ColiComplete® Substrate-Supporting Disc Method for Confirmed Detection of Total Coliforms and Escherichia coli in All Foods: Comparative Study

Feldsine, Philip T; Falbo-Nelson, Maria T; Hustead, David L

doi:10.1093/jaoac/77.1.58

Cited by 7 publications

(3 citation statements)

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“…For the presence of the Total Coliform and Escherichia coli in the Greek yogurt sample, the AOAC Total Coliform and Escherichia coli in All Foods, Substrate Supporting Disc Method was used [ 36 ]. Individual product units were diluted 10 −1 by homogenizing 50 g of product with 450 mL of BPO 4 buffer (Fisher Scientific).…”

Section: Methodsmentioning

confidence: 99%

Molecular Identification of Isolated Fungi from Unopened Containers of Greek Yogurt by DNA Sequencing of Internal Transcribed Spacer Region

et al. 2014

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In our previous study, we described the development of an internal transcribed spacer (ITS)1 sequencing method, and used this protocol in species-identification of isolated fungi collected from the manufacturing areas of a compounding company known to have caused the multistate fungal meningitis outbreak in the United States. In this follow-up study, we have analyzed the unopened vials of Greek yogurt from the recalled batch to determine the possible cause of microbial contamination in the product. A total of 15 unopened vials of Greek yogurt belonging to the recalled batch were examined for the detection of fungi in these samples known to cause foodborne illness following conventional microbiological protocols. Fungi were isolated from all of the 15 Greek yogurt samples analyzed. The isolated fungi were genetically typed by DNA sequencing of PCR-amplified ITS1 region of rRNA gene. Analysis of data confirmed all of the isolated fungal isolates from the Greek yogurt to be Rhizomucor variabilis. The generated ITS1 sequences matched 100% with the published sequences available in GenBank. In addition, these yogurt samples were also tested for the presence of five types of bacteria (Salmonella, Listeria, Staphylococcus, Bacillus and Escherichia coli) causing foodborne disease in humans, and found negative for all of them.

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Section: Methodsmentioning

confidence: 99%

Molecular Identification of Isolated Fungi from Unopened Containers of Greek Yogurt by DNA Sequencing of Internal Transcribed Spacer Region

et al. 2014

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“…Bacteria concentration is a time‐consuming procedure in regular microbiology laboratory practices that involves cell‐culturing processes to obtain a significant sample. This could be improved by using DEP as a means of concentration in tiny fluidic spaces.…”

Section: Introductionmentioning

confidence: 99%

Combined dielectrophoretic and impedance system for on‐chip controlled bacteria concentration: Application to Escherichia coli

et al. 2015

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Abbreviations: Impedance analysis (IA), escherichia coli (E. coli), digital lock-in (DLIA), analog-to-digital converter (ADC), finite element method (FEM). 2 AbstractThe present paper reports a bacteria autonomous controlled concentrator prototype with a userfriendly interface for bench-top applications. It is based on a micro-fluidic lab-on-a-chip and its associated custom instrumentation, which consists in a dielectrophoretic actuator, to preconcentrate the sample, and an impedance analyser, to measure concentrated bacteria levels.The system is composed by a single micro-fluidic chamber with interdigitated electrodes and custom electronics instrumentation. The prototype is supported by a real-time platform connected to a remote computer which automatically controls the system and displays impedance data which is used to monitor bacteria accumulation status on-chip. The system automates the whole concentrating operation. Performance has been studied for controlled volumes of Escherichia Coli (E. coli) samples injected into the micro-fluidic chip at constant flow rate of 10 µl/min. A media conductivity correcting protocol has been developed, as so as the preliminary results shown the distortion of impedance analyser measurement produced by bacterial media conductivity variations through time. With the correcting protocol, the measured impedance values were related to the quantity of bacteria concentrated with a correlation of 0.988 and a coefficient of variation of 3.1%. Feasibility of E. coli on-chip automated concentration, using the miniaturized system, has been demonstrated and impedance monitoring protocol adjusted and optimized, to handle electrical properties changes of the bacteria media over time.3

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“…The objective of our work is to apply a modification to classical interdigitated electrodes DEP setups in order to improve cell concentration for biological bench‐top applications. A device based on a large number of interdigitated metal electrodes placed in a microfluidic channel has been used to concentrate bacteria and other biological entities in a number of publications . Multiple electrode shapes have been used to better control electric field gradients .…”

Section: Introductionmentioning

confidence: 99%

Dielectrophoretic concentrator enhancement based on dielectric poles for continuously flowing samples

et al. 2015

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We describe a novel continuous-flow cell concentrator microdevice based on dielectrophoresis, and its associated custom-made control unit. The performances of a classical interdigitated metal electrode-based dielectrophoresis microfluidic device and this enhanced version, that includes insulator-based pole structures, were compared using the same setup. Escherichia coli samples were concentrated at several continuous flows and the device's trapping efficiencies were evaluated by exhaustive cell counts. Our results show that pole structures enhance the retention up to 12.6%, obtaining significant differences for flow rates up to 20 μL/min, when compared to an equivalent classical interdigitated electrodes setup. In addition, we performed a subsequent proteomic analysis to evaluate the viability of the biological samples after the long exposure to the actuating electrical field. No Escherichia coli protein alteration in any of the two systems was observed.

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ColiComplete® Substrate-Supporting Disc Method for Confirmed Detection of Total Coliforms and Escherichia coli in All Foods: Comparative Study

Cited by 7 publications

References 0 publications

Molecular Identification of Isolated Fungi from Unopened Containers of Greek Yogurt by DNA Sequencing of Internal Transcribed Spacer Region

Molecular Identification of Isolated Fungi from Unopened Containers of Greek Yogurt by DNA Sequencing of Internal Transcribed Spacer Region

Combined dielectrophoretic and impedance system for on‐chip controlled bacteria concentration: Application to Escherichia coli

Dielectrophoretic concentrator enhancement based on dielectric poles for continuously flowing samples

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