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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    Evaluation of Mycotoxin Screening Tests in a Verification Study Involving First Time Users
    Lattanzio, Veronica M.T. ; Holst, Christoph von; Lippolis, Vincenzo ; Girolamo, Annalisa De; Logrieco, Antonio F. ; Mol, Hans G.J. ; Pascale, Michelangelo - \ 2019
    Toxins 11 (2019)2. - ISSN 2072-6651 - 18 p.
    cereals - immunoassay - mass spectrometry - mycotoxins - screening - validation

    (AFB₁) in maize and wheat using LFD and LC-HRMS, respectively. The results of analyses were used to calculate intermediate precision (RSDip, covering the inter-analyst variability in preparing the analytical samples and the precision under repeatability conditions) cut-off values and false suspect rates. RSDip ranged from 6.5% to 30% for DON, and from 16% to 33% for AFB₁. The highest obtained variances were associated with the AFB₁ analyses due to working with much lower mass fractions. The rate of false suspect results were lower than 0.1% for all tested methods. All methods showed a fit-for-purpose method performance profile, which allowed a clear distinction of samples containing the analytes at the screening target concentration (STC) from negative control samples. Moreover, the first time users obtained method performances similar to those obtained for validation studies previously performed on the screening methods included in the training course.

    Abscisic acid influences tillering by modulation of strigolactones in barley
    Wang, Hongwen ; Chen, Wanxin ; Eggert, Kai ; Charnikhova, Tatsiana ; Bouwmeester, Harro ; Schweizer, Patrick ; Hajirezaei, Mohammad R. ; Seiler, Christiane ; Sreenivasulu, Nese ; Wirén, Nicolaus von; Kuhlmann, Markus - \ 2018
    Journal of Experimental Botany 69 (2018)16. - ISSN 0022-0957 - p. 3883 - 3898.
    Abscisic acid - barley - cereals - hormone regulation - phytohormone cross-talk - shoot branching - strigolactone biosynthesis - tillering

    Strigolactones (SLs) represent a class of plant hormones that are involved in inhibiting shoot branching and in promoting abiotic stress responses. There is evidence that the biosynthetic pathways of SLs and abscisic acid (ABA) are functionally connected. However, little is known about the mechanisms underlying the interaction of SLs and ABA, and the relevance of this interaction for shoot architecture. Based on sequence homology, four genes (HvD27, HvMAX1, HvCCD7, and HvCCD8) involved in SL biosynthesis were identified in barley and functionally verified by complementation of Arabidopsis mutants or by virus-induced gene silencing. To investigate the influence of ABA on SLs, two transgenic lines accumulating ABA as a result of RNAi-mediated down-regulation of HvABA 8'-hydroxylase 1 and 3 were employed. LC-MS/MS analysis confirmed higher ABA levels in root and stem base tissues in these transgenic lines. Both lines showed enhanced tiller formation and lower concentrations of 5-deoxystrigol in root exudates, which was detected for the first time as a naturally occurring SL in barley. Lower expression levels of HvD27, HvMAX1, HvCCD7, and HvCCD8 indicated that ABA suppresses SL biosynthesis, leading to enhanced tiller formation in barley.

    Using yield gap analysis to give sustainable intensification local meaning
    Silva, João Vasco - \ 2017
    Wageningen University. Promotor(en): M.K. Ittersum, co-promotor(en): K.E. Giller; P. Reidsma. - Wageningen : Wageningen University - ISBN 9789463437141 - 361
    crops - yields - crop yield - modeling - simulation models - cereals - farming systems - yield losses - gewassen - opbrengsten - gewasopbrengst - modelleren - simulatiemodellen - graansoorten - bedrijfssystemen - oogstverliezen

    Yield gap analysis is useful to understand the relative contribution of growth-defining, -limiting and -reducing factors to actual yields. This is traditionally performed at the field level using mechanistic crop growth simulation models, and directly up-scaled to the regional and global levels without considering a range of factors intersecting at farm and farming system levels. As an example, these may include farmers' objectives and resource constraints, farm(er) characteristics, rotational effects between subsequent crops or decisions on resource allocation and prioritization of crop management. The objective of this thesis is to gain insights into yield gaps from a farm(ing) systems perspective in order to identify opportunities for sustainable intensification at local level.

    Three contrasting case studies representing a gradient of intensification and capturing a diversity of agricultural systems were selected for this purpose, namely mixed crop-livestock systems in Southern Ethiopia, rice based-farming systems in Central Luzon (Philippines) and arable farming systems in the Netherlands. A theoretical framework combining concepts of production ecology and methods of frontier analysis was developed to decompose yield gaps into efficiency, resource and technology yield gaps. This framework was applied and tested for the major crops in each case study using crop-specific input-output data for a large number of individual farms. In addition, different statistical methods and data analyses techniques were used in each case study to understand the contribution of farmers' objectives, farm(er) characteristics, cropping frequency and resource constraints to yield gaps and management practices at crop level.

