The Bruker MALDI Biotyper
method utilizes matrix-assisted laser desorption/ionization time-of-flight MS for the rapid and accurate identification and confirmation of Gram-negative bacteria from ...select media types. The alternative method was evaluated in a method extension study of AOAC INTERNATIONAL
2017.09 using nonselective and selective agars to identify
spp.,
spp.,
spp., and select Gram-negative bacteria. Results obtained by the Bruker MALDI Biotyper were compared to the traditional biochemical methods as prescribed in the appropriate reference methods.
Two collaborative studies were organized, one in the United States focusing on
spp. and other Gram-negative bacteria and one in Europe focusing on
spp. and other Gram-negative bacteria. Fourteen collaborators from seven laboratories located within the United States participated in the first collaborative study for
spp. Fifteen collaborators from 15 service laboratories located within Europe participated in the second collaborative study for
spp. For each target organism (either
spp. or
spp.), a total of 24 blind-coded isolates were evaluated. In each set of 24 organisms, there were 16 inclusivity organisms (
spp. or
spp.) and 8 exclusivity organisms (non-
spp. and non-
spp. closely related Gram-negative organisms). For the
spp. method extension, 17 collaborators from eight laboratories located within the United States (seven laboratories) and Canada (one laboratory) participated in the collaborative study. A total of 24 blind-coded isolates were evaluated. In each set of 24 organisms, there were 16 inclusivity organisms (
spp.) and 8 exclusivity organisms (non-
spp. closely related Gram-negative organisms).
After testing was completed, the total percentage of correct identifications from each agar type for each strain was determined at a percentage of 100.0% to the genus level for the
study and a percentage of 100.0% to the genus level for the
study. For the
method extension, a correct identification and confirmation rate of 100.0% was obtained for the
organisms at the species level. For non-
non-
, and non-
organisms, 100.0% were correctly identified.
The results indicated that the alternative method produced equivalent results when compared to the confirmatory procedures specified by each reference method.
The method extension can be modified to include the identification and confirmation of
,
, and
.
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The Bruker MALDI Biotyper® method utilizes matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS for the rapid and accurate identification and confirmation of Gram-negative ...bacteria from select media types. The alternative method was evaluated using nonselective and selective agars to identify Cronobacter spp., Salmonella spp., and select Gram-negative bacteria. Results obtained by the Bruker MALDI Biotyper were compared to the traditional biochemical methods as prescribed in the appropriate reference methods. Two collaborative studies were organized, one in the United States focusing on Cronobacter spp. and other Gram-negative bacteria, and one in Europe focusing on Salmonella spp. and other Gram-negative bacteria. Fourteen collaborators from seven laboratories located within the United States participated in the first collaborative study for Cronobacter spp. Fifteen collaborators from 15 service laboratories located within Europe participated in the second collaborative study for Salmonella spp. For each target organism (either Salmonella spp. or Cronobacter spp.), a total of 24 blind-coded isolates were evaluated. In each set of 24 organisms, there were 16 inclusivity organisms (Cronobacter spp. or Salmonella spp.) and 8 exclusivity organisms (closely related non-Cronobacter spp. and non-Salmonella spp. Gram-negative organisms). After testing was completed, the total percentage of correct identifications from each agar type for each strain was determined at a percentage of 100.0% to the genus level for the Cronobacter study and a percentage of 100.0% to the genus level for the Salmonella study. For both non-Cronobacter and non-Salmonella organisms, a percentage of 100.0% was correctly identified. The results indicated that the alternative method produced equivalent results when compared to the confirmatory procedures specified by each reference method.
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The automated system for enumeration of total viable count (TVC) in foods, TEMPO TVC, uses a dehydrated culture medium and an enumeration card containing 48 wells across 3 different dilutions for the ...automatic determination of the most probable number (MPN). The alternative method was compared in a multilaboratory collaborative study to AOAC Method 966.23 for determination of aerobic plate count for nondairy products and the Standard Methods for the Examination of Dairy Products (SMEDP) Standard Plate Count for dairy products. Five food types, raw ground beef, raw ground chicken, cooked whitefish fillets, bagged lettuce, and milk, were analyzed for TVC by 14 collaborating laboratories throughout the United States and Canada. Three lots of naturally contaminated food products representing a wide range of counts were tested for each of the 5 food types. The study demonstrated that the overall repeatability, reproducibility, and mean log counts of the TEMPO TVC method were statistically comparable to those of the 2 standard methods at the 5% level.
