Validation of the ANSR® Listeria monocytogenes Method for Detection of Listeria monocytogenes in Selected Food and Environmental Samples

2016 ◽  
Vol 99 (1) ◽  
pp. 112-123
Author(s):  
Oscar Caballero ◽  
Susan Alles ◽  
Quynh-Nhi Le ◽  
R Lucas Gray ◽  
Edan Hosking ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Storage Temperature ◽  
Reference Method ◽  
Single Step ◽  
Stainless Steel Surface ◽  
Method Performance ◽  
Inspection Service ◽  
Nicking Enzyme ◽  
Performance Results ◽  
The U.S

Abstract Work was conducted to validate performance of the ANSR® for Listeria monocytogenes method in selected food and environmental matrixes. This DNA-based assay involves amplification of nucleic acid via an isothermal reaction based on nicking enzyme amplification technology. Following single-step sample enrichment for 16–24 h for most matrixes, the assay is completed in 40 min using only simple instrumentation. When 50 distinct strains of L. monocytogenes were tested for inclusivity, 48 produced positive results, the exceptions being two strains confirmed by PCR to lack the assay target gene. Forty-seven nontarget strains (30 species), including multiple non-monocytogenes Listeria species as well as non-Listeria, Gram-positive bacteria, were tested, and all generated negative ANSR assay results. Performance of the ANSR method was compared with that of the U.S. Department of Agriculture, Food Safety and Inspection Service Microbiology Laboratory Guidebook reference culture procedure for detection of L. monocytogenes in hot dogs, pasteurized liquid egg, and sponge samples taken from an inoculated stainless steel surface. In addition, ANSR performance was measured against the U.S. Food and Drug Administration Bacteriological Analytical Manual reference method for detection of L. monocytogenes in Mexican-style cheese, cantaloupe, sprout irrigation water, and guacamole. With the single exception of pasteurized liquid egg at 16 h, ANSR method performance as quantified by the number of positives obtained was not statistically different from that of the reference methods. Robustness trials demonstrated that deliberate introduction of small deviations to the normal assay parameters did not affect ANSR method performance. Results of accelerated stability testing conducted using two manufactured lots of reagents predicts stability at the specified storage temperature of 4°C of more than 1 year.

Validation of the ANSR® for Campylobacter Method for Detection of Thermophilic Campylobacter spp. in Chicken Carcass Rinse and Turkey Sponge Samples

2016 ◽  
Vol 99 (6) ◽  
pp. 1555-1564 ◽  
Author(s):  
Ryan Viator ◽  
Susan Alles ◽  
Quynh-Nhi Le ◽  
Edan Hosking ◽  
Preetha Biswas ◽  
...  
Keyword(s):  
Target Genes ◽  
Reference Method ◽  
Common Species ◽  
Single Step ◽  
Fluorescence Detector ◽  
Method Performance ◽  
Chicken Carcass ◽  
Inspection Service ◽  
Nicking Enzyme ◽  
Performance Validation

Abstract A performance validation of the ANSR® for Campylobacter method was conducted in selected matrixes. This assay used selective nicking enzyme amplification technology to amplify target genes. Samples were enriched for 20 to 24 h and then lysed. The assay was completed within 50 min using real-time detection in a combination incubator/fluorescence detector and software. When 50 distinct strains of Campylobacter jejuni, C. lari, or C. coli were tested for inclusivity, all 50 strains produced positive results. In exclusivity testing, 31 strains of related organisms, including seven nontarget Campylobacter strains and other common species, were evaluated. All 31 species generated negative ANSR assay results, including the nontarget Campylobacter strains. The ANSR for Campylobacter method was compared to the U.S. Department of Agriculture, Food Safety and Inspection Service Microbiology Laboratory Guidebook reference method using naturally contaminated chicken carcass rinse or turkey carcass sponge samples. ANSR method performance was not statistically different from the reference method using two different enrichment options. Equivalent results were observed at both time points (20 and 24 h) and in both atmospheres (microaerobic and aerobic) to reference methods. Method performance with chicken carcass rinse was confirmed in an independent laboratory study. Additionally, in robustness testing, small, deliberate changes to the assay parameters minimally affected ANSR method performance. Finally, accelerated stability results from three independently manufactured lots supported a shelf life of 6 months when stored at 4°C. The ANSR assay offered greater efficiency and flexibility when compared to the reference method with a 20–24 h single-step enrichment in a microaerobic or an aerobic atmosphere.