    Yield gaps were largest for maize and wheat in Southern Ethiopia (ca. 80\\% of the water-limited yield), intermediate for rice in Central Luzon (ca. 50\\% of the climatic potential yield) and smallest for the major arable crops in the Netherlands (ca. 30\\% of the climatic potential yield). The underlying causes of these yield gaps also differed per case study. The technology yield gap explained most of the yield gap observed in Southern Ethiopia, which points to a lack of adoption of technologies able to reach the water-limited yield. The efficiency yield gap was most important for different arable crops in the Netherlands, which suggests a sub-optimal timing, space and form of the inputs applied. The three intermediate yield gaps contributed similarly to the rice yield gap in Central Luzon meaning that sub-optimal quantities of inputs used are as important in this case study as the causes mentioned for the other case studies.

    Narrowing the yield gap of the major crops does not seem to entail trade-offs with gross margin per unit land in each case study. However, the opposite seems to be true for N use efficiency and labour productivity particularly in Southern Ethiopia and Central Luzon, and to a less extent in the Netherlands. This means that (sustainable) intensification of smallholder agriculture in the tropics needs to go hand-in-hand with agronomic interventions that increase land productivity while ensuring high resource use efficiency and with labour-saving technologies that can reduce the drudgery of farming without compromising crop yields.

    Other insights at farm(ing) system level were clearer in Southern Ethiopia than in Central Luzon or in the Netherlands. For example, alleviating capital constraints was positively associated with intensification of maize-based farming systems around Hawassa and increases in oxen ownership (an indicator of farm power) was associated with extensification of wheat-based farming systems around Asella. In Central Luzon, farm and regional factors did not lead to different levels of intensification within the variation of rice farms investigated and the most striking effect was that direct-seeding (and thus slightly lower rice yields) was mostly adopted in larger farms, and used lower amounts of hired labour, compared to transplanting. In the Netherlands, the analysis of rotational effects on crop yields provided inconclusive results but confounding effects with e.g. rented land do not allow to conclude that these are not at stake in this farming system.

    This thesis broadens the discussion on yield gaps by moving from the technical aspects underlying their estimation towards the broader farm level opportunities and constraints undermining their closure. Overall, insights from contrasting case studies support conventional wisdom that intensification of agriculture needs to occur in the 'developing South', where yield gaps are large and resource use efficiency low, while a focus on improving sustainability based on sustainable intensification (or even extensification) is more appropriate in the 'developed North', where yield gaps are small and resource use efficiency high.

    Organising trade : a practice-oriented analysis of cooperatives and networks trading cereals in South Mali
    Mangnus, E.P.M. - \ 2015
    Wageningen University. Promotor(en): Cees Leeuwis, co-promotor(en): Sietze Vellema. - Wageningen : Wageningen University - ISBN 9789462574311 - 178
    coöperaties - voedselcoöperaties - graansoorten - handel - katoen - geschiedenis - platteland - landbouw - agrarische handel - mali - west-afrika - cooperatives - food cooperatives - cereals - trade - cotton - history - rural areas - agriculture - agricultural trade - mali - west africa


    Farmer organisations have become the centrepiece of pro-poor market development strategies in Africa. Assumed to facilitate scale, quality of produce and professionalism they are regarded as a solution for farmers that are hampered from economic opportunities. In Mali public as well as private actors encourage farmers to trade through one specific organisational form, namely cooperatives. Nevertheless, in reality the landscape is much more diverse. A wide array of organisations can be observed and the models stimulated by external actors do not always succeed in improving the position of farmers. Considering the gap in knowledge, this dissertation poses the following question:

    How and in what ways do people organise trading of cereals in South Mali?

    The central aim of this thesis is to contribute to a better understanding of organisation of food trade in rural markets, by examining how and in what ways people in South Mali organise trade in cereals and sesame. Trading includes the procurement of cereals or sesame, organisation of finance, information gathering, bargaining, the organisation of transport and selling.

    Organisation of trade has been studied from different angles. Studies taking a structural approach explain organisation as emerging from context. Studies that approach organisations from an instrumental perspective regard organisation as a means for efficiently solving a shared problem. Both strands provide insights for understanding organisational functioning and performance but leave open questions regarding how people organise to realise trading and why this results in organisational diversity. This thesis examines organising trade by adopting a practice-oriented approach, which has as entry point that organisation takes shape in the realization of everyday practice. Focus is on what people actually do to realise trading.

