Influence of agricultural practices on fusarium infection of cereals and subsequent contamination of grain by trichothecene mycotoxins

Grain Harvesting Strategies to Minimize Grain Quality Losses Due to Fusarium Head Blight in Wheat

Fusarium head blight (FHB) reduces wheat grain yield and quality, leading to price discounts due to Fusarium-damaged kernels (FDK), deoxynivalenol (DON) contamination of grain, and reduced test weight (weight per unit volume of grain). Experiments were conducted to determine whether changing combine harvester configurations to differentially remove diseased kernels affected the yield and quality of grain harvested from plots with different mean levels of FHB index (IND, mean proportion of diseased spikelets per spike), achieved with inoculations at different spore densities. Plots were harvested using four combine configurations, with C1 being the standard, set at a fan speed of 1,375 rpm and a shutter opening of 70 mm, and C2, C3, and C4 regulated to fan speeds and shutter openings of 1,475 rpm and 70 mm, 1,475 rpm and 90 mm, and 1,375 rpm and 90 mm, respectively. C3 and C4 consistently had significantly lower mean arcsine-transformed FDK and log-transformed DON and higher mean test weight than did C1. However, C3 and C4 also resulted in significantly lower mean amounts of harvested grain than did C1. The estimated mean responses to combine configuration were consistent across a range of mean IND levels (5 to 35%). Using a common price discount schedule based on the incidence of FDK, DON, and test weight, and the mean values found in the current investigation for these grain-quality variables, configurations C2, C3, and C4 resulted in between $10 and 40/t lower estimated grain price discounts than C1, with the lowest discounts corresponding to C3 and C4. Using the discount values, a range of grain prices, and the mean yield values from this investigation, estimated gross cash income (GCI; mean estimated yield × grain price adjusted for discounts due to inferior quality) was generally higher for grain harvested with C2 and C4 than with C1 or C3, with C4 being the most consistent across a range of IND levels (5 to 35%) and grain prices ($118 to 276/t). For all modified configurations, the greatest increases in GCI over C1 were observed at the lowest tested grain price, and the improvement of GCI over C1 increased with increasing IND up to the highest disease level tested. Thus, these results showed that, when harvesting grain from FHB-affected fields, the improvement in grain quality and reduction in price discounts with a combine adjustment could be great enough to counteract the reduction in harvested grain that results from the adjustment.

Expert study to select indicators of the occurrence of emerging mycotoxin hazards

This article describes a Delphi-based expert judgment study aimed at the selection of indicators to identify the occurrence of emerging mycotoxin hazards related to Fusarium spp. in wheat supply chains. A panel of 29 experts from 12 European countries followed a holistic approach to evaluate the most important indicators for different chain stages (growth, transport and storage, and processing) and their relative importance. After three e-mailing rounds, the experts reached consensus on the most important indicators for each of the three stages: wheat growth, transport and storage, and processing. For wheat growth, these indicators include: relative humidity/rainfall, crop rotation, temperature, tillage practice, water activity of the kernels, and crop variety/cultivar. For the transport and storage stage, they include water activity in the kernels, relative humidity, ventilation, temperature, storage capacity, and logistics. For wheat processing, indicators include quality data, fraction of the cereal used, water activity in the kernels, quality management and traceability systems, and carryover of contamination. The indicators selected in this study can be used in an identification system for the occurrence of emerging mycotoxin hazards in wheat supply chains. Such a system can be used by risk managers within governmental (related) organizations and/or the food and feed industry in order to react proactively to the occurrence of these emerging mycotoxins.

Survey of deoxynivalenol and deoxynivalenol-3-glucoside in cereal-based products by liquid chromatography electrospray ionization tandem mass spectrometry

It is well known that cereal crops exposed to deoxynivalenol (DON) infection are capable of detoxifying this mycotoxin through the plant metabolism. In this context, one major pathway is the conjugation of DON to a glucose moiety giving rise to 3-β-D-glucopyranosyl-4-deoxynivalenol (D3G). Though no longer toxic for plants, this metabolite may potentially be hydrolysed in the digestive tract of humans and animals, releasing thus the toxic precursor (DON). The co-occurrence of DON and D3G in cereal-based products has already been reported but data about their absolute and relative concentrations are still insufficient. In order to contribute to a better understanding of the significance of D3G, the quantitative determination of DON and D3G has been carried out in 22 cereal samples and 4 malt-based products collected from 9 countries by liquid chromatography-tandem mass spectrometry (LCMS/ MS). DON was detected in all cereal samples (min: 3 µg/kg; max: 2,864 µg/kg; median: 176 µg/kg) but only in 1 malt-based product (16 µg/kg) whereas D3G was detected in 21 cereal samples (min: <1 µg/kg; max: 367 µg/kg; median: 19 µg/kg) and only in 1 malt-based product (6 µg/kg). The proportion of D3G in relation to DON concentration was within a 6-29% range with an average value at 12±7% in the tested samples.

