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Sharma R, Verma A, Shinde N, Mann B, Gandhi K, Wichers JH, van Amerongen A. Adulteration of cow's milk with buffalo's milk detected by an on-site carbon nanoparticles-based lateral flow immunoassay. Food Chem 2021; 351:129311. [PMID: 33636533 DOI: 10.1016/j.foodchem.2021.129311] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 12/26/2020] [Accepted: 02/04/2021] [Indexed: 01/10/2023]
Abstract
A competitive lateral flow immunoassay using amorphous carbon nanoparticles (CNPs) and non-immunoglobulin antigen has been developed for the rapid detection of adulteration of cow's milk with buffalo's milk. Purified polyclonal antibodies against a specific buffalo's milk protein fraction were conjugated to CNPs and sprayed on a conjugate pad. The test line consisted of buffalo's skimmed milk proteins (1.6 μg/cm), while the control line contained anti-rabbit antibodies raised in goat (0.5 μg/cm). In the test procedure milk sample is mixed with 100 mM borate buffer (pH 8.8 containing 1% BSA and 0.05% Tween 20) and pipetted onto the sample-cum-conjugate pad. A black/grey test line can be observed if the sample is free from buffalo's milk. The sensitivity of the test i.e. no visible test line is 5% adulteration of cow's milk with buffalo's milk. The test has applicability at the milk receiving stations and can be applied to heated milk samples.
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Affiliation(s)
- Rajan Sharma
- Dairy Chemistry Division, ICAR-National Dairy Research Institute, Karnal 132 001, India.
| | - Archana Verma
- Animal Genetics & Breeding Division, ICAR-National Dairy Research Institute, Karnal 132 001, India
| | - Nitin Shinde
- Dairy Chemistry Division, ICAR-National Dairy Research Institute, Karnal 132 001, India
| | - Bimlesh Mann
- Dairy Chemistry Division, ICAR-National Dairy Research Institute, Karnal 132 001, India
| | - Kamal Gandhi
- Dairy Chemistry Division, ICAR-National Dairy Research Institute, Karnal 132 001, India
| | - Jan H Wichers
- BioSensing & Diagnostics, Wageningen Food & Biobased Research, Wageningen University & Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands.
| | - Aart van Amerongen
- BioSensing & Diagnostics, Wageningen Food & Biobased Research, Wageningen University & Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands.
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van Overbeek LS, Wichers JH, van Amerongen A, van Roermund HJW, van der Zouwen P, Willemsen PTJ. Circulation of Shiga Toxin-Producing Escherichia coli Phylogenetic Group B1 Strains Between Calve Stable Manure and Pasture Land With Grazing Heifers. Front Microbiol 2020; 11:1355. [PMID: 32714297 PMCID: PMC7340143 DOI: 10.3389/fmicb.2020.01355] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 05/27/2020] [Indexed: 12/31/2022] Open
Abstract
Escherichia coli strains carrying Shiga toxins 1 and 2 (stx1 and stx2), intimin (eae), and hemolysin (ehxA) production genes were found in grass shoot, rhizosphere soil, and stable manure samples from a small-scale cattle farm located at the center of Netherlands, using cultivation-dependent and -independent microbiological detection techniques. Pasture land with grazing heifers in the first year of sampling in 2014 and without grazing cattle in 2015 was physically separated from the stable that housed rose calves during both years. Manure from the stable was applied to pasture via injection into soil once per year in early spring. Among a variety of 35 phylogenetic distinctly related E. coli strains, one large group consisting of 21 closely resembling E. coli O150:H2 (18), O98:H21 (2), and O84:H2 (1) strains, all belonging to phylogenetic group B1 and carrying all screened virulence traits, was found present on grass shoots (10), rhizosphere soil (3), and stable manure (8) in 2014, but not anymore in 2015 when grazing heifers were absent. Presence and absence of these strains, obtained via enrichments, were confirmed via molecular detection using PCR-NALFIA in all ecosystems in both years. We propose that this group of Shiga toxin-producing E. coli phylogenetic group B1 strains was originally introduced via stable manure injection into the pasture. Upon grazing, these potential pathogens proliferated in the intestinal track systems of the heifers resulting in defecation with higher loads of the STEC strain onto the grass cover. The STEC strain was further smeared over the field via the hooves of the heifers resulting in augmentation of the potential pathogen in the pasture in 2014, whereas in 2015, in the absence of heifers, no augmentation occurred and only a more diverse group of potentially mild virulent E. coli phylogenetic group A and B1 strains, indigenous to pasture plants, remained present. Via this model, it was postulated that human pathogens can circulate between plants and farm animals, using the plant as an alternative ecosystem. These data indicate that grazed pasture must be considered as a potential carrier of human pathogenic E. coli strains and possibly also of other pathogens.
