Decision support system for integrated management of mycotoxins in feed and food supply chains

Mycotoxins present a global food safety threat of our feed and food. Mycotoxins are toxic metabolites of certain fungi in agricultural products that are harmful to animal and human health. The presence of mycotoxins in these products depends on a variety of management and environmental factors in the field, during storage and/or processing of feed and food commodities. To date, information on mycotoxin management is available, but is not easy to access by supply chain actors. This study aimed to design, build and test a Decision Support System (DSS) that can help decision making on mycotoxin management by various actors along the feed and food supply chains. As part of this, available knowledge and data on mycotoxin prevention and control were collected and synthesised into easy to understand guidelines and tools for various groups of end-users. The DSS consists of four different modules: (a) static information module and (b) scenario analysis module, (c) dynamic module for forecasting mycotoxins, and (d) dynamic module for real-time monitoring of moulds/mycotoxins in grain silos. Intended end-users are all end-user groups for modules (a) and (b); growers and collectors for module (c) and; post-harvest storage managers for module (d). The DSS is user-friendly and accessible through PCs, tablets and smartphones (see https://mytoolbox-platform.com/ ). In various phases of the DSS development, the tool has been demonstrated to groups of end-users, and their suggestions have been taken into account, whenever possible. Also, a near final version has been tested with individual farmers on the easiness to use the system. In this way we aimed to maximise the DSS uptake by actors along the chain. Ultimately, this DSS will improve decision making on mycotoxin management; it will assist in reducing mycotoxin contamination in the key crops of Europe, thereby reducing economic losses and improving animal and human health.

The impact of management practices to prevent and control mycotoxins in the European food supply chain: MyToolBox project results

The presence of mycotoxins in cereals has led to large economic losses in Europe. In the course of the European project MyToolBox, prevention and control measures to reduce mycotoxin contamination in cereals were developed. This study aimed to estimate the impact of these prevention and control measures on both the reduction in crop losses and the increased volume of crops suitable for food and/or feed. It focused on the following measures: the use of fungicides during wheat cultivation, the use of resistant maize cultivars and/or biocontrol during maize cultivation, the use of real time sensors in storage silos, the use of innovative milling strategies during the pasta making process, and the employment of degrading enzymes during the process of bioethanol and Dried Distillers Grains with Solubles (DDGS) production. The impact assessment was based on the annual volume of cereals produced, the annual levels of mycotoxin contamination, and experimental data on the prevention and control measures collected in the course of the MyToolBox project. Results are expressed in terms of reduced volumes of cereals lost, or as additional volumes of cereals available for food meeting the current European legal limits. Results showed that a reduction in crop losses as well as an increase in the volume of crops suitable as food and/or feed is feasible with each proposed prevention or control measure along the supply chain. The impact was the largest in areas and in years with the highest mycotoxin contamination levels but would have less impact in years with low mycotoxin levels. In further research, the impact assessment may be validated using future data from more years and European sites. Decision makers in the food and feed supply chain can use this impact assessment to decide on the relevant prevention and control strategies to apply.

Determination of Zearalenone in Barley, Maize and Wheat Flour, Polenta, and Maize-Based Baby Food by Immunoaffinity Column Cleanup with Liquid Chromatography: Interlaboratory Study

An interlaboratory study was performed on behalf of the UK Food Standards Agency to evaluate the effectiveness of an affinity column cleanup liquid chromatography (LC) method for the determination of zearalenone (ZON) in a variety of cereals and cereal products at proposed European regulatory limits. The test portion is extracted with acetonitrile:water. The sample extract is filtered, diluted, and applied to an affinity column. The column is washed, and ZON is eluted with acetonitrile. ZON is quantified by reversed-phase LC with fluorescence detection. Barley, wheat and maize flours, polenta, and a maize-based baby food naturally contaminated, spiked, and blank (very low level) were sent to 28 collaborators in 9 European countries and 1 collaborator in New Zealand. Participants were asked to spike test portions of all samples at a ZON concentration equivalent to 100 μg/kg. Average recoveries ranged from 91–111%. Based on results for 4 artificially contaminated samples (blind duplicates) and 1 naturally contaminated sample (blind duplicate), the relative standard deviation for repeatability (RSDr) ranged from 6.9–35.8%, and the relative standard deviation for reproducibility (RSDR) ranged from 16.4–38.2%. The method showed acceptable within- and between-laboratory precision for all 5 matrixes, as evidenced by HorRat values <1.7.

Determination of Deoxynivalenol in Cereals and Cereal Products by Immunoaffinity Column Cleanup with Liquid Chromatography: Interlaboratory Study

An interlaboratory study was performed on behalf of the UK Food Standards Agency to evaluate the effectiveness of an immunoaffinity column cleanup liquid chromatographic (LC) method for the determination of deoxynivalenol in a variety of cereals and cereal products at proposed European regulatory limits. The test portion was extracted with water. The sample extract was filtered and applied to an immunoaffinity column. After being washed with water, the deoxynivalenol was eluted with acetonitrile or methanol. Deoxynivalenol was quantitated by reversed-phase LC with UV determination. Samples of artificially contaminated wheat-flour, rice flour, oat flour, polenta, and a wheat based breakfast cereal, naturally contaminated wheat flour, and blank (very low level) samples of each matrix were sent to 13 collaborators in 7 European countries. Participants were asked to spike test portions of all samples at a range of deoxynivalenol concentrations equivalent to 200–2000 ng/g deoxynivalenol. Average recoveries ranged from 78 to 87%. Based on results for 6 artificially contaminated samples (blind duplicates), the relative standard deviation for repeatability (RSDr) ranged from 3.1 to 14.1%, and the relative standard deviation for reproducibility (RSDR) ranged from 11.5 to 26.3%. The method showed acceptable within-laboratory and between-laboratory precision for all 5 matrixes, as evidenced by HorRat values <1.3.

Liquid Chromatographic Determination of Deoxynivalenol in Baby Food and Animal Feed: Interlaboratory Study

An interlaboratory study was conducted for the determination of deoxynivalenol in baby food and animal feed by high-performance liquid chromatography with UV detection. The study included 14 participants representing a cross section of industry, official food control, and research facilities. Mean recoveries reported ranged from 89% (at 120 g/kg) to 85% (at 240 g/kg) for baby food and from 100% (at 200 g/kg) to 93% (at 400 g/kg) for animal feed. On the basis of the results for spiked samples (blind duplicates at 2 levels), as well as those for naturally contaminated samples (blind duplicates at 3 levels), the relative standard deviation for repeatability (RSDr) in analyses of baby food ranged from 6.4 to 14.0% and in analyses of animal feed, from 6.1 to 16.5%. The relative standard deviation for reproducibility (RSDR) in analyses of baby food ranged from 9.4 to 19.5% and in analyses of animal feed, from 10.5 to 25.2%. The HorRat values ranged from 0.4 to 1.0 and from 0.7 to 1.3, for baby food and animal feed, respectively. The method showed acceptable performance for within-laboratory and between-laboratory precision for each matrix, as required by European legislation.

