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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Cost-Effective Sampling and Analysis for Mycotoxins in a Cereal Batch
Focker, M. ; Fels-Klerx, H.J. van der; Oude Lansink, A.G.J.M. - \ 2018
Risk Analysis (2018). - ISSN 0272-4332 - 14 p.
Modeling - mycotoxins - sampling

The presence of hazards (e.g., contaminants, pathogens) in food/feed, water, plants, or animals can lead to major economic losses related to human and animal health or the rejection of batches of food or feed. Monitoring these hazards is important but can lead to high costs. This study aimed to find the most cost-effective sampling and analysis (S&A) plan in the cases of the mycotoxins deoxynivalenol (DON) in a wheat batch and aflatoxins (AFB1) in a maize batch. An optimization model was constructed, maximizing the number of correct decisions for accepting/rejecting a batch of cereals, with a budget as major constraint. The decision variables were the choice of the analytical method: instrumental method (e.g., liquid chromatography combined with mass-spectrometry (LC-MS/MS)), enzyme-linked-immuno-assay (ELISA), or lateral flow devices (LFD), the number of incremental samples collected from the batch, and the number of aliquots analyzed. S&A plans using ELISA showed to be slightly more cost effective than S&A plans using the other two analytical methods. However, for DON in wheat, the difference between the optimal S&A plans using the three different analytical methods was minimal. For AFB1 in maize, the cost effectiveness of the S&A plan using instrumental methods or ELISA were comparable whereas the S&A plan considering onsite detection with LFDs was least cost effective. In case of nonofficial controls, which do not have to follow official regulations for sampling and analysis, onsite detection with ELISA for both AFB1 in maize and DON in wheat, or with LFDs for DON in wheat, could provide cost-effective alternatives.

Food Safety Issues Related to Uses of Insects for Feeds and Foods
Fels-Klerx, H.J. van der; Camenzuli, L. ; Belluco, S. ; Meijer, N. ; Ricci, A. - \ 2018
Comprehensive reviews in food science and food safety 17 (2018)5. - ISSN 1541-4337 - p. 1172 - 1183.
edible insects - feed - food - review - safety

Edible insects are expected to become an important nutrient source for animals and humans in the Western world in the near future. However, before insects can be put on the market, the safety of their use for feed and food is warranted. This literature study was prepared to provide an overview of the actual knowledge of possible food safety hazards, including chemical, microbiological, and allergenic agents and prions, to human and animal health upon the use of insects for food and feed, and to highlight data gaps and suggest the way forward. From the data available, heavy metals of concern are cadmium in black soldier fly and arsenic in yellow mealworm larvae. Investigated mycotoxins do not seem to accumulate. Residues of pesticides, veterinary drugs, and hormones, as well as dioxins and PCBs, are sometimes found in insects. Contamination of insects with pathogens to human health is a consequence of a combination of the substrates used and the farming and processing steps applied. Insects harbor a wide variety of microorganisms, and some human pathogenic bacteria may be present. In addition, insects may harbor and transmit parasites. There is no evidence so far insects may harbor pathogenic viruses or prions, but they may act as vectors. Insects and insect-derived products may have allergenic potential. In this review, evidence on some safety aspects is displayed, and data gaps are identified. Recommendations are given for future research to fill the most relevant data gaps.

Comparison of three modelling approaches for predicting deoxynivalenol contamination in winter wheat
Liu, Cheng ; Manstretta, Valentina ; Rossi, Vittorio ; Fels-Klerx, H.J. van der - \ 2018
Toxins 10 (2018)7. - ISSN 2072-6651
Cereal grains - DON - Food safety - Forecast - Mycotoxin - Validation

Forecasting models for mycotoxins in cereal grains during cultivation are useful for pre-harvest and post-harvest mycotoxin management. Some of such models for deoxynivalenol (DON) in wheat, using two different modelling techniques, have been published. This study aimed to compare and cross-validate three different modelling approaches for predicting DON in winter wheat using data from the Netherlands as a case study. To this end, a published empirical model was updated with a new mixed effect logistic regression method. A mechanistic model for wheat in Italy was adapted to the Dutch situation. A new Bayesian network model was developed to predict DON in wheat. In developing the three models, the same dataset was used, including agronomic and weather data, as well as DON concentrations of individual samples in the Netherlands over the years 2001–2013 (625 records). Similar data from 2015 and 2016 (86 records) were used for external independent validation. The results showed that all three modelling approaches provided good accuracy in predicting DON in wheat in the Netherlands. The empirical model showed the highest accuracy (88%). However, this model is highly location and data-dependent, and can only be run if all of the input data are available. The mechanistic model provided 80% accuracy. This model is easier to implement in new areas given similar mycotoxin-producing fungal populations. The Bayesian network model provided 86% accuracy. Compared with the other two models, this model is easier to implement when input data are incomplete. In future research, the three modelling approaches could be integrated to even better support decision-making in mycotoxin management.