Validation of the ANSR®E. coli O157:H7 Method for Detection of E. coli O157:H7

2016 ◽  
Vol 99 (3) ◽  
pp. 705-716 ◽  
Author(s):  
Ryan Viator ◽  
Susan Alles ◽  
Quynh-Nhi Le ◽  
Edan Hosking ◽  
Evan Meister ◽  
...  
Keyword(s):  
Target Genes ◽  
Ground Beef ◽  
Reference Method ◽  
Single Step ◽  
Fluorescence Detector ◽  
Method Performance ◽  
E Coli ◽  
Reference Methods ◽  
Inspection Service ◽  
The U.S

Abstract A performance validation of the ANSR® for E. coli O157:H7 method was conducted in selected food matrixes. This assay uses selective nicking enzyme amplification technology to amplify target genes. Samples are enriched for 12–24 h and then lysed. The assay is completed within 40 min using real-time detection in a combination incubator/fluorescence detector and software. When 44 distinct strains of Escherichia coli O157:H7 and 6 strains of E. coli O157:NM were tested for inclusivity, all 50 strains produced positive results. In exclusivity testing, 57 strains representing 33 species of closely related Gram-negative bacteria belonging to the Enterobacteriaceae family, including 11 non-H7 O157 strains and shiga toxin-producing E. coli other than O157:H7, were evaluated. All 57 nontarget strains generated negative ANSR assay results. Using 80% lean ground beef and beef trim (approximately 20% fat), ANSR method performance was compared to the U.S. Department of Agriculture, Food Safety and Inspection Service Microbiology Laboratory Guidebook reference culture procedure. ANSR performance with baby spinach and sprout irrigation water was measured against the U.S. Food and Drug Administration Bacteriological Analytical Manual reference method. ANSR method performance was not statistically different to that of the reference methods using two different enrichment options. For ground beef and beef trim, the standard enrichment in modified Tryptone Soya Broth can be analyzed using the ANSR assay with a 1:10 dilution of the enrichment in phosphate-buffered saline and produces equivalent results to the reference method. Additionally, in most matrixes tested (exception is spinach which required 24 h enrichment) the assay offers great efficiency and flexibility over the reference method with a 12–24 h single-step enrichment. Equivalent results were observed at both time points (12 and 24 h) to reference methods. Small changes to the assay parameters minimally affected ANSR method performance. Finally, accelerated stability results from three independently manufactured lots support a shelf-life of 6 months when stored at 4°C.

scholarly journals Validation of the One Broth One Plate for Salmonella Method for Detection of Salmonella Spp. in Select Food and Environmental Samples: AOAC Performance Tested MethodSM 102002

2020 ◽  
Author(s):  
Susan Alles ◽  
Brooke Roman ◽  
Quynh-Nhi Le ◽  
Magdalena Kurteu ◽  
Ezzeddine Elmerhebi ◽  
...  
Keyword(s):  
Validation Study ◽  
Environmental Samples ◽  
Reference Method ◽  
Black Pepper ◽  
Single Step ◽  
Probability Of Detection ◽  
Stainless Steel Surface ◽  
Salmonella Spp ◽  
Simple Method ◽  
The U.S

