scholarly journals Comparison of FoodChek E. coli Test and AOAC Research Institute Performance Tested Method 010603 for Detection of E. coli O157 in Raw Ground Beef

2010 ◽  
Vol 93 (3) ◽  
pp. 922-927 ◽  
Author(s):  
Richard J Flanagan ◽  
Gabriela Martinez
Keyword(s):  
Magnetic Nanoparticle ◽  
Raw Materials ◽  
Detection System ◽  
Detection Threshold ◽  
Reference Method ◽  
Superparamagnetic Nanoparticles ◽  
E Coli ◽  
Detection Assay ◽  
Highly Sensitive ◽  
Research Institute

Abstract The FoodChek E. coli O157 assay [AOAC Research Institute (RI) Performance Tested Method (PTM) 060902] is a rapid detection system that incorporates the use of antibody-coated superparamagnetic nanoparticles in a lateral flow immunoassay format. The system comprises a commercially available enrichment medium, a magnetic nanoparticle immunoassay, and an automated reader for detection. Assay detection threshold is improved relative to traditional immunoassays through use of a magnetic nanoparticle label and a highly sensitive magnetic particle detector. FoodChek E. coli O157 is a reintroduction of the previously certified AOAC PTM 010603. The original assay was evaluated and approved in internal and independent laboratory studies. Vacci-Test Corp. has contracted with the original supplier of the PTM to remanufacture the test under identical conditions and with identical raw materials. This report is intended to show that FoodChek E. coli is identical in performance to the previously approved PTM. The results showed no difference for the parameters evaluated. Three kit lots along with three lots of media and media supplement were compared in lot-to-lot and stability testing. The results indicated no difference in performance across the three lots. The results showed sensitivity of >99 and a specificity rate of >98 for the FoodChek method and a significantly higher sensitivity than the reference method.

Rapid Detection of Listeria in Ice Cream in 13 Hours Using the Roka Listeria Detection Assay

2018 ◽  
Vol 101 (6) ◽  
pp. 1806-1812
Author(s):  
Elba Veronica Arias-Rios ◽  
Kristina Tenney ◽  
Tam Mai ◽  
Sam Anderson ◽  
Ruth Marie Cantera ◽  
...  
Keyword(s):  
Early Detection ◽  
New Media ◽  
Rapid Detection ◽  
Method Comparison ◽  
Reference Method ◽  
Ice Cream ◽  
Detection Methods ◽  
Media Formulation ◽  
Detection Assay ◽  
Highly Sensitive

Abstract Background: Listeria contamination is a major concern in the ice cream industry; therefore, early and accurate detection is vital. Current detection methods require about a 24 h enrichment period for detection. Objective: Enhance the early detection of Listeria in ice cream using the highly sensitive isothermal ribosomal RNA-based Roka/Atlas Listeria Detection Assay. Methods: The R2 Medium was developed for Listeria enrichment by Molecular Epidemiology, Inc. (Seattle, WA). Comparative growth curve studies were performed on the new R2 Medium for Listeria and the currently validated media for the Roka Listeria Detection Assay. Subsequently, a method comparison between the Roka Listeria Detection Assay and the U.S. Food and Drug Administration’s (FDA) Bacteriological Analytical Manual (BAM) Chapter 10 reference method on ice cream was carried out. Results: The R2 Medium supports the growth of L. monocytogenes better than Buffered Listeria Enrichment Broth, Demi-Fraser broth, and Modified University of Vermont Broth, as indicated by the faster growth rate of the organism. When used as an enrichment medium in a method comparison study of ice cream, the results showed that R2 Medium–enriched samples tested with the Roka Listeria Detection Assay gave an equivalent performance compared with the 24 h FDA-BAM reference method at 10 and 18 h post-enrichment for Listeria. Conclusions: The results from this study indicate that the new R2 Medium and the highly sensitive Roka Listeria Detection Assay allowed for the rapid detection of Listeria species in ice cream in 13 h. Highlights: The Roka Listeria Detection Assay, in conjunction with a new media formulation (R2 Medium), allowed for the early detection of Listeria in ice cream and may be applied in other food matrixes and environmental samples.

scholarly journals Electrochemical Detection of Waterborne Bacteria Using Bi-Functional Magnetic Nanoparticle Conjugates

