Method Modification Study for the Thermo Scientific SureTect™ Listeria Species Assay–Matrix Extension

2016 ◽  
Vol 99 (2) ◽  
pp. 417-427
Author(s):  
Jonathan Cloke ◽  
Katharine Evans ◽  
David Crabtree ◽  
Annette Hughes ◽  
Helen Simpson ◽  
...  

Abstract The Thermo Scientific™ SureTect™ Listeria species assay is a new real-time PCR assay for the detection of all species of Listeria in food and environmental samples. The assay was originally certified as Performance Tested MethodsSM (PTM) 071304 in 2013. This report details the method modification study undertaken to extend the performance claims of the assay for matrixes of raw ground turkey, raw ground pork, bagged lettuce, raw pork sausages, pasteurized 2% fat milk, raw cod, pasteurized brie cheese, and ice cream. The method modification study was conducted using the AOAC Research Institute (RI) PTM program to validate the SureTect PCR assay in comparison to the reference method detailed in ISO 11290-1:1996 including amendment 1:2004. All matrixes were tested by Thermo Fisher Scientific (Basingstoke, United Kingdom). In addition, three matrixes (raw cod, bagged lettuce, and pasteurized brie cheese) were analyzed independently as part of the AOAC RI-controlled independent laboratory study by the University of Guelph, Canada. Using probability of detection statistical analysis, there was no significant difference in the performance between the SureTect assay and the International Organization for Standardization reference method for any of the matrixes analyzed in this study.

2015 ◽  
Vol 98 (5) ◽  
pp. 1315-1324 ◽  
Author(s):  
Jonathan Cloke ◽  
Katharine Evans ◽  
David Crabtree ◽  
Annette Hughes ◽  
Helen Simpson ◽  
...  

Abstract The Thermo Scientific™ SureTect™ Listeria monocytogenes assay is a real-time PCR assay for the detection of Listeria monocytogenes in food and environmental samples, which was certified during 2013 by the AOAC Research Institute (RI) as Performance Tested MethodSM (PTM) 061302 for a representative range of key food matrixes and production surfaces. This report details the method modification study, which was conducted during 2014, using the AOAC-RI PTM program to extend the validated matrix claims of the assay in comparison to the reference method detailed in International Organization for Standardization 11290-1:1996, including Amendment 1:2004, to gain certification for raw ground turkey, raw ground pork, pasteurized 2% milk, raw pork sausages, raw cod, pasteurized brie cheese, cooked sliced ham, and bagged lettuce. All matrixes were tested by Thermo Fisher Scientific, Microbiology Division, Basingstoke, UK. In addition, brie cheese, bagged lettuce, and raw cod were analyzed independently by the University of Guelph, Canada, during the AOAC-RI controlled independent laboratory study. Using probability of detection (POD) statistical analysis, a significant difference was demonstrated between the candidate and reference methods for the high spiking level with raw ground pork and brie cheese. For all other matrixes and the low spiked levels for raw ground pork and brie cheese, no significant difference by POD was seen between the two methods during the study.


2016 ◽  
Vol 99 (2) ◽  
pp. 407-416
Author(s):  
Jonathan Cloke ◽  
Julia Arizanova ◽  
David Crabtree ◽  
Helen Simpson ◽  
Katharine Evans ◽  
...  

Abstract The Thermo Scientific™ SureTect™ Listeria species Real-Time PCR Assay was certified during 2013 by the AOAC Research Institute (RI) Performance Tested MethodsSM program as a rapid method for the detection of Listeria species from a wide range of food matrixes and surface samples. A method modification study was conducted in 2015 to extend the matrix claims of the product to a wider range of food matrixes. This report details the method modification study undertaken to extend the use of this PCR kit to the Applied Biosystems™ 7500 Fast PCR Instrument and Applied Biosystems RapidFinder™ Express 2.0 software allowing use of the assay on a 96-well format PCR cycler in addition to the current workflow, using the 24-well Thermo Scientific PikoReal™ PCR Instrument and Thermo Scientific SureTect software. The method modification study presented in this report was assessed by the AOAC-RI as being a level 2 method modification study, necessitating a method developer study on a representative range of food matrixes covering raw ground turkey, 2% fat pasteurized milk, and bagged lettuce as well as stainless steel surface samples. All testing was conducted in comparison to the reference method detailed in International Organization for Standardization (ISO) 6579:2002. No significant difference by probability of detection statistical analysis was found between the SureTect Listeria species PCR Assay or the ISO reference method methods for any of the three food matrixes and the surface samples analyzed during the study.