    Two case study organisations are central to the study. Both are typical for how trade in rural Mali is organised. The first is a cooperative engaged in the trading of sesame in Miena, South-East Mali. The second is a cereal trading network in N’golobougou, in the centre of South Mali. Both provide an example of people collaborating and coordinating to perform trading and as such are excellent cases for tracing the formation of organisational traits that explain performance and diversity in trading cereals in South Mali.

    Empirical Chapters

    Chapter 2 presents a historical overview of how the organisation of trade of cereals and cotton at farmer level developed in Mali on extensive literature research. It focuses on the efforts of the Malian state to organise rural society, how producers responded, and how the interaction between the two shaped organisation. The analysis starts in the 18th century, in which cotton and cereal trade was intertwined and likewise organised. From the colonial period onwards, organisation dynamics in food and export crops evolved distinctly. For both sectors the most important events and changes are detailed. The chapter found that the political economy at stake influences the set of organisational options people can choose from and that imposed models rarely get adopted in practice.

    Chapter 3 traces the emergence and development of the sesame cooperative in Miena. It builds on two strands of literature that emphasize the specific socio-historical context of an organisation. The first body highlights the resilience of existing relations and institutions by showing how these get reproduced in new organisations. The second body of literature claims that individuals involved in collective action have the capacity to influence which institutions get reproduced and which new ones get adopted, also called ‘blended’. To collect the data 35 in depth interviews with cooperative members, (ex) officials from the cotton company CMDT, local officers and NGO-workers active in the research location were collected over a period of three months. Time was spent at the weekly market, in village meetings and at peoples’ homes. Moreover 20 informal talks with villagers and traders on the market were afterwards noted down. Three distinct processes - the historical organisation of cotton farmers, the interaction between state and society and the local trade practices - are found to underlie the current functioning of the cooperative. This chapter shows how both the reproduction and blending happen purposively; in order to (continue) performance in trading.

    Chapter 4 addresses the question: How do traders in Mali perform collectively? Following the methodological orientation, labelled as technography, the chapter zooms in on the use of skills and know-how by a group of people coordinating the collection and trade of cereals. Data were collected through 24 in-depth interviews with traders and 37 semi-structured interviews with pisteurs and interviews with key resource persons. Moreover, trade practices were observed during 10 market days in a row. The analysis shows that the success of the traders’ network can be explained by: (i) the use of skills and know-how for adapting to changing economic, social and environmental contexts; (ii) the network’s ability to select capable people and distribute the many trading tasks; and (iii) the network’s effective governance, based on a strict code of conduct specific to each role. The chapter shows how rules steering the distribution of tasks and collaboration in the traders’ network emerge out of the daily practice of trading.

    Chapter 5 uses evidence from a network of cereal traders in the market of N’golobougou to examine how the characteristics of traders, their positions within different networks, and different kinds of relationships between traders influence performance in trading. 26 traders were extensively interviewed on the history, functioning and the size of their business. Semi-structured interviews focused on their relations in trading. A social network analysis (SNA) is applied to describe the positions of individual traders in the networks and the type of relations that link them. Qualitative analysis is used to understand the motivations underlying their position and collaboration. The findings demonstrate that trading is a complex and multifaceted activity. Within the network distinct networks have emerged to organise the collection of cereals, to arrange finance and to acquire information. Pre-existing social relations facilitate trading but do not guarantee individual success. Proven ability and reputation are equally important in cooperation and relate to the way powerful members of the network acquire a central position, which goes stepwise and takes time.


    Collaboration is crucial for trading under the circumstances of rural Mali. Both case studies highlight the role of key individuals who spotted opportunities and mobilised others to collaborate. Different trading activities require specific skills, know-how and tools and people tend to specialise. Most skills are acquired in practice; few of them can be taught by instruction. Accordingly to what is present in terms of capacities, people’s availability and know-how, and tools, groups will distribute tasks among their members.

    People also need to coordinate how skills, know-how and tools are distributed over time and space. Trading in South Mali requires bridging of long distances, adaptation to seasonality, securing finance and transport, and finding buyers. The temporal dimension of trading is visible in how traders adapt to seasonality and to how it is adjusted to people’s availability in time. Trading is also spatially situated. Poor infrastructure and long travel distances are characteristic of rural South Mali. Both the cooperative as well as the trading network therefore have a layered structure of actors close to the field, actors in the central village or market where the sesame or cereals are collected, and actors in the city to which the sesame or cereals are transported.

    People do not organise in a random constellation. The range of options they can choose from are importantly influenced by the institutions active in decision-making at village level, the relationship between state and rural communities, the social networks people operate in, and the historically developed rules and regulations in market transactions. Also, previous ways of organising play a role in today’s way of organising. The empirical analyses demonstrate that organising trade is ‘path dependent’. Nevertheless, people only reproduce those procedures, habits and actions that are deemed necessary to perform. They blend old and new ways of coordination and collaboration to allow the practice of trade to continue.

