Publications (85) View all
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Article: Monitoring phytoplankton and marine biotoxins in production waters of the Netherlands: results after one decade
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ABSTRACT: Shellfish products may be contaminated with marine biotoxins which, after consumption, may lead to human illness. The Netherlands has a regular monitoring programme for marine biotoxins and the possible toxic phytoplankton in shellfish production waters. The aim of the current study was to evaluate the presence of potential toxic phytoplankton species and marine biotoxins in Dutch production waters over the last decade, and to analyse the relationship between toxin levels and abundance of possible causative phytoplankton species. The results of the monitoring programme of the period 1999–2009 were used. The presence of Alexandrium spp. were negligible, but Pseudo-nitzschia spp. and phytoplankton causing diarrhetic shellfish poisoning (DSP toxin-producing phytoplankton) were present in nearly all three main production areas and years. The main DSP toxin-producing species was Dinophysis acuminata followed by D. rotundata and Prorocentrum lima. Toxins causing paralytic shellfish poisoning (PSP) and amnesic shellfish poisoning (ASP) were present in only a few individual shellfish samples, all at low levels. At the end of 2002, an episode of DSP toxicity was recorded, based on the rat bioassay results. Of the samples that were chemically analysed for DSP toxins in 2007 and 2008, about half of the samples in 2007 contained these toxins, although levels were low and no positive results were obtained using the rat bioassay. There was a slight positive correlation between concentrations of DSP toxin-producing phytoplankton and levels of DSP toxins in 2007. Increased DSP toxin levels were found up to 5 weeks after the peak in DSP toxin-producing phytoplankton. This positive, but weak, relationship needs to be confirmed in future research using more samples and chemical methods to quantify the presence of DSP toxins. If this relationship is further substantiated and quantified, it could be used within the current monitoring programme in the Netherlands to predict the risk areas regarding DSP toxicity in shellfish.Food Additives & Contaminants: Part A. 10/2012; 29(10):1616-1629. -
Article: Validation and transferability study of a method based on near-infrared hyperspectral imaging for the detection and quantification of ergot bodies in cereals.
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ABSTRACT: In recent years, near-infrared (NIR) hyperspectral imaging has proved its suitability for quality and safety control in the cereal sector by allowing spectroscopic images to be collected at single-kernel level, which is of great interest to cereal control laboratories. Contaminants in cereals include, inter alia, impurities such as straw, grains from other crops, and insects, as well as undesirable substances such as ergot (sclerotium of Claviceps purpurea). For the cereal sector, the presence of ergot creates a high toxicity risk for animals and humans because of its alkaloid content. A study was undertaken, in which a complete procedure for detecting ergot bodies in cereals was developed, based on their NIR spectral characteristics. These were used to build relevant decision rules based on chemometric tools and on the morphological information obtained from the NIR images. The study sought to transfer this procedure from a pilot online NIR hyperspectral imaging system at laboratory level to a NIR hyperspectral imaging system at industrial level and to validate the latter. All the analyses performed showed that the results obtained using both NIR hyperspectral imaging cameras were quite stable and repeatable. In addition, a correlation higher than 0.94 was obtained between the predicted values obtained by NIR hyperspectral imaging and those supplied by the stereo-microscopic method which is the reference method. The validation of the transferred protocol on blind samples showed that the method could identify and quantify ergot contamination, demonstrating the transferability of the method. These results were obtained on samples with an ergot concentration of 0.02 % which is less than the EC limit for cereals (intervention grains) destined for humans fixed at 0.05 %.Analytical and Bioanalytical Chemistry 02/2013; · 3.78 Impact Factor -
Article: Type-B trichothecene calibrants: Comparison of HPLC and GC-results within an intercomparison study.
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ABSTRACT: Within the EC-financed project "Feasibility Study for the Production of Certified Calibrants for the Determination of Deoxynivalenol and other B-Trichothecenes", an intercomparison study was performed with 13 European participants.Main goals of the intercomparison study were to check the feasibility of a small batch of gravimetrically prepared calibrants, to directly compare common and individually prepared calibrants, to test the practicability of toxin mixtures as calibrant solutions and finally to give recommendations for the means of certification. Additionally, it focused on the comparison of gas chromatography (GC) and high performance liquid chromatography (HPLC) for the determination of pure type-B trichothecene solutions, which is described in this publication.The participating laboratories received calibrant solutions as well as toxin solutions of unknown concentration and employed mainly HPLC-UV; GC-ECD (electron capture detection) and GC-MS (mass spectrometry) methods were used less often.The intercomparison study generally suffered from a high rate of outliers (22% of all the data). Throughout the study, 48% of all GC results were classified as outliers and it soon became apparent, that GC results highly infuenced the outcome of the study and that the used GC methods were not robust enough for the certification of type-B trichothecene calibrants. The high discrepancy between HPLC and GC results in the intercomparison study presumably lies in the crucial step of derivatisation.Mycotoxin Research 12/2005; 21(4):224-30. -
Article: DON calibrant: Towards the production of certified B-trichothecene calibrants.
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ABSTRACT: Within an EC-funded project calibrants with certified concentrations of Deoxynivalenol (DON), 3-Acetyl-Deoxynivalenol (3-Ac-DON), 15-Acetyl-Deoxynivalenol (15-Ac-DON) and Nivalenol (NIV) in acetonitrile have been produced. So far the project has led to improved isolation and purification of the solid toxins fromFusarium cultures. In addition, conditions for the production, ampouling and transport of the toxin solutions have been optimised. Further investigations should lead to knowledge about storage conditions and internationally accepted molar absorption coefficients for DON, 3-Ac-DON, 15-Ac-DON and NIV in acetonitrile. The intercomparison study which is currently carried out will also help to support knowledge and experience exchange between laboratories in the field ofFusarium mycotoxin analysis.Mycotoxin Research 03/2005; 21(1):7-10. -
Article: Morbillivirus in monk seal mass mortality.
Nature 09/1997; 388(6645):838-9. · 36.28 Impact Factor
