Food Protection Trends - February 2009 - 81

evaluating the “ins and outs” of commercially available molecular detection systems, which set the stage for representatives from Applied Biosystems, Bio-Rad, DuPont Qualicon, and idaho Technologies, who described the technology behind their molecular detection assays. The remainder of the second day of the symposium was composed of several interactive discussions and activities, including a question and answer session with company representatives and instructors on selection of an appropriate molecular detection system, considerations for application of molecular detection systems, and a presentation of case studies that focused on troubleshooting and correct interpretation of results. Dr. Nightingale described the fundamentals of primer/ probe design, which was followed by a hands-on primer design activity. That evening, workshop participants and instructors took a trip to estes Park, CO to enjoy a scenic drive through Roosevelt National Forest, followed by dinner set in the Rocky Mountains. One of the major objectives of the hands-on laboratory session was to guide participants through the process of designing a custom PCR assay. The first day of the laboratory session began with an introduction to DNA sequence databases followed by a one-on-one activity where instructors assisted participants to identify a suitable target for development of a custom PCR assay. Participants designed and ordered primers for their custom assay, which were received on the second day of the workshop. instructors assisted participants with developing protocols (i.e., master mix formulations and thermal cycling conditions) for their individually designed PCR assays. Participants set up and ran custom PCR reactions followed by analysis of PCR products, including a troubleshooting discussion session led by Dr. Wiedmann. in addition to designing their own PCR assays, participants also used an established PCR protocol to amplify a Listeria-specific gene, followed by analysis and purification of PCR products and submission of purified PCR products for DNA sequencing. instructors showed participants how to analyze their sequence results using DNA software analysis tools in order to identify the Listeria spp. whose product was amplified by PCR. Furthermore, participants set-up reactions and analyzed unknown samples using the commercially available BAX® Listeria monocytogenes detection system and the TaqMan® PCR assay to detect Escherichia coli O157:H7. The laboratory session also included extensive discussion sessions on interpretation of results from commercially available molecular detection systems, including how to deal with scenarios where atypical results, such as intermediate positives and shifted peaks resulting from the melt-curve analysis. At the end of the workshop, all participants were given opportunities for one-on-one discussions with instructors to address specific issues of interest. This workshop will be offered at Colorado State University annually with rotating topics. Specifically, the 2009 workshop, which will be held August 3–7, will focus on nucleic acid-based sub-typing and characterization of food-associated microorganisms. in addition, this new workshop series will be offered at international venues. The first international “Molecular Methods in Food Microbiology Symposium and Workshop Series” will take place at Mahidol University in Bangkok, Thailand, March 30– April 3, 2009, and will focus on nucleic acid-based detection of foodborne pathogens and spoilage organisms. Please contact Kendra Nightingale (kendra.nightingale@colostate. edu) or visit our webpage (http://ansci.colostate.edu/ content/view/701/105/) for additional information on upcoming workshops. *Corresponding Author: Department of Animal Science, Colorado State University, Fort Collins, CO 80523, USA: Voice: 970.491.1556; Fax: 970.491.5326; e-mail: kendra.nightingale@colostate.edu. FEBRUARY 2009 | FOOD PROTECTION TRENDS 81

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Food Protection Trends - February 2009

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