Wageningen, Netherlands
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Barros E.,South African Council for Scientific and Industrial Research | Lezar S.,South African Council for Scientific and Industrial Research | Anttonen M.J.,University of Eastern Finland | Van Dijk J.P.,RIKILT Institute of Food Safety | And 3 more authors.
Plant Biotechnology Journal | Year: 2010

The aim of this study was to evaluate the use of four nontargeted analytical methodologies in the detection of unintended effects that could be derived during genetic manipulation of crops. Three profiling technologies were used to compare the transcriptome, proteome and metabolome of two transgenic maize lines with the respective control line. By comparing the profiles of the two transgenic lines grown in the same location over three growing seasons, we could determine the extent of environmental variation, while the comparison with the control maize line allowed the investigation of effects caused by a difference in genotype. The effect of growing conditions as an additional environmental effect was also evaluated by comparing the Bt-maize line with the control line from plants grown in three different locations in one growing season. The environment was shown to play an important effect in the protein, gene expression and metabolite levels of the maize samples tested where 5 proteins, 65 genes and 15 metabolites were found to be differentially expressed. A distinct separation between the three growing seasons was also found for all the samples grown in one location. Together, these environmental factors caused more variation in the different transcript/protein/metabolite profiles than the different genotypes. © 2010 Blackwell Publishing Ltd.


Meneely J.P.,Queen's University of Belfast | Ricci F.,University of Rome Tor Vergata | van Egmond H.P.,RIKILT Institute of Food Safety | Elliott C.T.,Queen's University of Belfast
TrAC - Trends in Analytical Chemistry | Year: 2011

This article describes the trends in analytical techniques for the determination of trichothecene mycotoxins, namely deoxynivalenol, and T-2 and HT-2 toxins in cereals and cereal products with particular emphasis on screening and rapid approaches. The driving force behind the changing methodologies is mainly attributed to legislative demands. However, for commercial and governmental testing laboratories, the need to use validated official methods is ever increasing to ensure quality assurance of results. Much research has been undertaken to improve screening assays, highlighted by the number of new methods using a variety of formats and platforms, including optical and electrochemical biosensors. Significant advances in the traditional reference methods have also been demonstrated in addition to the emergence of a variety of commercial immunoaffinity and solid-phase extraction columns for clean up. The use of liquid chromatography coupled to tandem mass spectrometry for mycotoxin detection is ever increasing, allowing simultaneous determination of many toxins in various sample matrices. © 2010 Elsevier Ltd.


Nielen M.W.F.,RIKILT Institute of Food Safety | Nielen M.W.F.,Wageningen University | Hooijerink H.,RIKILT Institute of Food Safety | Zomer P.,RIKILT Institute of Food Safety | Mol J.G.J.,RIKILT Institute of Food Safety
TrAC - Trends in Analytical Chemistry | Year: 2011

Since its introduction, desorption electrospray ionization (DESI) mass spectrometry (MS) has been mainly applied in pharmaceutical and forensic analysis. We expect that DESI will find its way in many different fields, including food analysis. In this review, we summarize DESI developments aimed at controlling chemical contaminants in food. Data are given for analysis of pesticides, natural toxins, veterinary drugs, food additives, adulteration, packaging migrants, and for applications of food forensics. We discuss practical aspects of DESI, including its strengths and weaknesses, highlighting specific features of performing chemical reactions during the desorption/ionization process in order to enhance sensitivity and selectivity.Finally, we discuss the position of DESI with respect to current food-analysis regulation and legislation. We envisage that DESI can be a rapid, qualitative or semi-quantitative, screening tool, ultimately being applied on site prior to sampling and transport of samples to food-control laboratories. © 2010 Elsevier Ltd.


