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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    Scientific opinion on the proposed amendment of the EU specifications for titanium dioxide (E 171) with respect to the inclusion of additional parameters related to its particle size distribution
    Younes, Maged ; Aquilina, Gabriele ; Castle, Laurence ; Engel, Karl Heinz ; Fowler, Paul ; Frutos Fernandez, Maria Jose ; Gürtler, Rainer ; Gundert-Remy, Ursula ; Husøy, Trine ; Mennes, Wim ; Agneta Oskarsson, Peter Moldeus ; Rainieri, Sandra ; Shah, Romina ; Waalkens-Berendsen, Ine ; Wölfle, Detlef ; Gaffet, Eric ; Mast, Jan ; Peters, Ruud ; Rincon, Ana Maria ; Fürst, Peter - \ 2019
    EFSA Journal 17 (2019)7. - ISSN 1831-4732
    E 171 - food additive - particle size - specifications - Titanium dioxide

    The present opinion deals with the assessment of the data provided by interested business operators in support of an amendment of the EU specifications for titanium dioxide (E 171) with respect to the inclusion of additional parameters related to its particle size distribution. Titanium dioxide which is used as a food additive E 171 in food undergoes no surface treatment and is not coated. It consists of anatase or rutile generally containing small amounts of the other phase (rutile or anatase, < 2% m/m) and it may also contain small quantities (< 0.5%) of constituent particle growth and crystal phase control agents (alumina, sodium or potassium in combination with phosphate). Particle size analyses, by TEM, SEM, XDC or DC, have been carried out on five commercial brands of anatase E 171 and one of rutile E 171 manufactured by the only three EU manufacturers that, according to information submitted by interested business operators, produce food-grade titanium dioxide. Interested business operators proposed to introduce in the EU specifications for E 171 a specification of more than 100 nm for median Feret min diameter and less than 50% of the number of constituent particles below 100 nm; measured by EM in both cases. The Panel, after reviewing the data, concluded that a specification of more than 100 nm for median minimal external dimension, equivalent to less than 50% of the number of constituent particles with a median minimal external dimension below 100 nm, should be inserted in the current EU specifications. The Panel considered that the conclusions made, and the uncertainties identified, in the previous EFSA assessments on E 171 remain valid. The Panel reiterates the need for the further research as recommended in the previous opinions in order to decrease the level of uncertainty and acknowledged that additional studies with characterised E 171 are being carried out by interested business operators.

    Perspective : Fundamental limitations of the randomized controlled trial method in nutritional research: The example of probiotics
    Zeilstra, Dennis ; Younes, Jessica A. ; Brummer, Robert J. ; Kleerebezem, Michiel - \ 2018
    Advances in Nutrition 9 (2018)5. - ISSN 2161-8313 - p. 561 - 571.
    Nutrition - Probiotics - RCT limitations - Study design

    Studies on the relation between health and nutrition are often inconclusive. There are concerns about the validity of many research findings, and methods that can deliver high-quality evidence-such as the randomized controlled trial (RCT) method-have been embraced by nutritional researchers. Unfortunately, many nutritional RCTs also yield ambiguous results. It has been argued that RCTs are ill-suited for certain settings, including nutritional research. In this perspective, we investigate whether there are fundamental limitations of the RCT method in nutritional research. To this end, and to limit the scope, we use probiotic studies as an example. We use an epistemological approach and evaluate the presuppositions that underlie the RCT method. Three general presuppositions are identified and discussed. We evaluate whether these presuppositions can be considered true in probiotic RCTs, which appears not always to be the case. This perspective concludes by exploring several alternative study methods that may be considered for future probiotic or nutritional intervention trials.