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Affiliation(s)
- Leonard S van Overbeek
- Wageningen University and Research (WUR), Wageningen Research (WR), Wageningen, Netherlands
| | - Jan H Wichers
- Wageningen University and Research (WUR), Wageningen Research (WR), Wageningen, Netherlands
| | - Aart van Amerongen
- Wageningen University and Research (WUR), Wageningen Research (WR), Wageningen, Netherlands
| | | | | | - Peter T J Willemsen
- Wageningen University and Research (WUR), Wageningen Research (WR), Wageningen, Netherlands
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Capps KL, McLaughlin EM, Murray AWA, Aldus CF, Wyatt GM, Peck MW, Van Amerongen A, Ariëns RMC, Wichers JH, Baylis CL, Wareing DRA, Bolton FJ, Aird H, Allen R, Anderson P, Boughtflower M, Chen Q, Davies A, Dennis J, Gibson SJ, Green RA, Hilton J, Jorgensen F, Leuschner R, Loder C, Mackey B, Meldrum R, Millar I, Reid T, Robinson AJ, Robinson; I, Smith H, Surman S, Vickers D, Wood M. Validation of Three Rapid Screening Methods for Detection of Verotoxin-Producing Escherichia coli in Foods: Interlaboratory Study. J AOAC Int 2019. [DOI: 10.1093/jaoac/87.1.68] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
An interlaboratory study was conducted for the validation of 3 methods for the detection of all verotoxin-producing Escherichia coli (VTEC) in foods. The methods were a multi-analyte 1-step lateral flow immunoassay (LFIA) for detection of E. coli O157 and verotoxin (VT); an enzyme-linked immunosorbent assay targeted against VT1, VT2, and VT2c (VT-ELISA); and a polymerase chain reaction (PCR) method for detection of VT genes (VT-PCR). Aliquots (25 g or 25 mL) of 4 food types (raw minced [ground] beef, unpasteurized milk, unpasteurized apple juice [cider], and salami) were individually inoculated with low numbers (<9 to 375 cells/25 g) of 6 test strains of E. coli (serogroups O26, O103, O111, O145, and O157) with differing VT-producing capabilities. Five replicates for each test strain and 5 uninoculated samples were prepared for each food type. Fourteen participating laboratories analyzed samples using the LFIA, 9 analyzed the samples by ELISA, and 9 by PCR. The LFIA for O157 and VT had a specificity (correct identification of negative samples) of 92 and 94%, respectively, and a sensitivity (correct identification of positive samples) of 94 and 55%, respectively. The VT-ELISA and VT-PCR
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Affiliation(s)
- Katherine L Capps
- Central Science Laboratory, Sand Hutton, York, North Yorkshire, YO41 1LZ, United Kingdom
| | - Emiline M McLaughlin
- Central Science Laboratory, Sand Hutton, York, North Yorkshire, YO41 1LZ, United Kingdom
| | - Alistair W A Murray
- Central Science Laboratory, Sand Hutton, York, North Yorkshire, YO41 1LZ, United Kingdom
| | - Clare F Aldus
- Institute of Food Research, Norwich Research Park, Colney, Norwich, NR4 7UA, United Kingdom
| | - Gary M Wyatt
- Institute of Food Research, Norwich Research Park, Colney, Norwich, NR4 7UA, United Kingdom
| | - Michael W Peck
- Institute of Food Research, Norwich Research Park, Colney, Norwich, NR4 7UA, United Kingdom
| | - Aart Van Amerongen
- Agrotechnology and Food Innovations A&F B.V., Bornsesteeg 59, 6708 PD Wageningen, The Netherlands
| | - Renata M C Ariëns
- Agrotechnology and Food Innovations A&F B.V., Bornsesteeg 59, 6708 PD Wageningen, The Netherlands