Hollman P.C.H.,Wageningen University | Hollman P.C.H.,RIKILT Institute of Food Safety | Geelen A.,Wageningen University | Kromhout D.,Wageningen University
Journal of Nutrition | Year: 2010

Flavonols are strong antioxidants in plant foods and tea is a major dietary source. There is evidence from prospective cohort studies that tea and flavonols are inversely related to stroke incidence. We conducted a metaanalysis of prospective cohort studies to assess quantitatively the strength of the association between flavonol intake and stroke incidence. Prospective cohort studies with data from individuals free of cardiovascular diseases (CVD) or stroke at baseline were included in the metaanalysis. Persons were followed for between 6 and 28 y. Data from 6 cohorts involving 111,067 persons with at least 2155 nonfatal and fatal cases were pooled. A random effects model was used. In all studies included, adjustments were made for major CVD risk factors except for 2 that did not adjust for alcohol and energy intake. A high intake of flavonols compared with a low intake was inversely associated with nonfatal and fatal stroke with a pooled relative risk of 0.80 (95% CI: 0.65, 0.98). Visual inspection of Begg's funnel plot and Egger's test (P = 0.01) indicated potential publication bias. We conclude that flavonols may reduce stroke risk. © 2010 American Society for Nutrition.


Stolker A.A.M.,RIKILT Institute of Food Safety | Peters R.J.B.,RIKILT Institute of Food Safety | Zuiderent R.,Thermo Fisher Scientific | Dibussolo J.M.,West Chester University | Martins C.P.B.,Thermo Fisher Scientific
Analytical and Bioanalytical Chemistry | Year: 2010

There is an increasing interest in screening methods for quick and sensitive analysis of various classes of veterinary drugs with limited sample pre-treatment. Turbulent flow chromatography in combination with tandem mass spectrometry has been applied for the first time as an efficient screening method in routine analysis of milk samples. Eight veterinary drugs, belonging to seven different classes were selected for this study. After developing and optimising the method, parameters such as linearity, repeatability, matrix effects and carry-over were studied. The screening method was then tested in the routine analysis of 12 raw milk samples. Even without internal standards, the linearity of the method was found to be good in the concentration range of 50 to 500 μg/L. Regarding repeatability, RSDs below 12% were obtained for all analytes, with only a few exceptions. The limits of detection were between 0.1 and 5.2 μg/L, far below the maximum residue levels for milk set by the EU regulations. While matrix effects-ion suppression or enhancement-are obtained for all the analytes the method has proved to be useful for screening purposes because of its sensitivity, linearity and repeatability. Furthermore, when performing the routine analysis of the raw milk samples, no false positive or negative results were obtained. © 2010 The Author(s).


Lommen A.,RIKILT Institute of Food Safety
Methods in Molecular Biology | Year: 2012

This paper gives a step-by-step account of how to install, set up, and run MetAlign software, which can be downloaded freely ( http://www.metalign.wur.nl/ UK/Download+and+publications ). The software is used for accurate mass and nominal mass data coming from different kinds of GC-MS and LC-MS platforms. The algorithms are beyond the scope of this paper and were published separately. © 2011 Springer Science+Business Media, LLC.


Luque N.,Institute of Fine Chemistry and Nanochemistry | Ballesteros-Gomez A.,Institute of Fine Chemistry and Nanochemistry | van Leeuwen S.,RIKILT Institute of Food Safety | Rubio S.,Institute of Fine Chemistry and Nanochemistry
Journal of Chromatography A | Year: 2012

In this work, we propose a microextraction method based on a new supramolecular solvent (SUPRAS) made up of reverse aggregates of hexanoic acid, combined with liquid chromatography/triple quadrupole mass spectrometry (LC/QQQ MS-MS) for the determination of the perfluoroalkyl substances (PFASs) in blood serum. A SUPRAS is a nano-structured liquid made up of surfactant aggregates synthesized through a self-assembly process. The method involved the acidification of 765μL of blood serum (600μmol of hydrochloric acid per mL of serum) followed by the addition of hexanoic acid (97μL) and tetrahydrofuran (THF) (600μL), conditions under which the supramolecular solvent (∼360μL) formed in situ after vortex-shaking and centrifugation. Parameters affecting extraction efficiency and concentration factors were studied. The overall sample treatment took only 20min and several samples (20-30) can be simultaneously analyzed using conventional lab equipments, making additional investments unnecessary. Recoveries for the internal standards in samples ranged from 75 to 89% with relative standard deviations between 1 and 15%. Calibration was based on the use of internal standards. The method was very sensitive with detection limits ranging from 2 to 20pgmL -1 for PFASs. The approach developed was successfully applied to the determination of PFASs in different blood serum samples. The concentration of PFASs found in samples of animal origin ranged between 17 and 197.3pgmL -1 and between 84 and 5168pgmL -1 in samples of human origin. Both the analytical and operational features of this method make it suitable for the evaluation of exposure to PFASs. © 2012 Elsevier B.V.


