Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Monitoring the Quality of Perishable Foods: Opportunities for Intelligent Packaging
    Heising, J.K. ; Dekker, M. ; Bartels, P.V. ; Boekel, M.A.J.S. van - \ 2014
    Critical Reviews in Food Science and Nutrition 54 (2014)5. - ISSN 1040-8398 - p. 645 - 654.
    time-temperature integrators - free fatty-acids - shelf-life - spoilage bacteria - fish spoilage - milk - products - sensor - indicators - biosensor
    This review paper discusses opportunities for intelligent packaging for monitoring directly or indirectly quality attributes of perishable packaged foods. The possible roles of intelligent packaging as a tool in supply chain management are discussed as well as the barriers to implement this kind of technology in commercial applications. Cases on pasteurized milk and fresh cod fillets illustrate the application of different intelligent packaging concepts to monitor and estimate quality attributes. Conditions influencing quality (e.g., temperature-time) can be monitored to predict the quality of perishable products when the initial quality is known and rather constant (e.g., pasteurized milk). Products with a highly variable initial quality (e.g., fresh fish) require sensors monitoring compounds correlated with quality.
    A capture approach for supercoiled plasmid DNA using a triplex-forming oligonucleotide
    Ruigrok, V.J.B. ; Westra, E.R. ; Brouns, S.J.J. ; Escudé, C. ; Smidt, H. ; Oost, J. van der - \ 2013
    Nucleic acids research 41 (2013)10. - ISSN 0305-1048
    lac repressor - padlock oligonucleotides - helix formation - sequence - binding - protein - replication - operators - association - biosensor
    Proteins that recognize and bind specific sites in DNA are essential for regulation of numerous biological functions. Such proteins often require a negative supercoiled DNA topology to function correctly. In current research, short linear DNA is often used to study DNA-protein interactions. Although linear DNA can easily be modified, for capture on a surface, its relaxed topology does not accurately resemble the natural situation in which DNA is generally negatively supercoiled. Moreover, specific binding sequences are flanked by large stretches of non-target sequence in vivo. Here, we present a straightforward method for capturing negatively supercoiled plasmid DNA on a streptavidin surface. It relies on the formation of a temporary parallel triplex, using a triple helix forming oligonucleotide containing locked nucleic acid nucleotides. All materials required for this method are commercially available. Lac repressor binding to its operator was used as model system. Although the dissociation constants for both the linear and plasmid-based operator are in the range of 4 nM, the association and dissociation rates of Lac repressor binding to the plasmid-based operator are ~18 times slower than on a linear fragment. This difference underscores the importance of using a physiologically relevant DNA topology for studying DNA-protein interactions
    Development of an immunochromatographic assay based on carbon nanoparticles for the determination of the phytoregulator forchlorfenuron
    Suaréz-Pantaleón, C. ; Wichers, J.H. ; Abad-Somovilla, A. ; Amerongen, A. van - \ 2013
    Biosensors and Bioelectronics 42 (2013). - ISSN 0956-5663 - p. 170 - 176.
    lateral flow immunoassay - antibody-based immunoassay - computer image-analysis - rapid detection - sensitive detection - dipstick assay - water samples - strip test - validation - biosensor
    Rapid analytical methods enabling the determination of diverse targets are essential in a number of research areas, from clinical diagnostics to feed and food quality and safety. Herein, the development of a quantitative immunochromatographic assay for the detection of the synthetic phytoregulator forchlorfenuron (CPPU) is described. The competitive lateral flow immunoassay (LFIA) was based on the immobilization onto a nitrocellulose membrane of an ovalbumin–CPPU conjugate (test line) and on the use of an immunodetection ligand consisting of carbon nanoparticles labeled with an anti-CPPU monoclonal antibody through interaction with a secondary antibody. The presence of CPPU in horticultural samples was visually interpreted by the decrease in the black signal intensity of the test line, according to the competitive character of the format. The quantitative determination of the analyte was easily performed by a two-step procedure consisting of flatbed scanning of the strips followed by computer-based image analysis of the pixel gray volumes of the test lines. Under optimized conditions, the immunochromatographic test afforded a limit of quantification in buffer of 89 ng/L. The accuracy of the strip test was assessed by the analysis of fruit samples with incurred residues, and the obtained results were compared with those derived from two reference methods, ELISA and HPLC. The LOQ of the CPPU-specific LFIA in kiwifruits and grapes was established at 33.4 µg/kg. The excellent analytical performance of the developed strip test demonstrates the potential of immunochromatographic assays for the quantitative monitoring of small organic molecules in complex matrices.
