Fumonisins, trichothecenes and zearalenone in cereals

Dietary L-arginine supplementation protects weanling pigs from deoxynivalenol-induced toxicity

This study was conducted to determine the positive effects of dietary supplementation with l-arginine (Arg) on piglets fed a deoxynivalenol (DON)-contaminated diet. A total of eighteen, 28-day-old healthy weanling pigs were randomly assigned into one of three groups: uncontaminated basal diet (control group), 6 mg/kg DON-contaminated diet (DON group) and 6 mg/kg DON + 1% l-arginine (DON + ARG group). After 21 days of Arg supplementation, piglets in the DON and DON + ARG groups were challenged by feeding 6 mg/kg DON-contaminated diet for seven days. The results showed that DON resulted in damage to piglets. However, clinical parameters, including jejunal morphology, amino acid concentrations in the serum, jejunum and ileum, were improved by Arg (p < 0.05). Furthermore, the mRNA levels for sodium-glucose transporter-1 (SGLT-1), glucose transporter type-2 (GLUT-2) and y⁺l-type amino acid transporter-1 (y⁺LAT-1) were downregulated in the DON group, but the values were increased in the DON + ARG group (p < 0.05). Collectively, these results indicate that dietary supplementation with Arg exerts a protective role in pigs fed DON-contaminated diets.

Fusarium graminearum Isolates from Wheat and Maize in New York Show Similar Range of Aggressiveness and Toxigenicity in Cross-Species Pathogenicity Tests

This study aimed to assess whether pathogenic Fusarium graminearum isolates from wheat and maize were more aggressive on their host of origin and whether aggressiveness was influenced further by B-trichothecene chemotype. Fifteen isolates were selected from a contemporary collection of isolates surveyed in New York in 2011 to 2012 to represent diversity of host of origin and chemotype. Three pathogenicity assays were used to evaluate and compare these isolates. Fusarium head blight (FHB) severity and trichothecene production in wheat, and maize seedling blight were evaluated in greenhouse inoculation experiments, and Gibberella ear rot (GER) severity and trichothecene production were evaluated in maize ears inoculated in the field. Our results showed among F. graminearum isolates a wide variation in aggressiveness and mycotoxin production toward wheat and maize and these isolates could not be structured by their host of origin or by chemotype. Moreover, aggressiveness rank order changed according to the host/organ evaluated. This indicates that relative susceptibility at the seedling stage may not predict susceptibility of ears. Significant correlations were observed of total trichothecenes (deoxynivalenol [DON] and its acetylated derivatives) produced with FHB and GER severity on wheat and maize, respectively. One isolate did not produce DON or ADON in wheat or maize kernels, yet was aggressive on both hosts. Nine of the fifteen isolates produced small amounts of zearalenone (ZON) in maize kernels, but not in wheat kernels, and ZON level was not correlated with GER severity. F. graminearum isolates from New York showed wide variation in aggressiveness and mycotoxin production toward susceptible wheat and maize. Neither host of origin nor trichothecene chemotype appeared to structure the populations we sampled.

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.

Fusarium graminearum Possesses Virulence Factors Common to Fusarium Head Blight of Wheat and Seedling Rot of Soybean but Differing in Their Impact on Disease Severity

Fusarium graminearum is a toxigenic fungal pathogen that causes Fusarium head blight (FHB) and crown rot on cereal crops worldwide. This fungus also causes damping-off and crown and root rots at the early stage of crop development in soybean cultivated in North and South America. Several F. graminearum genes were investigated for their contribution to FHB in cereals but no inherent study is reported for the dicotyledonous soybean host. In this study we determined the disease severity on soybean seedlings of five single gene disrupted mutants of F. graminearum, previously characterized in wheat spike infection. Three of these mutants are impaired on a specific function as the production of deoxynivalenol (DON, Δtri5), lipase (ΔFgl1), and xylanase (Δxyl03624), while the remaining two are MAP kinase mutants (ΔFgOS-2, Δgpmk1), which are altered in signaling pathways. The mutants that were reduced in virulence (Δtri5, ΔFgl1, and ΔFgOS-2) or are avirulent (Δgpmk1) on wheat were correspondently less virulent or avirulent in soybean seedlings, as shown by the extension of lesions and seedling lengths. The Δxyl03624 mutant was as virulent as the wild type mirroring the behavior observed in wheat. However, a different ranking of symptom severity occurred in the two hosts: the ΔFgOS-2 mutant, that infects wheat spikelets similarly to Δtri5 and ΔFgl1 mutants, provided much reduced symptoms in soybean. Differently from the other mutants, we observed that the ΔFgOS-2 mutant was several fold more sensitive to the glyceollin phytoalexin suggesting that its reduced virulence may be due to its hypersensitivity to this phytoalexin. In conclusion, lipase and DON seem important for full disease symptom development in soybean seedlings, OS-2 and Gpmk1 MAP kinases are essential for virulence, and OS-2 is involved in conferring resistance to the soybean phytoalexin.