Systematic Review of Methods to Determine the Cost-Effectiveness of Monitoring Plans for Chemical and Biological Hazards in the Life Sciences
Focker, M. ; Fels-Klerx, H.J. van der; Oude Lansink, A.G.J.M. - \ 2018
Comprehensive reviews in food science and food safety 17 (2018)3. - ISSN 1541-4337 - p. 633 - 645.
Cost-effectiveness - Food safety - Hazards - Models - Monitoring
This study reviews the methods used to determine the cost-effectiveness of monitoring plans for hazards in animals (diseases), plants (pests), soil, water, food, and animal feed, and assesses their applicability to food safety hazards. The review describes the strengths and weaknesses of each method, provides examples of different applications, and concludes with comments about their applicability to food safety. A systematic literature search identified publications assessing the cost-effectiveness of monitoring plans in the life sciences. Publications were classified into 4 groups depending on their subject: food safety, environmental hazards, animal diseases, or pests. Publications were reviewed according to the type of model and input data used, and the types of costs included. Three types of models were used: statistical models, simulation models, and optimization models. Input data were either experimental, historical, or simulated data. Publications differed according to the costs included. More than half the publications only included monitoring costs, whereas other publications included monitoring and management costs, or all costs and benefits. Only a few publications were found in the food safety category and all were relatively recent studies. This suggests that cost-effectiveness analysis of monitoring strategies in food safety is just starting and more research is needed to improve the cost-effectiveness of monitoring hazards in foods.
Efficiency of organic stream conversion by black soldier fly larvae: a review of the scientific literature
Bosch, G. ; Veenenbos, M.E. ; Zanten, H.H.E. van; Meijer, N.P. ; Fels-Klerx, H.J. van der; Loon, J.J.A. van - \ 2018
Journal of Insects as Food and Feed 4 (2018)supplement 1. - ISSN 2352-4588 - p. S44 - S44.
Black soldier fly larvae to upcycle organic streams: a review of the scientific literature
Bosch, G. ; Veenenbos, M.E. ; Zanten, H.H.E. van; Meijer, N.P. ; Fels-Klerx, H.J. van der; Loon, J.J.A. van - \ 2018
Tolerance and excretion of the mycotoxins aflatoxin B1, zearalenone, deoxynivalenol, and ochratoxin A by alphitobius diaperinus and hermetia illucens from contaminated substrates
Camenzuli, Louise ; Dam, Ruud van; Rijk, Theo de; Andriessen, Rob ; Schelt, Jeroen van; Fels-Klerx, H.J.I. van der - \ 2018
Toxins 10 (2018)2. - ISSN 2072-6651
Alphitobius diaperinus - Bioaccumulation - Black soldier fly - Contaminants - Excretion - Feed safety - Food safety - Hermetia illucens - Insects - Lesser mealworm
This study aimed to investigate the potential accumulation of mycotoxins in the lesser mealworm (Alphitobius diaperinus, LMW) and black soldier fly (Hermetia illucens, BSF) larvae. Feed was spiked with aflatoxin B1, deoxynivalenol (DON), ochratoxin A or zearalenone, and as a mixture of mycotoxins, to concentrations of 1, 10, and 25 times the maximum limits set by the European Commission for complete feed. This maximum limit is 0.02 mg/kg for aflatoxin B1, 5 mg/kg for DON, 0.5 mg/kg for zearalenone and 0.1 mg/kg for ochratoxin A. The mycotoxins and some of their metabolites were analysed in the larvae and residual material using a validated and accredited LC-MS/MS-based method. Metabolites considered were aflatoxicol, aflatoxin P1, aflatoxin Q1, and aflatoxin M1, 3-acetyl-DON, 15-acetyl-DON and DON-3-glycoside, and α- and β-zearalenol. No differences were observed between larvae reared on mycotoxins individually or as a mixture with regards to both larvae development and mycotoxin accumulation/excretion. None of the mycotoxins accumulated in the larvae and were only detected in BSF larvae several orders of magnitude lower than the concentration in feed. Mass balance calculations showed that BSF and LMW larvae metabolized the four mycotoxins to different extents. Metabolites accounted for minimal amounts of the mass balance, except for zearalenone metabolites in the BSF treatments, which accounted for an average maximum of 86% of the overall mass balance. Both insect species showed to excrete or metabolize the four mycotoxins present in their feed. Hence, safe limits for these mycotoxins in substrates to be used for these two insect species possibly could be higher than for production animals. However, additional analytical and toxicological research to fully understand the safe limits of mycotoxins in insect feed, and thus the safety of the insects, is required.