Validation of an Immunoassay for Detection and Quantitation of a Genetically Modified Soybean in Food and Food Fractions Using Reference Materials: Interlaboratory Study

An immunoassay for detection of a specific genetically modified soybean (Roundup-Ready®) was validated on dried soybean powder in an interlaboratory study. Different percentages of genetically modified soybeans in nonmodified soybean matrix were evaluated in a blind study. Thirty-eight laboratories from 13 countries participated. The immunoassay was evaluated for 2 endpoints: (1) To give a semiquantitative result, i.e., determination of a given sample above or below a given threshold, or (2) to compute a quantitative result, i.e., percentage of genetically modified soybeans in the sample. Semiquantitative results showed that a given sample which contained <2% genetically modified soybeans was identified as below 2% with a 99% confidence level. Quantitative use of the assay resulted in a repeatability (r) and reproducibility (R) that were computed to be RSDr = 7% and RSDR = 10%, respectively, for a sample containing 2% genetically modified soybeans. Application of this method depends on availability of appropriate reference materials for a specific food matrix. Only matrix-matched reference materials can be used for analysis of food or food fractions.

Carbon dioxide production as an indicator of Aspergillus flavus colonisation and aflatoxins/cyclopiazonic acid contamination in shelled peanuts stored under different interacting abiotic factors

Aspergillus flavus is the main xerophylic species colonising stored peanuts resulting in contamination with aflatoxins (AFs) and cyclopiazonic acid (CPA). This study evaluated the relationship between storage of shelled peanuts under interacting abiotic conditions on (a) temporal respiration (R) and cumulative CO₂ production, (b) dry matter losses (DMLs) and (c) aflatoxin B₁ (AFB₁) and CPA accumulation. Both naturally contaminated peanuts and those inoculated with A. flavus were stored for 7-days under different water activities (a_w; 0.77-0.95) and temperatures (20-35°C). There was an increase in the temporal CO₂ production rates in wetter and warmer conditions, with the highest respiration at 0.95 a_w + A. flavus inoculum at 30°C (2474 mg CO₂kg^-1h^-1). The DMLs were modelled to produce contour maps of the environmental conditions resulting in maximum/minimum losses. Maximum mycotoxin contamination was always at 0.95 a_w although optimal temperatures were 25-30°C for AFs and 30-35°C for CPA. These results showed a correlation between CO₂ production and mycotoxin accumulation. They also provide valuable information for the creation of a database focused on the development of a post-harvest decision support system to determine the relative risks of contamination with these mycotoxins in stored shelled peanuts.

Machine learning algorithms for the automated classification of contaminated maize at regulatory limits via infrared attenuated total reflection spectroscopy

Mould infested maize poses a severe problem for farmers, food producers and for consumers worldwide. Mycotoxins are secondary metabolites produced by certain mould species that contaminate food and feed. The consumption of these toxins may cause serious health problems for humans and animals. The trichothecene deoxynivalenol (DON) constitutes one of the most commonly occurring Fusarium toxins encountered in maize and requires improved methods to limit its entrance into the food and feed system. While a variety of chromatographic and mass spectrometry methods for the identification of such toxins have been established, these are considered time-consuming, cost-intensive and require highly qualified personnel. Alternatively, optical techniques, such as mid-infrared spectroscopy offer rapid detection of fungal infections in cereals and other commodities with minimised sample preparation and analysis time. The present study demonstrates a rapid fungal contamination detection strategy in maize taking advantage of IR-spectroscopy combined with advanced machine learning algorithms. The developed method represents an advancement for the analysis of differences in protein and carbohydrate content revealed in the associated IR-spectra related to the amount of toxin contamination at the European Union (EU) regulatory limits for DON in maize (i.e. 1,250 μg/kg). The employed maize varieties are naturally infected samples or have been infected with Fusarium verticillioides, Fusarium graminearum or Fusarium culmorum. Sieved maize samples at the EU regulatory limit were correctly classified using machine learning approaches, therefore enabling the differentiation between DON-contaminated and non-contaminated maize samples. Specifically, a variety of machine learning methods, including Adaptive Boosting (AdaBoost), Random Forests, Support Vector Machine (SVM) and Multilayer Perceptron (MLP) demonstrated excellent classification and validation performance using the obtained IR-spectra. As a result, 183 maize samples of different varieties and infection levels were accurately classified. 94% of the non-contaminated samples and 91% of the contaminated samples were correctly classified using an MLP classification approach.

Influence of storage environment on maize grain: CO2 production, dry matter losses and aflatoxins contamination

Poor storage of cereals, such as maize can lead to both nutritional losses and mycotoxin contamination. The aim of this study was to examine the respiration of maize either naturally contaminated or inoculated with Aspergillus flavus to examine whether this might be an early and sensitive indicator of aflatoxin (AF) contamination and relative storability risk. We thus examined the relationship between different interacting storage environmental conditions (0.80-0.99 water activity (a_w) and 15-35°C) in naturally contaminated and irradiated maize grain + A. flavus on relative respiration rates (R), dry matter losses (DMLs) and aflatoxin B1 and B2 (AFB1-B2) contamination. Temporal respiration and total CO₂ production were analysed by GC-TCD, and results used to calculate the DMLs due to colonisation. AFs contamination was quantified at the end of the storage period by HPLC MS/MS. The highest respiration rates occurred at 0.95 a_w and 30-35°C representing between 0.5% and 18% DMLs. Optimum AFs contamination was at the same a_w at 30°C. Highest AFs contamination occurred in maize colonised only by A. flavus. A significant positive correlation between % DMLs and AFB1 contamination was obtained (r = 0.866, p < 0.001) in the irradiated maize treatments inoculated with A. flavus. In naturally contaminated maize + A. flavus inoculum loss of only 0.56% DML resulted in AFB1 contamination levels exceeding the EU legislative limits for food. This suggests that there is a very low threshold tolerance during storage of maize to minimise AFB1 contamination. This data can be used to develop models that can be effectively used in enhancing management for storage of maize to minimise risks of mycotoxin contamination.

Diversity and fate of fungal metabolites during the preparation of oshikundu, a Namibian traditional fermented beverage

Sorghum and pearl millet, ingredients for the popular Namibian traditional fermented beverage oshikundu, are prone to fungal infection, raising concerns for consumer health from mycotoxin exposure. This study aimed at determining the diversity of fungal metabolites in street-vended ingredients and their transfer rates into oshikundu. A total of 105 samples (40 sorghum malt, 40 pearl millet, 25 oshikundu) were analysed for 700 fungal, bacterial and plant metabolites, using liquid chromatography-tandem mass spectrometry. Of 98 quantified metabolites, 84 were fungal, some being mycotoxins. Aspergillus metabolites were most prevalent (50%, n=42), including aflatoxins, aflatoxin precursors, cyclopiazonic acid and 3-nitropropionic acid from Aspergillus flavus; helvolic acid, gliotoxin and fumiquinazolines from Aspergillus fumigatus and cytochalasin E, patulin and tryptoquivalines from Aspergillus clavatus. High levels of up to 2,280 μg/kg for cyclopiazonic acid and 11,900 μg/kg for 3-nitropropionic acid were quantified in sorghum malts. Other metabolites included fumonisins, curvularin, alternariol and dihydroergosine produced by Fusarium, Penicillium, Alternaria and Claviceps genera, respectively. European Union legislated mycotoxins occurred in cereals at a prevalence range of 3-75%, while none were quantifiable in oshikundu. Aflatoxin B1 was quantified in pearl millet meals (13%) and sorghum malts (50%), with 15% sorghum malts having levels above the European Union regulatory limit of 5 μg/kg. Fumonisin B1 was quantified in pearl millet meals (50%) and sorghum malts (75%) at maximum levels of 3,060 μg/kg and 123 μg/kg respectively, and levels in 5% pearl millet meals were above the European Union regulatory limit of 2,000 μg/kg. Zearalenone and ochratoxin A were quantified in the cereals at levels below European Union regulatory limits. For most metabolites quantifiable in oshikundu, transfer rates from cereals to oshikundu were above 50%, necessitating the use of good quality ingredients for preparing oshikundu and assessment of consumer exposure to mycotoxins.

