InstantLabs®E. coli O157 Food Safety Kit

2015 ◽  
Vol 98 (1) ◽  
pp. 71-81
Author(s):  
Neil Sharma ◽  
Lauren Bambusch ◽  
Apala Upadhyay ◽  
Thu Le ◽  
Chris Lopez ◽  
...  

Abstract The InstantLabs®E. coli O157 Food Safety Kit was validated against the International Organization for Standardizationreference method 16654 for the detection of Escherichia coli O157. The matrixes, raw ground beef, raw beef trim, Romaine lettuce, pasteurized apple juice, and raw ground chicken, were inoculated with appropriate CFU/test portion of E. coli O157 to generate fractional positives (5–15) in 20 inoculated samples. The matrixeswere co-inoculated with Salmonella at 2–5 times the level of E. coli O157 to demonstrate the potential for using the same enrichment culture for the detection of multiple organisms. Samples were enriched in prewarmed FASTGRO SE broth at 42 ± 1°C for 10–20 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 E. coli O157 in all tested samples. Inclusivity and exclusivity testing revealed no false negatives and no false positives among the 50 E. coli O157 serovars and 30 non-E. coli O157 species examined. Finally, the method was shown to be robust when variations were applied to enrichment time, volume for DNA extraction, and heat block time.

2014 ◽  
Vol 97 (6) ◽  
pp. 1576-1584
Author(s):  
Neil Sharma ◽  
Lauren Bambusch ◽  
Thu Le ◽  
Melinda Hayman ◽  
Sergio J Montez

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).


2014 ◽  
Vol 97 (6) ◽  
pp. 1585-1591
Author(s):  
Neil Sharma ◽  
Lauren Bambusch ◽  
Thu Le ◽  
Amit Morey ◽  
Melinda Hayman ◽  
...  

Abstract The performance of InstantLabs®Salmonella Species Food Safety Kit to detect Salmonella in four food matrixes was validated against the International Organization for Standardization (ISO) reference method 6579:2002. The matrixes (raw ground beef, raw chicken breast, raw ground chicken, and lettuce) were inoculated with low levels of Salmonella (<1 CFU/test portion) to generate fractional positives (5–15) in 20 inoculated samples. These matrixes were co-inoculated with Escherichia coli O157:H7 at two to five times the level of Salmonella. Samples were validated using 375 g (meat) or 25 g (lettuce and poultry) test portions enriched in FASTGRO™ SE at 42 ± 1°C for 12 h and 10 h, respectively. All samples were confirmed using the ISO reference method, regardless of initial screen result. The InstantLabs test method was shown to perform as well as or better than the reference method for the detection of Salmonella species in ground beef, chicken breast, ground chicken, and lettuce. Inclusivity and exclusivity testing revealed no false negatives among the 100 Salmonella serovars and no false positives among the 30 non-Salmonella species examined, respectively.


Author(s):  
Jasmin Kaur Jasuja ◽  
Stefan Zimmermann ◽  
Irene Burckhardt

AbstractOptimisation of microbiological diagnostics in primarily sterile body fluids is required. Our objective was to apply EUCAST’s RAST on primarily sterile body fluids in blood culture bottles with total lab automation (TLA) and to compare results to our reference method Vitek2 in order to report susceptibility results earlier. Positive blood culture bottles (BACTEC™ Aerobic/Anaerobic/PEDS) inoculated with primarily sterile body fluids were semi-automatically subcultured onto Columbia 5% SB agar, chocolate agar, MacConkey agar, Schaedler/KV agar and Mueller-Hinton agar. On latter, cefoxitin, ampicillin, vancomycin, piperacillin/tazobactam, meropenem and ciprofloxacin were added. After 6 h, subcultures and RAST were imaged and MALDI-TOF MS was performed. Zone sizes were digitally measured and interpreted following RAST breakpoints for blood cultures. MIC values were determined using Vitek2 panels. During a 1-year period, 197 Staphylococcus aureus, 91 Enterococcus spp., 38 Escherichia coli, 11 Klebsiella pneumoniae and 8 Pseudomonas aeruginosa were found. Categorical agreement between RAST and MIC was 96.5%. Comparison showed no very major errors, 2/7 (28.6%) and 1/7 (14.3%) of major errors for P. aeruginosa and meropenem and ciprofloxacin, 1/9 (11.1%) for K. pneumoniae and ciprofloxacin, 4/69 (7.0%) and 3/43 (5.8%) for Enterococcus spp. and vancomycin and ampicillin, respectively. Minor errors for P. aeruginosa and meropenem (1/8; 12.8%) and for E. coli and ciprofloxacin (2/29; 6.5%) were found. 30/550 RAST measurements were within area of technical uncertainty. RAST is applicable and performs well for primarily sterile body fluids in blood culture bottles, partially better than blood-based RAST. Official EUCAST evaluation is needed.