| | - Jan H Wichers
- Agrotechnology and Food Innovations A&F B.V., Bornsesteeg 59, 6708 PD Wageningen, The Netherlands
| | - Christopher L Baylis
- Campden & Chorleywood Food Research Association, Chipping Campden, Gloucestershire, GL55 6LD, United Kingdom
| | - David R A Wareing
- Preston Public Health Laboratory, Royal Preston Hospital, PO Box 202, Sharoe Green LN, Fulwood, Preston, Lancashire, PR2 9HG, United Kingdom
| | - Frederick J Bolton
- Preston Public Health Laboratory, Royal Preston Hospital, PO Box 202, Sharoe Green LN, Fulwood, Preston, Lancashire, PR2 9HG, United Kingdom
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Ross GMS, Bremer MGEG, Wichers JH, van Amerongen A, Nielen MWF. Rapid Antibody Selection Using Surface Plasmon Resonance for High-Speed and Sensitive Hazelnut Lateral Flow Prototypes. Biosensors (Basel) 2018; 8:E130. [PMID: 30558252 PMCID: PMC6316566 DOI: 10.3390/bios8040130] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 12/06/2018] [Accepted: 12/12/2018] [Indexed: 12/20/2022]
Abstract
Lateral Flow Immunoassays (LFIAs) allow for rapid, low-cost, screening of many biomolecules such as food allergens. Despite being classified as rapid tests, many LFIAs take 10⁻20 min to complete. For a really high-speed LFIA, it is necessary to assess antibody association kinetics. By using a label-free optical technique such as Surface Plasmon Resonance (SPR), it is possible to screen crude monoclonal antibody (mAb) preparations for their association rates against a target. Herein, we describe an SPR-based method for screening and selecting crude anti-hazelnut antibodies based on their relative association rates, cross reactivity and sandwich pairing capabilities, for subsequent application in a rapid ligand binding assay. Thanks to the SPR selection process, only the fast mAb (F-50-6B12) and the slow (S-50-5H9) mAb needed purification for labelling with carbon nanoparticles to exploit high-speed LFIA prototypes. The kinetics observed in SPR were reflected in LFIA, with the test line appearing within 30 s, almost two times faster when F-50-6B12 was used, compared with S-50-5H9. Additionally, the LFIAs have demonstrated their future applicability to real life samples by detecting hazelnut in the sub-ppm range in a cookie matrix. Finally, these LFIAs not only provide a qualitative result when read visually, but also generate semi-quantitative data when exploiting freely downloadable smartphone apps.
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Affiliation(s)
- Georgina M S Ross
- RIKILT, Wageningen University & Research. P.O Box 230, 6700 AE Wageningen, The Netherlands.
| | - Maria G E G Bremer
- RIKILT, Wageningen University & Research. P.O Box 230, 6700 AE Wageningen, The Netherlands.
| | - Jan H Wichers
- Wageningen Food & Biobased Research, BioSensing & Diagnostics, Wageningen University & Research, P.O Box 17, 6700 AA, Wageningen, The Netherlands.
| | - Aart van Amerongen
- Wageningen Food & Biobased Research, BioSensing & Diagnostics, Wageningen University & Research, P.O Box 17, 6700 AA, Wageningen, The Netherlands.
| | - Michel W F Nielen
- RIKILT, Wageningen University & Research. P.O Box 230, 6700 AE Wageningen, The Netherlands.
- Wageningen University, Laboratory of Organic Chemistry, Helix Building 124, Stippeneng 4. 6708 WE Wageningen, The Netherlands.