Differential gene expression and metabolomic analyses of Brachypodium distachyon infected by deoxynivalenol producing and non-producing strains of Fusarium graminearum

BACKGROUND

Fusarium Head Blight (FHB) caused primarily by Fusarium graminearum (Fg) is one of the major diseases of small-grain cereals including bread wheat. This disease both reduces yields and causes quality losses due to the production of deoxynivalenol (DON), the major type B trichothecene mycotoxin. DON has been described as a virulence factor enabling efficient colonization of spikes by the fungus in wheat, but its precise role during the infection process is still elusive. Brachypodium distachyon (Bd) is a model cereal species which has been shown to be susceptible to FHB. Here, a functional genomics approach was performed in order to characterize the responses of Bd to Fg infection using a global transcriptional and metabolomic profiling of B. distachyon plants infected by two strains of F. graminearum: a wild-type strain producing DON (Fgdon+) and a mutant strain impaired in the production of the mycotoxin (Fgdon-).

RESULTS

Histological analysis of the interaction of the Bd21 ecotype with both Fg strains showed extensive fungal tissue colonization with the Fgdon+ strain while the florets infected with the Fgdon- strain exhibited a reduced hyphal extension and cell death on palea and lemma tissues. Fungal biomass was reduced in spikes inoculated with the Fgdon- strain as compared with the wild-type strain. The transcriptional analysis showed that jasmonate and ethylene-signalling pathways are induced upon infection, together with genes encoding putative detoxification and transport proteins, antioxidant functions as well as secondary metabolite pathways. In particular, our metabolite profiling analysis showed that tryptophan-derived metabolites, tryptamine, serotonin, coumaroyl-serotonin and feruloyl-serotonin, are more induced upon infection by the Fgdon+ strain than by the Fgdon- strain. Serotonin was shown to exhibit a slight direct antimicrobial effect against Fg.

CONCLUSION

Our results show that Bd exhibits defense hallmarks similar to those already identified in cereal crops. While the fungus uses DON as a virulence factor, the host plant preferentially induces detoxification and the phenylpropanoid and phenolamide pathways as resistance mechanisms. Together with its amenability in laboratory conditions, this makes Bd a very good model to study cereal resistance mechanisms towards the major disease FHB.

Apoptosis and gene expression in the developing mouse brain of fusarenon-X-treated pregnant mice

Fusarenon-X (FX), a type B trichothecene mycotoxin, is mainly produced by Fusarium crookwellense, which occurs naturally in agricultural commodities, such as wheat and barley. FX has been shown to exert a variety of toxic effects on multiple targets in vitro. However, the embryonic toxicity of FX in vivo remains unclear. In the present study, we investigated FX-induced apoptosis and the relationship between the genetic regulatory mechanisms and FX-induced apoptosis in the developing mouse brain of FX-treated pregnant mice. Pregnant mice were orally administered FX (3.5 mg/kg b.w.) and were assessed at 0, 12, 24 and 48 h after treatment (HAT). Apoptosis in the fetal brain was determined using hematoxylin and eosin staining, the TUNEL method, immunohistochemistry for PCNA and electron microscopy. Gene expressions were evaluated using microarray and real time-reverse transcription polymerase chain reaction (qRT-PCR). Histopathological changes showed that the number of apoptotic cells in the telencephalon of the mouse fetus peaked at 12 HAT and decreased at 24 and 48 HAT. FX induced the up-regulation of Bax, Trp53 and Casp9 and down-regulated Bcl2 but the expression levels of Fas and Casp8 mRNA remained unchanged. These data suggested that FX induces apoptosis in the developing mouse brain in FX-treated dams. Moreover, the genetic regulatory mechanisms of FX-induced apoptosis are regulated by Bax, Bcl2, Trp53 and Casp9 or can be defined via an intrinsic apoptotic pathway.