    The findings in this thesis show that collaboration does not rely on social relations only. Cooperating to achieve a practical end, i.e. to trade, is also skill and competence based. Organisational sustainability depends on how grouped or networked actors coordinate actions in response to changing circumstances and opportunities. Hence, organisational diversity can be understood from the fact that organisation emerges from a situated practice.


    Organisation in trade emerges gradually and adaptively from what is present in terms of skills, capacities, know-how and experience in trading. As this is situation specific it is essential to recognize the uniqueness of each organisational form and suggests reconsidering the one-size-fit-all approaches often promoted in development interventions. Imposed organisational structures may be enabling to some extent but they leave little room for exploring the range of possible ways to achieve trading. For understanding how people organise trade it is important to understand the way they perform the actual practice in the specific social and material circumstances. The empirical chapters argue in favour of tutor–apprentice relations between experienced actors and new members, leaving decision-making power and rule setting in the hands of the most experienced traders. Current development projects supporting links between farmers and buyers often aim to be ‘inclusive’ and ‘pro-poor’, meaning that they should be accessible to anyone. The field research shows that organisations in trade in Mali are very selective in membership to assure the group achieves its objectives. Governments and other development actors should be aware of the trade-offs between inclusive, democratic organisational models, and effectiveness and performance in trading.

    Jaarverslagen van de KNPV-werkgroepen over 2014: Werkgroep Bodempathogenen en bodemmicrobiologie
    Os, G.J. van; Postma, J. - \ 2015
    Gewasbescherming 46 (2015)2. - ISSN 0166-6495 - p. 46 - 46.
    jaarverslagen - werkgroepen - gewasbescherming - bodempathogenen - bodemmicrobiologie - fusarium - oömyceten - onkruidkunde - nematoda - pathogenen - resistentie tegen insecticiden - resistentie tegen herbiciden - weerstand - bacteriologie - graansoorten - annual reports - working groups - plant protection - soilborne pathogens - soil microbiology - fusarium - oomycetes - weed science - nematoda - pathogens - insecticide resistance - herbicide resistance - resistance - bacteriology - cereals
    Dit artikel omvat de jaarverslagen van de volgende KNPV-werkgroepen over 2014: Bodempathogenen en bodemmicrobiologie; Fusarium; Oömyceten; Nematoden; Onkruidbeheersing; Middelenresistentie; Fytobacteriologie; Gewasbescherming en Maatschappelijk Debat; Jongeren; Fytobacteriologie; Graanziekten.
    Survey on sterigmatocystin in food
    Mol, J.G.J. ; Pietri, A. ; MacDonald, S.J. ; Anagnostopoulos, C. ; Spanjer, M. - \ 2015
    Parma, Italy : EFSA (EFSA supporting publiation 2015 EN-774) - 56
    sterigmatocystine - mycotoxinen - graansoorten - bieren - noten - voedselveiligheid - voedselanalyse - sterigmatocystin - mycotoxins - cereals - beers - nuts - food safety - food analysis
    A total of 1 259 samples of cereal grains, cereal products, beer and nuts were analysed for the presence of the mycotoxin sterigmatocystin. Samples were mainly collected at processing plants, storage facilities, wholesale and retail between August 2013 and November 2014, in nine European countries (mostly Greece, Italy, the Netherlands and the United Kingdom (UK), additionally in Cyprus, Germany, Latvia, Lithuania, and Poland). The products originated from 27 European countries and 18 other countries (mostly rice and nuts). The samples comprised cereal grains (221 wheat, 35 rye, 33 maize, 59 barley, 51 oats, 2 spelt, 117 rice), grain milling products (125), pasta (115), bread/rolls (143), breakfast cereals/muesli (97), fine bakery ware (90), cereal-based infant food (54), beer (53), peanuts (28) and hazelnuts (36). All samples were analysed by methods based on liquid chromatography with tandem mass spectrometry (LC-MS/MS).
    Proficiency test for allergens in food 2014
    Bremer, M.G.E.G. ; Alamenou, P. ; Elbers, I.J.W. - \ 2015
    Wageningen : RIKILT Wageningen UR (RIKILT report 2015.002) - 38
    graansoorten - zuigelingenvoedsel - allergenen - voedselallergieën - laboratoriumproeven - tests - cereals - infant foods - allergens - food allergies - laboratory tests - tests