Abstract Background One Broth One Plate for Salmonella (OBOP Salmonella) is a rapid and simple method for detection of Salmonella spp. in food and environmental samples using traditional culture methodology. The method utilizes single-step enrichment followed by plating to a selective/differential, chromogenic agar. Objective The purpose of the validation study was to measure the effectiveness of the OBOP Salmonella method in comparison to reference culture procedures. Methods Performance of the OBOP Salmonella method was compared to that of the U.S. Food and Drug Administration Bacteriological Analytical Manual Chapter 5 reference method for queso fresco, smoked salmon, cantaloupe, chocolate, black pepper, chili powder, dry pet food, and sponge samples from a stainless steel surface, or to that of the U.S. Department of Agriculture Microbiology Laboratory Guidebook Chapter 4.10 method for raw ground turkey, chicken carcass rinse, and pasteurized liquid egg. Inclusivity/exclusivity, robustness, and stability/lot-to-lot consistency testing was also performed. Results In the matrix study, there were no statistically significant differences in performance between the OBOP Salmonella and reference methods, as determined by probability of detection analysis (P < 0.05), for any of the matrixes examined. All 104 Salmonella spp. strains produced positive results in inclusivity testing, and all 33 non-salmonellae exclusivity strains tested negative with the OBOP Salmonella method. Conclusions Results of the validation study show that the OBOP Salmonella method is a reliable procedure for detection of Salmonella spp. in select matrixes. The method is simple to perform, requires no specialized equipment, and produces results in as little as 37 h.

Detection of Listeria spp. Using ACTERO Listeria Enrichment Media

2014 ◽  
Vol 97 (4) ◽  
pp. 1127-1136
Author(s):  
David Claveau ◽  
Sergiy Olishevskyy ◽  
Michael Giuffre ◽  
Gabriela Martinez
Keyword(s):  
Stainless Steel ◽  
Environmental Samples ◽  
Incubation Temperature ◽  
Reference Method ◽  
Selective Medium ◽  
Single Step ◽  
Department Of Agriculture ◽  
Steel Surfaces ◽  
Inspection Service ◽  
The U.S

Abstract ACTERO™ Listeria Enrichment Media (ACTERO Listeria) is a selective medium developed for a single-step recovery and enrichment of Listeria spp. from environmental samples. Robustness testing of the ACTERO Listeria medium demonstrated good performance when minor changes were introduced to the incubation temperature and time. All 54 Listeria strains tested, representing the most frequently isolated Listeria species from food (L. monocytogenes, L. ivanovii, L. seeligeri, L. welshimeri, and L. grayi), were successfully enriched in ACTERO Listeria. None of the 30 nontarget strains tested in the exclusivity study was recovered after incubation in ACTERO Listeria. Recovery of Listeria was consistent across three independently produced lots of the ACTERO Listeria, and the prepared medium was stable for 45 days when stored at 4°C in the dark. Matrix studies performed with environmental sponge samples from plastic and stainless steel surfaces demonstrated similar recovery of Listeria spp. in a single-step enrichment using ACTERO Listeria from plastic, and significantly better recovery from stainless steel surfaces when compared to the U.S. Department of Agriculture-Food Safety and Inspection Service reference method. The results of this study prove that ACTERO Listeria Enrichment Media can be effectively used in replacement of the two-step enrichment suggested by the reference method without affecting the recovery of Listeria spp. from environmental samples.

scholarly journals Validation of a Modification to Performance-Tested MethodSM 070601: Reveal® Listeria Test for Detection of Listeria spp. in Selected Foods and Selected Environmental Samples

2009 ◽  
Vol 92 (2) ◽  
pp. 449-458 ◽  
Author(s):  
Susan Alles ◽  
Linda X Peng ◽  
Mark A Mozola
Keyword(s):  
Ceramic Tile ◽  
Environmental Samples ◽  
Reference Method ◽  
Single Step ◽  
Method Performance ◽  
Media Formulation ◽  
Independent Laboratory ◽  
Significant Difference ◽  
Crab Meat ◽  
Time Point