Deficient glutathione in the pathophysiology of mycotoxin-related illness

Evidence for the role of oxidative stress in the pathophysiology of mycotoxin-related illness is increasing. The glutathione antioxidant and detoxification systems play a major role in the antioxidant function of cells. Exposure to mycotoxins in humans requires the production of glutathione on an “as needed” basis. Research suggests that mycotoxins can decrease the formation of glutathione due to decreased gene expression of the enzymes needed to form glutathione. Mycotoxin-related compromise of glutathione production can result in an excess of oxidative stress that leads to tissue damage and systemic illness. The review discusses the mechanisms by which mycotoxin-related deficiency of glutathione may lead to both acute and chronic illnesses.

Occurrence and within field variability of Fusarium mycotoxins and their masked forms in maize crops in Belgium

Maize ear rot caused by several Fusarium species is an important fungal disease. Apart from yield losses, ear rot fungi can produce mycotoxins and masked forms in infected grains. Masked mycotoxins have received increased attention in view of their bioavailability and potential toxicity in animals and humans, but their presence and relevance in the field still remain undisclosed. To get a better insight, the present study assessed the presence of various Fusarium parent and masked mycotoxins, i.e. deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, deoxynivalenol-3-glucoside, zearalenone, α-zearalenol, β-zearalenol, zearalenone-14-glucoside, zearalenone-14-sulfate, α-zearalenol-14-glucoside, β-zearalenol-14-glucoside, T-2 and HT-2 toxin, in various commercial maize varieties grown under natural infection conditions in Flanders, Belgium. The results showed that the maize varieties were co-contaminated with both parent and masked mycotoxins. Moreover, a positive correlation between these forms was established. A higher contamination with a particular mycotoxin appeared to be coupled with an elevated load of another (masked) mycotoxin. The results highlight the importance to screen for multiple mycotoxins, both parent and masked, to guarantee food and feed safety. Furthermore, analysis was carried out to elucidate the distribution of the various mycotoxins in the field. The maize variety did not significantly influence mycotoxin accumulation, except for deoxynivalenol. Subdivisions in the field with higher mycotoxin levels for deoxynivalenol and its derivatives, zearalenone and its derivatives, and the sum of T-2 and HT-2 toxin were observed.

Fumonisin and T-2 toxin production of Fusarium spp. isolated from complete feed and individual agricultural commodities used in shrimp farming

Fusarium spp. are plant pathogens producing fumonisins and trichothecenes that both affect human and animal health. In the present study, 40 fungal strains were isolated and species identified from 35 shrimp feed samples and from 61 agricultural raw materials. F. verticillioides was the predominant species (85 %) mostly found in corn and soybean meal, while no Fusarium contamination was detected in shrimp feed. Levels of 10 % of F. oxysporum were isolated from peanut and 5 % of F. equiseti contamination in corn and peanut. To determine the ability of toxin production, enzyme-linked immunosorbent assay, polymerase chain reaction, and ultra-pressure liquid chromatography-tandem mass spectrometry were performed. All but four of the fumonisin-producing strains contained the FUM1 gene. No Fusarium synthesized T-2 toxin nor contained the Tri5 gene. This survey brings more data on mycotoxin contamination in the food chain of animal feed production, and leads to the awareness of the use of contaminated raw materials in shrimp farming.

Effects of dietary arginine and glutamine on alleviating the impairment induced by deoxynivalenol stress and immune relevant cytokines in growing pigs

Deoxynivalenol (DON) is a mycotoxin that reduces feed intake and animal performance, especially in swine. Arginine and glutamine play important roles in swine nutrition. The objective of this study was to determine the effects of dietary supplementation with arginine and glutamine on both the impairment induced by DON stress and immune relevant cytokines in growing pigs. A total of forty 60-d-old healthy growing pigs with a mean body weight of 16.28±1.54 kg were randomly divided into 5 groups, and assigned to 3 amino acid treatments fed 1.0% arginine (Arg), 1.0% glutamine (Gln) and 0.5% Arg+0.5% Gln, respectively, plus a toxin control and a non-toxin control. Pigs in the 3 amino acid treatments were fed the corresponding amino acids, and those in non-toxin control and toxin control were fed commercial diet with 1.64% Alanine as isonitrogenous control for 7 days. The toxin control and amino acid treatments were then challenged by feeding DON-contaminated diet with a final DON concentration of 6 mg/kg of diet for 21 days. No significant differences were observed between toxin control and the amino acid groups with regard to the average daily gain (ADG), although the values for average daily feed intake (ADFI) in the amino acid groups were significantly higher than that in toxin control (P<0.01). The relative liver weight in toxin control was significantly greater than those in non-toxin control, arginine and Arg+Glu groups (P<0.01), but there were no significant differences in other organs. With regard to serum biochemistry, the values of BUN, ALP, ALT and AST in the amino acid groups were lower than those in toxin control. IGF1, GH and SOD in the amino acid groups were significantly higher than those in toxin control (P<0.01). The IL-2 and TNFα values in the amino acid groups were similar to those in non-toxin control, and significantly lower than those in toxin control (P<0.01). These results showed the effects of dietary supplementation with arginine and glutamine on alleviating the impairment induced by DON stress and immune relevant cytokines in growing pigs.