Developments in mycotoxin analysis: an update for 2016-2017

This review summarises developments in the determination of mycotoxins over a period between mid-2016 and mid-2017. Analytical methods to determine aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxins, patulin, trichothecenes and zearalenone are covered in individual sections. Advances in proper sampling strategies are discussed in a dedicated section, as are methods used to analyse botanicals and spices and newly developed LC-MS based multi-mycotoxin methods. This critical review aims to briefly discuss the most important recent developments and trends in mycotoxin determination as well as to address limitations of the presented methodologies.

Mycotoxin contamination of foods in Southern Africa: A 10-year review (2007-2016)

Major staple foods in Southern Africa are prone to mycotoxin contamination, posing health risks to consumers and consequent economic losses. Regional climatic zones favor the growth of one or more main mycotoxin producing fungi, Aspergillus, Fusarium and Penicillium. Aflatoxin contamination is mainly reported in maize, peanuts and their products, fumonisin contamination in maize and maize products and patulin in apple juice. Lack of awareness of occurrence and risks of mycotoxins, poor agricultural practices and undiversified diets predispose populations to dietary mycotoxin exposure. Due to a scarcity of reports in Southern Africa, reviews on mycotoxin contamination of foods in Africa have mainly focused on Central, Eastern and Western Africa. However, over the last decade, a substantial number of reports of dietary mycotoxins in South Africa have been documented, with fewer reports documented in Botswana, Lesotho, Malawi, Mozambique, Zambia and Zimbabwe. Despite the reported high dietary levels of mycotoxins, legislation for their control is absent in most countries in the region. This review presents an up-to-date documentation of the epidemiology of mycotoxins in agricultural food commodities and discusses the implications on public health, current and recommended mitigation strategies, legislation, and challenges of mycotoxin research in Southern Africa.

Developments in mycotoxin analysis: an update for 2015-2016

This review summarises developments in the determination of mycotoxins over a period between mid-2015 and mid-2016. Analytical methods to determine aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxins, patulin, trichothecenes and zearalenone are covered in individual sections. Advances in proper sampling strategies are discussed in a dedicated section, as are methods used to analyse botanicals and spices and newly developed liquid chromatography mass spectrometry based multi-mycotoxin methods. This critical review aims to briefly discuss the most important recent developments and trends in mycotoxin determination as well as to address limitations of presented methodologies.

Safe food and feed through an integrated toolbox for mycotoxin management: the MyToolBox approach

There is a pressing need to mobilise the wealth of knowledge from the international mycotoxin research conductedover the past 25-30 years, and to perform cutting-edge research where knowledge gaps still exist. This knowledgeneeds to be integrated into affordable and practical tools for farmers and food processors along the chain inorder to reduce the risk of mycotoxin contamination of crops, feed and food. This is the mission of MyToolBox – a four-year project which has received funding from the European Commission. It mobilises a multi-actorpartnership (academia, farmers, technology small and medium sized enterprises, food industry and policystakeholders) to develop novel interventions aimed at achieving a significant reduction in crop losses due tomycotoxin contamination. Besides a field-to-fork approach, MyToolBox also considers safe use options ofcontaminated batches, such as the efficient production of biofuels. Compared to previous efforts of mycotoxin reduction strategies, the distinguishing feature of MyToolBox is to provide the recommended measures to theend users along the food and feed chain in a web-based MyToolBox platform (e-toolbox). The project focuseson small grain cereals, maize, peanuts and dried figs, applicable to agricultural conditions in the EU and China. Crop losses using existing practices are being compared with crop losses after novel pre-harvest interventionsincluding investigation of genetic resistance to fungal infection, cultural control (e.g. minimum tillage or cropdebris treatment), the use of novel biopesticides suitable for organic farming, competitive biocontrol treatment and development of novel modelling approaches to predict mycotoxin contamination. Research into post-harvestmeasures includes real-time monitoring during storage, innovative sorting of crops using vision-technology, novelmilling technology and studying the effects of baking on mycotoxins at an industrial scale.

Microbial secondary metabolites in homes in association with moisture damage and asthma

We aimed to characterize the presence of microbial secondary metabolites in homes and their association with moisture damage, mold, and asthma development. Living room floor dust was analyzed by LC-MS/MS for 333 secondary metabolites from 93 homes of 1-year-old children. Moisture damage was present in 15 living rooms. At 6 years, 8 children had active and 15 lifetime doctor-diagnosed asthma. The median number of different metabolites per house was 17 (range 8-29) and median sum load 65 (4-865) ng/m(2) . Overall 42 different metabolites were detected. The number of metabolites present tended to be higher in homes with mold odor or moisture damage. The higher sum loads and number of metabolites with loads over 10 ng/m(2) were associated with lower prevalence of active asthma at 6 years (aOR 0.06 (95% CI <0.001-0.96) and 0.05 (<0.001-0.56), respectively). None of the individual metabolites, which presence tended (P < 0.2) to be increased by moisture damage or mold, were associated with increased risk of asthma. Microbial secondary metabolites are ubiquitously present in home floor dust. Moisture damage and mold tend to increase their numbers and amount. There was no evidence indicating that the secondary metabolites determined would explain the association between moisture damage, mold, and the development of asthma.

Fungal secondary metabolite analysis applied to Cultural Heritage: the case of a contaminated library in Venice

The secondary metabolite production of several fungal strains of Aspergillus creber, Aspergillus jensenii, Aspergillus penicillioides, Aspergillus protuberus, Aspergillus vitricola, Cladosporium cladosporioides, Eurotium chevalieri, Eurotium halophilicum, Penicillium brevicompactum and Penicillium chrysogenum were characterised by liquid chromatography tamdem mass spectometry. All fungi were isolated from both air and book covers as well as from settled dust from a contaminated library in Venice (Italy). For A. creber and A. jensenii, we identified sterigmatocystin, methoxysterigmatocystin, versicolorin A and related precursors/side metabolites from the biosynthetic pathways. Deoxybrevianamid E, neoechinulin A, pseurotin A and D, and rugulusovin were principally detected from the strains of E. halophilicum, an emerging fungal species implicated in book contaminations in specific indoor niches. The analysis of settled dust showed a wide range of toxic or bioactive fungal metabolites. Forty-five different metabolites were identified in different concentrations; in particular, high amounts of asperglaucide, alamethicin, andrastin A, terrecyclic acid and neoechinulin A were detected. Also one bacterial metabolite, chloramphenicole was detected. This study increases the knowledge about metabolite production of several fungal species, as well as on the indoor presence of fungi that are not detected by aerobiological sampling. These results emphasise how routine dusting operations are necessary and essential in order to prevent further microbiological developments in library environments.