Efficacy of chlorine dioxide on Escherichia coli inactivation during pilot-scale fresh-cut lettuce processing
Banach, J.L. ; Overbeek, L.S. van; Nierop Groot, M.N. ; Zouwen, P.S. van der; Fels-Klerx, H.J. van der - \ 2018
International Journal of Food Microbiology 269 (2018). - ISSN 0168-1605 - p. 128 - 136.
Disinfection by-products - Fresh-cut produce wash - Microbial cross-contamination - Pilot - Water disinfection
Controlling water quality is critical in preventing cross-contamination during fresh produce washing. Process wash water (PWW) quality can be controlled by implementing chemical disinfection strategies. The aim of this study was to evaluate the pilot-scale efficacy of chlorine dioxide (ClO2) during processing on the reduction of Escherichia coli in the PWW and on processed fresh-cut ‘Lollo Rossa’ lettuce. The objective was to have a residual target concentration of either 5 or 3 mg/L ClO2 in the washing tank (3.5 m3) before and during 800 kg of lettuce processing (90 min). After 90 min., a nonpathogenic, non-Extended Spectrum Beta-Lactamase (ESBL) E. coli inoculum from an overnight culture broth (37 °C) was added to the tank resulting in an approximate final level of 106 CFU/mL. PWW and lettuce samples for microbiological and chemical analyses were taken before and after the input and supply halted. ClO2 concentrations quickly decreased after ClO2 input halted, yet a residual concentration of ≥2.5 mg/L and ≥2.1 mg/L ClO2, respectively for 5 and 3 mg/L pilots, was present 12 min after the supply halted. No detectable levels of E. coli (limit of detection 5 log) were determined in the water within 1 min after E. coli was added to the ClO2 containing wash water. Results demonstrated that ClO2 use at the semi-commercial pilot scale was able to reduce the E. coli peak contamination in the PWW. After storage (5 days, 4 °C), background microbial communities (i.e., fluorescent Pseudomonads and total heterotrophic bacteria) grew out on lettuce. Overall, ClO2 decreased the potential for cross-contamination between batches compared to when no sanitizer was used. Chlorate levels of the lettuce sampled before entering the wash water ranged from 7.3–11.6 μg/kg. The chlorate levels of the lettuce sampled after being washed in the ClO2 containing wash water, as well as after rinsing and centrifugation, ranged from 22.8–60.4 μg/kg; chlorite levels ranged from 1.3–1.6 mg/kg, while perchlorate levels were below the limit of quantification (LOQ, <5 ng/g). In this study, we report the semi-commercial pilot-scale evaluation of ClO2, for its ability to maintain the PWW quality and to prevent cross-contamination in the washing tank during fresh-cut lettuce processing. Furthermore, we provide quantitative values of ClO2 disinfection by-products chlorate and chlorite as well as of perchlorate from PWW and/or lettuce samples.