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van Overbeek LS, van Doorn J, Wichers JH, van Amerongen A, van Roermund HJW, Willemsen PTJ. The arable ecosystem as battleground for emergence of new human pathogens. Front Microbiol 2014; 5:104. [PMID: 24688484 PMCID: PMC3960585 DOI: 10.3389/fmicb.2014.00104] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 02/27/2014] [Indexed: 01/10/2023] Open
Abstract
Disease incidences related to Escherichia coli and Salmonella enterica infections by consumption of (fresh) vegetables, sprouts, and occasionally fruits made clear that these pathogens are not only transmitted to humans via the "classical" routes of meat, eggs, and dairy products, but also can be transmitted to humans via plants or products derived from plants. Nowadays, it is of major concern that these human pathogens, especially the ones belonging to the taxonomical family of Enterobacteriaceae, become adapted to environmental habitats without losing their virulence to humans. Adaptation to the plant environment would lead to longer persistence in plants, increasing their chances on transmission to humans via consumption of plant-derived food. One of the mechanisms of adaptation to the plant environment in human pathogens, proposed in this paper, is horizontal transfer of genes from different microbial communities present in the arable ecosystem, like the ones originating from soil, animal digestive track systems (manure), water and plants themselves. Genes that would confer better adaptation to the phytosphere might be genes involved in plant colonization, stress resistance and nutrient acquisition and utilization. Because human pathogenic enterics often were prone to genetic exchanges via phages and conjugative plasmids, it was postulated that these genetic elements may be hold key responsible for horizontal gene transfers between human pathogens and indigenous microbes in agroproduction systems. In analogy to zoonosis, we coin the term phytonosis for a human pathogen that is transmitted via plants and not exclusively via animals.
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Affiliation(s)
- Leonard S van Overbeek
- Plant Research International, Wageningen University and Research Centre Wageningen, Netherlands
| | - Joop van Doorn
- Applied Plant Research, Wageningen University and Research Centre Lisse, Netherlands
| | - Jan H Wichers
- Food and Biobased Research, Wageningen University and Research Centre Wageningen, Netherlands
| | - Aart van Amerongen
- Food and Biobased Research, Wageningen University and Research Centre Wageningen, Netherlands
| | - Herman J W van Roermund
- Central Veterinary Institute, Wageningen University and Research Centre Lelystad, Netherlands
| | - Peter T J Willemsen
- Central Veterinary Institute, Wageningen University and Research Centre Lelystad, Netherlands
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Posthuma-Trumpie GA, Wichers JH, Koets M, Berendsen LBJM, van Amerongen A. Amorphous carbon nanoparticles: a versatile label for rapid diagnostic (immuno)assays. Anal Bioanal Chem 2012; 402:593-600. [PMID: 21904801 PMCID: PMC3249172 DOI: 10.1007/s00216-011-5340-5] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 08/13/2011] [Accepted: 08/15/2011] [Indexed: 12/16/2022]
Abstract
Carbon nanoparticles (CNPs) labeled with reporter molecules can serve as signaling labels in rapid diagnostic assays as an alternative to gold, colored latex, silica, quantum dots, or up-converting phosphor nanoparticles. Detailed here is the preparation of biomolecule-labeled CNPs and examples of their use as a versatile label. CNPs can be loaded with a range of biomolecules, such as DNA, antibodies, and proteins (e.g., neutravidin or a fusion protein of neutravidin with an enzyme), and the resulting conjugates can be used to detect analytes of high or low molecular mass.
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Affiliation(s)
| | - Jan H. Wichers
- Food and Biobased Research, Wageningen University and Research Centre, P.O. Box 17, 6700 AA Wageningen, The Netherlands
| | - Marjo Koets
- Food and Biobased Research, Wageningen University and Research Centre, P.O. Box 17, 6700 AA Wageningen, The Netherlands
| | - Luciënne B. J. M. Berendsen
- Food and Biobased Research, Wageningen University and Research Centre, P.O. Box 17, 6700 AA Wageningen, The Netherlands
| | - Aart van Amerongen
- Food and Biobased Research, Wageningen University and Research Centre, P.O. Box 17, 6700 AA Wageningen, The Netherlands
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van Dam GJ, Wichers JH, Ferreira TMF, Ghati D, van Amerongen A, Deelder AM. Diagnosis of schistosomiasis by reagent strip test for detection of circulating cathodic antigen. J Clin Microbiol 2004; 42:5458-61. [PMID: 15583265 PMCID: PMC535219 DOI: 10.1128/jcm.42.12.5458-5461.2004] [Citation(s) in RCA: 182] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2004] [Revised: 05/07/2004] [Accepted: 06/24/2004] [Indexed: 11/20/2022] Open
Abstract
A newly developed reagent strip assay for the diagnosis of schistosomiasis based on parasite antigen detection in urine of infected individuals was evaluated. The test uses the principle of lateral flow through a nitrocellulose strip of the sample mixed with a colloidal carbon conjugate of a monoclonal antibody specific for Schistosoma circulating cathodic antigen (CCA). The strip assay to diagnose a group of highly infected schoolchildren in Mwanza, Tanzania, demonstrated a high sensitivity and association with the intensity of infection as measured both by egg counts, and by circulating anodic antigen and CCA levels determined by enzyme-linked immunosorbent assay. A specificity of ca. 90% was shown in a group of schistosome-negative schoolchildren from Tarime, Tanzania, an area where schistosomiasis is not endemic. The test is easy to perform and requires no technical equipment or special training. The stability of the strips and the conjugate in the dry format lasts for at least 3 months at ambient temperature in sealed packages, making it suitable for transport and use in areas where schistosomiasis is endemic. This assay can easily be developed to an end-user format.