    Development of surface plasmon resonance-based sensor for detection of silver nanoparticles in food and the environment
    Rebe-Raz, S. ; Leontaridou, M. ; Bremer, M.G.E.G. ; Peters, R.J.B. ; Weigel, S. - \ 2012
    Analytical and Bioanalytical Chemistry 403 (2012)10. - ISSN 1618-2642 - p. 2843 - 2850.
    heavy-metals - metallothionein - immobilization - biosensor - ions - nanosilver - proteins
    Silver nanoparticles are recognized as effective antimicrobial agents and have been implemented in various consumer products including washing machines, refrigerators, clothing, medical devices, and food packaging. Alongside the silver nanoparticles benefits, their novel properties have raised concerns about possible adverse effects on biological systems. To protect consumer’s health and the environment, efficient monitoring of silver nanoparticles needs to be established. Here, we present the development of human metallothionein (MT) based surface plasmon resonance (SPR) sensor for rapid detection of nanosilver. Incorporation of human metallothionein 1A to the sensor surface enables screening for potentially biologically active silver nanoparticles at parts per billion sensitivity. Other protein ligands were also tested for binding capacity of the nanosilver and were found to be inferior to the metallothionein. The biosensor has been characterized in terms of selectivity and sensitivity towards different types of silver nanoparticles and applied in measurements of real-life samples—such as fresh vegetables and river water. Our findings suggest that human MT1-based SPR sensor has the potential to be utilized as a routine screening method for silver nanoparticles, that can provide rapid and automated analysis dedicated to environmental and food safety monitoring.
    A non-destructive ammonium detection method as indicator for freshness for packed fish: Application on cod
    Heising, J.K. ; Dekker, M. ; Bartels, P.V. ; Boekel, M.A.J.S. van - \ 2012
    Journal of Food Engineering 110 (2012)2. - ISSN 0260-8774 - p. 254 - 261.
    gadus-morhua - quality - trimethylamine - spoilage - biosensor - fillets - sensor
    This paper introduces a non-destructive method for monitoring headspace ammonium as an indicator for changes in the freshness status of packed fish. Electrodes in an aqueous phase in the package monitor changes in the concentration of ammonia produced in/on the packed fish and released in the headspace. The outputs of an ammonium ion-selective electrode (NH4+-ISE) were compared with the volatile amines content of the fish fillets. The method was tested in triplicate with fresh cod fillets stored between -0.5 and 1.9 °C. Changes in the ammonia content of the fish could be monitored in the aqueous phase with the NH4+-ISE. The changes in the NH4+-ISE signal correlated with the content of volatile amines (TVB-N) in the cod fillets. This non-destructive method might be the basis for the development of an intelligent packaging for monitoring freshness of packed fish.
    Multiplex bioanalytical methods for food and environmental monitoreing
    Rebe, S. ; Haasnoot, W. - \ 2011
    TrAC : Trends in Analytical Chemistry 30 (2011)9. - ISSN 0165-9936 - p. 1526 - 1537.
    surface-plasmon resonance - escherichia-coli o157-h7 - beta-lactam antibiotics - salmonella-typhimurium - suspension array - rapid detection - quantum dots - biosensor - bacteria - milk
    Recent advances in miniaturization of analytical systems and newly emerging technologies offer platforms with greater automation and multiplexing capabilities than traditional biological binding assays. Multiplexed bioanalytical techniques provide control agencies and food industries with new possibilities for improved, more efficient monitoring of food and environmental contaminants. This review deals with recent developments in planar-array and suspension-array technologies, and their applications in detecting pathogens, food allergens and adulterants, toxins, antibiotics and environmental contaminants.
    Volatile organic compounds as a diagnostic marker of late blight infected potato plants: A pilot study
    Laothawornkitkul, J. ; Jansen, R.M.C. ; Smid, H.M. ; Bouwmeester, H.J. ; Muller, J. ; Bruggen, A.H.C. van - \ 2010
    Crop Protection 29 (2010)8. - ISSN 0261-2194 - p. 872 - 878.
    phytophthora-infestans - botrytis-cinerea - damaged plants - in-vitro - tomato - leaves - lipoxygenase - emissions - variability - biosensor
    Volatiles from potato plants infected with Phytophthora infestans (Mont.) de Bary were monitored by in situ headspace sampling. The sampling was done in four periods i.e. 28–42, 52–66, 76–90, and 100–114 h after inoculation (HAI). The headspace samples were analyzed by a gas chromatography–flame ionization detector (GC–FID) to assess the differences in volatile fingerprints between the infected-plant group and control groups, i.e. non-inoculated-plant and empty-vessel groups. The samples were subsequently analyzed by gas chromatography–mass spectrometry to identify specific peaks observed by GC–FID. Spore germination, infection, symptom development and sporulation were also monitored to ascertain the disease developmental stage when marker volatiles were first generated. The first symptoms of infection were visible after two days. Three marker volatiles i.e. (E)-2-hexenal, 5-ethyl-2(5H)-furanone and benzene-ethanol were found in the third and fourth trapping periods (3–4 days after inoculation) when sporangiophores were already formed. The volatile metabolites from blighted plants could be applied for sensor development to detect the occurrence of the disease in the field as well as for investigation of volatile production in relation to plant responses to infection.
