InstantLabs®Listeria monocytogenes Food Safety Kit

2014 ◽  
Vol 97 (3) ◽  
pp. 852-861
Author(s):  
Neil Sharma ◽  
Lauren Bambusch ◽  
Thu Le ◽  
Amit Morey
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Food Safety ◽  
Reference Method ◽  
Cheddar Cheese ◽  
Ice Cream ◽  
Test Method ◽  
Listeria Species ◽  
Whole Milk ◽  
Raw Shrimp

Abstract The InstantLabs®Listeria monocytogenes Food Safety Kit was validated against the International Organization for Standardization (ISO) reference method 11290-1 for the detection of Listeria monocytogenes and other Listeria species. The matrixes (stainless steel, sealed concrete, ice cream, whole milk, cheddar cheese, raw shrimp, hot dogs, deli turkey, and lettuce) were inoculated with approximately 1 CFU/test portion of L. monocytogenes to generate fractional positives (5–15) in 20 inoculated samples. Enrichments were also fractionally inoculated with L. grayii for side-by-side testing of the Listeria Species Food Safety Kit. Stainless steel and sealed concrete samples were validated using 4 × 4″ and 1 × 1″ test areas, respectively, and enriched in Buffered Listeria Enrichment Broth (BLEB) at 35 ± 1°C for 22–28 h. All food samples were tested at 25 g and enriched in BLEB at 35 ± 1°C for 24–28 h. All samples were confirmed using the ISO reference method, regardless of initial screen result. The InstantLabs test method performed as well as or better than the reference method for the detection of L. monocytogenes on stainless steel and sealed concrete and in ice cream, whole milk, cheddar cheese, raw shrimp, hot dogs, deli turkey, and lettuce. Inclusivity and exclusivity testing revealed no false negatives and no false positives among the 50 L. monocytogenes serovars and 30 non-L. monocytogenes species examined. The method was shown to be robust when the enrichment times, volumes for DNA extraction, and heat block times were varied.

Evaluation of the Thermo Scientific™ SureTect™ Listeria monocytogenes Assay

2014 ◽  
Vol 97 (1) ◽  
pp. 133-154 ◽  
Author(s):  
Jonathan Cloke ◽  
Carlos Leon-Velarde ◽  
Nathan Larson ◽  
Keron Dave ◽  
Katharine Evans ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Reference Method ◽  
Ice Cream ◽  
Probability Of Detection ◽  
Specific Method ◽  
Food Contact Surfaces ◽  
Significant Difference ◽  
Thermo Fisher Scientific ◽  
Reliable Performance

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.

Comparative Evaluation of Veriflow®Listeria Species to USDA Culture-Based Method for the Detection of Listeria spp. in Food and Environmental Samples

2017 ◽  
Vol 100 (5) ◽  
pp. 1434-1444 ◽  
Author(s):  
Adam C Joelsson ◽  
Shawn P Terkhorn ◽  
Ashley S Brown ◽  
Amrita Puri ◽  
Benjamin J Pascal ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Ceramic Tile ◽  
Pcr Amplification ◽  
Reference Method ◽  
Probability Of Detection ◽  
Complex Data ◽  
Listeria Species ◽  
Environmental Surfaces ◽  
Study Results ◽  
Significant Difference

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).

InstantLabs®Salmonella Species Food Safety Kit

2014 ◽  
Vol 97 (6) ◽  
pp. 1576-1584
Author(s):  
Neil Sharma ◽  
Lauren Bambusch ◽  
Thu Le ◽  
Melinda Hayman ◽  
Sergio J Montez
Keyword(s):  
Food Safety ◽  
Wheat Flour ◽  
Enrichment Culture ◽  
Hold Time ◽  
Reference Method ◽  
Test Method ◽  
Test Portion ◽  
Screen Result ◽  
Oat Flour ◽  
Better Than