2014 ◽  
Vol 97 (2) ◽  
pp. 521-538 ◽  
Author(s):  
Jonathan Cloke ◽  
Katharine Evans ◽  
David Crabtree ◽  
Annette Hughes ◽  
Helen Simpson ◽  
...  

Abstract The Thermo Scientific™ SureTect™ Listeria species Assay is a new real-time PCR assay for the detection of all species of Listeria in food and environmental samples. This validation study was conducted using the AOAC Research Institute (RI) Performance Tested MethodsSM program to validate the SureTect Listeria species Assay in comparison to the reference method detailed in International Organization for Standardization 11290-1:1996 including amendment 1:2004 in a variety of foods plus plastic and stainlesssteel. The food matrixes validated were smoked salmon, processed cheese, fresh bagged spinach, cantaloupe, cooked prawns, cooked sliced turkey meat, cooked sliced ham, salami, pork frankfurters, and raw ground beef. All matrixes were tested by Thermo Fisher Scientific, Microbiology Division, Basingstoke, UK. Inaddition, three matrixes (pork frankfurters, fresh bagged spinach, and stainless steel surface samples) were analyzed independently as part of the AOAC-RI-controlled independent laboratory study by the University of Guelph, Canada. Using probability of detection statistical analysis, a significant difference infavour of the SureTect assay was demonstrated between the SureTect and reference method for high level spiked samples of pork frankfurters, smoked salmon, cooked prawns, stainless steel, and low-spiked samples of salami. For all other matrixes, no significant difference was seen between the two methods during the study. Inclusivity testing was conducted with 68 different isolates of Listeria species, all of which were detected by the SureTect Listeria species Assay. None of the 33 exclusivity isolates were detected by the SureTect Listeria species Assay. Ruggedness testing was conducted to evaluate the performance of the assay with specific method deviations outside of the recommended parameters open to variation, which demonstrated that the assay gave reliable performance. Accelerated stability testing was additionally conducted, validating the assay shelf life.


2017 ◽  
Vol 100 (5) ◽  
pp. 1434-1444 ◽  
Author(s):  
Adam C Joelsson ◽  
Shawn P Terkhorn ◽  
Ashley S Brown ◽  
Amrita Puri ◽  
Benjamin J Pascal ◽  
...  

Abstract Veriflow®Listeria species (Veriflow LS) is a molecular-based assay for the presumptive detection of Listeria spp. from environmental surfaces (stainless steel, sealed concrete, plastic, and ceramic tile) and ready-to-eat (RTE) food matrixes (hot dogs and deli meat). The assay utilizes a PCRdetection method coupled with a rapid, visual, flow-based assay that develops in 3 min post-PCR amplification and requires only a 24 h enrichment for maximum sensitivity. The Veriflow LS system eliminates the need for sample purification, gel electrophoresis, or fluorophore-based detection of target amplification and does not require complex data analysis. This Performance Tested MethodSM validation study demonstrated the ability of the Veriflow LS assayto detect low levels of artificially inoculated Listeria spp. in six distinct environmental and food matrixes. In each unpaired reference comparison study, probability of detection analysis indicated that there was no significant difference between the Veriflow LS method and the U.S. Department of Agriculture Food Safety and Inspection Service Microbiology Laboratory Guide Chapter 8.08 reference method. Fifty-one strains of various Listeria spp. were detected in the inclusivity study, and 35 nonspecific organisms went undetected in the exclusivity study. The study results show that the Veriflow LS is a sensitive, selective, and robust assay for the presumptive detection of Listeria spp. sampled from environmental surfaces (stainless steel, sealed concrete, plastic, and ceramic tile) and RTE food matrixes (hot dogs and delimeat).


2014 ◽  
Vol 97 (3) ◽  
pp. 868-875 ◽  
Author(s):  
F Morgan Wallace ◽  
Bridget Andaloro ◽  
Dawn Fallon ◽  
Nisha Corrigan ◽  
Stephen Varkey ◽  
...  

Abstract A multilaboratory study was conducted to evaluate the ability of the DuPont™ BAX® System Real-Time PCR Assay for Salmonella to detect the target species in a variety of foods and environmental surfaces. Internal validation studies were performed by DuPont Nutrition & Health on 24 different sample types to demonstrate the reliability of the test method among a wide variety of sample types. Two of these matrixes—pork and turkey frankfurters and pasteurized, not-from-concentrate orange juice without pulp—were each evaluated in 14 independent laboratories as part of the collaborative study to demonstrate repeatability and reproducibility of the internal laboratory results independent of the end user. Frankfurter samples were evaluated against the U. S. Department of Agriculture, Food Safety and Inspection Service reference method as a paired study, while orange juice samples were evaluated against the U. S. Food and Drug Administration reference method as an unpaired study, using a proprietary media for the test method. Samples tested in this study were artificially inoculated with a Salmonella strain at levels expected to produce low (0.2–2.0 CFU/test portion) or high (5 CFU/test portion) spike levels on the day of analysis. For each matrix, the collaborative study failed to show a statistically significant difference between the candidate method and the reference method using the probability of detection statistical model.