    Implementation of PROMETHEUS 4‐step approach for evidence use in EFSA scientific assessments: benefits, issues, needs and solutions
    Aiassa, Elisa ; Martino, Laura ; Barizzone, Fulvio ; Ciccolallo, Laura ; Garcia, Ana ; Georgiadis, Marios ; Guajardo, Irene Muñoz ; Tomcikova, Daniela ; Alexander, Jan ; Calistri, Paolo ; Gundert‐remy, Ursula ; Hart, Andrew David ; Hoogenboom, Ron Laurentius ; Messean, Antoine ; Naska, Androniki ; Navarro, Maria Navajas ; Noerrung, Birgit ; Ockleford, Colin ; Wallace, Robert John ; Younes, Maged ; Abuntori, Blaize ; Alvarez, Fernando ; Aryeetey, Monica ; Baldinelli, Francesca ; Barrucci, Federica ; Bau, Andrea ; Binaglia, Marco ; Broglia, Alessandro ; Castoldi, Anna Federica ; Christoph, Eugen ; Sesmaisons‐Lecarré, Agnes De; Georgiadis, Nikolaos ; Gervelmeyer, Andrea ; Istace, Frederique ; López‐Gálvez, Gloria ; Manini, Paola ; Maurici, Daniela ; Merten, Caroline ; Messens, Winy ; Mosbach‐Schulz, Olaf ; Putzu, Claudio ; Bordajandi, Luisa Ramos ; Smeraldi, Camilla ; Tiramani, Manuela ; Martínez, Silvia Valtueña ; Sybren, Vos ; Hardy, Anthony Richard ; Hugas, Marta ; Kleiner, Juliane ; Seze, Guilhem De - \ 2018
    EFSA Supporting Publications 15 (2018)4. - ISSN 2397-8325
    In 2014, the European Food Safety Authority (EFSA) started the PROMETHEUS (PROmoting METHods for Evidence Use in Scientific assessments) project to improve further and increase the consistency of the methods it uses in its scientific assessments. The project defined a set of principles for the scientific assessment process and a 4‐step approach (plan/carry out/verify/report) for their fulfilment, which was tested in ten case studies, one from each EFSA panel. The present report describes the benefits, issues, needs and solutions related to the implementation of the 4‐step approach in EFSA, identified in a dedicated workshop in October 2017. The key benefits of the approach, which was deemed applicable to all types of EFSA scientific assessment including assessments of regulated products, are: 1) increased ‘scientific value’ of EFSA outputs, i.e. the extent of impartiality, methodological rigour, transparency and engagement; 2) guarantee of fitness‐for‐purpose, as it implies tailoring the methods to the specificities of each assessment; 3) efficiency gain, since preparing a protocol for the assessment upfront helps more streamlined processes throughout the implementation phase; 4) innovation, as the approach promotes the pioneering practice of ‘planning before doing’ (well established in primary research) for broad scientific assessments in regulatory science; and 5) increased harmonisation and consistency of EFSA assessments. The 4‐step approach was also considered an effective system for detecting additional methodological and/or expertise needs and a useful basis for further defining a quality management system for EFSA's scientific processes. The identified issues and solutions related to the implementation of the approach are: a) lack of engagement and need for effective communication on benefits and added value; b) need for further advances especially in the field of problem formulation/protocol development, evidence appraisal and evidence integration; c) need for specialised expertise in the previous aspects; and specific needs for d) assessments of regulated products and e) outsourced projects.
    Deazaflavins as photocatalysts for the direct reductive regeneration of flavoenzymes
    Schie, M.M.C.H. van; Younes, S.H.H. ; Rauch, M.C.R. ; Pesic, M. ; Paul, C.E. ; Arends, I.W.C.E. ; Hollmann, F. - \ 2018
    Molecular Catalysis 452 (2018). - ISSN 2468-8231 - p. 277 - 283.
    Biocatalysis - Flavin - Old yellow enzyme - Oxygen dilemma - Photochemistry
    Deazaflavins are potentially useful redox mediators for the direct, nicotinamide-independent regeneration of oxidoreductases. Especially the O2-stability of their reduced forms have attracted significant interest for the regeneration of monooxygenases. In this contribution we further investigate the photochemical properties of deazaflavins and investigate the scope and limitations of deazaflavin-based photoenzymatic reaction systems.
    General aspects of microbiological food safety : sources of contamination, processes, and health risks
    Schothorst, M. van; Jongeneel, S.E. - \ 1999
    In: International food safety handbook / van der Heijden, K., Younes, M., Fishbein, L., Miller, S., Basel : Marcel Dekker - p. 397 - 408.
    Microbiological and hygienic aspects of food safety
    Schothorst, M. van - \ 1999
    In: International food safety handbook / van der Heijden, K., Younes, M., Fishbein, L., Miller, S., Basel : Marcel Dekker - p. 27 - 46.
    Toxic equivalency factors (TEFs) for PCBs, PCDDs, PCDFs for humans and wildlife
    Berg, M. van den; Birnbaum, L. ; Bosveld, A.T.C. ; Brunstrom, B. ; Cook, P. ; Feeley, M. ; Giesy, J.P. ; Hanberg, A. ; Hasegawa, R. ; Kennedy, S.W. ; Kubiak, T. ; Larsen, J.C. ; Leeuwen, F.X.R. van; Liem, A.K.D. ; Nolt, C. ; Peterson, R.E. ; Poellinger, L. ; Safe, S. ; Schrenk, D. ; Tillitt, D. ; Tysklind, M. ; Younes, M. ; Waern, F. ; Zacharewski, T. - \ 1998
    Environmental Health Perspectives 106 (1998)12. - ISSN 0091-6765 - p. 775 - 792.
    An expert meeting was organized by the World Health Organization (WHO) and held in Stockholm on 15-18 June 1997. The objective of this meeting was to derive consensus toxic equivalency factors (TEFs) for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and dioxinlike polychlorinated biphenyls (PCBs) for both human, fish, and wildlife risk assessment. Based on existing literature data, TEFs were (re)evaluated and either revised (mammals) or established (fish and birds). A few mammalian WHO-TEFs were revised, including 1,2,3,7,8-pentachlorinated DD, octachlorinated DD, octachlorinated DF, and PCB 77. These mammalian TEFs are also considered applicable for humans and wild mammalian species. Furthermore, it was concluded that there was insufficient in viva evidence to continue the use of TEFs for some di-ortho PCBs, as suggested earlier by Ahlborg et al. [Chemosphere 28:1049-1067 (1994)]. In addition, TEFs for fish and birds were determined. The WHO working group attempted to harmonize TEFs across different taxa to the extent possible. However, total synchronization of TEFs was not feasible, as there were orders of a magnitude difference in TEFs between taxa for some compounds. In this respect, the absent or very low response of fish to mono-ortho PCBs is most noticeable compared to mammals and birds. Uncertainties that could compromise the TEF concept were also reviewed, including nonadditive interactions, differences in shape of the dose-response curve, and species responsiveness. In spite of these uncertainties, it was concluded that the TEF concept is still the most plausible and feasible approach for risk assessment of halogenated aromatic hydrocarbons with dioxinlike properties. VA:IBN
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