Abstract The InstantLabs®Salmonella Species Food Safety Kit was validated against the International Organization for Standardization (ISO) reference method 6579:2002 for the detection of Salmonella species. The matrixes (unprocessed rolled oats, wheat flour, and oat flour) were inoculated with 1 CFU/test portion of Salmonella to generate fractional positives (5–15) in 20 inoculated samples. The matrixes were co-inoculated with Escherichia coli O157:H7 at 2–5 times the level of Salmonella to demonstrate the potential for using the same enrichment culture in the future to detect of multiple organisms. Samples were validated using 750 g test portion enriched in FASTGRO SE at 42 ± 1°C for 16–20 h. All samples were confirmed using the ISO reference method, regardless of initial screen result. The InstantLabs test method performed as well as or better than the reference method for the detection of Salmonella species in unprocessed rolled oats, wheat flour, and oat flour. Inclusivity and exclusivity testing revealed no false negatives and no false positives among the 100 Salmonella serovars and 30 non-Salmonella species examined. Finally, the method was shown to be robust when variations to enrichment time, DNA extract hold time, and DNA volume were varied (data not shown).

Crystal Diagnostics Xpress™ LM Kit for the Rapid Detection of Listeria monocytogenes from Environmental Surfaces

2017 ◽  
Vol 100 (1) ◽  
pp. 165-175
Author(s):  
Curtis H Stumpf ◽  
Brian Bullard ◽  
Weidong Zhoa ◽  
Stephanie Kuzenko-Hentosh ◽  
Gary D Niehaus
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Ceramic Tile ◽  
Reference Method ◽  
Rapid Screening ◽  
Bacterial Strains ◽  
Department Of Agriculture ◽  
Environmental Surfaces ◽  
Low Concentrations ◽  
Low Levels

Abstract The Crystal Diagnostics (CDx) Xpress™ LM kit is used for rapid screening of low concentrations of Listeria monocytogenes on environmental surfaces such as stainless steel, plastic, and ceramic tile. In addition to the Xpress LM kit, the CDx Xpress System comprises an automatic Xpress Reader,a BioCassette™ that incorporates antibody-coupled microspheres, and liquid crystal for selective identification of the intended microbe. All 56 of the 56 tested L. monocytogenes strains evaluated were detected, and 50 of the 50 nontarget bacterial strains were excluded when the test was conducted under the described kit conditions. Shelf-life testing of the antibody-coated microspheres and other CDx consumables indicated that all materials were stable for a minimum of 6 months (ongoing), and lot-to-lot testing demonstrated no significant differences among lots. The internal and independent laboratory tests on stainless steel, plastic, and ceramic tile surfa es demonstrated that the method is equivalent to the U.S. Department of Agriculture (USDA) reference method, and there were no significant differences between the CDx Xpress LM kit presumptive and confirmed results for any of the matrixes. Overall, the CDx Xpress LM kit is one of the fastest to provide the sensitivity and specificity equivalent to the USDA reference method in screening low levels of L. monocytogenes surface contamination and, when combined with chromogenic culturing of presumptive positives, provides a streamlined confirmation process to rapidly and accurately differentiate L. monocytogenes from other microbes.

Attachment of Listeria monocytogenes and Salmonella typhimurium to Stainless Steel and Buna-N in the Presence of Milk and Individual Milk Components

1993 ◽  
Vol 56 (6) ◽  
pp. 479-484 ◽  
Author(s):  
DAVID M. HELKE ◽  
EILEEN B. SOMERS ◽  
AMY C. L. WONG
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Salmonella Typhimurium ◽  
Dairy Industry ◽  
Skim Milk ◽  
Whole Milk ◽  
Milk Components ◽  
Phosphate Buffered Saline ◽  
Β Lactoglobulin

The effects of milk and individual milk components on the attachment of Listeria monocytogenes and Salmonella typhimurium to two commonly used materials in the dairy industry were studied. Attachment of both organisms to stainless steel and Buna-N was significantly inhibited by the presence of skim, 2%, whole, or chocolate 2% milk compared to the phosphate-buffered saline (PBS) control. The addition of individual milk components, casein, α-lactalbumin, and β-lactoglobulin to the attachment menstruum significantly reduced attachment. Pretreating surfaces with milk and milk components for 1 h prior to attachment in PBS gave similar results. The presence of lactose did not affect attachment of either organism; however, attachment of S. typhimurium was significantly decreased on pretreated Buna-N. Cells of either organism pretreated with skim milk or β-lactoglobulin prior to attachment in PBS showed significantly less attachment than untreated cells. Pretreating S. typhimurium cells with casein had no effect on attachment to stainless steel. Pretreatment of S. typhimurium with lactose increased attachment to both surfaces while pretreatment had no effect on L. monocytogenes. Attachment of both organisms was significantly reduced in diluted whole milk. Both organisms attached significantly less to surfaces soiled with one or more layers of whole milk.