2014 ◽  
Vol 97 (1) ◽  
pp. 133-154 ◽  
Author(s):  
Jonathan Cloke ◽  
Carlos Leon-Velarde ◽  
Nathan Larson ◽  
Keron Dave ◽  
Katharine Evans ◽  
...  

Abstract The Thermo Scientific™ SureTect™Listeria monocytogenes Assay is a new real-time PCR assay for the detection of Listeria monocytogenes in food and environmental samples. This assay was validated using the AOAC Research Institute (AOAC-RI) Performance Tested MethodsSM program in comparison to the reference method detailed in International Organization for Standardization 11290-1:1996, including Amendment 1:2004 with the following foods and food contact surfaces: smoked salmon, processed cheese, fresh bagged spinach, fresh cantaloupe, cooked prawns (chilled product), cooked sliced turkey meat (chilled product), ice cream, pork frankfurters, salami, ground raw beef meat (12% fat), plastic, and stainless steel. All matrixes were tested by Thermo Fisher Scientific, Microbiology Division, Basingstoke, UK. In addition, three matrixes (pork frankfurters, bagged lettuce, and stainless steel) were analyzed independently as part of the AOAC-RI controlled laboratorystudy by the University of Guelph, Canada. Using probability of detection (POD) statistical analysis, a significant difference was demonstrated between the candidate and reference methods for salami, cooked sliced turkey and ice cream in favor of the SureTect assay. For all other matrixes, no significant difference by POD was seen between the two methods during the study. Inclusivity and exclusivity testing was also conducted with 53 and30 isolates, respectively, which demonstrated that the SureTect assay was able to detect all serotypes of L. monocytogenes. None of the exclusivity isolates analyzed were detectedby the SureTect assay. Ruggedness testing was conducted to evaluate the performance of the assay with specific method deviations outside the recommended parameters open to variation, i.e., enrichment time and temperature and lysis temperature, which demonstrated that the assay gave reliable performance. Accelerated stability testing was alsoconducted, validating the assay shelf life.


2016 ◽  
Vol 99 (3) ◽  
pp. 676-685
Author(s):  
Jonathan Cloke ◽  
Julia Arizanova ◽  
David Crabtree ◽  
Helen Simpson ◽  
Katharine Evans ◽  
...  

Abstract In 2013, the Thermo Scientific™ SureTect™ Listeria monocytogenes Real-Time PCR Assay was certified by the AOAC Research Institute (RI) Performance Tested MethodsSM program as a rapid method for the detection of L. monocytogenes from a wide range of food matrixes and surface samples. This report details the method modification studies undertaken to extend the analysis of this PCR assay to the Applied Biosystems™ 7500 Fast PCR Instrument and Applied Biosystems RapidFinder™ Express 2.0 software allowing the use of the SureTect assay on a 96 well format PCR cycler in addition to the current workflow, which uses the 24 well Thermo Scientific PikoReal™ PCR Instrument and Thermo Scientific SureTect software. Because this study was deemed by AOAC-RI to be a level 2 method modification study, a representative range of food matrixes covering raw ground turkey, 2% fat pasteurized milk, and bagged lettuce as well as stainless steel surface samples were analyzed with the Applied Biosystems 7500 Fast PCR Instrument and RapidFinder Express 2.0 software. All testing was conducted in comparison to the reference method detailed in International Organization for Standardization (ISO) 6579:2002. No significant difference by probability of detection statistical analysis was found between the SureTect Listeria monocytogenes PCR Assay or the ISO reference method methods for any of the matrixes analyzed during the study.


2017 ◽  
Vol 100 (1) ◽  
pp. 82-98
Author(s):  
Patrick Bird ◽  
Jonathan Flannery ◽  
Erin Crowley ◽  
James Agin ◽  
David Goins ◽  
...  