Individual and combined cytotoxic effects of Fusarium toxins (deoxynivalenol, nivalenol, zearalenone and fumonisins B1) on swine jejunal epithelial cells

Fusarium mycotoxins occur worldwide in foods such as cereals and animal forages, leading to acute and chronic exposures in human and animals. Intestinal epithelial cells (IECs) are an important first target site for these dietary toxins. This study investigated the cytotoxicity of four common Fusarium mycotoxins, deoxynivalenol (DON), nivalenol (NIV), zearalenone (ZEA) and fumonisin B1 (FB1) on a normal porcine jejunal epithelial cell line, IPEC-J2. A dose response relationship between individual mycotoxins and cell viability (MTT assay) was initially investigated, and subsequently cytotoxic and non-cytotoxic concentrations were selected to investigate combinations of two, three and all four of the mycotoxins. For individual mycotoxins, a dose response was observed with cell viability, such that the potency ranking was NIV>DON>ZEA>FB1. At cytotoxic doses of individual mycotoxins, all mixtures gave reduced cell viability compared to control. At noncytotoxic concentrations of individual mycotoxins, all mixtures were cytotoxic with DON-NIV, DON-ZEA, DON-NIV-FB1, DON-ZEA-FB1, NIV-ZEA-FB1 and all four mixed causing the greatest loss of cell viability. The latter observation in particular raises concerns over safety margins based on single toxin species, and suggests that the effects of multiple complex mixtures need to be better understood to assess health risks.

Ca(2+)-dependent suicidal erythrocyte death following zearalenone exposure

Zearalenone, a cereal mycotoxin with mycoestrogen activity and effect on fertility, is known to trigger apoptosis of a variety of nucleated cell types including hematopoietic progenitor cells. In analogy to apoptosis of nucleated cells, eryptosis, the suicidal death of erythrocytes, leads to cell shrinkage and cell membrane scrambling with phosphatidylserine exposure at the erythrocyte surface. The most important stimulator of eryptosis is an increase in cytosolic Ca(2+) activity ([Ca(2+)]i). The present study explored whether zearalenone triggers eryptosis. Erythrocyte volume was estimated from forward scatter, phosphatidylserine exposure at the erythrocyte surface from annexin-V binding, hemolysis from hemoglobin release, and [Ca(2+)]i from Fluo3 fluorescence. A 48-h exposure to zearalenone (≥25 μM) was followed by a significant increase in [Ca(2+)]i and annexin-V binding, and a significant decrease in forward scatter. The effect on annexin-V binding was significantly blunted in the nominal absence of extracellular Ca(2+). Zearalenone stimulates the suicidal erythrocyte death, an effect at least partially due to stimulation of Ca(2+) entry.

Human exposure to mycotoxins and their masked forms through cereal-based foods in Belgium

In the present study, a quantitative dietary exposure assessment of mycotoxins and their masked forms was conducted on a national representative sample of the Belgian population using the contamination data of cereal-based foods. Cereal-based food products (n=174) were analysed for the occurrence of deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, zearalenone, α-zearalenol, β-zearalenol, T-2-toxin, HT-2-toxin, and their respective masked forms, including, deoxynivalenol-3-glucoside, zearalenone-4-glucoside, α-zearalenol-4-glucoside, β-zearalenol-4-glucoside and zearalenone-4-sulfate. Fibre-enriched bread, bran-enriched bread, breakfast cereals, popcorn and oatmeal were collected in Belgian supermarkets according to a structured sampling plan and analysed during the period from April 2010 to October 2011. The habitual intake of these food groups was estimated from a national representative food intake survey. According to a probabilistic exposure analysis, the mean (and P95) mycotoxin intake for the sum of the deoxynivalenol-equivalents, zearalenone-equivalents, and the sum of HT-2-and T-2-toxin for all cereal-based foods was 0.1162 (0.4047, P95), 0.0447 (0.1568, P95) and 0.0258 (0.0924, P95) μg kg(-1)body weight day(-1), respectively. These values were below the tolerable daily intake (TDI) levels for deoxynivalenol, zearalenone and the sum of T-2 and HT-2 toxin (1.0, 0.25 and 0.1 μg kg(-1)body weight day(-1), respectively). The absolute level exceeding the TDI for all cereal-based foods was calculated, and recorded 0.85%, 2.75% and 4.11% of the Belgian population, respectively.