Isolation and characterisation of enzymatic zearalenone hydrolysis reaction products

Zearalenone (ZEA) is an oestrogenic mycotoxin produced by several Fusarium species, and it frequently contaminates cereals used for food or animal feed. A ZEA-lactonase of Gliocladium roseum was previously described to hydrolyse ZEA to an unstable intermediate, which spontaneously decarboxylates to non-oestrogenic, decarboxylated hydrolysed ZEA (DHZEN). We expressed a codon-optimised version of the ZEA-lactonase (ZHD101) gene of G. roseum MA 918 with a secretion leader in Pichia pastoris and purified the recombinant enzyme from culture supernatant by His-tag mediated affinity chromatography. After incubation of the enzyme with ZEA, we detected the previously elusive primary reaction product hydrolysed ZEA (HZEN) by liquid chromatography tandem mass spectrometry, purified it by preparative high-performance liquid chromatography, and confirmed its postulated structure ((E)-2,4-dihydroxy-6-(10-hydroxy-6-oxo-1-undecen-1-yl)benzoic acid) by nuclear magnetic resonance techniques. Spontaneous decarboxylation to DHZEN ((E)-1-(3,5-dihydroxy-phenyl)-10-hydroxy-1-undecen-6-one), but not to a previously reported isomer, was observed. Biomass resuspensions of G. roseum strains MA 918 and the strains used for previous work, NBRC 7063 and ATCC 8684, all converted ZEA to HZEN, DHZEN, and further unknown metabolites. We studied partitioning of HZEN and DHZEN between aqueous phases and organic solvents, and found that HZEN did not partition into chloroform as extraction solvent, under the conditions used by previous authors. In contrast, extraction with ethyl acetate at pH 2.0 was suitable for simultaneous extraction of HZEN and DHZEN. The detection of HZEN and its availability as an analytical standard may assist further work towards possible application of ZEA-lactonase (e.g. determining kinetic parameters) for detoxification of ZEA.

Developments in mycotoxin analysis: an update for 2014-2015

This review summarises developments in the determination of mycotoxins over a period between mid-2014 and mid-2015. In tradition with previous articles of this series, analytical methods to determine aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxins, patulin, trichothecenes and zearalenone are covered in individual sections. Advances in proper sampling strategies are discussed in a dedicated section, as are new methods used to analyse botanicals and spices and newly developed LC-MS based multi-mycotoxin methods. The critical review aims to briefly discuss the most important developments and trends in mycotoxin determination as well as to address shortcomings of current methodologies.

In vitro binding assessment and in vivo efficacy of several adsorbents against aflatoxin B1

Aflatoxins are a class of mycotoxins that impair poultry health and performance. Some clays have the ability to adsorb aflatoxins. In our study, mineralogical composition of the tested clays was confirmed by powder X-ray diffraction and simultaneous thermal analysis and their properties like pH, electrical conductivity, exchangeable cations, cation exchange capacity and clay content were determined. For their in vitro assessment regarding aflatoxin B1 (AFB1) adsorption, adsorption tests under ‘intensified conditions’ (low adsorbent and high toxin concentration) were carried out in buffers at various pH values and in real gastric juice followed by isothermal analysis in phosphate buffer. In vivo we used a completely randomised design with 4 replicate pens of 5 chicks assigned to each dietary treatment from hatch to 21 days. Dietary treatments included a negative and a positive control diet (2 mg/kg AFB1), and treatment groups receiving 2 mg/kg AFB1 and 0.5% of one of 8 adsorbents. Results of in vitro experiments ranked the adsorbents as ‘good’ (R, MB, B7, M32, M34, M5; 6 bentonites containing a cis-vacant smectite), ‘average’ (bentonite C2 containing a trans-vacant smectite) or ‘poor’ (zeolite Z08, containing clinoptilolite). The addition of AFB1 significantly reduced feed intake and/or body weight gain of the chicks compared to the negative control and to the treatment groups, except for C2 and Z08. Except Z08, all adsorbents numerically decreased the liver weight compared to the AFB1-fed group. Kidney weights were significantly increased by the addition of AFB1 compared to the control and most adsorbents, except C2 and Z08. Similarly, ‘good’ adsorbents significantly prevented the decrease in serum albumin and serum total protein. The ability of adsorbents to ameliorate AFB1 toxicity in poultry basically correlated with the in vitro findings meaning that ‘poor’ and ‘average’ adsorbents did not (Z08) or only partially (C2) protect against AFB1 in vivo.

Mycotoxin profile of Fusarium armeniacum isolated from natural grasses intended for cattle feed

Fusarium armeniacum has been found as a saprophyte on natural grasses devoted to cattle feed in Argentina. This species has been reported as highly toxigenic due to the production of trichothecenes type A, but the information available about its toxigenic profile is incomplete. Thus, the aim of the present study was to determine the toxigenic ability of 50 F. armeniacum isolates recovered from natural grasses using a multitoxin method based on LC-MS/MS. In addition, morphological identification of 15 selected isolates was confirmed by sequencing the translation elongation factor 1α. Out of the 327 metabolites analysed, only 10 were detected: T-2 toxin (T-2), T-2 triol, T-2 tetraol, HT-2 toxin (HT-2), diacetoxyscirpenol (DAS), monoacetoxyscirpenol (MAS), neosolaniol (NEO), aurofusarin (AUF), beauvericin (BEA) and zearalenone (ZEA). The most common group of mycotoxins produced by the isolates on rice under laboratory conditions was trichothecenes type A, and some minor Fusarium mycotoxins, such as BEA and AUF. Some isolates were also able to produce ZEA. Among the trichothecene type A, HT-2, T-2, NEO were clearly synthesised at the highest levels and frequency, followed by DAS and MAS. HT-2, T-2, NEO and DAS production was detected in 48 (96%), 47 (94%), 47 (94%) and 38 (76%) isolates, respectively. The ability of F. armeniacum, to produce ZEA and AUF has been demonstrated here for the first time. Given the new information provided about the toxigenic profile of this species, commonly associated with natural grasses in Argentina, the threat to animal health posed by this fungus should not be underestimated.

Effect of fungicide application to control Fusarium head blight and 20 Fusarium and Alternaria mycotoxins in winter wheat (Triticum aestivum L.)