SDIX RapidChek™ Listeria F.A.S.T.™ Environmental Test System for the Detection of Listeria species on Environmental Surfaces

2012 ◽  
Vol 95 (3) ◽  
pp. 850-859 ◽  
Author(s):  
Mark T Muldoon ◽  
Anne-Christine Olsson Allen ◽  
Vera Gonzales ◽  
Meredith Sutzko ◽  
Klaus Lindpaintner
Keyword(s):  
Reference Method ◽  
Storage Conditions ◽  
Test System ◽  
Test Method ◽  
Broth Culture ◽  
Bacterial Strains ◽  
Chi Square ◽  
Listeria Species ◽  
Environmental Surfaces ◽  
Inspection Service

Abstract The SDIX RapidChekTMListeria F.A.S.T. test system was validated against the U. S. Department of Agriculture-Food Safety and Inspection Service (USDA-FSIS) cultural reference method for the detection of Listeria species on stainless steel, plastic, rubber, and painted concrete. The SDIX method uses a proprietary RapidChek Listeria enrichment media for a one-step, 24–40 h enrichment at 30°C, and detects Listeria on an immunochromatographic lateral flow device in 10 min. Different Listeria species were used to spike each of the environmental surfaces. Environmental surfaces were spiked at levels ranging from 50 to 400 CFU/surface (1 in.2 swabs for painted concrete, 4 in.2 for sponge). A total of 120 spiked samples were tested by the SDIX method at 24 and 40 h and the cultural reference method. Total confirmed positives were 49, 54, and 48 for the SDIX 24 h method, the SDIX 40 h method, and the USDA-FSIS cultural reference method, respectively. Nonspiked samples from all environmental surfaces were reported as negative for Listeria spp. by all methods. The overall Chi square was 0.017 (P = 0.104) and 0.611 (P = 0.566) after a 24 and 40 h enrichment, respectively, indicating that the test method was equivalent in performance to the reference method at both enrichment times. The SDIX method was evaluated for the detection of 50 Listeria and 35 non-Listeria bacterial strains. All 50 Listeria strains were detected by the method (100% sensitivity). Five out of 35 non-Listeria species gave light test signals when grown in nonselective broth culture and tested undiluted. However, when grown in the RapidChek Listeria F.A.S.T. proprietary media, only one bacterial strain (Staphylococcus aureus) was detected, giving a very low test signal (97% specificity). The method was shown to be robust toward several alterations in testing and storage conditions.

scholarly journals Independent Validation for the Polyskope 1.0 Multiplex Pathogen Detection Assay for the Detection of Shiga Toxin-Producing Escherichia coli Non-O157 STEC, Escherichia coli O157, Listeria monocytogenes, and Salmonella Species

2019 ◽  
Vol 102 (5) ◽  
pp. 1455-1471
Author(s):  
Benjamin Bastin ◽  
Leo Horine ◽  
Patrick Bird ◽  
M Joseph Benzinger ◽  
James Agin ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Shiga Toxin ◽  
Reference Method ◽  
Test Method ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Independent Validation ◽  
Reference Methods ◽  
Environmental Surface

