RAPID ISOLATION AND DETECTION OF <i>ESCHERICHIA COLI</i> O157:H7 IN FRESH PRODUCE

Prentice, Nicole; Murray, John S.; Scott, Michael F.; Coombs, Jana; Parton, A.

doi:10.1111/j.1745-4581.2006.00069.x

Cited by 17 publications

(10 citation statements)

References 5 publications

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“…The beads might be combined with an au- tomated recirculating immunomagnetic capture system, similar to the AOAC-validated method currently in use for pooling and concentrating Escherichia coli O157:H7, Salmonella spp., or Listeria spp. (Prentice et al, 2006).…”

Section: Discussionmentioning

confidence: 95%

“…Compared to antibodies, CBD beads have similar equilibrium constants, but offer the advantage of in vitro production thus not relying on the use of laboratory animals (Loessner et al, 2002). Bead-based separation protocols are fast, are easy to perform, and have the inherent option of automation (Prentice et al, 2006). As a prerequisite for further developments, the suitability of these beads for separation of L. monocytogenes directly from raw milk rather than from the enrichment broth was thoroughly assessed in the present study.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of Paramagnetic Beads Coated with RecombinantListeriaPhage Endolysin–Derived Cell-Wall-Binding Domain Proteins for Separation ofListeria monocytogenesfrom Raw Milk in Combination with Culture-Based and Real-Time Polymerase Chain Reaction–Based Quantification

Walcher

Stessl

Wagner

et al. 2010

Foodborne Pathogens and Disease

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The aim of this study was to evaluate a fast and simple bead-based method using paramagnetic beads covered with recombinant Listeria phage endolysin-derived cell-wall-binding domain proteins specific for Listeria spp. for separation of the foodborne pathogen Listeria monocytogenes from artificially contaminated raw milk. The method was combined with subsequent detection and quantification by the traditional plate-count technique and real-time polymerase chain reaction (PCR). To account for differences in cell properties, recovery rates and the detection limit were determined using five different L. monocytogenes strains for preparation of a 10-fold dilution series in raw milk, spanning an 8-log scale. Two independent test series were performed for each strain, yielding mean recovery rates of 46.6% to 122.8% for detection with the plate-count method, and 64.7% to 95.1% for detection by real-time PCR. A high correlation was found between the number of L. monocytogenes added to the samples and the number of colony forming units recovered by plate count (0.980), as well as the number of bacterial cell equivalents obtained by real-time quantitative PCR (0.987). The detection limit of the combined cell-wall-binding domain proteins/real-time PCR approach ranged from 10(2) to 10(3) colony forming units per milliliter, which is close to the theoretical detection limit of the method.

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Section: Discussionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Evaluation of Paramagnetic Beads Coated with RecombinantListeriaPhage Endolysin–Derived Cell-Wall-Binding Domain Proteins for Separation ofListeria monocytogenesfrom Raw Milk in Combination with Culture-Based and Real-Time Polymerase Chain Reaction–Based Quantification

Walcher

Stessl

Wagner

et al. 2010

Foodborne Pathogens and Disease

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“…Therefore, it was not considered a false positive when a positive BAX result could not be confirmed. The use of immunomagnetic separation as a method of sample cleanup improves confiimation and PCR detection (10,13). BPW + n enrichment had two less Salmonella-positive BAX results (trial 1, irrigation water, 30°C) than TT enrichments.…”

Section: Detection Of Salmonella By Fda Bammentioning

confidence: 99%

Evaluation of PCR Detection of Salmonella in Alfalfa Sprouts and Spent Irrigation Water Collected during Sprouting of Naturally Contaminated Seed