New 3-O-Alkyl-4a,10a-dihydrofusarubins produced by Fusarium sp. Mj-2

Five new 3-O-alkyl-4a,10a-dihydrofusarubins (2-6) were isolated from the culture filtrate of a strain of Fusarium sp. (Mj-2), together with the known metabolite, anhydrofusarubin (1). The structures of the new metabolites were elucidated by spectroscopic analyses to be 3-O-butyl, 3-O-3'-methylbutyl, 3-O-2'-methylbutyl and 3-O-2'-phenylethyl-4a,10a-dihydrofusarubin A, and an isomer of 3-O-2'-phenylethyl-4a,10a-dihydrofusarubin A. Their antifungal and antibacterial activities were evaluated together with a 3-O-methyl derivative (7) prepared from 3-O-butyl-4a,10a-dihydrofusarubin A (2), indicating that the size of the O-substituent at C-3 in the 4a,10a-dihydrofusarubins negatively affected the metabolites' antimicrobial activity.

Occurrence of deoxynivalenol and zearalenone in commercial fish feed: an initial study

The control of mycotoxins is a global challenge not only in human consumption but also in nutrition of farm animals including aquatic species. Fusarium toxins, such as deoxynivalenol (DON) and zearalenone (ZEN), are common contaminants of animal feed but no study reported the occurrence of both mycotoxins in fish feed so far. Here, we report for the first time the occurrence of DON and ZEN in samples of commercial fish feed designed for nutrition of cyprinids collected from central Europe. A maximal DON concentration of 825 μg kg(-1) feed was found in one feed whereas average values of 289 μg kg(-1) feed were noted. ZEN was the more prevalent mycotoxin but the concentrations were lower showing an average level of 67.9 μg kg(-1) feed.

Fusaodavinvin, a Novel Metabolite Containing Sulfur from the Endophytic Fungus Fusarium sp. (CTGU-ZL-34)

A novel metabolite containing sulfur, fusaodavinvin (1), was isolated from an endophytic fungus Fusarium sp.(CTGU-ZL-34), together with seven known compounds 2-8, and their structures were elucidated by NMR spectroscopy and MS. This is the first record of 3-(2R-hydroxyl-1-one-propane)-indole (compound 2) from nature. The isolated compounds were evaluated using the A549, Hep G2, Caski and MCF-7 cell lines by the MTT method, and compound 1 displayed significant inhibiting activity of four cancer cell lines with IC50 values of 11.5, 15.3, 15.2 and 60.5 μg/mL, respectively. However, compound 2 displayed no significant anticancer activity to the above four cancer cell lines.

[Determination of fumonisins B1 and B2 in corn by high performance liquid chromatography with post-column derivatization method]

A high performance liquid chromatography-fluorescence detection with post-column derivatization method was developed to detect fumonisin B1 (FB1) and fumonisin B2 (FB2) in corn. Several factors, such as the pH of derivatization buffer, concentration and flow rate of derivatization reagents, excitation wavelength, emission wavelength, which affected the detection of fumonisins were optimized. The separation was performed on a ZORBAX SB C18 column operated at 40 degrees C with the gradient elution by two mobile phases of 0.1 mol/L sodium dihydrogen phosphate solution (pH 3.3) and methanol at a flow rate of 0.8 mL/min. The derivatization was performed at ambient temperature. The o-phthalaldehyde (OPA) flow rate was 0.4 mL/min. The results showed that the optimum conditions were pH 10.5 of the derivatization reagent, OPA concentration at 2 g/L, and excitation wavelength of 335 nm, emission wavelength of 440 nm. The linear plots of FB1 and FB2 were obtained between 0.2 to 20 mg/L, with the correlation coefficients above 0.999 for both FB1 and FB2. The limits of detection of fumonisins B1 and B2 were 0.02 mg/kg. The mean recoveries at the three spiked levels of 0.1 - 4.0 mg/kg were 82.5% - 89.8%. This method is accurate, simple, rapid and suitable for the determination of fumonisins B1 and B2 in corn.

