AOAC 133rd Annual Meeting - Final Program

Poster Abstracts | Wednesday

isolates were all successfully detected and exclusivity testing (31 non-target isolates) showed no cross reactions. The interlabora- tory study results from 12 laboratories were analyzed and the sensitivity, specificity of the alternative and reference method fulfilled the acceptability limits of EN ISO 16140-2:2016. The Listeria Precis™ Detection method is equivalent to the EN ISO 11290-1/A1:2005 reference method for the detection of Listeria Monocytogenes from a broad range of foods and environmental samples. Presenter: Jessica Williams, Thermo Fisher Scientific, Basingstoke, United Kingdom, Email: jessica.williams@thermofisher.com P-W-070 Jessica Williams , Ana-Maria Leonte , Thermo Fisher Scientific, Basingstoke, United Kingdom; Gail Betts , Campden BRI, Chipping Campden, United Kingdom MicroVal Validation of the Thermo Scientific™ Brilliance™ Staph 24 Enumeration Method in Accordance with ISO 16140-2:2016 The Thermo Scientific™ Brilliance™ Staph 24 Enumeration method (alternative method) for the enumeration of coagulase positive Staphylococci species (CPS) from a broad range of foods. The method was compared to EN ISO 6881-1:1999 DAM2:2017(E) during a MicroVal renewal study comprising of; relative trueness, accuracy profile, inclusivity and exclusivity, and inter-laboratory studies. The relative trueness study results satis- fied the requirements of EN ISO 16140-2:2016. The accuracy profile tolerance intervals were within the EN ISO 16140-2:2016 acceptability limits for all five matrix/strain combinations. Inclusivity studies showed 49 out of 51 CPS strains were success- fully detected; the remaining 2 strains were not detected by either method. Exclusivity testing (35 non-target isolates) showed 2 cross reactions from both methods and a further 3 cross reaction from the reference method only. The ILS results from 11 laboratories were scatter plotted to compare methods; the data meets the Acceptability Limits for all levels of contamination, therefore is equivalent to the reference method. The Brilliance™ Staph 24 Enumeration method is equivalent to the EN ISO 6881- 1:1999 DAM2:2017(E) reference method for the enumeration of coagulase positive Staphylococci species from a broad range of foods and environmental samples. Presenter: Jessica Williams, Thermo Fisher Scientific, Basingstoke, United Kingdom, Email: jessica.williams@thermofisher.com P-W-071 Jessica Williams , Charlotte Cooper , Katharine Evans , David Crabtree , Annette Hughes , Dean Leak , Agata Dziegiel , Thermo Fisher Scientific, Basingstoke, United Kingdom Salmonella Detection from Large Milk Powder Samples Using the Thermo Scientific™ SureTect™ Salmonella Species PCR Assay Powdered Infant formula (PIF), milk powders and ingredients are at risk of Salmonella and Cronobacter contamination. Distinct reference methodologies for detection of these patho- gens require separate enrichments of different sizes must be prepared. A harmonized enrichment would be advantageous

for both cost and effort. The purpose of these studies was to compare Salmonella detection from large milk powder samples using the Thermo Scientific™ SureTect™ Salmonella Species PCR Assay versus ISO 6579-1:2017. The enrichment condi- tions of the SureTect™ Cronobacter Species PCR Assay were used for the candidate method. Twelve probiotic PIF samples of 300 g were Salmonella -spiked and enriched alongside four unspiked samples in Buffered Peptone Water with vancomycin, before testing via the candidate method. ISO 6579 was run in parallel as an unpaired study. In a second unpaired study 36 PIF, milk powder and ingredient samples of 375 g were spiked with S. Typhimurium or S. Infantis, injured by dessication, and tested alongside seven unspiked samples using the same study design. In the 300 g study the candidate and ISO methods confirmed Salmonella in 12 and 11 spiked samples respec- tively after 16 hours incubation. In the 375 g study comparable results were also achieved for both the candidate and ISO methods. Comparable Salmonella detection was seen between the candidate and ISO methods, with the candidate method enabling a single large enrichment to be tested for Salmonella and Cronobacter . Presenter: Jessica Williams, Thermo Fisher Scientific, Basingstoke, United Kingdom, Email: jessica.williams@thermofisher.com P-W-072 Charlotte Cooper , Katharine Evans , David Crabtree , Annette Hughes , Jessica Williams , Thermo Fisher Scientific, Basingstoke, United Kingdom Improved Salmonella Detection from Primary Production Samples Using Multiplex PCR Methodology The primary production environment contains high levels of diverse microflora, causing challenges in Salmonella detection from primary production samples (PPS). Limitations in traditional methods can cause under-reporting of PPS contamination levels. The study purpose was to compare Salmonella detection from PPS using the Thermo Scientific™ RapidFinder™ Salmonella species, Typhimurium and Enteritidis Multiplex Flex PCR Kit versus ISO 6579-1:2017. Fifty-seven Salmonella -spiked PPS of 25 g were enriched with 12 unspiked samples in 225 mL TT-broth followed by a short Buffered Peptone Water enrichment before immunomagnetic separation, PCR and confirmation. ISO 6579 was performed with a replicate dataset as an unpaired study. Following the same study design, a commercial poultry producer tested 13 Salmonella -spiked and ten unspiked PPS for the candidate method and a replicate dataset for ISO. From the 69 PPS, the candidate and ISO methods detected Salmonella in 39 versus 34 samples, S . Typhimurium in 16 versus 12 samples and S . Enteritidis in 14 versus ten samples respectively. The poul- try producer identified S . species, Typhimurium and Enteritidis in 16, eight and two samples respectively with the candidate method, and 14 Salmonella through ISO without differenti- ating between serovars. These datasets show the enhanced Salmonella detection by the candidate method versus ISO 6579, improving monitoring accuracy of contamination in the primary production environment. Presenter: Jessica Williams, Thermo Fisher Scientific, Basingstoke, United Kingdom, Email: jessica.williams@thermofisher.com

104 SEPTEMBER 6–12, 2019 SHERATON DENVER DOWNTOWN HOTEL