Biosensors ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 36
Author(s):  
Dharanivasan Gunasekaran ◽  
Yoram Gerchman ◽  
Sefi Vernick
Keyword(s):  
Electrochemical Detection ◽  
Electrochemical Method ◽  
Magnetic Nanoparticle ◽  
Specific Binding ◽  
Dependent Manner ◽  
Igg Antibody ◽  
E Coli ◽  
Amine Functionalized ◽  
Highly Sensitive ◽  
Dose Dependent

Detection of microbial contamination in water is imperative to ensure water quality. We have developed an electrochemical method for the detection of E. coli using bi-functional magnetic nanoparticle (MNP) conjugates. The bi-functional MNP conjugates were prepared by terminal-specific conjugation of anti-E. coli IgG antibody and the electroactive marker ferrocene. The bi-functional MNP conjugate possesses both E. coli-specific binding and electroactive properties, which were studied in detail. The conjugation efficiency of ferrocene and IgG antibodies with amine-functionalized MNPs was investigated. Square-wave voltammetry enabled the detection of E. coli concentrations ranging from 101–107 cells/mL in a dose-dependent manner, as ferrocene-specific current signals were inversely dependent on E. coli concentrations, completely suppressed at concentrations higher than 107 cells/mL. The developed electrochemical method is highly sensitive (10 cells/mL) and, coupled to magnetic separation, provides specific signals within 1h. Overall, the bi-functional conjugates serve as ideal candidates for electrochemical detection of waterborne bacteria. This approach can be applied for the detection of other bacteria and viruses.

scholarly journals Multiple Bacteria Identification in the Point-of-Care: an Old Method Serving a New Approach

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3351
Author(s):  
Sara Viveiros ◽  
Mónica Rodrigues ◽  
Débora Albuquerque ◽  
Sofia A. M. Martins ◽  
Susana Cardoso ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Limit Of Detection ◽  
Detection System ◽  
Point Of Care ◽  
Bovine Mastitis ◽  
Cross Reactivity ◽  
Superparamagnetic Nanoparticles ◽  
Nucleic Acid Amplification ◽  
Streptococcus Uberis ◽  
Detection Assay

The accurate diagnosis of bacterial infections is of critical importance for effective treatment decisions. Due to the multietiologic nature of most infectious diseases, multiplex assays are essential for diagnostics. However, multiplexability in nucleic acid amplification-based methods commonly resorts to multiple primers and/or multiple reaction chambers, which increases analysis cost and complexity. Herein, a polymerase chain reaction (PCR) offer method based on a universal pair of primers and an array of specific oligonucleotide probes was developed through the analysis of the bacterial 16S ribosomal RNA gene. The detection system consisted of DNA hybridization over an array of magnetoresistive sensors in a microfabricated biochip coupled to an electronic reader. Immobilized probes interrogated single-stranded biotinylated amplicons and were obtained using asymmetric PCR. Moreover, they were magnetically labelled with streptavidin-coated superparamagnetic nanoparticles. The benchmarking of the system was demonstrated to detect five major bovine mastitis-causing pathogens: Escherichia coli, Klebsiella sp., Staphylococcus aureus, Streptococcus uberis, and Streptococcus agalactiae. All selected probes proved to specifically detect their respective amplicon without significant cross reactivity. A calibration curve was performed for S. agalactiae, which demonstrates demonstrating a limit of detection below 30 fg/µL. Thus, a sensitive and specific multiplex detection assay was established, demonstrating its potential as a bioanalytical device for point-of-care applications.

scholarly journals A plate diffusion method for detecting fluoroquinolone residues in raw cow’s milk 

2014 ◽  
Vol 32 (No. 3) ◽  
pp. 260-264 ◽  
Author(s):  
P. Navrátilová ◽  
J. Vyhnálková ◽  
L. Vorlová ◽  
J. Jeřábková
Keyword(s):  
Czech Republic ◽  
Antimicrobial Agents ◽  
Raw Materials ◽  
Reference Method ◽  
Coli Strain ◽  
Animal Origin ◽  
Diffusion Method ◽  
The Czech Republic ◽  
E Coli ◽  
Modified Method