Azole fungicides have been reported to be the most effective active substances in the control of Fusarium Head Blight (FHB) and in the reduction of the main mycotoxins that occur in cereal grain, such as deoxynivalenol (DON). Four field experiments have been conducted in North West Italy, over a period of 2 growing seasons, in order to evaluate the effect of azole fungicide (prothioconazole) applications on the prevalence of emerging mycotoxins in common winter wheat under naturally-infected field conditions. Wheat samples have been analysed by means of a dilute-and-shoot multi-mycotoxin LC-MS/MS method. Twenty fungal metabolites were detected: enniatins, aurofusarin, moniliformin, equisetin, DON, deoxynivalenol-3-glucoside, culmorin, bikaverin, beauvericin, fumonisins, fusaric acid, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, nivalenol, zearalenone, decalonectrin, butenolide, tentoxin, alternariol and alternariol methyl ether. The most abundant fungal metabolites were DON and culmorin, with an average contamination in the untreated control of 1,360 μg/kg and 875 μg/kg, respectively, in the growing season with the highest disease pressure (2011-2012). On average, the results have shown that the fungicide application significantly reduced the enniatins (from 127 μg/kg to 46 μg/kg), aurofusarin (from 62 μg/kg to 21 μg/kg), moniliformin (from 32 μg/kg to 16 μg/kg), tentoxin (from 5.2 μg/kg to 2.5 μg/kg) and equisetin (from 0.72 μg/kg to 0.06 μg/kg) contents in all the experiments. However, DON, deoxynivalenol-3-glucoside and culmorin were only significantly reduced in the growing season with the highest disease pressure. The other fungal metabolites were mainly found in traces in the untreated plots. These results, which have been obtained in different environmental and agronomic conditions, have underlined for the first time that the fungicide usually applied to control the FHB and DON content, also consistently reduces the main emerging mycotoxins of winter wheat in temperate areas.

Characterisation and determination of metabolites formed by microbial and enzymatic degradation of ergot alkaloids

Ergot alkaloids are frequent contaminants of cereal crops. Strategies for their inactivation include the use of microorganisms or enzymes as feed additives capable of degrading ergot alkaloids. Recently, an ergopeptine-degrading Rhodococcus erythropolis strain MTHt3 (DSM 25948) has been isolated from soil and the involved enzymes ErgA and ErgB have been identified. The aim of the current study was to characterise the metabolites formed by degradation of various ergopeptines with the MTHt3 strain, its lysate and the purified enzyme ErgA. Using preparative HPLC, 1H-, 13C- and 2D-NMR as well as HR-MS measurements, two main groups of metabolites formed during microbial and enzymatic degradation of ergopeptines were identified: diketopiperazines (cyclic dipeptides, DKPs) and unstable ergine hydroxy carboxylic acids. However, degradation by strain, lysate and enzyme yielded different end-products. Whereas DKPs were transient and lysergic acid the only final product upon incubation of ergopeptines with the R. erythropolis strain, incubation with the lysate resulted in formation of lysergic acid and two isomeric DKPs at different ratios. Enzymatic degradation by ErgA yielded only one DKP isomer and ended at the stage of the ergine hydroxy carboxylic acids which then spontaneously degraded to ergine. In conclusion, we succeeded in identification of metabolites formed by microbial and enzymatic degradation of ergot alkaloids which is a crucial step in the future development of feed additives for gastro intestinal detoxification of ergopeptines in farm animals.

Fungal metabolites diversity in maize and associated human dietary exposures relate to micro-climatic patterns in Malawi

This study investigated the diversity of fungal metabolites in maize across four agro-ecological zones of Malawi. A total of 90 maize samples (for human consumption), collected from farmsteads, were analysed for 235 fungal metabolites using liquid chromatography-tandem mass spectrometry. A total of 65 metabolites were found in the samples. 75% of samples from the hottest agro-ecological zone contained either aflatoxins, fumonisins, deoxynivalenol, zearalenone; or a combination thereof in levels exceeding European Union (EU) maximum levels, whereas the related fraction was only 17% in the cool temperature zone. Aflatoxins, citrinin, 3-nitropropionic acid, monocerin and equisetin were most prevalent and in higher levels in samples from hot agro-ecological zones, whereas deoxynivalenol, nivalenol, zearalenone and aurofusarin were most prevalent in cool agro-ecologies. On the basis of per-capita maize consumption, estimated daily intakes for all samples from hot ecologies were well above the JECFA's provisional maximum tolerable daily intake (PMTDI) of 2.0 μg/kg body weight (bw)/day for fumonisins, whereas the PMTDI of 1.0 μg/kg bw/day for deoxynivalenol was exceeded in relatively more (90%) samples from the cool highlands than the other zones. These results demonstrate the influence of micro-climatic conditions on mycotoxin prevalence patterns and underscores the need for development of agro-ecological specific mycotoxin dietary exposure management strategies.

Mycotoxins and other fungal metabolites in grain dust from Norwegian grain elevators and compound feed mills

Employees at grain elevators and compound feed mills are exposed to large amounts of grain dust during work, frequently leading to airway symptoms and asthma. Although the exposure to grain dust, microorganisms, β-1→3-glucans and endotoxins has been extensively studied, the focus on the mycotoxin content of grain dust has previously been limited to one or few mycotoxins. Our objective was therefore to screen settled grain dust from grain elevators and compound feed mills for fungal metabolites by LC/MS-MS and explore differences between work places, seasons and climatic zones. Seventy fungal metabolites and two bacterial metabolites were detected. Trichothecenes, depsipeptides, ergot alkaloids, and other metabolites from Fusarium, Claviceps, Alternaria, Penicillium, Aspergillus, and other fungi were represented. The prevalence of individual metabolites was highly variable, and the concentration of each metabolite varied considerably between samples. The prevalence and concentration of most metabolites were higher in grain elevators compared to compound feed mills. Differences between seasons and climatic zones were inconclusive. All samples contained multiple mycotoxins, indicating a highly complex pattern of possible inhalational exposure. A mean exposure of 20 ng/m3 of fungal metabolites was estimated, whereas a worst case scenario estimated as much as 10 ?g/m3. Although many of these compounds may be linked to toxicological and immunological effects through experimental or epidemiological studies, it still remains to be determined whether the detected concentrations implicate adverse health outcomes when inhaled.

Quantitation of multiple mycotoxins and cyanogenic glucosides in cassava samples from Tanzania and Rwanda by an LC-MS/MS-based multi-toxin method

A multi-mycotoxin method based on liquid chromatography/tandem mass spectrometry (LC-MS/MS) was used for a mycotoxin survey in 627 samples of processed cassava collected from different districts across Tanzania and Rwanda after the method performance for this matrix had been determined. Matrix effects as well as extraction efficiencies were found to be similar to most other previously investigated matrices with the exception of distinct matrix effects in the negative ionisation mode for early eluting compounds. Limits of detection were far below the regulatory limits set in the European Union for other types of commodities. Relative standard deviations were generally lower than 10% as determined by replicates spiked on two concentration levels. The sample-to-sample variation of the apparent recoveries was determined for 15 individually spiked samples during three different analytical sequences. The related standard deviation was found to be lower than 15% for most of the investigated compounds, thus confirming the applicability of the method for quantitative analysis. The occurrence of regulated mycotoxins was lower than 10% (with the exception of zearalenone) and the related limits were exceeded only in few samples, which suggests that cassava is a comparatively safe commodity as regards mycotoxins. The most prevalent fungal metabolites were emodin, kojic acid, beauvericin, tryptophol, 3-nitropropionic acid, equisetin, alternariol methylether, monocerin, brevianamide F, tenuazonic acid, zearalenone, chrysophanol, monilifomin, enniatins, apicidin and macrosporin. The related concentrations exceeded 1 mg kg(-1) only in few cases. However, extremely high levels of cyanogenic plant toxins, which had been previously added to the method, were observed in few samples, pointing out the need for improved post-harvest management to decrease the levels of these compounds.