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Background: The Bruker MALDI BiotyperR method utilizes matrix-assisted laser desorption/ionization time-of-flight MS for the rapid and accurate identification and confirmation of Gram-negative ...bacteria from select media types. The alternative method was evaluated in a method extension study of AOAC INTERNATIONAL First Action Official MethodSM 2017.09 using nonselective and selective agars to identify Cronobacter spp., Salmonella spp., Campylobacter spp., and select Gram-negative bacteria. Results obtained by the Bruker MALDI Biotyper were compared to the traditional biochemical methods as prescribed in the appropriate reference methods. Methods: Two collaborative studies were organized, one in the United States focusing on Cronobacter spp. and other Gram-negative bacteria and one in Europe focusing on Salmonella spp. and other Gram-negative bacteria. Fourteen collaborators from seven laboratories located within the United States participated in the first collaborative study for Cronobacter spp. Fifteen collaborators from 15 service laboratories located within Europe participated in the second collaborative study for Salmonella spp. For each target organism (either Salmonella spp. or Cronobacter spp.), a total of 24 blind-coded isolates were evaluated. In each set of 24 organisms, there were 16 inclusivity organisms (Cronobacter spp. or Salmonella spp.) and 8 exclusivity organisms (non-Cronobacter spp. and non-Salmonella spp. closely related Gram-negative organisms). For the Campylobacter spp. method extension, 17 collaborators from eight laboratories located within the United States (seven laboratories) and Canada (one laboratory) participated in the collaborative study. A total of 24 blind-coded isolates were evaluated. In each set of 24 organisms, there were 16 inclusivity organisms (Campylobacter spp.) and 8 exclusivity organisms (non-Campylobacter spp. closely related Gram-negative organisms). Results: After testing was completed, the total percentage of correct identifications from each agar type for each strain was determined at a percentage of 100.0% to the genus level for the Cronobacter study and a percentage of 100.0% to the genus level for the Salmonella study. For the Campylobacter method extension, a correct identification and confirmation rate of 100.0% was obtained for the Campylobacter organisms at the species level. For non-Cronobacter, non-Salmonella, and non-Campylobacter organisms, 100.0% were correctly identified. Conclusions: The results indicated that the alternative method produced equivalent results when compared to the confirmatory procedures specified by each reference method. Highlights: The method extension can be modified to include the identification and confirmation of Campylobacter jejuni, Campylobacter coli, and Campylobacter lari.
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The design of a 20 GHz RF MEMS switch uses proven elements from previous designs operating from DC to 7 GHz. Extensive analysis of the RF performance of the original switch showed certain bandwidth ...limitations. Elimination of RF resonances, along with the addition of incremental ground vias and shortening of conducting stubs significantly improved performance. Prototypes of the modified switch have demonstrated outstanding RF performance from DC to more than 20 GHz. Typical performance shows less than 0.4 dB insertion loss, more than 20 dB return loss, and 25 dB isolation (@ 20 GHz).
Abstract
Background
CERTUS Environmental Listeria species Detection Kit (CERTUS EL Detection Kit) is a real-time, bio-contained assay designed to accurately detect Listeria species (L. grayi, L. ...innocua, L. ivanovii, L. marthii, L. monocytogenes, L. seeligeri, and L. welshimeri) from environmental surface matrixes using an antibody-coupled magnetic microparticle with a Surface Enhanced Raman Spectroscopy (SERS) nanoparticle technology test system paired with proprietary CERTUS EL Selective Growth Media and CERTUS Detection Unit.
Objective
The method was evaluated for AOAC®Performance Tested MethodSM certification.
Methods
Inclusivity and exclusivity, matrix studies, product consistency and stability were conducted to evaluate the CERTUS EL Detection Kit.
Results
In the matrix studies, stainless steel, ceramic tile, plastic (polystyrene) and sealed concrete environmental surfaces (4 × 4” test areas) were tested. No statistically significant differences were found by Probability of Detection analysis (POD) in any of the matrixes when results were compared to the U.S. Food and Drug Administration cultural microbiology reference method for Listeria. The CERTUS EL Detection Kit correctly identified all 50 target Listeria isolates and correctly excluded all 30 non-target strains that were analyzed. Probability of Detection analysis of CERTUS EL Detection Kit robustness, product consistency (lot-to-lot) and stability studies demonstrated no statistically significant differences, and no variation was observed between instruments.
Conclusions
The data collected in these studies demonstrate that the CERTUS EL Detection Kit is a reliable method for the rapid and specific detection of Listeria from stainless steel, ceramic tile, plastic (polystyrene) and sealed concrete environmental surfaces.