Keijer J.,Wageningen University | Bekkenkamp-Grovenstein M.,Wageningen University | Venema D.,RIKILT Institute of Food Safety | Dommels Y.E.M.,RIKILT Institute of Food Safety
Biochimica et Biophysica Acta - Bioenergetics | Year: 2011

Cancer cells are resistant to apoptosis and show a shift in energy production from mitochondrial oxidative phosphorylation to cytosolic glycolysis. Apoptosis resistance and metabolic reprogramming are linked in many cancer cells and both processes center on mitochondria. Clearly, mutated cancer cells escape surveillance and turn into selfish cells. However, many of the mechanisms that operate cellular metabolic control still function in cancer cells. This review describes the metabolic importance of glucose and glutamine, glycolytic enzymes, oxygen, growth cofactors and mitochondria and focuses on the potential role of bioactive food components, including micronutrients. The role of B- and A-vitamin cofactors in (mitochondrial) metabolism is highlighted and the cancer protective potential of omega-3 fatty acids and several polyphenols is discussed in relation to metabolic reprogramming, including the mechanisms that may be involved. Furthermore, it is shown that cancer cell growth reduction by limiting the growth cofactor folic acid seems to be associated with reversal of metabolic reprogramming. Altogether, reversal of metabolic reprogramming may be an attractive strategy to increase susceptibility to apoptotic surveillance. Food bioactive components that affect various aspects of metabolism may be important tools to reverse glycolytic to oxidative metabolism and enhance sensitivity to apoptosis. The success of such a strategy may depend on several actors, acting in concert. Growth cofactors may be one of these, which call for careful (re)evaluation of their function in normal and in cancer metabolism. This article is part of a Special Issue entitled: Bioenergetics of Cancer. © 2010 Elsevier B.V. All rights reserved.


Nielen M.W.F.,RIKILT Institute of Food Safety | Nielen M.W.F.,Wageningen University | Nijrolder A.W.J.M.,RIKILT Institute of Food Safety | Hooijerink H.,RIKILT Institute of Food Safety | Stolker A.A.M.,RIKILT Institute of Food Safety
Analytica Chimica Acta | Year: 2011

Hormone and veterinary drug screening and forensics can benefit from the recent developments in desorption electrospray ionization (DESI) mass spectrometry (MS). In this work the feasibility of DESI application for the rapid screening of intact esters of anabolic steroids in bovine hair has been studied. Using a linear ion trap both full scan and data-dependent collision induced dissociation MSn spectra were acquired in minutes for testosterone cypionate, testosterone decanoate and estradiol benzoate standard solutions deposited on a glass or PTFE surface. However direct analysis of incurred hair failed due to inefficient desorption ionization and the minute quantities of steroid esters present. Therefore a simplified ultrasonic liquid extraction procedure was developed, allowing rapid DESI analysis of a few microliters of the concentrate and a total analysis time of 2-4h per batch instead of 3 days. The potential of this DESI approach is clearly demonstrated by MS3 data from hair samples incurred with high levels (300-800μgkg-1) of steroid esters, levels which do occur in samples from controlled- and illegally treated animals. For much lower levels state-of-the-art ultra high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) screening methods remain the method of choice and might benefit from the proposed simplified extraction as well. © 2010 Elsevier B.V.


Van Leeuwen S.P.J.,VU University Amsterdam | De Boer J.,VU University Amsterdam | Van Leeuwen S.P.J.,RIKILT Institute of Food Safety | Van Bavel B.,Örebro University
TrAC - Trends in Analytical Chemistry | Year: 2013

The first worldwide interlaboratory study on persistent organic pollutants (POPs) under the Stockholm Convention was organized, with a participation of 103 laboratories from Asia, Europe, the Americas, Africa and Australia, of which the majority submitted data on polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). The participating laboratories were requested to analyze different matrices (i.e. two test solutions, and test materials for fish, sediment, fly ash and human milk). All results were statistically evaluated according to the procedures used in the European Union-based QUASIMEME proficiency-testing scheme. © 2013 .

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