1998 ◽  
Vol 81 (2) ◽  
pp. 403-418 ◽  
Author(s):  
Phyllis Entis ◽  
◽  
D Bryant ◽  
J Bryant ◽  
R G Bryant ◽  
...  

abstract Fifteen laboratories took part in a collaborative study to validate a method for enumerating Escherichia coli 0157:H7. The method is based on use of a hydrophobic grid membrane filter and consists of 24 h presumptive enumeration on SD-39 Agar and serological confirmation to yield a confirmed E. coli 0157:H7 count. Six food products were analyzed: pasteurized apple cider, pasteurized 2% milk, cottage cheese, cooked ground pork, raw ground beef, and frozen whole egg. The test method produced significantly higher confirmed count results than did the reference method for milk, pork, and beef. Test method results were numerically higher than but statistically equivalent to reference method results for cheese, cider, and egg. The test method produced lower repeatability and reproducibility values than did the reference method for most food/inoculation level combinations and values very similar to those of the reference method for the remaining combinations. Overall, 94% of presumptive positive isolates from the test method were confirmed serologically as E. coli 0157:H7, and 98% of these were also biochemically typical of E. coli 0157:H7 (completed test). Corresponding rates for the reference method were 69 and 98%, respectively. On the basis of the results of this collaborative study and the precollaborative study that preceded it, it is recommended that this method be adopted official first action for enumeration of E. coli 0157:H7 in meats, poultry, dairy foods, infant formula, liquid eggs, mayonnaise, and apple cider


2010 ◽  
Vol 61 (1) ◽  
pp. 67-76 ◽  
Author(s):  
A. Mavridou ◽  
E. Smeti ◽  
G. Mandilara ◽  
P. Boufa ◽  
M. Vagiona-Arvanitidou ◽  
...  

In this study ten laboratories in Greece compared the performance of reference method TTC Tergitol 7 Agar (with the additional test of β-glucuronidase production) with five alternative methods, to detect E. coli in water, in line with European Water Directive recommendations. The samples were prepared by spiking drinking water with sewage effluent following a standard protocol. Chlorinated and non-chlorinated samples were used. The statistical analysis was based on the mean relative difference of confirmed counts and was performed in line with ISO 17994. The results showed that in total, three of the alternative methods (Chromocult Coliform agar, Membrane Lauryl Sulfate agar and Trypton Bilex-glucuronidase medium) were not different from TTC Tergitol 7 agar (TTC Tergitol 7 agar vs Chromocult Coliform agar, 294 samples, mean RD% 5.55; vs MLSA, 302 samples, mean RD% 1; vs TBX, 297 samples, mean RD% −2.78). The other two alternative methods (Membrane Faecal coliform medium and Colilert 18/ Quantitray) gave significantly higher counts than TTC Tergitol 7 agar (TTC Tergitol 7 agar vs MFc, 303 samples, mean RD% 8.81; vs Colilert-18/Quantitray, 76 samples, mean RD% 18.91). In other words, the alternative methods generated performance that was as reliable as, or even better than, the reference method. This study will help laboratories in Greece overcome culture and counting problems deriving from the EU reference method for E. coli counts in water samples.


2015 ◽  
Vol 98 (5) ◽  
pp. 1301-1314 ◽  
Author(s):  
Jonathan Cloke ◽  
Erin Crowley ◽  
Patrick Bird ◽  
Ben Bastin ◽  
Jonathan Flannery ◽  
...  