    In the autumn of 2014 a proficiency test for allergens in baby cereal was organized by RIKILT, Wageningen UR. This PT-test enabled laboratories to evaluate their competence for the analysis of allergens in baby cereal. Both quantitative and qualitative methods were accepted. The proficiency test was carried out according to ISO/IEC 17043, however this specific test is not part of the accreditation.
    Mengteelten graan met erwten of veldbonen
    Beeckman, A. ; Govaerts, W. - \ 2014
    Biokennis bericht Dierlijke sectoren (2014)1. - 4 p.
    gemengde teelt - graansoorten - erwten - tuinbonen - voedergewassen - eiwitleverende planten - peulvruchten - biologische landbouw - rassenkeuze (gewassen) - mixed cropping - cereals - peas - faba beans - fodder crops - protein plants - grain legumes - organic farming - choice of varieties
    Door de stijgende krachtvoederprijzen – voornamelijk bij de eiwitrijke componenten – stijgt de interesse in eiwitteelten van eigen bodem. De teelt van peulvruchten zoals lupinen, erwten en veldbonen in monocultuur blijft echter een risicovolle onderneming. De voorbije jaren werd zowel in Vlaanderen als in Nederland ruime ervaring opgedaan met mengteelten. Hieronder een aantal praktische wenken gebaseerd op de ervaring en proefresultaten van voorbije jaren.
    Rapid detection of pesticides not amenable to multi-residue methods by flow injection-tandem mass spectrometry
    Mol, J.G.J. ; Dam, R.C.J. van - \ 2014
    Analytical and Bioanalytical Chemistry 406 (2014)27. - ISSN 1618-2642 - p. 6817 - 6825.
    liquid-chromatography - aminomethylphosphonic acid - quantitative-analysis - sample preparation - maleic hydrazide - lc-ms/ms - glyphosate - cereals - vegetables - dilution
    Flow injection combined with tandem mass spectrometry (MS/MS) was investigated for the rapid detection of highly polar pesticides that are not amenable to multi-residue methods because they do not partition into organic solvents and require dedicated chromatographic conditions. The pesticides included in this study were amitrole, chlormequat, cyromazine, daminozide, diquat, ethephon, fosetyl-Al, glufosinate, glyphosate and its metabolite aminomethylphosphonic acid, maleic hydrazide, mepiquat and paraquat. The composition of the flow-injection solvent was optimized to achieve maximum MS/MS sensitivity. Instrumental limits of detection varied between
    Meerjarig graan; Mogelijkheden van meerjarige graanachtigen voor erosiebestrijding
    Wander, J.G.N. ; Crijns, S. ; Duijzer, F. ; Emmens, E. ; Russchen, H.J. ; Meuffels, G.J.H.M. - \ 2014
    Dronten : DLV Plant - 38
    akkerbouw - graansoorten - thinopyrum - duurzaam bodemgebruik - teeltsystemen - bodemvruchtbaarheid - bemesting - watererosie - winderosie - meerjarige teelt - rassen (planten) - tarwe - nederland - zuid-limburg - veenkolonien - arable farming - cereals - thinopyrum - sustainable land use - cropping systems - soil fertility - fertilizer application - water erosion - wind erosion - perennial cropping - varieties - wheat - netherlands - zuid-limburg - veenkolonien
    Meerjarige granen, waaronder Thinopyrum intermedium, wortelen dieper en intensiever en houden daardoor bodem, voedingsstoffen en water goed vast. Voor Nederlandse omstandigheden zou de teelt van dergelijke gewassen dan ook kunnen zorgen voor minder water en/of winderosie, minder milieubelasting (minder uitspoeling) en zuiniger gebruik van inputs.
    6-Plex microsphere immunoassay with imaging planar array detection for mycotoxins in barley
    Peters, J. ; Cardall, A. ; Haasnoot, W. ; Nielen, M.W.F. - \ 2014
    The Analyst 139 (2014)16. - ISSN 0003-2654 - p. 3968 - 3976.
    flow-cytometric immunoassay - surface-plasmon resonance - suspension array - liquid-chromatography - fusarium mycotoxins - multiplex dipstick - mass-spectrometry - cereals - deoxynivalenol - ochratoxin
    Mycotoxins are produced by fungi as secondary metabolites. They often multi-contaminate food and feed commodities posing a health risk to humans and animals. A fast and easy to apply multiplex screening of these commodities could be useful to detect multi-contamination. For this, we developed a semi-quantitative 6-plex immunoassay using a suspension array of paramagnetic colour-coded microspheres combined with imaging planar array detection for the mycotoxins aflatoxin B1, ochratoxin A, zearalenone, deoxynivalenol, T2-toxin, HT-2 toxin and fumonisin B1. Mycotoxin specific monoclonal antibodies were coupled to different sets of microspheres and mycotoxins conjugated to the fluorescent protein R-phycoerythrin served as reporter molecules. Competition between free mycotoxins in the sample and mixed reporter molecules for antibody binding sites on mixed microspheres created a multiplex direct inhibition immunoassay. The reagents