Data analyses and modelling for risk based monitoring of mycotoxins in animal feed
Ine van der Fels-Klerx, H.J. ; Adamse, Paulien ; Punt, Ans ; Asselt, Esther D. van - \ 2018
Toxins 10 (2018)2. - ISSN 2072-6651
Aflatoxin B - Contaminant - Deoxynivalenol - Feed - Model - Risk - Trend analyses
Following legislation, European Member States should have multi-annual control programs for contaminants, such as for mycotoxins, in feed and food. These programs need to be risk based implying the checks are regular and proportional to the estimated risk for animal and human health. This study aimed to prioritize feed products in the Netherlands for deoxynivalenol and aflatoxin B1 monitoring. Historical mycotoxin monitoring results from the period 2007–2016 were combined with data from other sources. Based on occurrence, groundnuts had high priority for aflatoxin B1 monitoring; some feed materials (maize and maize products and several oil seed products) and complete/complementary feed excluding dairy cattle and young animals had medium priority; and all other animal feeds and feed materials had low priority. For deoxynivalenol, maize by-products had a high priority, complete and complementary feed for pigs had a medium priority and all other feed and feed materials a low priority. Also including health consequence estimations showed that feed materials that ranked highest for aflatoxin B1 included sunflower seed and palmkernel expeller/extracts and maize. For deoxynivalenol, maize products were ranked highest, followed by various small grain cereals (products); all other feed materials were of lower concern. Results of this study have proven to be useful in setting up the annual risk based control program for mycotoxins in animal feed and feed materials.
Critical review of methods for risk ranking of food related hazards, based on risks for human health
Fels-Klerx, H.J. van der; Asselt, E.D. van; Raley, M. ; Poulsen, M. ; Marvin, H.J.P. - \ 2018
Critical Reviews in Food Science and Nutrition 58 (2018)2. - ISSN 1040-8398 - p. 178 - 193.
This study aimed to critically review methods for ranking risks related to food safety and dietary hazards on the basis of their anticipated human health impacts. A literature review was performed to identify and characterize methods for risk ranking from the fields of food, environmental science and socio-economic sciences. The review used a predefined search protocol, and covered the bibliographic databases Scopus, CAB Abstracts, Web of Sciences, and PubMed over the period 1993–2013.

All references deemed relevant, on the basis of of predefined evaluation criteria, were included in the review, and the risk ranking method characterized. The methods were then clustered – based on their characteristics - into eleven method categories. These categories included: risk assessment, comparative risk assessment, risk ratio method, scoring method, cost of illness, health adjusted life years, multi-criteria decision analysis, risk matrix, flow charts/decision trees, stated preference techniques and expert synthesis. Method categories were described by their characteristics, weaknesses and strengths, data resources, and fields of applications.

It was concluded there is no single best method for risk ranking. The method to be used should be selected on the basis of risk manager/assessor requirements, data availability, and the characteristics of the method. Recommendations for future use and application are provided.
Chemical amd physical hazards in the egg production chain in the Netherlands
Fels-Klerx, H.J. van der; Asselt, E.D. van; Pikkemaat, M. ; Hoogenboom, R. ; Leeuwen, S.P.J. van; Horne, P. van; Boon, P.E. ; Razenberg, L. ; Mengelers, M. ; Leenstra, F. - \ 2017
Wageningen : RIKILT Wageningen University & Research (RIKILT-rapport 2016.005) - 57
Chemische en fysische gevaren in de Nederlandse aardappelketen
Nijkamp, M.M. ; Asselt, E.D. van; Janssens, B. ; Razenberg, L. ; Wit-Bos, L. de; Fels-Klerx, H.J. van der - \ 2017
Wageningen : RIKILT Wageningen University & Research (Rikilt rapport 2017.010) - 91
Arsenic, lead, cadmium and mercury in animal feed and feed materials : Trend analysis of monitoring result collected in the Netherlands
Adamse, P. ; Fels-Klerx, H.J. van der; Jong, J. de - \ 2017
Wageningen : RIKILT Wageningen University & Research (RIKILT report 2017.006) - 123
New feed ingredients : the insect opportunity
Raamsdonk, L.W.D. van; Fels-Klerx, H.J. van der; Jong, J. de - \ 2017
Food Additives & Contaminants. Pt. A, Chemistry, Analysis, Control, Exposure & Risk Assessment 34 (2017)8. - ISSN 1944-0049 - p. 1384 - 1397.