Photochemical trans-/cis-isomerization and quantitation of zearalenone in edible oils

The emphasis of the present work was to investigate the photochemical conversion of trans- to cis-zearalenone in edible oils under real-life conditions. For quantitation purposes a cis-zearalenone standard was synthesized and characterized for its identity and purity (≥95%) by (1)H NMR, X-ray crystallography, HPLC fluorescence and mass spectrometric detection. In a sample survey of 12 edible oils (9 corn oils, 3 hempseed oils) from local supermarkets all corn oils contained trans-zearalenone (median 194 μg/kg), but no cis-zearalenone was detected. For alteration studies trans-zearalenone contaminated corn oils were exposed to sunlight over 4 and 30 weeks, revealing an obvious shift toward cis-zearalenone up to a cis/trans ratio of 9:1 by storage in colorless glass bottles. Irradiation experiments of trans-zearalenone in different organic solvents confirmed the preferred formation of cis-zearalenone possibly caused by entropic effects rather than by enthalpic entities as investigated by quantum chemical and classical force field simulations.

Natural occurrence of mycotoxins and their masked forms in food and feed products

A total of 174 cereal-based food products, 67 compound feeds and 19 feed raw materials were analysed for the occurrence of deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, zearalenone, α-zearalenol, β-zearalenol, and their respective masked forms, including deoxynivalenol-3-glucoside, zearalenone-4-glucoside, α-zearalenol-4-glucoside, β-zearalenol-4-glucoside and zearalenone-4-sulfate. Fibre-enriched bread, bran-enriched bread, cornflakes, popcorn and oatmeal were collected in Belgian supermarkets from April 2010 to October 2011. All food samples analysed were contaminated with an average of 2 to 6 mycotoxins, including 1 to 3 masked forms. Feed raw materials that were used in the analysed compound feeds were collected by the manufacturer. Feed raw materials included were beet pulp, sunflower seed meal, soy bean, soy peel, oats, barley, maize germs, maize gluten feed, maize, wheat gluten feed, wheat bran pellets, wheat bran and wheat. Beet pulp, sunflower seed meal, soy bean and soy peel were hardly contaminated. The feed raw materials that were mostly infected with deoxynivalenol, zearalenone and derivatives were maize and its by-products. Also, the glucosylated and sulfated forms occurred in substantial amounts. As well, wheat and its by-products were contaminated with α-zearalenol (wheat gluten feed and wheat bran) and zearalenone (wheat). The contamination pattern and level of feed raw materials were reflected in the corresponding compound feeds.

Exposure assessment of the tehran population (iran) to zearalenone mycotoxin

Zearalenone (ZEA) mycotoxin is a potent estrogenic metabolite. It is the primary toxin causing infertility, abortion or other breeding problems. A HPLC method was validated for ZEA in foods using a monolithic column with sample clean-up on an immunoaffinity column. A certified reference material (CRM) from FAPAS (UK) was analyzed. A survey of ZEA was performed on the 72 samples of rice, bread, puffed corn snack and wheat flour collected from Tehran retail market. The average recovery and coefficient of variation in different foods ranged 92.7-107.1 and 4.9-13.8%, respectively. The amount of ZEA in corn CRM was in the acceptable range of FAPAS. The limit of quantification was 3 ng/g for rice, bread and wheat flour and 2.7 ng/g for puffed corn snack. The retention time of zearalenone was 2.6 min. All samples had contamination level lower than the maximum tolerated level of ZEA in foods in Iran. The mean intake of ZEA from all samples was much lower than the tolerable daily intake estimated by JECFA. This is the first survey on ZEA contamination in bread and rice in Iran as well as the first study on exposure assessment of Tehran population to ZEA.