Abstract Background: The Polyskope 1.0 Multiplex Assay is a novel test to simultaneously detect Escherichia coli O157, non-O157 Shiga Toxin-Producing E. coli (STEC), Listeria monocytogenes, and Salmonella species in a single enrichment using real-time PCR. Objective: A Performance Tested MethodSM study was conducted to validate Polyskope 1.0 for inclusivity and exclusivity as well as a matrix comparison study. Method: This assay was evaluated in an unpaired independent validation study compared with reference methods according to AOAC INTERNATIONAL validation guidelines. Polyskope 1.0 evaluated raw ground beef (25 g), deli turkey (25 g), baby spinach (25 g), and stainless-steel environmental surface sponges (4 × 4 in. test area) after inoculation with a suspension of the three target microorganisms. All matrices were compared with appropriate reference methods from the U.S. Food and Drug Administration Bacteriological Analytical Manual, U.S. Department of Agriculture Food Safety and Inspection Service Microbiology Laboratory Guidebook, or International Organization for Standardization standards. Results: Polyskope 1.0 demonstrated no statistically significant differences between candidate and reference method results or between presumptive and confirmed results for three food matrices and one environmental surface. Results from inclusivity and exclusivity evaluations indicated the test method can accurately detect the target analytes and excluded all nontarget organisms. No differences were observed with the stability or lot-to-lot evaluations. Polyskope 1.0 demonstrated robustness by remaining unaffected by small variations in method parameters, which had no statistically significant effect on the results for all eight variations. Conclusions and Highlights: Polyskope 1.0 was shown to be a specific, highly accurate, and robust method for the detection of Listeria monocytogenes, Salmonella species, non-O157 STECs, and E. coli O157 across four matrices.

Atlas® Listeria monocytogenes LmG2 Detection Assay Using Transcription Mediated Amplification to Detect Listeria monocytogenes in Selected Foods and Stainless Steel Surface

2014 ◽  
Vol 97 (5) ◽  
pp. 1343-1358 ◽  
Author(s):  
Vanessa Bres ◽  
Hua Yang ◽  
Ernie Hsu ◽  
Yan Ren ◽  
Ying Cheng ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Ice Cream ◽  
Food Samples ◽  
Steel Grade ◽  
Stainless Steel Surface ◽  
Dilution Ratio ◽  
Reference Methods ◽  
Detection Assay ◽  
The U.S

Abstract The Atlas Listeria monocytogenes LmG2 Detection Assay, developed by Roka Bioscience Inc., was compared to a reference culture method for seven food types (hot dogs, cured ham, deli turkey, chicken salad, vanilla ice cream, frozen chocolate cream pie, and frozen cheese pizza) and one surface (stainless steel, grade 316). A 125 g portion of deli turkey was tested using a 1:4 food:media dilution ratio, and a 25 g portion for all other foods was tested using 1:9 food:media dilution ratio. The enrichment time and media for Roka's method was 24 to 28 h for 25 g food samples and environmental surfaces, and 44 to 48 h for 125 g at 35 ± 2°C in PALCAM broth containing 0.02 g/L nalidixic acid. Comparison of the Atlas Listeria monocytogenes LmG2 Detection Assay to the reference method required an unpaired approach. For each matrix, 20 samples inoculated at a fractional level and five samples inoculated at a high level with a different strain of Listeria monocytogenes were tested by each method. The Atlas Listeria monocytogenes LmG2 Detection Assay was compared to the Official Methods of Analysis of AOAC INTERNATIONAL 993.12 method for dairy products, the U.S. Department of Agriculture, Food Safety and Inspection Service, Microbiology Laboratory Guidebook 8.08 method for ready-to-eat meat and environmental samples, and the U.S. Food and Drug Administration Bacteriological Analytical Manual, Chapter 10 method for frozen foods. In the method developer studies, Roka's method, at 24 h (or 44 h for 125 g food samples), had 126 positives out of 200 total inoculated samples, compared to 102 positives for the reference methods at 48 h. In the independent laboratory studies, vanilla ice cream, deli turkey and stainless steel grade 316 were evaluated. Roka's method, at 24 h (or 44 h for 125 g food samples), had 64 positives out of 75 total inoculated samples compared to 54 positives for the reference methods at 48 h. The Atlas Listeria monocytogenes LmG2 Detection Assay detected all 50 L. monocytogenes strains that encompassed 13 serotypes across the various lineages and none of the 30 exclusive organisms, including seven other Listeria species. The product consistency and kit stability studies revealed no statistical differences between the three lots tested or to the term of the shelf life. Finally, the robustness study demonstrated no statistical differences when samples were incubated at 33 ± 2°C or 37 ± 2°C, when enrichment aliquots were 1.3 mL or 1.7 mL, or when the samples were analyzed the same day or five days later. Overall the Atlas Listeria monocytogenes LmG2 Detection Assay is statistically equivalent to or better than the reference methods and is robust to the tested variations.