Abstract 3M Molecular Detection Assay (MDA) 2–Listeria uses loop-mediated isothermal amplification and bioluminescence detection to rapidly detect Listeria species in a broad range of food types and environmental surfaces. Using an unpaired study design, MDA 2–Listeria was compared with the U.S. Department of Agriculture, Food Safety and Inspection Service's Microbiology Laboratory Guidebook Chapter 8.09 “Isolation and identification of Listeria monocytogenes from red meat, poultry and egg products, and environmental samples” reference method for the detection of Listeria in deli turkey and raw chicken breast fillet. Technicians from 13 laboratories located within the continental United States and Canada participated in the collaborative study. Each matrix was evaluated at three levels of contamination: uninoculated control (0 CFU/test portion), low inoculum (0.2–2 CFU/test portion), and high inoculum (2–5 CFU/test portion). Statistical analysis was conducted according to the probability of detection (POD) statistical model. Results obtained for the low-inoculum-level test portions produced a difference between two laboratory POD values (dLPOD) with 95% confidence intervals of 0.04 (–0.08, 0.17) for deli turkey, indicating the difference between the methods was not statistically significant at the P = 0.05. For raw chicken breast fillet, a dLPOD value with 95% confidence interval of 0.16 (0.04, 0.28) indicated a statistically significant difference between the two methods, with an observed higher proportion of positive results by the candidate method than the reference method.


2013 ◽  
Vol 96 (3) ◽  
pp. 532-541
Author(s):  
Olga Petrauskene ◽  
Yan Cao ◽  
Patrick Zoder ◽  
Lily Y Wong ◽  
Priya Balachandran ◽  
...  

Abstract The Applied Biosystems Performance Tested MethodSM for detecting Listeria species in food and environmental samples was compared to the Health Canada reference method (MFHPB-30) for the analysis of five ready-to-eat (RTE) meats (deli turkey, hot dogs, liver paté, deli ham, and raw fermented sausage) and a stainless steel surface. The MicroSEQ method includes the MicroSEQ®Listeria spp. Detection Kit and the option of two different sample preparation kits, either the automated high-throughput PrepSEQ™ Nucleic Acid Extraction Kit or the manual low- to mid-throughput PrepSEQ™ Rapid Spin Sample Preparation Kit. For each sample matrix, 20 replicates were analyzed at two inoculum levels: for RTE meats a low-level inoculum at 0.2–2 CFU/25 g and a high-level inoculum at 2–5 CFU/25 g; and for environmental surfaces, a low-level inoculum at 0.2–2 CFU/5 cm2 sampling area and a high-level inoculum at 2–5 CFU/5 cm2 sampling area. Five control replicates were also analyzed at 0 CFU/25 g (uninoculated) for food or 0 CFU/5 cm2 sampling area for environmental surface. Both sample preparation methods returned identical results. There was no statistically significant difference in the number of positive samples detected by the MicroSEQ Listeria species method and the MFHPB-30 reference method for three RTE meats and for the one stainless steel environmental surface tested. For deli turkey, there was a statistically significant difference in the number of positive results detected by the MicroSEQ method and the Health Canada MFHPB-30 reference method for the low inoculation level, with the MicroSEQ method detecting more positives. For hot dogs, statistical equivalence was not applicable since hot dogs were spiked with 10x Listeria innocua as competitive background, and the MicroSEQ method detects all known Listeria. Because the MicroSEQ method uses real-time PCR to detect pathogens, it provides faster time-to-results with equivalent detection compared to culture methods. The MicroSEQ method detects Listeria species within 2 to 3 h following 24 to 28 h enrichment compared to culture methods that take at least 5 days for presumptive positive results.


2021 ◽  
Author(s):  
Paul A. Granato ◽  
Simon R. Kimball ◽  
Brenda R. Alkins ◽  
Deirdre C. Cross ◽  
Melissa M. Unz

Abstract Purpose With over 50 SARS-CoV-2 gene amplification assays that have been EUA cleared with minimal experimental validation performed, it is likely that not all of these assays are comparable in their ability to detect SARS-CoV-2 in clinical specimens. Thermo Fisher Scientific is a relatively new company in the molecular diagnostics field and the purpose of this study was to compare the performance of the Thermo Fisher TaqPath™ Combo Kit with an established test, the Cepheid Xpert® Xpress SARS-CoV-2 assay, for its ability to detect SARS-CoV-2 in nasopharyngeal specimens.Methods A total of 300 randomly selected nasopharyngeal specimens were evaluated and tested by the TaqPath and GeneXpert assays. Discordant test specimens were arbitrated by performing an alternative PCR assay and Sanger sequencing.Results The TaqPath assay had a 96.7% and 99.6% positive and negative agreement respectively when compared to the Xpert Xpress test. However, after test arbitration, the three discordant specimens were arbitrated in favor of the TaqPath assay producing a positive and negative percent agreement of 100% for the TaqPath Combo Kit while the Xpress SARS-CoV-2 assay had a positive and negative percent agreement of 98.3% and 99.2% respectively.Conclusions The TaqPath Combo Kit is a high complexity assay that compares favorably with the Xpert Xpress test and can be reliably used for the detection of SARS-CoV-2 in nasopharyngeal specimens.


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