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Affiliation(s)
- G J van Dam
- Department of Parasitology, Leiden University Medical Center, P.O. Box 9600, 2300 RC, Leiden, The Netherlands.
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Capps KL, McLaughlin EM, Murray AWA, Aldus CF, Wyatt GM, Peck MW, van Amerongen A, Ariëns RMC, Wichers JH, Baylis CL, Wareing DRA, Bolton FJ. Validation of three rapid screening methods for detection of verotoxin-producing Escherichia coli in foods: interlaboratory study. J AOAC Int 2004; 87:68-77. [PMID: 15084089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
An interlaboratory study was conducted for the validation of 3 methods for the detection of all verotoxin-producing Escherichia coli (VTEC) in foods. The methods were a multi-analyte 1-step lateral flow immunoassay (LFIA) for detection of E. coli O157 and verotoxin (VT); an enzyme-linked immunosorbent assay targeted against VT1, VT2, and VT2c (VT-ELISA); and a polymerase chain reaction (PCR) method for detection of VT genes (VT-PCR). Aliquots (25 g or 25 mL) of 4 food types (raw minced [ground] beef, unpasteurized milk, unpasteurized apple juice [cider], and salami) were individually inoculated with low numbers (<9 to 375 cells/25 g) of 6 test strains of E. coli (serogroups O26, O103, O111, O145, and O157) with differing VT-producing capabilities. Five replicates for each test strain and 5 uninoculated samples were prepared for each food type. Fourteen participating laboratories analyzed samples using the LFIA, 9 analyzed the samples by ELISA, and 9 by PCR. The LFIA for O157 and VT had a specificity (correct identification of negative samples) of 92 and 94%, respectively, and a sensitivity (correct identification of positive samples) of 94 and 55%, respectively. The VT-ELISA and VT-PCR had a specificity of 98 and 99%, respectively, and a sensitivity of 89 and 72%, respectively.
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Affiliation(s)
- Katherine L Capps
- Central Science Laboratory, Sand Hutton, York, North Yorkshire, YO41 1LZ, United Kingdom
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Aldus CF, Van Amerongen A, Ariëns RMC, Peck MW, Wichers JH, Wyatt GM. Principles of some novel rapid dipstick methods for detection and characterization of verotoxigenic Escherichia coli. J Appl Microbiol 2003; 95:380-9. [PMID: 12859772 DOI: 10.1046/j.1365-2672.2003.01989.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS The verotoxigenic Escherichia coli (VTEC) serotype most commonly associated with verotoxin (VT) production is O157:H7, but other serotypes have also been implicated in food-borne illness. These serotypes exhibit much greater genetic and biochemical diversity than E. coli O157:H7, making screening for all VTEC difficult. Here we describe development and testing of novel multi-analyte antibody-based dipstick methods for presumptive detection of VTEC cells and VTs, including non-O157 serotypes. METHODS AND RESULTS The dipsticks are formatted as paddle-style and lateral flow devices. Test materials included raw milk, minced beef, apple juice and salami, spiked with VTEC. Prototype paddle dipsticks gave 47 of 48 E. coli O157-positive samples correct, and, simultaneously, 27 of 31 O26-positive samples correct, across the four food types. Prototype lateral flow dipsticks gave 12 of 12 E. coli O157-positive milk samples correct and, simultaneously, 28 of 28 positive VT samples correct. CONCLUSIONS This work demonstrates that simple and rapid detection of more than one VTEC characteristic (toxin production and type, serogroup) is possible in a single dipstick test device, directly from a food enrichment culture. SIGNIFICANCE AND IMPACT OF THE STUDY The development of simple easy-to-use rapid methods for simultaneous detection and preliminary characterization of VTEC will enable the risk presented by all VTEC to be more thoroughly assessed (e.g. in surveillance studies, outbreak investigations).