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RIDA®QUICK Gliadin is an immuno-chromatographic test for the detection of gluten in foods, on surfaces, and in Cleaning-in-Place (CIP) waters. This test kit has been adopted as Final Action AOAC ...INTERNATIONAL Official Methods of AnalysisSM 2015.16 for gluten in corn products. The assay is based on the monoclonal antibody R5, which recognizes gluten in wheat, barley, and rye. Four different surfaces were contaminated with a gliadin material and analyzed by a direct swabbing of the surface with the dip-stick. The outcome was an LOD95% concentration of the assay between 1.6 and 3.0 μg/100 cm2 gluten. For CIP waters that contain cleansing reagents, 100% positive results were obtained for minimum gluten concentration between 50 and 100 ng/mL. If the CIP water does not contain these reagents, the minimum detectable gluten level is 10 ng/mL. The independent validation study consisted of a method comparison study of recovery from a CIP solution and from a stainless-steel surface. The test kit was evaluated at six different concentration levels for both matrices, with 20 or 30 replicates per concentration level. The probability of detection was calculated for each contamination level. Additionally, the LOD95% concentration was estimated for each matrix analyzed.
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Abstract
Testing milk for antibiotics before acceptance into dairies is required by the U.S. Pasteurized Milk Ordinance. Technological advances in tests have reduced screening times and improved ...detection accuracy. This work describes the validation of the Charm Rapid One Step Assay Beta-Lactam 30 Second Test according to the U.S. Food and Drug Administration Center for Veterinary Medicine protocol for raw commingled milk. Milk is added to the lateral flow test strip in an incubator/reader to deliver a 30 second result. Independent laboratory validation followed sensitivity, interference, and incurred residue protocols. Sensitivity, in parts per billion (ppb = µg/kg), using a probit curve determined 90% percent detection with 95% confidence, which met National Conference of Interstate Milk Shipments (NCIMS) specifications. Six U.S. approved beta-lactam drugs were detected below, but within 50% of, target/tolerance levels for penicillin G 2.9 ppb, ampicillin 5.9 ppb, amoxicillin 5.8 ppb, cephapirin 13 ppb, cloxacillin 8.1 ppb, and ceftiofur metabolites 73 ppb. No interferences were observed from 33 animal drugs at 100 ppb, somatic cells at 1.2 million/mL, or bacterial levels of >300 000 CFU/mL. Incurred residue detection levels were similar to levels determined with the spiked parent compound. The data support NCIMS that the BL30SEC method met U.S. criteria for testing milk for beta-lactams.
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Solus One
is designed to accurately detect
species (
subspecies
and
) from select food matrixes and stainless-steel and plastic environmental surfaces. Solus One
uses an antibody-based technology ...test system that is paired with media and our proprietary media supplement, the Solus One
supplement combined with a manual or automated sample preparation method.
Solus One
was evaluated for inclusivity and exclusivity, and a matrix comparison study was done for six food matrixes (raw beef trim, pasteurized liquid egg, raw salmon, cheddar cheese, Romaine lettuce, nonfat dry milk) and two environmental surfaces (stainless steel and polystyrene).
Solus One
was compared with the U.S. Food and Drug Administration
Chapter 5:
(July 2018) and the U.S. Department of Agriculture Food Safety and Inspection Service
, 4.09 (January 2017) in the matrix study. Both the manual and automated sample preparation methods were performed for cheddar cheese and stainless-steel environmental surfaces.
For the inclusivity and exclusivity evaluation, Solus One
correctly detected all 108 target organism isolates and correctly excluded all 35 nontarget strains that were analyzed.
In the method comparison study, both Solus One
manual and automated sample preparation methods demonstrated no significant differences based on probability of detection (POD) statistical analysis between presumptive and confirmed results or between candidate and reference method results for the six food matrixes after 20-22 h and two environmental surfaces after 16-20 h of enrichment time. POD analysis of Solus One
method robustness, product consistency, and stability studies using the automated sample preparation method demonstrated no statistically significant differences.
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The Bruker MALDI Biotyper® method utilizes matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS for the rapid and accurate confirmation and identification of Gram-positive ...bacteria from select media types. This alternative method was evaluated using nonselective and selective agar plates to identify and confirm Listeria monocytogenes, Listeria species, and select Gram-positive bacteria. Results obtained by the Bruker MALDI Biotyper were compared with the traditional biochemical methods as prescribed in the appropriate reference method standards. Sixteen collaborators from 16 different laboratories located within the European Union participated in the collaborative study. A total of 36 blind-coded isolates were evaluated by each collaborator. In each set of 36 organisms, there were 16 L. monocytogenes strains, 12 non-monocytogenes Listeria species strains, and 8 additional Gram-positive exclusivity strains. After testing was completed, the total percentage of correct identifications (to both genus and species level) and confirmation from each agar type for each strain was determined at a percentage of 99.9% to the genus level and 98.8% to the species level. The results indicated that the alternative method produced equivalent results when compared with the confirmatory procedures specified by each reference method.
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