Determination of nivalenol in food and feed: an update

Based on the recent scientific opinion published by the EFSA CONTAM panel on the risks to human and animal health related to the presence of nivalenol in food and feed, this article provides an update on the determination of this Fusarium mycotoxin. After a brief introduction into the chemistry of nivalenol, chromatographic methods as well as other approaches are being discussed. Methods for the determination of nivalenol are well established and can be applied for the analysis of cereals, food, feed and biological samples. Accurate quantification of nivalenol is mostly carried out by liquid chromatography coupled with (multi-stage) mass spectrometry (MS) often within a multi-analyte approach. Some novel techniques, such as direct analysis in real time (DART) MS and electrochemical methods, have shown potential to determine nivalenol, but applications for routine measurements are not yet available. None of the currently available analytical methods has been formally validated in interlaboratory validation studies. While a certified calibrant for nivalenol is available, no matrix reference materials have been developed. Due to the scarcity of appropriate antibodies also no rapid immunochemical methods specific for nivalenol have become available.

Developments in mycotoxin analysis: an update for 2012-2013

This review highlights developments in mycotoxin analysis and sampling over a period between mid-2012 and mid-2013. It covers the major mycotoxins: aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxins, patulin, trichothecenes and zearalenone. A wide range of analytical methods for mycotoxin determination in food and feed were developed last year, in particular immunochemical methods and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS)-based methods. After a section on sampling and sample preparation, due to the rapid spread and developments in the field of LC-MS/MS multimycotoxin methods, a separate section has been devoted to this area of research. It is followed by a section on mycotoxins in botanicals and spices, before continuing with the format of previous reviews in this series with dedicated sections on method developments for the individual mycotoxins.

Determination of T-2 and HT-2 toxins in food and feed: an update

Based on the recent scientific opinion of the European Food Safety Authority (EFSA) Panel on Contaminants in the Food Chain on the risks to human and animal health related to the presence of T-2 and HT-2 toxins in food and feed that was published by EFSA in the EFSA Journal, this article provides an update on the determination of these Fusarium mycotoxins. After a brief introduction into the chemistry of these toxins, both chromatographic and immuno-analytical methods are discussed for the determination of these type A trichothecenes. During the last decade, liquid chromatography with (tandem) mass spectrometry has become the most frequently used method for the determination of T-2 and HT-2 toxins, often within a multi-analyte approach. However, complex matrices and the resulting signal suppression effects, as observed particularly in electrospray-mass spectrometry methods owing to matrix effects, may require careful optimisation of clean-up, usage of matrix matched standards, or e.g. the use of internal standards. For specific purposes where extremely low limits of quantification are needed, e.g. for the analysis of duplicate diets, a dedicated gas chromatography method with multistage mass spectrometry has become available. Other novel analytical approaches to determine T-2 and HT-2 toxins in food and feed include biosensor-based methods in surface plasmon resonance and electrochemical formats, as well as DNA microchip assays. For rapid screening, several immunochemical methods (mostly ELISAs) have become available and some are sold as commercial test kits. Whereas these methods work fast, cross-reactivities with other trichothecenes can have an undesired effect on their accuracy. While proficiency tests including T-2 and HT-2 toxins have been carried out, none of the chromatographic or immunochemical methods have been formally validated in interlaboratory validation studies. There are no certified reference materials available for T-2 and HT-2 toxins.

Evaluation of zearalenone, α-zearalenol, β-zearalenol, zearalenone 4-sulfate and β-zearalenol 4-glucoside levels during the ensiling process

Zearalenone-producing Fusarium species can contaminate maize before ensiling and cause reproductive problems in animals. Suspect feeds are only routinely analysed for zearalenone (ZEA), not considering other oestrogenic metabolites or masked derivatives. The aims of the present study were to monitor the levels of ZEA, α-zearalenol (α-ZOL), β-zearalenol (β-ZOL), zearalenone-4-sulfate (ZEA-4S) and β-zearalenol-4-glucoside (β-ZOL-4G) in artificially contaminated maize silage and determine the effect of the ensiling process on these toxins. A laboratory silo model was designed using polystyrene bags filled with previously contaminated chopped whole-plant maize, stored in a dry and cool room and sampled at days 7, 45, 90, 120 and 127. ZEA, α-ZOL, β-ZOL, ZEA-4S and β-ZOL-4G levels were quantified by liquid chromatography – tandem mass spectrometry. Chemical and physical analysis indicated silage maintained good quality in all stages. pH was reduced favourably (P<0.05) from 4.69 to 3.80 during the preservation stage. Dry matter, moisture content and water activity did not vary from day 7 to 127. ZEA, α-ZOL, β-ZOL and ZEA-4S levels also did not change from day 7 to 127, indicating no significant degradation by the ensiling process or silage-native microbiota. This study suggests that ZEA levels remain invariable during the ensiling process, as well as the levels of its derivatives. The presence of highly oestrogenic metabolites, like α-ZOL and the masked ZEA-4S, which are not screened in the routine analyses, increases the overall toxicity of ZEA-contaminated silage.

Comparison of single and multi-analyte methods based on LC-MS/MS for mycotoxin biomarker determination in human urine

The performances of four LC-MS/MS methodologies for determination of up to eight mycotoxin biomarkers in human urines were compared by involving three laboratories that analysed common urine samples spiked at two levels of each biomarker. Each laboratory received a calibration solution, spiked urines and the corresponding unspiked urine. The two spiking levels for each biomarker were chosen by considering the levels naturally occurring in human urines and the limits of quantification of the LC-MS/MS methodologies used by the participating laboratories. The results of each laboratory were evaluated for their z-score values. The percentage of satisfactory z-scores (| z | < 2) were: 100% for deoxynivalenol, de-epoxy deoxynivalenol, aflatoxin M1, β-zearalenol and zearalenone, 87% for α-zearalenol, 50% for ochratoxin A and 42% for fumonisin B1. Good method performances were obtained for most biomarkers at the levels tested in this study, as demonstrated by the overall percentage of satisfactory z-scores for all analytes (87%). Unsatisfactory/questionable z-scores (| z | ≯2) were obtained for fumonisin B1 (7/12 results), ochratoxin A (4/8 results) and ?-zearalenol (1/8 results). The percentage of satisfactory z-scores for fumonisin B1 and ochratoxin A increased from 42 to 83% for fumonisin B1 and from 50 to 62% for ochratoxin A when laboratories 1 and 2 used own calibrants. Factors that could explain the different results obtained for fumonisin B1 and ochratoxin A with provided and own calibration solutions could not be identified in this study and should be carefully investigated in future studies.