Abstract The Thermo Scientific™ SureTect™ Escherichia coli O157:H7 Assay is a new real-time PCR assay which has been validated through the AOAC Research Institute (RI) Performance Tested MethodsSM program for raw beef and produce matrixes. This validation study specifically validated the assay with 375 g 1:4 and 1:5 ratios of raw ground beef and raw beef trim in comparison to the U.S. Department of Agriculture, Food Safety Inspection Service, Microbiology Laboratory Guidebook (USDS-FSIS/MLG) reference method and 25 g bagged spinach and fresh apple juice at a ratio of 1:10, in comparison to the reference method detailed in the International Organization for Standardization 16654:2001 reference method. For raw beef matrixes, the validation of both 1:4 and 1:5 allows user flexibility with the enrichment protocol, although which of these two ratios chosen by the laboratory should be based on specific test requirements. All matrixes were analyzed by Thermo Fisher Scientific, Microbiology Division, Vantaa, Finland, and Q Laboratories Inc, Cincinnati, Ohio, in the method developer study. Two of the matrixes (raw ground beef at both 1:4 and 1:5 ratios) and bagged spinach were additionally analyzed in the AOAC-RI controlled independent laboratory study, which was conducted by Marshfield Food Safety, Marshfield, Wisconsin. Using probability of detection statistical analysis, no significant difference was demonstrated by the SureTect kit in comparison to the USDA FSIS reference method for raw beef matrixes, or with the ISO reference method for matrixes of bagged spinach and apple juice. Inclusivity and exclusivity testing was conducted with 58 E. coli O157:H7 and 54 non-E. coli O157:H7 isolates, respectively, which demonstrated that the SureTect assay was able to detect all isolates of E. coli O157:H7 analyzed. In addition, all but one of the nontarget isolates were correctly interpreted as negative by the SureTect Software. The single isolate giving a positive result was an E. coli O157:NM isolate. Nonmotile isolates of E. coli O157 have been demonstrated to still contain the H7 gene; therefore, this result is not unexpected. Robustness testing was conducted to evaluate the performance of the SureTect assay with specific deviations to the assay protocol, which were outside the recommended parameters and which are open to variation. This study demonstrated that the SureTect assay gave reliable performance. A final study to verify the shelf life of the product, under accelerated conditions was also conducted.


2015 ◽  
Vol 98 (2) ◽  
pp. 371-378 ◽  
Author(s):  
Melinda Miller ◽  
Shawn Ramsaroop ◽  
Chris Lopez ◽  
Bharath Brahmanda

Abstract RAPID-B® is a high performance, integrated microbiology/infectious disease diagnostic system. The system uses hardware and software that are specifically designed for optimal detection using custom, immuno-based reagents designed to react to cell surface antigens of the target bacteria. The Vivione Bioscience RAPID-B Escherichia coli O157 and non-O157 Shiga toxin-producing E. coli (STEC) kits were validated alongside the U.S. Department of Agriculture, Food Safety and Inspection Service (FSIS), Microbiology Laboratory Guidebook (MLG) 5.07 (for E. coli O157) and FSIS MLG 5B.04 (fornon-O157 STEC) reference methods for the detection of E. coli O157 and STEC. The matrixes, ground beef and beef trim, were inoculated with appropriate CFU/test portion of E. coli O157 and STEC so as to generate fractional positives results, 5 to 15 positives out of 20 inoculated samples. Samples were enriched in prewarmed Brain Heart Infusion broth at 42 ± 1°C for 6.5–7.5 h or 8.5–9.5 h depending on thesample size. All samples were confirmed using the MLG reference method, regardless of initial screen result. The RAPID-B test methods were statistically equivalent to the reference method for the detection ofE. coli O157 and STEC in all testedsamples. Inclusivity and exclusivity testing of the RAPID-B methods showed 100% specificity for both kits. Finally, the RAPID-B test methods were shown to be robust when variations were applied to enrichment time, broth temperature, and vortexing time.


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.


2019 ◽  
Vol 102 (5) ◽  
pp. 1455-1471
Author(s):  
Benjamin Bastin ◽  
Leo Horine ◽  
Patrick Bird ◽  
M Joseph Benzinger ◽  
James Agin ◽  
...  

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.


2014 ◽  
Vol 97 (3) ◽  
pp. 852-861
Author(s):  
Neil Sharma ◽  
Lauren Bambusch ◽  
Thu Le ◽  
Amit Morey

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.


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