    Development of a novel and automated fluorescent immunoassay for the analysis of beta-lactam antibiotics
    Benito-Pena, E. ; Moreno-Bondi, M.C. ; Orellana, G. ; Maquieira, K. ; Amerongen, A. van - \ 2005
    Journal of Agricultural and Food Chemistry 53 (2005)17. - ISSN 0021-8561 - p. 6635 - 6642.
    linked-immunosorbent-assay - solid-phase extraction - enzyme-immunoassay - penicillin antibiotics - monoclonal-antibodies - immunoanalysis system - liquid-chromatography - milk - water - biosensor
    An automated immunosensor for the rapid and sensitive analysis of penicillin type -lactam antibiotics has been developed and optimized. An immunogen was prepared by coupling the common structure of the penicillanic -lactam antibiotics, i.e., 6-aminopenicillanic acid to keyhole limpet hemocyanin. Polyclonal antibodies raised in rabbits after immunization with this conjugate have been applied for the development of a competitive fluoroimmunoassay (FIA), using a novel fluorescent penicillin {[2S,5R,6R]-3,3-dimethyl-7-oxo-6-[(pyren-1ylacetyl)amino]-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxilic acid, PAAP} as the tracer and penicillin G as the reference antibiotic. Protein A/G covalently bound to an azlactone-activated polymeric support was used for the orientated capture of the antibody-antigen immunocomplexes. Upon desorption from the immunosupport, the emission signal generated by the PAAP-Ab complexes is related to the antibiotic concentration in the sample. The 50% binding inhibition concentration of penicillin G standard curves was at 30 ng mL-1 with a detection limit (10% binding inhibition) of 2.4 ng mL-1 and a dynamic range from 6.0 to 191 ng mL-1 (20-80% binding inhibition) penicillin G. The generic nature of the antiserum was shown by good relative cross-reactivities with penicillin type -lactam antibiotics such as amoxicillin (50%), ampicillin (47%), and penicillin V (145%) and a lower response to the isoxazolyl penicillins such as oxacillin, cloxacillin, and dicloxacillin. No cross-reactivity was obtained for cephalosporin type -lactam antibiotics (cephapirin), cloramphenicol, or fluoroquinolones (enrofloxacin and ciprofloxacin). The total analysis time was 23 min per determination, and the immunoreactor could be reused for more than 200 cycles without significant loss of activity. The immunosensor has been successfully applied to the direct analysis of penicillin G and amoxicillin in spiked influent and effluent sewage treatment plant water samples with excellent recoveries (mean values for penicillin G and amoxicillin, 99 and 105%, respectively). Results displayed by comparative analysis of the immunosensor with a chromatographic procedure for penicillins showed excellent agreement between both methods
    Detection and traceability of genetically modified organisms in the food production chain
    Miraglia, M. ; Berdal, K.G. ; Brera, C. ; Corbisier, P. ; Holst - Jensen, A. ; Kok, E.J. ; Marvin, H.J.P. ; Schimmel, H. ; Rentsch, J. ; Rie, J.P.P.F. van; Zagon, J. - \ 2004
    Food and Chemical Toxicology 42 (2004)7. - ISSN 0278-6915 - p. 1157 - 1180.