Mycotoxins in corn and wheat silage in Israel

Silage is an important feed source for intensive dairy herds worldwide. Fungal growth and mycotoxin production before and during silage storage is a well-known phenomenon, resulting in reduced nutritional value and a possible risk factor for animal health. With this in mind, a survey was conducted to determine for the first time the occurrence of mycotoxins in corn and wheat silage in Israel. A total of 30 corn and wheat silage samples were collected from many sources and analysed using a multi-mycotoxin method based on LC-MS/MS. Most mycotoxins recorded in the present study have not been reported before in Israel. Overall, 23 mycotoxins were found in corn silage; while wheat silage showed a similar pattern of mycotoxin occurrence comprising 20 mycotoxins. The most common post-harvest mycotoxins produced by the Penicillium roqueforti complex were not found in any tested samples, indicative of high-quality preparation and use of silage. Moreover, none of the European Union-regulated mycotoxins--aflatoxin B1, ochratoxin, T-2 toxin, diacetoxyscirpenol and deoxynivalenol--were found above their limits of detection (LODs). The Alternaria mycotoxins--macrosporin, tentoxin and alternariol methyl ether--were highly prevalent in both corn and wheat silage (>80%), but at low concentrations. The most prominent (>80%) Fusarium mycotoxins in corn silage were fusaric acid, fumonisins, beauvericin, monilifomin, equisetin, zearalenone and enniatins, whereas in wheat silage only beauvericin, zearalenone and enniatins occurred in more than 80% of the samples. The high prevalence and concentration of fusaric acid (mean = 765 µg kg⁻¹) in Israeli corn silage indicates that this may be the toxin of highest potential concern to dairy cow performance. However, more data from different harvest years and seasons are needed in order to establish a more precise evaluation of the mycotoxin burden in Israeli silage.

Investigation of various adsorbents for their ability to bind aflatoxin B1

The contamination of animal feed with mycotoxins represents a worldwide problem for the animal industry. The most applied method for protecting animals against aflatoxicosis is the utilization of clay minerals. In the course of a research project adsorption experiments were performed in buffer solutions in order to evaluate the ability to bind Aflatoxin B1 (AfB1) at various pH-values. In order to investigate the strength of binding, the chemisorption index was calculated. Isothermal analysis was used to determine the values for the maximum adsorption capacity. Adsorption experiments in simulated gastrointestinal fluid and real gastric juice were carried out. Furthermore binding capability of the materials regarding selected vitamins was examined. Special attention was paid to the formation of AfB2a during experimental conditions. Based on the obtainedin vitro results, highly promising sorbent materials were ranked for furtherin vivo studies. Some adsorbing bentonites were also analysed mineralogically, but the results did not indicate which smectite property influences the adsorption process for AfB1.

Validation of chemometric models for the determination of deoxynivalenol on maize by mid-infrared spectroscopy

Validation methods for chemometric models are presented, which are a necessity for the evaluation of model performance and prediction ability. Reference methods with known performance can be employed for comparison studies. Other validation methods include test set and cross validation, where some samples are set aside for testing purposes. The choice of the testing method mainly depends on the size of the original dataset. Test set validation is suitable for large datasets (>50), whereas cross validation is the best method for medium to small datasets (<50). In this study the K-nearest neighbour algorithm (KNN) was used as a reference method for the classification of contaminated and blank corn samples. A Partial least squares (PLS) regression model was evaluated using full cross validation. Mid-Infrared spectra were collected using the attenuated total reflection (ATR) technique and the fingerprint range (800-1800 cm(-1)) of 21 maize samples that were contaminated with 300 - 2600 µg/kg deoxynivalenol (DON) was investigated. Separation efficiency after principal component analysis/cluster analysis (PCA/CA) classification was 100%. Cross validation of the PLS model revealed a correlation coefficient of r=0.9926 with a root mean square error of calibration (RMSEC) of 95.01. Validation results gave an r=0.8111 and a root mean square error of cross validation (RMSECV) of 494.5 was calculated. No outliers were reported.

Short review: Metabolism of theFusarium mycotoxins deoxynivalenol and zearalenone in plants

Plants have a high capacity to transform and thereby detoxify deleterious or poisonous compounds, like mycotoxins. The formation of glucose conjugates has a central role in this process. Mammals, however, are able to (partly) release the precursor substances during digestion, reactivating the mycotoxins. This short review provides a brief summary about the metabolism of theFusarium mycotoxins deoxynivalenol and zearalenone in plants. Two examples are discussed in greater detail. First, the formation of deoxynivalenol-3-glucoside in wheat is linked to a quantitative trait locus that is often used forFusarium head blight resistance breeding. Secondly, the metabolism of zearalenone inArabidopsis thaliana results in at least 17 different metabolites, all of which are potentially hazardous for humans and animals.

Fungal and mycotoxin assessment of dried edible mushroom in Nigeria

In order to determine whether dried mushrooms are a foodstuff that may be less susceptible to infection by toxigenic molds and consequently to mycotoxin contamination, 34 dried market samples were analyzed. Fungal population was determined in the samples by conventional mycological techniques and molecular studies, while the spectrum of microbial metabolites including mycotoxins was analyzed by a liquid chromatography tandem mass spectrometric method covering 320 metabolites. Molds such as Fusarium, Penicillium, Trichoderma and aflatoxigenic species of Aspergillus (Aspergillus flavus and Aspergillus parvisclerotigenus) were recovered from all samples at varying levels. None of the mycotoxins addressed by regulatory limits in the EU was positively identified in the samples. However, 26 other fungal metabolites occurred at sub- to medium μg/kg levels in the samples, including aflatoxin/sterigmatocystin bio-precursors, bis-anthraquinone derivatives from Talaromyces islandicus, emerging toxins (e.g. enniatins) and other Fusarium metabolites, and clavine alkaloids. Although little is known on the toxicology of these substances, the absence of aflatoxins and other primary mycotoxins suggests that dried mushrooms may represent a relatively safe type of food in view of mycotoxin contamination.

Developments in mycotoxin analysis: an update for 2011-2012

This review highlights developments in mycotoxin analysis and sampling over a period between mid-2011 and mid- 2012. It covers the major mycotoxins aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxin, patulin, trichothecenes, and zearalenone. A section on mycotoxins in botanicals and spices is also included. Methods for mycotoxin determination continue to be developed using a wide range of analytical systems ranging from rapid immunochemical-based methods to the latest advances in mass spectrometry. This review follows the format of previous reviews in this series (i.e. sections on individual mycotoxins), but due to the rapid spread and developments in the field of multimycotoxin methods by liquid chromatography-tandem mass spectrometry, a separate section has been devoted to advances in this area of research.

Isotopic labeling-assisted metabolomics using LC-MS

Metabolomics has emerged as the latest of the so-called “omics” disciplines and has great potential to provide deeper understanding of fundamental biochemical processes at the biological system level. Among recent technological developments, LC–HRMS enables determination of hundreds to thousands of metabolites over a wide range of concentrations and has developed into one of the most powerful techniques in non-targeted metabolomics. The analysis of mixtures of in-vivo-stable isotopic-labeled samples or reference substances with un-labeled samples leads to specific LC–MS data patterns which can be systematically exploited in practically all data-processing steps. This includes recognition of true metabolite-derived analytical features in highly complex LC–MS data and characterization of the global biochemical composition of biological samples. In addition, stable-isotopic labeling can be used for more accurate quantification (via internal standardization) and identification of compounds in different organisms.