Development of a simultaneous liquid chromatography/tandem mass spectrometric method for the determination of type B trichothecenes, their derivatives, and precursors in wheat

A method coupling liquid chromatography with tandem mass spectrometry (LC/MS/MS) was developed for the simultaneous quantitative determination of trichothecenes, nivalenol, deoxynivalenol, deoxynivalenol-3-glucoside, fusarenon-X, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, isotrichodermin, calonectrin, 3-deacetylcalonectrin, 15-deacetylcalonectrin, 3,15-diacetylnivalenol, 4,15-diacetylnivalenol, 3,15-diacetyldeoxynivalenol, and 3,4,15-triacetylnivalenol. The analytical parameters of trichothecenes and their derivatives were optimized to enable their highly sensitive detection. Evaluation of clean-up procedures using Multisep #226 and #227 indicated that Multisep #227 was more suitable for their simultaneous detection in wheat. In performance validation studies using the LC/MS/MS method with Multisep #227 cleanup, good recoveries ranging from 84% to 115% with relative standard deviations from 0.4% to 7.2% were measured. The limits of detection and quantification ranged from 0.03 to 1.4 ng·g(-1) and from 0.1 to 4.7 ng·g(-1) , respectively. The effect of matrices using matrix-matched calibration was estimated to range from 80% to 117% after Multisep #227 cleanup. Multisep #227 clean-up procedure with matrix-free standard calibration achieved accurate quantification without having a considerable effect on matrix compounds. Using the developed method, several trichothecene derivatives and precursors were detected in fungally inoculated wheat samples. The developed LC/MS/MS method is a practical technique that can be used for the quantification of trichothecenes in wheat. This study is the first report of an analytical method used for the simultaneous quantification of major trichothecenes, their derivatives and precursors.

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.

Deoxynivalenol and its toxicity

Deoxynivalenol (DON) is one of several mycotoxins produced by certain Fusarium species that frequently infect corn, wheat, oats, barley, rice, and other grains in the field or during storage. The exposure risk to human is directly through foods of plant origin (cereal grains) or indirectly through foods of animal origin (kidney, liver, milk, eggs). It has been detected in buckwheat, popcorn, sorgum, triticale, and other food products including flour, bread, breakfast cereals, noodles, infant foods, pancakes, malt and beer. DON affects animal and human health causing acute temporary nausea, vomiting, diarrhea, abdominal pain, headache, dizziness, and fever. This review briefly summarizes toxicities of this mycotoxin as well as effects on reproduction and their antagonistic and synergic actions.

(-)-Epigallocatechin gallate suppresses the cytotoxicity induced by trichothecene mycotoxins in mouse cultural macrophages

Trichothecene mycotoxins are toxic secondary metabolites produced by a number of fungi including Fusarium species, which adversely affect lymphocytes. Deoxynivalenol (DON) and HT-2 toxin (HT-2) belong to the trichothecene group of mycotoxins and the occurrence of cereals and foodstuffs with these compounds are serious health problems. The aim of this study was to examine the effect of (-)-epigallocatechin gallate (EGCG), one of the main components in green tea catechins, on DON- or HT-2-induced cytotoxicity in mouse macrophages. EGCG had protective effects against the trichothecene-induced cytotoxicities of both mycotoxins. Additionally, EGCG suppressed the DON-induced activation of caspase-3/7, which is an indicator of apoptosis. These results indicate that EGCG might be useful in protection against DON- or HT-2-induced cell death, suggesting that EGCG could contribute to reducing the toxicities of trichothecenes.

Differential detection of potentially hazardous Fusarium species in wheat grains by an electronic nose

Fungal infestation on wheat is an increasingly grave nutritional problem in many countries worldwide. Fusarium species are especially harmful pathogens due to their toxic metabolites. In this work we studied volatile compounds released by F. cerealis, F. graminearum, F. culmorum and F. redolens using SPME-GC/MS. By using an electronic nose we were able to differentiate between infected and non-infected wheat grains in the post-harvest chain. Our electronic nose was capable of distinguishing between four wheat Fusaria species with an accuracy higher than 80%.

Determination of the LOQ in real-time PCR by receiver operating characteristic curve analysis: application to qPCR assays for Fusarium verticillioides and F. proliferatum