Evaluation of Applied Biosystems MicroSEQ® Real-Time PCR System for Detection of Listeria spp. in Food and Environmental Samples

2012 ◽  
Vol 95 (4) ◽  
pp. 1074-1083 ◽  
Author(s):  
Olga V Petrauskene ◽  
Yanxiang Cao ◽  
Patrick Zoder ◽  
Lily Y Wong ◽  
Priya Balachandran ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Sample Preparation ◽  
Real Time ◽  
Real Time Pcr ◽  
Reference Method ◽  
Test Method ◽  
Stainless Steel Surface ◽  
Acid Extraction ◽  
Chi Square ◽  
Chi Square Analysis

Abstract A complete system for real-time PCR detection of Listeria species was validated in five food matrixes and five environmental surfaces, namely, hot dogs, roast beef, lox (smoked salmon), pasteurized whole cow's milk, dry infant formula, stainless steel, plastic cutting board, ceramic tile, rubber sheets, and sealed concrete. The system consists of the MicroSEQ®Listeria spp. Detection Kit, two sample preparation kits (PrepSEQ® Nucleic Acid Extraction Kit and PrepSEQ Rapid Spin Sample Preparation Kit), the Applied Biosystems 7500 Fast Real-Time PCR instrument, and the RapidFinder™ Express v1.1 Software for data analysis. The test method was compared to the ISO 11290-1 reference method using an unpaired study design. The MicroSEQ Listeria spp. Detection Kit and the ISO 11290-1 reference method showed equivalent detection based on Chi-square analysis for all matrixes except hot dogs. For hot dogs, the MicroSEQ method detected more positives than the reference method for the low- and high-level inoculations, with all of the presumptive positives confirmed by the reference method. An independent validation study confirmed these findings on lox and stainless steel surface. The MicroSEQ kit detected all 50 Listeria strains tested and none of the 31 nontarget bacteria strains.

VIDAS® Listeria species Xpress (LSX)

2013 ◽  
Vol 96 (2) ◽  
pp. 242-245 ◽  
Author(s):  
Ronald Johnson ◽  
John Mills
Keyword(s):  
Stainless Steel ◽  
Reference Method ◽  
Culture Method ◽  
Culture Methods ◽  
Chi Square ◽  
Listeria Species ◽  
Standard Culture ◽  
Inspection Service ◽  
Chi Square Analysis ◽  
Positive Results

Abstract The AOAC GovVal study compared the VIDAS®Listeria species Xpress (LSX) to the Health Products and Food Branch MFHPB-30 reference method for detection of Listeria on stainless steel. The LSX method utilizes a novel and proprietary enrichment media, Listeria Xpress broth, enabling detection of Listeria species in environmental samples with the automated VIDAS in a minimum of 26 h. The LSX method also includes the use of the chromogenic media, chromID™ Ottaviani Agosti Agar (OAA) and chromID™ Lmono for confirmation of LSX presumptive results. In previous AOAC validation studies comparing VIDAS LSX to the U. S. Food and Drug Administration's Bacteriological Analytical Manual (FDA-BAM) and the U. S. Department of Agriculture-Food Safety and Inspection Service (USDA-FSIS) reference methods, the LSX method was approved as AOAC Official Method2010.02 for the detection of Listeria species in dairy products, vegetables, seafood, raw meats and poultry, and processed meats and poultry, and as AOAC Performance Tested Method 100501 in a variety of foods and on environmental surfaces. The GovVal comparative study included 20 replicate test portions each at two contamination levels for stainless steel where fractionally positive results (5–15 positive results/20 replicate portions tested) were obtained by at least one method at one level. Five uncontaminated controls were included. In the stainless steel artificially contaminated surface study, there were 25 confirmed positives by the VIDAS LSX assay and 22 confirmed positives by the standard culture methods. Chi-square analysis indicated no statistical differences between the VIDAS LSX method and the MFHPB-30 standard methods at the 5% level of significance. Confirmation of presumptive LSX results with the chromogenic OAA and Lmono media was shown to be equivalent to the appropriate reference method agars. The data in this study demonstrate that the VIDAS LSX method is an acceptable alternative method to the MFHPB-30 standard culture method for the detection of Listeria species on stainless steel.

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