were selected for no or low cross-interactions between the assays and cross-reactions with metabolites and possible masked forms were determined. A within-laboratory validation was carried out using blank and spiked barley samples. Furthermore, the 6-plex was used to screen available barley, and malted barley, reference materials. The validation showed very high inter and intra-day precision for all samples with a maximum relative standard deviation value of 10%. The screening assay allows easy and rapid multiplex detection of the target mycotoxins in barley according to EU legislation. With a cut off factor of 50%, based on the EU maximum levels, we were able to screen at 2 µg kg(-1) for aflatoxin B1, 2.5 µg kg(-1) for ochratoxin A, 625 µg kg(-1) for deoxynivalenol, 50 µg kg(-1) for zearalenone, 1000 µg kg(-1) for fumonisin B1 and 25 µg kg(-1) for T-2 toxin. Thanks to the transportable planar array system, the developed 6-plex has potential for future on-site testing. Future implementation of this method as a pre-screening tool, prior to instrumental analysis, is highly attractive since costly LC-MS/MS analysis of samples below the maximum levels can be avoided.
    Proficiency test for tropane alkaloids in food en feed
    Pereboom-de Fauw, D.P.K.H. ; Elbers, I.J.W. ; Mulder, P.P.J. ; Nijs, W.C.M. de - \ 2014
    Wageningen : RIKILT Wageningen UR (RIKILT report 2014.008) - 35
    voer - voedsel - voedselproducten - geldigheid - betrouwbaarheid - laboratoriummethoden - graansoorten - voedselconsumptie - voedselveiligheid - tropaanalkaloïden - feeds - food - food products - validity - reliability - laboratory methods - cereals - food consumption - food safety - tropane alkaloids
    Proficiency testing is conducted to provide laboratories with a powerful tool to evaluate and demonstrate the reliability of the data that are produced. Next to validation and accreditation, proficiency testing is an important requirement of the EU Additional Measures Directive 93/99/EEC [1] and is required by ISO 17025:200. The proficiency test for tropane alkaloids was organized by RIKILT, Wageningen UR in accordance with ISO 17043. The primary goal of this study was to provide laboratories with the opportunity to implement a method in their laboratory and to evaluate or demonstrate their performance regarding quantitative analysis of tropane alkaloids in cereals intended for human consumption and in animal feed.
    Graanstoppels en akkervogels
    Bos, J.F.F.P. - \ 2013
    Limosa 86 (2013)3. - ISSN 0024-3620 - p. 123 - 131.
    vogels - bouwland - fauna - agrarische bedrijfsvoering - graansoorten - overwintering - foerageren - verenigd koninkrijk - birds - arable land - fauna - farm management - cereals - overwintering - foraging - uk
    Graanstoppels vormen in najaar en winter een bron van voedsel voor vogels, met name als tijdens de voorafgaande graanteelt de inzet van herbiciden wordt beperkt, de stoppelvelden vanaf de nazomer bezet raken met onkruiden en ze niet te vroeg in de winter worden geploegd. In het Verenigd Koninkrijk is veel onderzoek gedaan naar de betekenis van graanstoppels voor overwinterende akkervogels. Dit artikel biedt een samenvatting van de inzichten die dit onderzoek heeft opgeleverd, met een doorkijkje naar kansen voor toepassing in Nederland
    Wintergranen voor waterberging
    Crijns, J. ; Meuffels, G.J.H.M. - \ 2013
    Horst : DLV Plant - 12
    erosiebestrijding - heuvels - bodemwater - graansoorten - proefprojecten - akkerranden - zuid-limburg - wintertarwe - akkerbouw - erosion control - hill land - soil water - cereals - pilot projects - field margins - zuid-limburg - winter wheat - arable farming
    Bij aanleg van een graanbufferstrook kan mogelijk het erosieremmend effect gecombineerd worden met plantaardige productie. Via een bevloeiingsproef is gezocht naar het waterbergend vermogen van een graanbufferstrook. In een perceel van proefboerderij Wijnandsrade (Zuid-Limburg) met een hellingspercentage van 4% werd aan de onderzijde van het perceel op de wendakker de proef aangelegd.
    Critical evaluation of LC-MS-based methods for simultaneous determination of deoxynivalenol, ochratoxin A, zearalenone, aflatoxins, fumonisins and T-2/HT-2 toxins in maize
    Girolamo, A. De; Solfrizzo, M. ; Lattanzio, V.M.T. ; Stroka, J. ; Alldrick, A. ; Egmond, H.P. van; Visconti, A. - \ 2013
    World Mycotoxin Journal 6 (2013)3. - ISSN 1875-0710 - p. 317 - 334.
    tandem mass-spectrometry - performance liquid-chromatography - multi-mycotoxin determination - immunoaffinity cleanup - ht-2 toxins - cereals - ms/ms - food - trichothecenes - t-2