Maks

2013

Journal of Food Protection

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This study evaluated the efficacy of a PCR-based system (DuPont Qualicon BAX) for detection of Salmonella in sprouts and spent irrigation water collected during sprouting of seeds naturally contaminated with Salmonella. Alfalfa seeds were grown in Mason jars at 20 and 30°C for 3 days. Levels of Salmonella present in the water and sprouts were determined by most-probable-number (MPN) analysis. Background microflora levels were also determined. Samples of spent irrigation water and sprouts were enriched overnight individually in tetrathionate broth and in buffered peptone water with novobiocin at 42°C and then run in the BAX system. Samples were also enriched according to the U.S. Food and Drug Administration's Bacteriological Analytical Manual (FDA BAM) method for Salmonella as a comparison. Salmonella levels were lower at 20°C compared with 30°C for some trials, and background microflora levels ranged from 10(7) to 10(8) CFU/g or ml at 20°C and 10(8) to 10(9) CFU/g or ml at 30°C. In trials with a Salmonella level >1.1 MPN/g or ml, both the BAX and FDA BAM methods were able to detect Salmonella in all samples. In trials with lower levels (0.21 MPN/g or ml or lower) of Salmonella, BAX was able to detect more positive samples than FDA BAM. For one trial with <0.003 MPN/g or ml of Salmonella, the presence of the pathogen was not indicated by either the BAX or the FDA BAM method. The results suggest that PCR detected low levels of Salmonella in sprouts or spent irrigation water collected from sprouting of naturally contaminated seeds.

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“…Various studies have attempted to reduce nonspecific binding to IMS beads by a variety of techniques. Prentice and others (2006) found that a 1 : 10 of dilution of produce enrichment broths with fresh media coupled with using Pathatrix beads that had been preblocked with skim milk for IMS improved isolation of E. coli O 157:H7 on TC‐SMAC by reducing the number of background organisms on the plates. Lau and others (2006) modified the FDA BAM procedure for isolation of E. coli O157:H7 from artificially contaminated lettuce and found that many mucoid types of microorganisms bound to the E. coli O157:H7 paramagnetic beads interfered with isolation of the inoculated organisms on TC‐SMAC agar.…”

Section: Resultsmentioning

confidence: 99%

Detection and Isolation of Low Levels of E. coli O157:H7 in Cilantro by Real‐Time PCR, Immunomagnetic Separation, and Cultural Methods with and without an Acid Treatment

Yoshitomi¹,

Jinneman²,

Zapata³

et al. 2012

Journal of Food Science

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Detection and recovery of Escherichia coli O157:H7 in fresh produce matrices (e.g., cilantro) can be complicated by high background microflora present in these foods. Rapid detection by molecular methods combined with effective enrichment and isolation procedures such as using immunomagnetic separation (IMS) techniques can quickly identify potential hazards to public health. Additional techniques such as acidification of enrichment broths can exploit acid resistance characteristics of pathogens such as E. coli O157:H7, facilitating their isolation in complex food matrices.

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RAPID ISOLATION AND DETECTION OF ESCHERICHIA COLI O157:H7 IN FRESH PRODUCE

Cited by 17 publications

References 5 publications

Evaluation of Paramagnetic Beads Coated with RecombinantListeriaPhage Endolysin–Derived Cell-Wall-Binding Domain Proteins for Separation ofListeria monocytogenesfrom Raw Milk in Combination with Culture-Based and Real-Time Polymerase Chain Reaction–Based Quantification

Evaluation of Paramagnetic Beads Coated with RecombinantListeriaPhage Endolysin–Derived Cell-Wall-Binding Domain Proteins for Separation ofListeria monocytogenesfrom Raw Milk in Combination with Culture-Based and Real-Time Polymerase Chain Reaction–Based Quantification

Evaluation of PCR Detection of Salmonella in Alfalfa Sprouts and Spent Irrigation Water Collected during Sprouting of Naturally Contaminated Seed

Detection and Isolation of Low Levels of E. coli O157:H7 in Cilantro by Real‐Time PCR, Immunomagnetic Separation, and Cultural Methods with and without an Acid Treatment

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