Abstract A modification to Performance-Tested MethodSM (PTM) 070601, Reveal® Listeria Test (Reveal), is described. The modified method uses a new media formulation, LESS enrichment broth, in single-step enrichment protocols for both foods and environmental sponge and swab samples. Food samples are enriched for 2730 h at 30C and environmental samples for 2448 h at 30C. Implementation of these abbreviated enrichment procedures allows test results to be obtained on a next-day basis. In testing of 14 food types in internal comparative studies with inoculated samples, there was a statistically significant difference in performance between the Reveal and reference culture U.S. Food and Drug Administration's Bacteriological Analytical Manual (FDA/BAM) or U.S. Department of Agriculture-Food Safety and Inspection Service (USDA-FSIS) methods for only a single food in one trial (pasteurized crab meat) at the 27 h enrichment time point, with more positive results obtained with the FDA/BAM reference method. No foods showed statistically significant differences in method performance at the 30 h time point. Independent laboratory testing of 3 foods again produced a statistically significant difference in results for crab meat at the 27 h time point; otherwise results of the Reveal and reference methods were statistically equivalent. Overall, considering both internal and independent laboratory trials, sensitivity of the Reveal method relative to the reference culture procedures in testing of foods was 85.9 at 27 h and 97.1 at 30 h. Results from 5 environmental surfaces inoculated with various strains of Listeria spp. showed that the Reveal method was more productive than the reference USDA-FSIS culture procedure for 3 surfaces (stainless steel, plastic, and cast iron), whereas results were statistically equivalent to the reference method for the other 2 surfaces (ceramic tile and sealed concrete). An independent laboratory trial with ceramic tile inoculated with L. monocytogenes confirmed the effectiveness of the Reveal method at the 24 h time point. Overall, sensitivity of the Reveal method at 24 h relative to that of the USDA-FSIS method was 153. The Reveal method exhibited extremely high specificity, with only a single false-positive result in all trials combined for overall specificity of 99.5.

Romer Labs RapidChek®Listeria monocytogenes Test System for the Detection of L. monocytogenes on Selected Foods and Environmental Surfaces

2018 ◽  
Vol 101 (5) ◽  
pp. 1490-1507
Author(s):  
Gregory Juck ◽  
Verapaz Gonzalez ◽  
Ann-Christine Olsson Allen ◽  
Meredith Sutzko ◽  
Kody Seward ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Reference Method ◽  
Test System ◽  
Probability Of Detection ◽  
Department Of Agriculture ◽  
Detection Analysis ◽  
Media System ◽  
Reference Methods ◽  
Environmental Surfaces ◽  
Inspection Service

Abstract The Romer Labs RapidChek®Listeria monocytogenes test system (Performance Tested Method 011805) was validated against the U.S. Department of Agriculture-Food Safety and Inspection Service Microbiology Laboratory Guidebook (USDA-FSIS/MLG), U.S. Food and Drug Association Bacteriological Analytical Manual (FDA/BAM), and AOAC Official Methods of Analysis (AOAC/OMA) cultural reference methods for the detection of L. monocytogenes on selected foods including hot dogs, frozen cooked breaded chicken, frozen cooked shrimp, cured ham, and ice cream, and environmental surfaces including stainless steel and plastic in an unpaired study design. The RapidChek method uses a proprietary enrichment media system, a 44–48 h enrichment at 30 ± 1°C, and detects L. monocytogenes on an immunochromatographic lateral flow device within 10 min. Different L. monocytogenes strains were used to spike each of the matrixes. Samples were confirmed based on the reference method confirmations and an alternate confirmation method. A total of 140 low-level spiked samples were tested by the RapidChek method after enrichment for 44–48 h in parallel with the cultural reference method. There were 88 RapidChek presumptive positives. One of the presumptive positives was not confirmed culturally. Additionally, one of the culturally confirmed samples did not exhibit a presumptive positive. No difference between the alternate confirmation method and reference confirmation method was observed. The respective cultural reference methods (USDA-FSIS/MLG, FDA/BAM, and AOAC/OMA) produced a total of 63 confirmed positive results. Nonspiked samples from all foods were reported as negative for L. monocytogenes by all methods. Probability of detection analysis demonstrated no significant differences in the number of positive samples detected by the RapidChek method and the respective cultural reference method.