The plate diffusion method is a reference method in the Czech Republic for determination of residues of antimicrobial agents in raw materials and foodstuffs of animal origin. A new method using the E. coli strain ATCC 11303 for the detection of fluoroquinolones was introduced in 2008. The aim of this study was to determine the detection capability (CCβ) of this modified method using this E. coli strain for selected fluoroquinolones registered in the Czech Republic for treating diseases in cattle – danofloxacin, marbofloxacin, ciprofloxacin, enrofloxacin, and flumequine. When comparing the maximum residue limits for individual fluoroquinolones and the CCβ values determined, we can state that the method displays very good sensitivity to ciprofloxacin and enrofloxacin (20 and 40 µg/l), marbofloxacin (70 µg/l), and danofloxacin (30 µg/l). The CCβ of the method for flumequine was not found in concentrations ≤ MRL. The method did not display sensitivity to flumequine even in a concentration equal to twelve times the MRL.

PCR-Based DNA Amplification and Presumptive Detection of Escherichia coli O157:H7 with an Internal Fluorogenic Probe and the 5′ Nuclease (TaqMan) Assay

1998 ◽  
Vol 64 (9) ◽  
pp. 3389-3396 ◽  
Author(s):  
R. D. Oberst ◽  
M. P. Hays ◽  
L. K. Bohra ◽  
R. K. Phebus ◽  
C. T. Yamashiro ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Detection System ◽  
False Negative ◽  
Detection Threshold ◽  
Ground Beef ◽  
Taqman Assay ◽  
Dna Recovery ◽  
E Coli ◽  
Presumptive Identification ◽  
Nuclease Assay

ABSTRACT Presumptive identification of Escherichia coli O157:H7 is possible in an individual, nonmultiplexed PCR if the reaction targets the enterohemorrhagic E. coli (EHEC)eaeA gene. In this report, we describe the development and evaluation of the sensitivity and specificity of a PCR-based 5′ nuclease assay for presumptively detecting E. coli O157:H7 DNA. The specificity of the eaeA-based 5′ nuclease assay system was sufficient to correctly identify all E. coliO157:H7 strains evaluated, mirroring the previously described specificity of the PCR primers. The SZ-primed,eaeA-targeted 5′ nuclease detection assay was capable of rapid, semiautomated, presumptive detection of E. coliO157:H7 when ≥103 CFU/ml was present in modified tryptic soy broth (mTSB) or modified E. coli broth and when ≥104 CFU/ml was present in ground beef-mTSB mixtures. Incorporating an immunomagnetic separation (IMS) step, followed by a secondary enrichment culturing step and DNA recovery with a QIAamp tissue kit (Qiagen), improved the detection threshold to ≥102 CFU/ml. Surprisingly, immediately after IMS, the sensitivity of culturing on sorbitol MacConkey agar containing cefeximine and tellurite (CT-SMAC) was such that identifiable colonies were demonstrated only when ≥104 CFU/ml was present in the sample. Several factors that might be involved in creating these false-negative CT-SMAC culture results are discussed. The SZ-primed,eaeA-targeted 5′ nuclease detection system demonstrated that it can be integrated readily into standard culturing procedures and that the assay can be useful as a rapid, automatable process for the presumptive identification of E. coli O157:H7 in ground beef and potentially in other food and environmental samples.

Impact of Raw Materials and Processing Techniques on The Microbiological Quality of Egyptian Domiati Cheese

2020 ◽  
Keyword(s):  
Raw Materials ◽  
Microbiological Quality ◽  
Raw Milk ◽  
Plate Count ◽  
E Coli ◽  
Fresh Cheese ◽  
Processing Techniques ◽  
The Impact ◽  
Total Yeast

Domiati cheese is the most popular brand of cheese ripened in brine in the Middle East in terms of consumed quantities. This study was performed to investigate the impact of the microbiological quality of the used raw materials, the applied traditional processing techniques and ripening period on the quality and safety of the produced cheese. Three hundred random composite samples were collected from three factories at Fayoum Governorate, Egypt. Collected samples represent twenty-five each of: raw milk, table salt, calf rennet, microbial rennet, water, environmental air, whey, fresh cheese, ripened cheese & swabs from: worker hands; cheese molds and utensils; tanks. All samples were examined microbiologically for Standard Plate Count (SPC), coliforms count, Staphylococcus aureus (S. aureus) count, total yeast & mould count, presence of E. coli, Salmonellae and Listeria monocytogenes (L. monocytogenes). The mean value of SPC, coliforms, S. aureus and total yeast & mould counts ranged from (79×102 CFU/m3 for air to 13×108 CFU/g for fresh cheese), (7×102 MPN/ cm2 for tank swabs to 80×106 MPN/ml for raw milk), (9×102 CFU/g for salt to 69×106 CFU/g for fresh cheese) and (2×102 CFU/cm2 for hand swabs to 60×104 CFU/g for fresh cheese), respectively. Whereas, E. coli, Salmonella and L. monocytogenes failed to be detected in all examined samples. There were significant differences in all determined microbiological parameters (p ≤0.05) between fresh and ripened cheese which may be attributed to different adverse conditions such as water activity, pH, salt content and temperature carried out to improve the quality of the product.

