Half-Fraser Broth for enrichment at 35 ± 2°C for 24–28 h. Comparison of Roka's method to reference methods requires an unpaired approach. Each method had a total of 545 samples inoculated with a Listeria strain. Each food and surface was inoculated with a different strain of Listeria at two different levels per method. For the dairy products (Brie cheese, whole milk, and ice cream), our method was compared to AOAC Official MethodSM993.12. For the ready-to-eat meats (deli chicken, cured ham, chicken salad, and hot dogs) and environmental surfaces (sealed concrete, stainless steel, and plastic), these samples were compared to the U.S. Department of Agriculture/Food Safety and Inspection Service-Microbiology Laboratory Guidebook (USDA/FSIS-MLG) method MLG 8.07. Cold-smoked salmon and romaine lettuce were compared to the U.S. Food and Drug Administration/Bacteriological Analytical Manual, Chapter 10 (FDA/BAM) method. Roka's method had 358 positives out of 545 total inoculated samples compared to 332 positive for the reference methods. Overall the probability of detection analysis of the results showed better or equivalent performance compared to the reference methods.