An assessment of reference method selective broths and plating media using 19 Listeria spp. highlights the importance of including diverse species in Listeria spp. method evaluations

2021 ◽  
Author(s):  
Catharine R Carlin ◽  
Sherry Roof ◽  
Martin Wiedmann
Keyword(s):  
Bacterial Growth ◽  
Reference Method ◽  
Sensu Stricto ◽  
Detection Methods ◽  
Department Of Agriculture ◽  
Method Performance ◽  
The Media ◽  
The U.S ◽  
Selection Of

Reference methods developed for L. monocytogenes are commonly used for Listeria spp. detection. Improved method performance data are needed, since the genus Listeria has expanded from 6 to 26 species and now includes several Listeria sensu lato species, which can show phenotypes distinct from Listeria sensu stricto . Here, we evaluated growth of 19 Listeria spp., including 12 recently described sensu lato species, using the media specified by (i) the U.S. Food and Drug Administration (FDA) Bacteriological Analytical Manual , (ii) the U.S. Department of Agriculture (USDA) Microbiology Laboratory Guidebook , and (iii) the International Organization for Standardization (ISO). The FDA enrichment procedure allowed all species to grow to detectable levels (≥ 4 log 10 ), yielded the highest mean growth (7.58 log 10 ), and was the only procedure where no sensu lato species yielded significantly higher bacterial growth than a sensu stricto species. With the USDA or ISO enrichment procedures several sensu lato species yielded significantly higher bacterial growth than either L. seeligeri or L. ivanovii , suggesting that these two sensu stricto species could be outgrown by sensu lato species. On selective and differential agars, L. seeligeri, L. ivanovii, and L. grayi yielded atypical colony morphologies and/or showed inhibited growth (which may lead to incorrect classification of a sample as negative), while several newly described sensu lato species grew well and showed typical morphologies. Overall, our study shows that the ability to detect different Listeria spp. can be impacted by the specific broth and selective and differential agars used. Our data will aid with selection of media and detection methods for environmental Listeria monitoring programs and facilitate selection of methods that are most likely to detect the targeted Listeria groups (e.g., Listeria sensu stricto, which appear to be the most appropriate index organisms for the pathogen L. monocytogenes ).

Prevalence, Types, and Geographical Distribution of Listeria monocytogenes from a Survey of Retail Queso Fresco and Associated Cheese Processing Plants and Dairy Farms in Sonora, Mexico†

2007 ◽  
Vol 70 (11) ◽  
pp. 2596-2601 ◽  
Author(s):  
R. I. MORENO-ENRIQUEZ ◽  
A. GARCIA-GALAZ ◽  
E. ACEDO-FELIX ◽  
H. GONZALEZ-RIOS ◽  
J. E. CALL ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Environmental Samples ◽  
Northern Region ◽  
Pulsed Field Gel Electrophoresis ◽  
Department Of Agriculture ◽  
Retail Markets ◽  
Processing Plants ◽  
Contact Surfaces ◽  
Inspection Service ◽  
The U.S

In the first part of this study, samples were collected from farms, cheese processing plants (CPPs), and retail markets located in various geographical areas of Sonora, Mexico, over a 12-month period during the summer of 2004 and winter of 2005. Four (all Queso Fresco [QF] from retail markets) of 349 total samples tested positive for Listeria monocytogenes (Lm). Of these four positive samples, three were collected in the northern region and one in the southern region of Sonora. Additionally, two were collected during the winter months, and two were collected during the summer months. For the second part of the study, a total of 39 samples from a farm, a CPP, and retail markets were collected and processed according to a combination of the Norma Oficial Mexicana NOM-143-SSA1-1995.10 method (NOM) and the U.S. Food and Drug Administration (FDA) Bacteriological Analytical Manual method, and 27 samples from these same locations were collected and processed according to the U.S. Department of Agriculture Food Safety and Inspection Service method (USDA-FSIS). The NOM-FDA method recovered the pathogen from 6 (15%) of 39 samples (one cheese and five product contact surfaces), while the USDA-FSIS method recovered the pathogen from 5 (18.5%) of 27 samples (all product contact surfaces). In addition, the 40 isolates recovered from the 15 total samples that tested positive for Lm grouped into five distinct pulsotypes that were ca. 60% related, as determined by pulsed-field gel electrophoresis analysis. The results of this study confirmed a 3.4% prevalence of Lm in QF collected from retail markets located in Sonora and no appreciable difference in the effectiveness of either the NOM-FDA or USDA-FSIS method to recover the pathogen from cheese or environmental samples.