    The results of a proficiency test for the LC-MS/(MS) determination of up to 11 mycotoxins (aflatoxins B1, B2, G1 and G2, fumonisins B1 and B2, ochratoxin A, deoxynivalenol, T-2 and HT-2 toxins and zearalenone) in maize were evaluated to identify possible strengths and weaknesses of various methodologies used by the 41 participating laboratories. The majority of laboratories (56%) used mixtures of acetonitrile:water for extraction. Other laboratories used methanol:water mixtures (17%) or performed two consecutive extractions with phosphate buffer solution (PBS) followed by methanol (15%). Few laboratories used mixtures of acetonitrile:water:methanol (7%), water:ethyl acetate (2.5%) or PBS alone (2.5%). The majority of laboratories (58%) used a clean-up step prior to chromatography. The remaining laboratories analysed crude extracts (37%) or used a mixed approach (5%). The amount of sample equivalent injected into LC-MS/(MS) ranged between 0.1-303 mg for purified extracts and 0.08-20 mg for directly analysed crude extracts. External (54%), matrix-matched (22%) or stable isotope-labelled internal standards calibration (24%) were used for toxin quantification. In general, extraction mixtures of water with acetonitrile, methanol or both provided good results for quantitative extraction of mycotoxins from maize. Laboratories using sample extract clean-up reported acceptable results for the majority of mycotoxins. Good results were also obtained by laboratories that analysed crude extracts although a high variability of results was observed for all tested mycotoxins. Matrix-matched calibration or isotope-labelled internal standards efficiently compensated matrix effects whereas external calibration gave reliable results by injecting =10 mg of matrix equivalent amounts. Unacceptable high recovery and high variability of fumonisin results were obtained by the majority of laboratories, which could not be explained and thus require further investigation. These findings provide the basis for the optimization and selection of methods to be used in future interlaboratory validation studies to derive their performance characteristics for simultaneous determination of mycotoxins in maize.
    Dephytinisation with Intrinsic Wheat Phytase and Iron Dephytinisation with Intrinsic Wheat Phytase and Iron Fonio (Digitaria exilis) Meals in West African Women
    Koreissi, Y. ; Fanou-Fogny, N.M.L. ; Moretti, D. ; Schuth, S. ; Dossa, R.A.M. ; Egli, I. ; Zimmerman, M.B. ; Brouwer, I.D. - \ 2013
    PLoS ONE 8 (2013)10. - ISSN 1932-6203
    phytic acid - inositol phosphates - humans - bioavailability - zinc - foods - purification - degradation - cereals - protein
    Low iron and high phytic acid content make fonio based meals a poor source of bioavailable iron. Phytic acid degradation in fonio porridge using whole grain cereals as phytase source and effect on iron bioavailability when added to iron fortified fonio meals were investigated. Grains, nuts and seeds collected in Mali markets were screened for phytic acid and phytase activity. We performed an iron absorption study in Beninese women (n = 16), using non-dephytinised fonio porridge (FFP) and dephytinised fonio porridge (FWFP; 75% fonio-25% wheat), each fortified with 57Fe or 58Fe labeled FeSO4. Iron absorption was quantified by measuring the erythrocyte incorporation of stable iron isotopes. Phytic acid varied from 0.39 (bambara nut) to 4.26 g/100 g DM (pumpkin seed), with oilseeds values higher than grains and nuts. Phytase activity ranged from 0.17±1.61 (fonio) to 2.9±1.3 phytase unit (PU) per g (whole wheat). Phytic acid was almost completely degraded in FWFP after 60 min of incubation (pH˜5.0, 50°C). Phytate:iron molar ratios decreased from 23.7:1 in FFP to 2.7:1 in FWFP. Iron fortification further reduced phytate:iron molar ratio to 1.9:1 in FFP and 0.3:1 in FWFP, respectively. Geometric mean (95% CI) iron absorption significantly increased from 2.6% (0.8–7.8) in FFP to 8.3% (3.8–17.9) in FWFP (P
    Gerstteler mist kennis: Fusarium in gerst is nog onontgonnen terrein
    Timmer, Ruud - \ 2013
    barley - malting barley - cereals - fusarium - plant pathogenic fungi - mycotoxins - plant protection - breed differences - arable farming
    Adviesbasis voor de bemesting van akkerbouwgewassen : stikstof
    Geel, W.C.A. van; Haan, J.J. de - \ 2013 2013 (2013)20 maart.
    stikstofmeststoffen - akkerbouw - graansoorten - aardappelen - suikerbieten - voedergewassen - uien - grassen - groenbemesters - bemesting - nitrogen fertilizers - arable farming - cereals - potatoes - sugarbeet - fodder crops - onions - grasses - green manures - fertilizer application