scholarly journals Comparison of the ColiPlate™ Kit with Two Common E. coli Enumeration Methods for Water

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1804
Author(s):  
Cassi J. Gibson ◽  
Abraham K. Maritim ◽  
Jason W. Marion
Keyword(s):  
High Risk ◽  
Natural Water ◽  
Membrane Filtration ◽  
Fecal Contamination ◽  
Reference Method ◽  
World Health ◽  
Risk Levels ◽  
E Coli ◽  
Field Samples ◽  
Very High

Quantitatively assessing fecal indicator bacteria in drinking water from limited resource settings (e.g., disasters, remote areas) can inform public health strategies for reducing waterborne illnesses. This study aimed to compare two common approaches for quantifying Escherichia coli (E. coli) density in natural water versus the ColiPlate™ kit approach. For comparing methods, 41 field samples from natural water sources in Kentucky (USA) were collected. E. coli densities were then determined by (1) membrane filtration in conjunction with modified membrane-thermotolerant E. coli (mTEC) agar, (2) Idexx Quanti-Tray® 2000 with the Colilert® substrate, and (3) the Bluewater Biosciences ColiPlate kit. Significant correlations were observed between E. coli density data for all three methods (p < 0.001). Paired t-test results showed no difference in E. coli densities determined by all the methods (p > 0.05). Upon assigning modified mTEC as the reference method for determining the World Health Organization-assigned “very high-risk” levels of fecal contamination (> 100 E. coli CFU/100 mL), both ColiPlate and Colilert exhibited excellent discrimination for screening very high-risk levels according to the area under the receiver operating characteristic curve (~89%). These data suggest ColiPlate continues to be an effective monitoring tool for quantifying E. coli density and characterizing fecal contamination risks from water.

scholarly journals Applicability and performance of EUCAST’s rapid antimicrobial susceptibility testing (RAST) on primarily sterile body fluids in blood culture bottles in laboratory routine with total lab automation

2021 ◽  
Author(s):  
Jasmin Kaur Jasuja ◽  
Stefan Zimmermann ◽  
Irene Burckhardt
Keyword(s):  
Blood Culture ◽  
Susceptibility Testing ◽  
Reference Method ◽  
Body Fluids ◽  
E Coli ◽  
Mueller Hinton ◽  
Mueller Hinton Agar ◽  
And Performance ◽  
Sterile Body Fluids ◽  
Better Than

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.

scholarly journals Dosimetric Properties of the Newly Developed LiF:Mg,Cu,Si TL Material

2012 ◽  
Vol 5 (1) ◽  
pp. 25-31 ◽  
Author(s):  
M. S. Rahman ◽  
J. I. Lee ◽  
J. L. Kim ◽  
G. Cho
Keyword(s):  
Dose Response ◽  
Linear Response ◽  
Detection Threshold ◽  
Atomic Energy ◽  
Energy Response ◽  
Energy Research ◽  
Higher Doses ◽  
Research Institute

The dosimetric properties of the newly developed thermoluminescence (TL) material (LiF:Mg,Cu,Si) at Korea Atomic Energy Research Institute (KAERI) were investigated. The energy response of the detector was performed for photon energies from 20 to 662 keV. The dose response for this TL material (LiF:Mg,Cu,Si) was linear up to 10 Gy and a sub-linear response was observed for higher doses. The reusability of this newly developed TL detector sufficiently satisfied IEC standards. Detection threshold of LiF:Mg,Cu,Si TL material was investigated and found to be 930 nGy by Harshaw 4500 TLD reader. © 2013 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: http://dx.doi.org/10.3329/jsr.v5i1.11935        J. Sci. Res. 5 (1), 25-31  (2013) 

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