AOAC 133rd Annual Meeting - Final Program

Poster Abstracts | Wednesday

P-W-078 Amanda Manolis , Thermo Fisher Scientific, Austin, TX, USA; Laura Vaahtoranta , Hanna Lehmusto , Nina Wickstrand , Emmi Hurskainen , Jonna Roivanen , Suvi Airikka , Ahmed Al-Mosawi , Thermo Fisher Scientific, Vantaa, Finland; Charlotte Cooper , Dean Leak , Thermo Fisher Scientific, Basingstoke, United Kingdom Performance Comparison of Shiga Toxigenic E. coli (STEC) Multiplex Molecular Assays Thermo Scientific™ SureTect™ E. coli O157:H7 and STEC Screening and Identification PCR Assays enable the simultane- ous detection and differentiation of E. coli O157:H7 and the top six non‐O157:H7 serogroups in raw beef, produce and dairy samples. The purpose of the study was to compare the sensitivity and specificity of the SureTect™ STEC Multiplex Assays against a leading commercially available real-time PCR assay designed to detect O157:H7 and the top six STEC O serogroups in raw beef samples. Samples were lysed prior to PCR and analyzed with SureTect™ STEC Multiplex Assays as detailed in the prod- uct’s manual. The alternative assay was performed on the same panel of samples according to the manufacturers´ instructions. The sensitivity of the STEC Multiplex ranged between 5-25 CFUs per PCR reaction depending on the O serogroup tested, whereas the alternative method returned less sensitivity across all strains. Both assays returned a false positive result for E. coli O45 with Enterobacter asburiae. In addition, the alternative assay returned a false positive result for E. coli O45 with Citrobacter werkmanii and Enterobacter ludwigii. The study demonstrated that the SureTect™ E. coli O157:H7 and STEC method is a more reliable workflow for the detection and differentiation of E. coli O157:H7 and the top six non-O157:H7 serogroups than the other commercially available real-time PCR assay. Presenter: Amanda Manolis, Thermo Fisher Scientific, Austin, TX, USA, Email: amanda.manolis@thermofisher.com P-W-079 Hilde Norli , Norwegian Veterinary Institute, Oslo, Norway Evaluation and Certification of Alternative Microbiological Methods by NordVal International There are many rapid (proprietary) microbiological methods for foods, feed and environmental samples; methods preferred to traditional reference methods. How reliable are the alternative methods? Can alternative methods be used in replacement for reference methods in official controls? Are alternative methods equivalent to reference methods? For documenting the perfor- mance and equivalency of methods, extensive validations and comparisons of methods need to be carried out. Further, in order to be trustworthy, the validations should to be carried out by independent expert laboratories, accredited for the reference method of interest, and the results reviewed by a third party. That is also the requirement given in the EU regulation (EC 2073/2005-Microbiological criteria). NordVal International is an independent organization evaluating the documentation and certifying (proprietary) alternative methods. The design and the evaluations are carried out according to ISO 16140-2:2016 “Protocol for the validation of alternative (proprietary) meth- ods against a reference method”. Food business operators are

method would be advantageous for both cost and effort. The purpose of these studies was to compare STEC detection from beef using the Thermo Scientific™ SureTect™ E. coli O157:H7 and STEC Screening and Identification PCR Assay versus ISO/ TS 13136:2012. Seven seasoned beef samples were spiked with STEC and enriched alongside four unspiked samples, using harmonised conditions with the SureTect™ Salmonella species PCR Assay, testing with the candidate method. ISO/TS 13136 was run in parallel as an unpaired study. In a second unpaired study, 14 raw and frozen beef samples were spiked with STEC and tested with eight unspiked samples, using the same study design. In the seasoned beef study, the candidate method detected STEC in seven spiked samples after eight hours incu- bation, while ISO confirmed five samples after 24 hours. In the second study, improved STEC detection was also seen from the candidate method compared to ISO/TS. The studies demonstrate enhanced STEC detection using the candidate method versus ISO/TS 13136:2012, enabling rapid detection from beef while enabling the same enrichment to also be tested for Salmonella . Presenter: Jessica Williams, Thermo Fisher Scientific, Basingstoke, United Kingdom, Email: jessica.williams@thermofisher.com P-W-077 Nur Hasan , Shah Rashed , CosmosID Inc., Rockville, MD, USA; Christopher Grim , Karen Jarvis , U.S. Food and Drug Administration, Laurel, MD, USA; Padmini Ramachandran , Andrea Ottesen , U.S. Food and Drug Administration, College Park, MD, USA Evaluation of Ion GeneStudio S5 Platform for Epidemiological Sub-Typing of Foodborne Pathogens and Compositional Profiling of the Food Microbiome Next-generation sequencing technologies are evolving rapidly in terms of instruments, chemistries, and techniques leading to significant advancement in throughput, read length, accuracy and reduced cost. Such advancements had major impact on genomic and microbiome applications by significantly improv- ing study outcome, time to answer, and minimizing the impact of errors on biological conclusions. Therefore, it is critical to evaluate their capabilities in specific applications. The study was designed to evaluate the utility of Ion GeneStudio™ S5 Food Protection System (Thermo Fisher Scientific) as compared to MiSeq and NextSeq platforms (Illumina) in achieving same biological conclusions, i.e., epidemiological sub-typing of food- borne pathogens and compositional characterization of food microbiome. To this end, 286 biological samples, previously sequenced by Illumina MiSeq or NextSeq platforms, including 100 bacterial isolates representing 7 foodborne pathogens and 181 food and environmental metagenomes were re-sequenced using Ion GeneStudio™ S5 with Ion Chef™ and Ion 550 chip targeting 3Mio reads per isolate and 15 Mio reads per metag- enome. Resultant datasets are currently being analyzed using CosmosID bioinformatics pipelines. The poster will demonstrate the results of this extensive comparative platform evaluation on general sequencing statistics as well as their impact on reach- ing similar biological conclusions for pathogen subtyping and multi-kingdom microbiome profiling. Presenter: Nur Hasan, CosmosID Inc., Rockville, MD, USA, Email: nur.hasan@cosmosid.com

106 SEPTEMBER 6–12, 2019 SHERATON DENVER DOWNTOWN HOTEL