    De stikstofbemestingsrichtlijnen geven de door de jaren heen gemiddelde optimale stikstofgift. De optimale stikstofgift is echter van veel factoren afhankelijk, zoals voorvrucht, bemestingsverleden, vochtvoorziening en ziektedruk. Op basis van de eigen ervaringen en kennis van percelen en gewassen kan de richtlijn dan ook aan de eigen situatie worden aangepast. Daar waar mogelijk zijn in deze adviesbasis richtlijnen gegeven voor dergelijke aanpassingen (o.a. onderwerken van groenbemesters en oogstresten en gebruik van dierlijke mest).
    A Dutch field survey on fungal infection and mycotoxin concentrations in maize
    Asselt, E.D. van; Azambuja, W. ; Moretti, A. ; Kastelein, P. ; Rijk, T.C. de; Stratakou, I. ; Fels-Klerx, H.J. van der - \ 2012
    Food Additives & Contaminants. Pt. A, Chemistry, Analysis, Control, Exposure & Risk Assessment 29 (2012)10. - ISSN 1944-0049 - p. 1556 - 1565.
    agricultural practices - fusarium infection - ear rot - deoxynivalenol - wheat - contamination - netherlands - fumonisin - impacts - cereals
    Mycotoxins are secondary metabolites produced by fungi that can cause adverse health effects. Due to climate change, temperatures are expected to rise and changes in rainfall patterns are foreseen. These developments may increase fungal occurrence and mycotoxin concentrations in maize. It is therefore useful to monitor mycotoxin levels in maize and record the accompanying agronomic factors and weather parameters. This paper describes a field survey in the Netherlands in which information on soil, cultivar, green manure, tillage as well as sowing, emergence, flowering and harvest dates of silage maize were collected from 148 growers. A small number of these growers (42 in total) were visited to collect maize samples revealing that 50% of the samples were contaminated with Fusarium species and mycotoxins were detected in 25% of the samples. The Fusarium species that was most commonly found was F. crookwellense followed by F. graminearum, F. culmorum, F. sporotrichiodes and F. equiseti. In total 31 mycotoxins were analysed. The predominant mycotoxins present were (sum of 3 and 15)-acetyl-DON and nivalenol; other mycotoxins found were alternariol, beauvericin, deoxynivalenol, diacetoxyscirpenol, moniliformin and zearalenone. Nivalenol was present in concentrations up to 1670¿µg¿kg–1 and acetylated DON was usually present at higher concentrations than DON. Statistical analysis of the current data showed no correlation between mycotoxins present and agronomic factors recorded. Field studies as described in this paper are useful and need to be continued in the future in order to observe trends in mycotoxin occurrence.
    Rapid identification of fusarium graminearum species complex using Rolling Circle Amplification (RCA)
    Davari, M. ; Diepeningen, A.D. van; Babai-Ahari, A. ; Arzanlou, M. ; Javad Najafzadeh, M. ; Lee, T.A.J. van der; Hoog, G.S. de - \ 2012
    Journal of Microbiological Methods 89 (2012)1. - ISSN 0167-7012 - p. 63 - 70.
    head blight pathogen - dna-sequence database - genealogical concordance - padlock probes - north-america - wheat - mycotoxins - cereals - barley - populations
    Rolling Circle Amplification (RCA) of DNA is a sensitive and cost effective method for the rapid identification of pathogenic fungi without the need for sequencing. Amplification products can be visualized on 1% agarose gel to verify the specificity of probe-template binding or directly by adding fluorescent dyes. Fusarium Head Blight (FHB) is currently the world's largest threat to the production of cereal crops with the production of a range of mycotoxins as an additional risk. We designed sets of RCA padlock probes based on polymorphisms in the elongation factor 1-a (EF-1a) gene to detect the dominant FHB species, comprising lineages of the Fusarium graminearum species complex (FGSC). The method also enabled the identification of species of the Fusarium oxysporum (FOSC), the Fusarium incarnatum-equiseti (FIESC), and the Fusarium tricinctum (FTSC) species complexes, and used strains from the CBS culture collection as reference. Subsequently probes were applied to characterize isolates from wheat and wild grasses, and inoculated wheat kernels. The RCA assays successfully amplified DNA of the target fungi, both in environmental samples and in the contaminated wheat samples, while no cross reactivity was observed with uncontaminated wheat or related Fusarium species. As RCA does not require expensive instrumentation, the technique has a good potential for local and point of care screening for toxigenic Fusarium species in cereals
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