Development, validation and application of an LC-MS/MS based method for the determination of deoxynivalenol and its conjugates in different types of beer

After water and tea, beer is the third most popular beverage worldwide. Brewed from malted cereal grains, beer is known to be potentially contaminated with mycotoxins. Some studies have shown that not only the Fusarium mycotoxins deoxynivalenol (DON) and 3-acetyl-DON (3-ADON), but also the conjugated mycotoxin deoxynivalenol-3-glucoside (D3G) can be found in beer on a regular basis, albeit usually at low concentrations. The aim of this work was to develop the first triple quadrupole LC-MS/MS based method for the determination of DON, D3G and 3-ADON in beer and to perform an in-house validation. The simple sample preparation includes degassing, precipitation of matrix compounds and reconstitution of the dried-down sample in solvent. Since different kinds of beer exist and method performance parameters will likely differ, we categorised the samples into pale, wheat, dark, bock and non-alcoholic beers, as well as shandies, and validated all six matrices. Although three individual beers for each category were spiked at eight levels prior to sample preparation, the repeatability of the overall method was still excellent with relative standard deviations from 4-16% for all analytes and types of beer. Limits of detection were in the sub- or low-μg/kg range. Apparent recoveries of 60-90% for DON, 39-69% for D3G and 96-124% for 3-ADON were obtained for the different types of beer, with dark and bock beers being the most difficult matrices. To prove the applicability of the method, ten beers of each category were analysed. While average concentrations of 6.6 μg/l for DON and D3G were found, no 3-ADON was detected in any of the samples.

Fast and reproducible chemical synthesis of zearalenone-14-β,D-glucuronide

The Fusarium mycotoxin zearalenone (ZEA) is mainly converted to the conjugate zearalenone-14-β,D-glucuronide (ZEA-14-GlcA) during phase II detoxification in humans and animals. This metabolite - previously described as zearalenone-4-O-β,D-glucuronide - is excreted via urine and could therefore serve as possible biomarker for ZEA exposure to estimate its intake. Direct determination of this substance is limited by the availability of a reference substance. So far, only the production of small amounts by enzymatic synthesis has been described. In this work, a fast and reproducible protocol for the chemical synthesis of ZEA-14-GlcA was developed, using substituted β-resorcylic acid esters as mycotoxin mimics and different glucuronyl donors for optimising the glycosylation (Königs-Knorr, trifluoroacetimidate method) and the deprotection step. This cost-effective procedure should be easily reproducible in other labs using standard equipment and common reagents.

Fungal and bacterial metabolites in commercial poultry feed from Nigeria

Metabolites of toxigenic fungi and bacteria occur as natural contaminants (e.g. mycotoxins) in feedstuffs making them unsafe to animals. The multi-toxin profiles in 58 commercial poultry feed samples collected from 19 districts in 17 states of Nigeria were determined by LC/ESI-MS/MS with a single extraction step and no clean-up. Sixty-three (56 fungal and seven bacterial) metabolites were detected with concentrations ranging up to 10,200 µg kg⁻¹ in the case of aurofusarin. Fusarium toxins were the most prevalent group of fungal metabolites, whereas valinomycin occurred in more than 50% of the samples. Twelve non-regulatory fungal and seven bacterial metabolites detected and quantified in this study have never been reported previously in naturally contaminated stored grains or finished feed. Among the regulatory toxins in poultry feed, aflatoxin concentrations in 62% of samples were above 20 µg kg⁻¹, demonstrating high prevalence of unsafe levels of aflatoxins in Nigeria. Deoxynivalenol concentrations exceeded 1000 µg kg⁻¹ in 10.3% of samples. Actions are required to reduce the consequences from regulatory mycotoxins and understand the risks of the single or co-occurrence of non-regulatory metabolites for the benefit of the poultry industry.

Synthesis of deoxynivalenol-3-ß-D-O-glucuronide for its use as biomarker for dietary deoxynivalenol exposure

Trichothecene mycotoxins are prevalent toxic secondary metabolic products of several fungal species and pose a serious threat to human and animal health. Deoxynivalenol (DON) is known to undergo rapid metabolisation after uptake. The formed glucuronides are urinary excreted and could therefore serve as possible biomarkers for daily uptake measurement. So far human exposure to the major toxin DON was estimated from dietary average intake or by measurement of the parent toxin after hydrolysis. These approaches are indirect and time-consuming. Due to the clear demand for a direct determination method and lack of an available reference substance we synthesised DON-3-O-ö-D-glucuronide. The Königs-Knorr procedure using acetobromo-α-D-glucuronic acid methyl ester as glucuronyl-donor was optimised to produce the target compound in mg scale allowing subsequent characterisation via nuclear magnetic resonance and LC-MS/MS.

Developments in mycotoxin analysis: an update for 2010-2011

This review highlights developments in mycotoxin analysis and sampling over a period between mid-2010 and mid-2011. It covers the major mycotoxins: aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxin, patulin, trichothecenes, and zearalenone. Analytical methods for mycotoxins continue to be developed and published. Despite much interest in immunochemical methods and in the rapid development of LC-MS methodology, more conventional methods, sometimes linked to novel clean-up protocols, have also been the subject of research publications over the above period. Occurrence of mycotoxins falls outside the main focus of this review; however, where relevant to analytical method development, this has been mentioned.

Occurrence of deoxynivalenol and its 3-beta-D-glucoside in wheat and maize

Deoxynivalenol-3-beta-D-glucoside (D3G), a phase II plant metabolite of the mycotoxin deoxynivalenol (DON), occurs in naturally Fusarium-contaminated cereals. In order to investigate the frequency of occurrence as well as the relative and absolute concentrations of D3G in naturally infected cereals, 23 wheat samples originating from fields in Austria, Germany and Slovakia as well as 54 maize samples from Austrian fields were analysed for DON and D3G by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Both analytes were detected in all the 77 field samples. DON was found at levels from 42 to 4130 ng g(-1) (977 +/- 1000 ng g(-1) on average). The D3G concentrations in all cereal samples were in the range 10-1070 ng g(-1) (216 +/- 253 ng g(-1) on average), corresponding to about 5-46 mol% of their DON concentrations (15 +/- 8 mol% on average).

Single-kernel analysis of fumonisins and other fungal metabolites in maize from South African subsistence farmers

Fumonisins are important Fusarium mycotoxins mainly found in maize and derived products. This study analysed maize from five subsistence farmers in the former Transkei region of South Africa. Farmers had sorted kernels into good and mouldy quality. A total of 400 kernels from 10 batches were analysed; of these 100 were visually characterised as uninfected and 300 as infected. Of the 400 kernels, 15% were contaminated with 1.84-1428 mg kg(-1) fumonisins, and 4% (n=15) had a fumonisin content above 100 mg kg(-1). None of the visually uninfected maize had detectable amounts of fumonisins. The total fumonisin concentration was 0.28-1.1 mg kg(-1) for good-quality batches and 0.03-6.2 mg kg(-1) for mouldy-quality batches. The high fumonisin content in the batches was apparently caused by a small number (4%) of highly contaminated kernels, and removal of these reduced the average fumonisin content by 71%. Of the 400 kernels, 80 were screened for 186 microbial metabolites by liquid chromatography-tandem mass spectrometry, detecting 17 other fungal metabolites, including fusaric acid, equisetin, fusaproliferin, beauvericin, cyclosporins, agroclavine, chanoclavine, rugulosin and emodin. Fusaric acid in samples without fumonisins indicated the possibility of using non-toxinogenic Fusaria as biocontrol agents to reduce fumonisin exposure, as done for Aspergillus flavus. This is the first report of mycotoxin profiling in single naturally infected maize kernels.