    modified maize - dna - pcr - quantification - technology - quantitation - biosensor - gene - probes - gmos
    Both labelling and traceability of genetically modified organisms are current issues that are considered in trade and regulation. Currently, labelling of genetically modified foods containing detectable transgenic material is required by EU legislation. A proposed package of legislation would extend this labelling to foods without any traces of transgenics. These new legislations would also impose labelling and a traceability system based on documentation throughout the food and feed manufacture system. The regulatory issues of risk analysis and labelling are currently harmonised by Codex Alimentarius. The implementation and maintenance of the regulations necessitates sampling protocols and analytical methodologies that allow for accurate determination of the content of genetically modified organisms within a food and feed sample. Current methodologies for the analysis of genetically modified organisms are focused on either one of two targets, the transgenic DNA inserted- or the novel protein(s) expressed- in a genetically modified product. For most DNA-based detection methods, the polymerase chain reaction is employed. Items that need consideration in the use of DNA-based detection methods include the specificity, sensitivity, matrix effects, internal reference DNA, availability of external reference materials, hemizygosity versus homozygosity, extrachromosomal DNA, and international harmonisation. For most protein-based methods, enzyme-linked immunosorbent assays with antibodies binding the novel protein are employed. Consideration should be given to the selection of the antigen bound by the antibody, accuracy, validation, and matrix effects. Currently, validation of detection methods for analysis of genetically modified organisms is taking place. In addition, new methodologies are developed, including the use of microarrays, mass spectrometry, and surface plasmon resonance. Challenges for GMO detection include the detection of transgenic material in materials with varying chromosome numbers. The existing and proposed regulatory EU requirements for traceability of genetically modified products fit within a broader tendency towards traceability of foods in general and, commercially, towards products that can be distinguished from each other. Traceability systems document the history of a product and may serve the purpose of both marketing and health protection. In this framework, segregation and identity preservation systems allow for the separation of genetically modified and non-modified products from "farm to fork". Implementation of these systems comes with specific technical requirements for each particular step of the food processing chain. In addition, the feasibility of traceability systems depends on a number of factors, including unique identifiers for each genetically modified product, detection methods, permissible levels of contamination, and financial costs. In conclusion, progress has been achieved in the field of sampling, detection, and traceability of genetically modified products, while some issues remain to be solved. For success, much will depend on the threshold level for adventitious contamination set by legislation.
    Minimally Invasive Technique Based on Ultraslow Ultrafiltration To Collect and Store Time Profiles of Analytes
    Savenije, B. ; Venema, H. ; Lambooij, E. ; Gerritzen, M.A. ; Korf, J. - \ 2003
    Analytical Chemistry 75 (2003)17. - ISSN 0003-2700 - p. 4397 - 4401.
    in-vivo - sampling probes - microdialysis - glucose - lactate - device - biosensor - rats - separation
    A device is described to collect and store continuously time profiles of analytes over periods of 24 h suitable to sample freely moving individuals (humans and animals). The device consists of a hollow fiber ultrafiltration probe, a long capillary and a nonmechanical unit (a disposable medical syringe) driven by vacuum to withdraw fluid. The principle is that at low rates (100 nL/min), sample fluid is collected through the ultrafiltration probe into the capillary. A time resolution of less than 5 min over a 24-h collection and storage period was achieved for lactate and glucose. To illustrate an in vivo application, devices were fixed under the wing of freely moving broiler chickens, with subcutaneous or intravenous probe placements. The device can be produced as a disposable, and it may become applied for ex vivo and in vitro monitoring
    Covalently Attached Saccharides on Silicon Surfaces
    Smet, L.C.P.M. de; Stork, G.A. ; Hurenkamp, G.H.F. ; Qiao-Yu, S. ; Topal, H. ; Vronen, P.J.E. ; Sieval, A.B. ; Wright, A. ; Visser, G.M. ; Zuilhof, H. ; Sudhölter, E.J.R. - \ 2003
    Journal of the American Chemical Society 125 (2003). - ISSN 0002-7863 - p. 13916 - 13917.
    hydrogen-terminated silicon - alkyl monolayers - si(111) surface - dna - hybridization - chemistry - biosensor - 1-alkenes - acid
    This paper presents the first functionalization of silicon surfaces with well-defined, covalently attached monolayers containing saccharides. Two methods were used to this aim: a thermal method (refluxing in mesitylene) and a recently developed, extremely mild photochemical method (irradiation with 447 nm at room temperature). The results were analyzed by FT-IR and angle-resolved X-ray photoelectron spectroscopy. The use of a two-dimensional detector in ARXPS allows for unparalleled, subnanometer resolution in the determination of the elemental composition of monolayers. Even for monolayers with a total thickness of only ~1.5 nm, a clear elemental depth profile can be obtained. Such analyses display for sialic acid-containing monolayers that the mild photochemical attachment does not destroy the (rather fragile) sialic acid moiety and that the sugar is present at the top of the monolayer and thus available for biological interactions.
    Direct versus competitive biosensor immunoassays for the detection of (dihydro)streptomycin residues in milk
    Haasnoot, W. ; Loomans, E.E.M.G. ; Cazemier, G. ; Dietrich, R. ; Verheijen, R. ; Bergwerff, A.A. ; Stephany, R.W. - \ 2002
    Food and Agricultural Immunology 14 (2002). - ISSN 0954-0105 - p. 15 - 27.
    surface plasmon resonance - dihydrostreptomycin - streptomycin - biosensor - immunoassy - milk - biosensor
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