Real-time PCR (qPCR) is the principal technique for the quantification of pathogen biomass in host tissue, yet no generic methods exist for the determination of the limit of quantification (LOQ) and the limit of detection (LOD) in qPCR. We suggest using the Youden index in the context of the receiver operating characteristic (ROC) curve analysis for this purpose. The LOQ was defined as the amount of target DNA that maximizes the sum of sensitivity and specificity. The LOD was defined as the lowest amount of target DNA that was amplified with a false-negative rate below a given threshold. We applied this concept to qPCR assays for Fusarium verticillioides and Fusarium proliferatum DNA in maize kernels. Spiked matrix and field samples characterized by melting curve analysis of PCR products were used as the source of true positives and true negatives. On the basis of the analysis of sensitivity and specificity of the assays, we estimated the LOQ values as 0.11 pg of DNA for spiked matrix and 0.62 pg of DNA for field samples for F. verticillioides. The LOQ values for F. proliferatum were 0.03 pg for spiked matrix and 0.24 pg for field samples. The mean LOQ values correspond to approximately eight genomes for F. verticillioides and three genomes for F. proliferatum. We demonstrated that the ROC analysis concept, developed for qualitative diagnostics, can be used for the determination of performance parameters of quantitative PCR.

Occurrence of fumonisins B(2) and B(4) in retail raisins

Concerns that raisins may be contaminated by fumonisins stem from the persistent occurrence of Aspergillus niger spores on raisins and the recent discovery of fumonisin production by A. niger on grapes, which leads to the widespread occurrence of fumonisin B(2) in wine. This study presents an LC-MS/MS survey of fumonisins in retail raisins. In 10 of 21 brands collected in Denmark, Germany, and The Netherlands, fumonisins B(2) and B(4) were detected at levels up to 13 and 1.3 μg/kg, respectively. Only fumonisin B(2) has been detected in wine, so the presence of fumonisin B(4) in raisins suggests that the fumonisins are produced mainly during the drying process concomitant with the decreasing water activity. Analysis of multiple packages from one manufacturer showed a 3-fold package-to-package variation, suggesting that a few raisins per package are contaminated.

Zearalenone occurrence and human exposure

Among the mycotoxins zearalenone (ZEA) is of interest because of the oestrogenic effects that it, and certain of its metabolites possess. The fungi that produce ZEA are found worldwide, particularly in cereal grains and derived products. This has prompted many surveys to detect these compounds in commodities and foods. As a result, the widespread occurrence of ZEA in foods is well documented. Previous summaries including extensive reports by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), the European Commission's Scientific Cooperation on Questions Relating to Food (SCOOP), and others, have provided significant information on the occurrence of ZEA in commodities and foods. Publication of occurrence data has continued at a rapid pace, and certain of that data, as well as highlights from previous intake and exposure assessments, are summarised herein. Comparing estimates of intake (exposure) with previous estimates of tolerable daily intakes, suggests that, for many of the countries where exposure assessments have been done, the populations are exposed to levels that would be considered safe. The situation may be different in populations that consume large quantities of foods that are susceptible to contamination, or in instances where contamination is atypically high. For much of the world estimates of exposure have not been reported, meaning that for much of the world, the true extent of the relevance of ZEA to human health remains uncharacterised.

Deoxynivalenol: mechanisms of action, human exposure, and toxicological relevance

The trichothecene mycotoxin deoxynivalenol (DON) is produced in wheat, barley and corn following infestation by the fungus Fusarium in the field and during storage. Colloquially known as "vomitoxin" because of its emetic effects in pigs, DON has been associated with human gastroenteritis. Since DON is commonly detected in cereal foods, there are significant questions regarding the risks of acute poisoning and chronic effects posed to persons ingesting this trichothecene. A further challenge is how to best manage perceived risks without rendering critical food staples unavailable to an ever-expanding world population. In experimental animal models, acute DON poisoning causes emesis, whereas chronic low-dose exposure elicits anorexia, growth retardation, immunotoxicity as well as impaired reproduction and development resulting from maternal toxicity. Pathophysiologic effects associated with DON include altered neuroendocrine signaling, proinflammatory gene induction, disruption of the growth hormone axis, and altered gut integrity. At the cellular level, DON induces ribotoxic stress thereby disrupting macromolecule synthesis, cell signaling, differentiation, proliferation, and death. There is a need to better understand the mechanistic linkages between these early dose-dependent molecular effects and relevant pathological sequelae. Epidemiological studies are needed to determine if relationships exist between consumption of high DON levels and incidence of both gastroenteritis and potential chronic diseases. From the perspective of human health translation, a particularly exciting development is the availability of biomarkers of exposure (e.g. DON glucuronide) and effect (e.g. IGF1) now make it possible to study the relationship between DON consumption and growth retardation in susceptible human populations such as children and vegetarians. Ultimately, a fusion of basic and translational research is needed to validate or refine existing risk assessments and regulatory standards for this common mycotoxin.