AOAC 133rd Annual Meeting - Final Program

Poster Abstracts | Wednesday

P-W-090 Andrew Jacobson , Hua Wang , Anna Maounounen- Laasri , Lanlan Yin , Thomas Hammack , U.S. Food and Drug Administration, College Park, MD, USA Evaluation of Three Buffered Pre-Enrichment Broths for Comparisons to Lactose Broth for the Detection of Salmonella in Low Moisture Foods Buffered pre-enrichments are more effective than lactose broth (LB) for the detection of Salmonella with some food matri- ces, however, these comparisons have not been performed for several low microbial/low moisture foods (LMF) with the Bacteriological Analytical Manual ( BAM) Salmonella culture method. This experiment compared effectiveness of 3 buffered preenrichment [Universal Preenrichment Broth (UPB), Buffered Peptone Water (BPW), and modified Buffered Peptone Water (mBPW)] to that of LB for the detection of S. enterica in egg noodles ( S . Eimsbuettel) and wheat flour ( S . Typhimurium). Salmonella -positive test portions that had occurred among 20 test portions analyzed for each preenrichment medium for the LMF were compared to determine relative effectiveness of the preenrichments to detect Salmonella (Fisher’s exact test) ( p < 0.05). Three, 4, 5, and 5 Salmonella -positive test portions occurred, respectively, for LB, UPB, BPW, and mBPW for detection of S . Eimsbuettel with egg noodles. Those for wheat flour with S . Typhimurium were 1, 1, 1, and 2. No significant differences between LB and buffered preenrichment broths for detection of Salmonella with egg noodles and wheat flour suggest that high buffer capacity of preenrichments do not improve Salmonella detection with these products. Additional experiments will be conducted at higher inoculation levels to determine if there is a significant difference in the recovery of Salmonella using LB and the buffered preenrichments. Presenter: Andrew Jacobson, U.S. Food and Drug Administration, College Park, MD, USA, Email: andrew.jacobson@cfsan.fda.gov P-W-091 Ron Johnson , John Mills , bioMérieux, Inc., Hazelwood, MO, USA; Jean-Louis Pittet , bioMérieux, Inc., Chemin de L’Orme, France Evaluation of the GENE-UP ® Cronobacter Method for the Detection of Cronobacter species in Foods and Environmental Surfaces, Collaborative Study: AOAC Official Method SM 2019.01 The GENE-UP ® Cronobacter (CRO) assay ( Performance Tested Method SM 081801) is a real-time PCR technology for the rapid detection of Cronobacter species in foods and environmental surfaces. The purpose of this validation was to evaluate the method’s interlaboratory performance and submit the result to AOAC INTERNATIONAL for adoption as First Action Official Method SM for the detection of Cronobacter species in select foods and environmental surfaces. The GENE-UP ® method was

cells/L), and 5 negative controls. Each sample contained 1 L liquid eggs. Preparation of egg samples followed FDA BAM method. Pre-enrichment cultures were used for LAMP and real-time PCR assay. LAMP assay was carried on the Genie III device. PCR (TaqMan Salmonella Enteritidis Detection Kit) was performed on ABI 7500 Fast real-time PCR instrument. There are 15 and 13 positives for SE among 20 samples tested for each trial with FDA BAM culture methods. All 10 positive control samples were positive; and all 10 negative control samples were negative for SE. LAMP and real-time PCR results matched the BAM culture results. The prot 6E gene-based LAMP and real-time PCR methods were equally effective in detecting SE from shell eggs in comparison with BAM culture method. These molecular methods could be used as quick effective tools for the detection of SE from shell eggs for FDA in outbreak investigation and enforcing the Egg Rule. Presenter: Guodong Zhang, U.S. Food and Drug Administration, College Park, MD, USA, Email: Guodong.Zhang@fda.hhs.gov P-W-089 Ron Johnson , John Mills , bioMérieux, Inc., Hazelwood, MO, USA; Jean-Louis Pittet , bioMérieux, Inc., Chemin de L’Orme, France Evaluation of the GENE-UP ® E. coli O157:H7 Method for the Detection of E. coli O157:H7 in Foods, Collaborative Study: AOAC Official Method SM 2019.03 The GENE-UP ® E. coli O157:H7 2 (ECO 2) assay ( Performance Tested Method SM 121805) incorporates Fluorescence Resonance Energy Transfer (FRET) hybridization probes into its proprietary PCR technology for the rapid detection of E. coli O157:H7 in foods. The purpose of this validation was to evaluate the method’s interlaboratory performance and submit the result to AOAC INTERNATIONAL for adoption as First Action Official Method SM for the detection of E. coli O157:H7 in select foods. The GENE-UP ® method was evaluated in a multi-laboratory study as part of the MicroVal validation process using unpaired test portions for one food matrix, raw milk cheese. The candi- date method was compared to the ISO 16654:2001 reference method. Fourteen participants from thirteen laboratories throughout the European Union participated. Three levels of contamination were evaluated: 0 CFU/test portion, ~5 CFU/ test portion and ~10 CFU/test portion. The dLPODC values with 95% confidence interval were; 0.00 (-0.04, 0.04), 0.27 (0.04, 0.49) and 0.17 (0.01, 0.33) for the non-inoculated, low and high contamination levels respectively. The dLPODC results indi- cate a significant difference between the candidate method and the reference method for both the low and high contamination levels, with the candidate method producing higher recovery of the target organism at both levels. Presenter: John Mills, bioMérieux, Inc., Hazelwood, MO, USA, Email: john.mills@biomerieux.com

110 SEPTEMBER 6–12, 2019 SHERATON DENVER DOWNTOWN HOTEL