energy balance - energy conversion - environment - feed safety - fraud - Insect - label control - legislation - monitoring - novel protein source - traceability - WISE
In the framework of sustainability and a circular economy, new ingredients for feed are desired and, to this end, initiatives for implementing such novel ingredients have been started. The initiatives include a range of different sources, of which insects are of particular interest. Within the European Union, generally, a new feed ingredient should comply with legal constraints in terms of ‘yes, provided that’ its safety commits to a range of legal limits for heavy metals, mycotoxins, pesticides, contaminants, pathogens etc. In the case of animal proteins, however, a second legal framework applies which is based on the principle ‘no, unless’. This legislation for eradicating transmissible spongiform encephalopathy consists of prohibitions with a set of derogations applying to specific situations. Insects are currently considered animal proteins. The use of insect proteins is a good case to illustrate this difference between a positive, although restricted, modus and a negative modus for allowing animal proteins. This overview presents aspects in the areas of legislation, feed safety, environmental issues, efficiency and detection of the identity of insects. Use of insects as an extra step in the feed production chain costs extra energy and this results in a higher footprint. A measure for energy conversion should be used to facilitate the comparison between production systems based on cold- versus warm-blooded animals. Added value can be found by applying new commodities for rearing, including but not limited to category 2 animal by-products, catering and household waste including meat, and manure. Furthermore, monitoring of a correct use of insects is one possible approach for label control, traceability and prevention of fraud. The link between legislation and enforcement is strong. A principle called WISE (Witful, Indicative, Societal demands, Enforceable) is launched for governing the relationship between the above-mentioned aspects.
Chemical and physical hazards in the dairy chain
Asselt, E.D. van; Marvin, H.J.P. ; Boon, P.E. ; Swanenburg, M. ; Zeilmaker, M. ; Mengelers, M.J.B. ; Fels-Klerx, H.J. van der - \ 2016
Wageningen : RIKILT Wageningen UR (RIKILT report 2016.003) - 43
IAFP's European Symposium on Food Safety, Athens, Greece, 11-13 May 2016
Banach, Jen - \ 2016
Banach JL, Van Overbeek L, Vollebregt M, Nierop Groot M, Van der Zouwen P, Van Kekem K, Berendsen L, Van der Fels-Klerx HJ. 2016. Efficacy of aqueous chlorine dioxide on Escherichia coli inactivation during fresh-cut “Lollo rossa” (Lactuca sativa) washing at the pilot scale.
Immunochemical detection methods for gluten in food products: where do we go from here?
Bruins Slot, I.D. ; Fels-Klerx, H.J. van der; Bremer, Maria G.E.G. ; R.J., Hamer - \ 2016
Critical Reviews in Food Science and Nutrition 56 (2016)15. - ISSN 1040-8398 - p. 2455 - 2466.
Accurate and reliable quantification methods for gluten in food are necessary to ensure proper product labelling and thus safeguard the gluten sensitive consumer against exposure. Immunochemical detection is the method of choice, as it is sensitive, rapid and relatively easy to use. Although a wide range of detection kits are commercially available, there are still many difficulties in gluten detection that have not yet been overcome. This review gives an overview of the currently commercially available immunochemical detection methods, and discusses the problems that still exist in gluten detection in food. The largest problems are encountered in the extraction of gluten from food matrices, the choice of epitopes targeted by the detection method, and the use of a standardized reference material. By comparing the available techniques with the unmet needs in gluten detection, the possible benefit of a new multiplex immunoassay is investigated. This detection method would allow for the detection and quantification of multiple harmful gluten peptides at once and would, therefore, be a logical advancement in gluten detection in food.