scholarly journals In-House Validation Study of the DuPont Qualicon BAX System Q7 Instrument with the BAX System PCR Assay for Salmonella (Modification of AOAC Official MethodSM 2003.09 and AOAC Research Institute Performance-Tested MethodSM 100201)

2009 ◽  
Vol 92 (3) ◽  
pp. 989-994 ◽  
Author(s):  
George Tice ◽  
Bridget Andaloro ◽  
H Kirk White ◽  
Lance Bolton ◽  
Siqun Wang ◽  
...  
Keyword(s):  
Validation Study ◽  
Reference Method ◽  
Pcr Assay ◽  
Paired Samples ◽  
Reference Methods ◽  
Comparable Performance ◽  
Aoac Official ◽  
Inspection Service ◽  
Positive Results ◽  
The U.S

Abstract In 2006, DuPont Qualicon introduced the BAX<sup/> system Q7 instrument for use with its assays. To demonstrate the equivalence of the new and old instruments, a validation study was conducted using the BAX system PCR Assay for Salmonella, AOAC Official MethodSM 2003.09, on three food types. The foods were simultaneously analyzed with the BAX system Q7 instrument and either the U.S. Food and Drug Administration Bacteriological Analytical Manual or the U.S. Department of AgricultureFood Safety and Inspection Service Microbiology Laboratory Guidebook reference method for detecting Salmonella. Comparable performance between the BAX system and the reference methods was observed. Of the 75 paired samples analyzed, 39 samples were positive by both the BAX system and reference methods, and 36 samples were negative by both the BAX system and reference methods, demonstrating 100 correlation. Inclusivity and exclusivity for the BAX system Q7 instrument were also established by testing 50 Salmonella strains and 20 non-Salmonella isolates. All Salmonella strains returned positive results, and all non-Salmonella isolates returned a negative response.

BIOTECON Diagnostics foodproof®Listeria monocytogenes Detection Kit, 5′ Nuclease in Combination with the foodproof ShortPrep II Kit

2012 ◽  
Vol 95 (1) ◽  
pp. 92-99 ◽  
Author(s):  
Benjamin Junge ◽  
Cordt Grönewald ◽  
Kornelia Berghof-Jäger
Keyword(s):  
Listeria Monocytogenes ◽  
Real Time ◽  
Food Samples ◽  
Food Groups ◽  
Rapid Preparation ◽  
Cultural Methods ◽  
The Matrix ◽  
Inspection Service ◽  
High Level ◽  
The U.S

Abstract A method was developed for the detection of Listeria monocytogenes in food. The method is based on real-time PCR using hydrolysis probes (5′ Nuclease). This advanced PCR method was designed to reduce the time necessary to achieve results from PCR reactions and to enable the user to monitor the amplification of the PCR product simultaneously, in real-time. After DNA isolation using the BIOTECON food proof® ShortPrep II Kit designed for the rapid preparation of L. monocytogenes DNA for direct use in PCR, the real- time detection of L. monocytogenes DNA is carried out using the food proof Listeria monocytogenes Detection Kit. The kit provides primers and hydrolysis probes for sequence-specific detection, convenient premixed reagents, and controls for reliable interpretation of results. For the internal comparison study, three different foods (soft cheese, coalfish, and smoked ham) were analyzed, chosen from the 15 food groups recommended by the AOAC Research Institute for detection of L. monocytogenes. From each food, 20 samples were inoculated with a low level (1–10 CFU/25 g) and 20 samples with a high level (10–50 CFU/25 g) of L. monocytogenes. Additionally, five nonspiked samples were prepared from each food. Depending on the matrix, the food samples were examined with the test kits and compared with the cultural methods according to the U.S. Food and Drug Administration's Bacteriological Analytical Manual or the U.S. Department of Agriculture/Food Safety and Inspection Service Microbiology Laboratory Guidebook.

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