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Affiliation(s)
- C F Aldus
- Institute of Food Research, Norwich Research Park, Norwich, NR4 7UA, UK
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van Amerongen A, van Loon D, Berendsen LB, Wichers JH. Quantitative computer image analysis of a human chorionic gonadotropin colloidal carbon dipstick assay. Clin Chim Acta 1994; 229:67-75. [PMID: 7988056 DOI: 10.1016/0009-8981(94)90229-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Colloidal particles are widely used in qualitative dipstick assays for the determination of various proteins and haptens. Recently, a new colloidal label has been introduced based on elemental carbon. With this carbon label we have prepared a human chorionic gonadotropin-specific dipstick assay with a sensitivity of 10 mIU/ml. In addition, an image- and data-processing procedure for the quantification of the dipstick assay has been developed. The sum of the pixel grey levels of a carbon line was taken as a measure for this quantitative purpose. The measurement range of the assay is almost three orders of magnitude, i.e. 10 mIU/ml to 500 mIU/ml. The deviation from the mean of two dipstick determinations was 1.22% on average. The within-run and between-run precision, expressed as coefficients of variation at 50 mIU/ml were 1.03% and 1.84%, at 150 mIU/ml 2.14% and 3.77% and at 450 mIU/ml 2.55% and 5.28%, respectively. We have correlated this quantitative sol particle immunoassay with a commercial human chorionic gonadotropin specific radioimmunoassay. In an experiment with 25 human urine samples containing the hormone in amounts from 5 to 300 mIU/ml the correlation coefficient was 0.999. The sol particle immunoassay quantified by computer image analysis has been termed Sol particle Image Processed ImmunoAssay (SIPIA).
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Affiliation(s)
- A van Amerongen
- Agrotechnological Research Institute (ATO-DLO), Wageningen, The Netherlands
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van Amerongen A, Wichers JH, Berendsen LB, Timmermans AJ, Keizer GD, van Doorn AW, Bantjes A, van Gelder WM. Colloidal carbon particles as a new label for rapid immunochemical test methods: quantitative computer image analysis of results. J Biotechnol 1993; 30:185-95. [PMID: 7690572 DOI: 10.1016/0168-1656(93)90112-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Colloidal carbon particles can serve as label in sol particle immunoassays. The universal applicability of these particles in qualitative and (semi)quantitative immunoassays has been demonstrated. Sol particle and/or dipstick immunoassays, not yet optimized in terms of sensitivity, are discussed. The colloidal label has been used successfully in a mouse immunoglobulin isotyping kit. Human serum albumin spotted onto nitrocellulose in a concentration range of 7.8 to 1000 ng could be detected using anti-albumin antibody absorbed onto colloidal carbon particles. It was also possible to perform a competitive assay with this conjugate for a concentration range of free human serum albumin varying from 0.25 to 6.75 micrograms. The Kunitz-type trypsin inhibitor from soybean was determined by a colloidal carbon based immunoassay in a range of 2.5 to 160 ng. In this assay, free and colloidal carbon-bound inhibitor competed for binding specific antibodies spotted onto a nitrocellulose membrane. An image- and data-processing procedure has been developed that enables a rapid and simple quantification of colloidal carbon sol particle immunoassays. The average grey level of a spot is taken as a measure for quantitative purposes. This so-called Sol-particle Image Processed ImmunoAssay (SIPIA) procedure is equally well applicable to assays using other colloidal particles.
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Affiliation(s)
- A van Amerongen
- Agrotechnological Research Institute ATO-DLO, Wageningen, The Netherlands
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