Aflatoxin B1 contamination in maize in Europe increases due to climate change
Battilani, P. ; Toscano, P. ; Fels-Klerx, H.J. van der; Moretti, A. ; Camardo Leggieri, Marco ; Brera, C. ; Rortais, A. ; Goumpertis, T. ; Robinson, T. - \ 2016
Scientific Reports 6 (2016). - ISSN 2045-2322
Climate change has been reported as a driver for emerging food and feed safety issues worldwide and its expected impact on the presence of mycotoxins in food and feed is of great concern. Aflatoxins have the highest acute and chronic toxicity of all mycotoxins; hence, the maximal concentration in agricultural food and feed products and their commodities is regulated worldwide. The possible change in patterns of aflatoxin occurrence in crops due to climate change is a matter of concern that may require anticipatory actions. The aim of this study was to predict aflatoxin contamination in maize and wheat crops, within the next 100 years, under a +2 °C and +5 °C climate change scenario, applying a modelling approach. Europe was virtually covered by a net, 50 × 50 km grids, identifying 2254 meshes with a central point each. Climate data were generated for each point, linked to predictive models and predictions were run consequently. Aflatoxin B1 is predicted to become a food safety issue in maize in Europe, especially in the +2 °C scenario, the most probable scenario of climate change expected for the next years. These results represent a supporting tool to reinforce aflatoxin management and to prevent human and animal exposure.
Modelling approach to limit aflatoxin B1 contamination in dairy cattle compound feed
Bouzembrak, Y. ; Fels-Klerx, H.J. van der - \ 2016
World Mycotoxin Journal 9 (2016)3. - ISSN 1875-0710 - p. 455 - 464.
Feeding dairy cattle with safe compound feed helps farmers to ensure food safety. However, several ingredients often used in compound feed production can be contaminated with aflatoxin B1 (AFB1), which may result into milk contaminated with aflatoxin M1. Given the number of ingredients and their amounts used in the production of compound feed, it is very costly to check every batch of ingredients for AFB1 contamination. Which is the reason, why a risk-based approach is taken in the latest years. This study aimed to estimate the probability of AFB1 contamination of compound feed for dairy cattle, and to limit this contamination, by optimisation of the compound feed formulation, using a modelling approach. The modelling approach comprised integrating a linear optimisation programming model to a Monte Carlo simulation model. This model was applied to the case of producing compound feed for dairy cattle in the Netherlands, using national monitoring data on AFB1 contamination in feed materials collected in the period 2000-2010. Results from this case study showed the model can be used to produce safe compound feed with the lowest possible probability of AFB1 contamination.
A study of the 2013 Western European issue of aflatoxin contamination of maize from the Balkan area
Rijk, T.C. de; Egmond, H.P. van; Fels-Klerx, H.J. van der; Herbes, R. ; Nijs, W.C.M. de; Samson, R.A. ; Slate, A.B. ; Spiegel, M. van der - \ 2015
World Mycotoxin Journal 8 (2015)5. - ISSN 1875-0710 - p. 641 - 651.
In March 2013 a large shipment of maize, intended for feed was subject of an alert in the Rapid Alert System for Food and Feed of the European Commission (EC) because the aflatoxin B1 (AFB1) level in the load exceeded the EC regulated maximum level of 20 µg/kg. Since the shipment had passed import controls and was already distributed (mainly to German farms), a massive recall followed. The aim of the current study was to investigate questions, raised by authorities and industry, related to the effectivity of EU sampling procedures, the influence of sample homogenisation procedures and sample storage conditions on the test results, and fungal identification as unexpected mycotoxins were identified during this study. The Netherlands Food and Consumer Product Safety Authority seized a shipload of maize in July 2013, suspected to be contaminated with AFB1. The shipload was sampled according to the 2009 and 2013 EC Sampling Regulations to compare the outcomes of both sampling protocols. Mycotoxin analysis of the incremental samples showed high mean levels of AFB1, aflatoxin G1 (AFG1), and ochratoxin A (OTA). Also an extreme inhomogeneous distribution of aflatoxins and OTA was proven. Analysis of samples homogenised according to the slurry method showed improved performance as compared to samples homogenised through dry homogenisation. Sampling and sample homogenisation according to the Regulation from 2013 showed a closer estimate of the ‘true’ AFB1 content as compared to sampling according to the Regulation from 2009. No influence of laboratory storage conditions on AFB1 concentration could be determined. Fungal identification revealed Aspergillus flavus as the main source of AFB1 in this shipment. Infrequent occurrence of Aspergillus parasiticus might have been the source of AFG1. The occurrence of sometimes large amounts of OTA could not be explained, however it was suggested that Aspergillus welwitschiae might have played a role.
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