Zearalenone risk in European wheat

Zearalenone is an oestrogenic mycotoxin produced by several Fusarium species which can infect cereals, in particular wheat and maize. The predominant species responsible for zearalenone production is Fusarium graminearum, which also produces the trichothecene mycotoxin, deoxynivalenol. The infection and subsequent mycotoxin production by Fusarium spp. is largely dependent on rainfall at flowering and before harvest. High concentrations of zearalenone in particular, appear to be produced during delayed wet harvests. There has been a recent and ongoing increase in F. graminearum incidence resulting in increased occurrence of deoxynivalenol and zearalenone across northern Europe, where delayed wet harvests are more common. Zearalenone contamination of grain is largely restricted to the outer layers of wheat grain and therefore is partitioned into the bran fraction during milling. This results in higher concentrations of zearalenone in high fibre cereal products. After the delayed wet harvest in the UK in 2008, 29% of wheat at harvest exceeded the European limit for unprocessed cereals of 100 µg/kg. This resulted in difficulties in sourcing bran which would allow production of high fibre breakfast cereals within zearalenone limits and the European Commission provided a temporary derogation for high fibre breakfast cereals of 100 µg/kg zearalenone until 31 October 2009. Rainfall data and zearalenone concentrations in UK wheat from the last ten years were used to predict the occurrence of high zearalenone in wheat (10% or more of unprocessed wheat greater than 100 µg/ kg zearalenone). High zearalenone was predicted to occur one year in five for northern Europe which matches the observed incidence for the UK within the last ten years. As a consequence, current legislative limits for zearalenone in cereals and cereal products could impact on the availability of high fibre cereal products one year in five.

On-farm experiments over 5 years in a grain maize/winter wheat rotation: effect of maize residue treatments on Fusarium graminearum infection and deoxynivalenol contamination in wheat

Over the course of 5 years, different maize residue treatments were conducted on 14 zero tillage on-farm sites in Switzerland to evaluate their effect on the development of Fusarium head blight (FHB) and the contamination with the mycotoxin deoxynivalenol (DON) in winter wheat grains and wheat straw following grain maize. Two experimental series with three and five different treatments were carried out, respectively. Fusarium graminearum (Schwabe) was the predominant FHB-causing species with an overall incidence of 15% infected wheat grains. A significant correlation between symptoms in the field, F. graminearum incidence and DON content in wheat grains and wheat straw was observed. The average DON content in both wheat grains and wheat straw was approximately 5,000 μg/kg and thus several times higher than the European maximum limit of 1,250 μg/kg for unprocessed small-grain cereals for human consumption. Of all grain samples, 74% were above the maximum limit. Pooled over both experimental series, the average reduction of DON in grains through treatments of the maize residue compared with a control treatment ranged between 21 and 38%. The effect of various other factors, including the year, the wheat variety, the site, the maize hybrid and the production system was evaluated as well. The year and the wheat variety were the most important FHB influencing factors. Over all treatments, the variety Levis showed a fivefold higher average DON content compared with the variety Titlis. From different categories of maize residue particles, intact pieces of 5-15 cm length were strongly correlated with F. graminearum incidence and DON content in grains. During the time course of this study, the recommendation from a preliminary version of the internet-based DON forecasting system FusaProg to apply or to omit a fungicide treatment was correct in 32 out of 42 cases. The results are currently being used to optimise the FusaProg models. This study has shown that in a grain maize/winter wheat rotation, the DON content in wheat grains frequently exceeded the European maximum limit, even with a thorough treatment of maize residues and less susceptible wheat varieties. Hence, in order to reduce the contamination risk in a zero tillage system, the crop rotation needs to be modified.

Fusarium mycotoxins in various barley cultivars and their transfer into malt

BACKGROUND

Fusarium toxins, secondary metabolites of toxinogenic Fusarium species, are found in a range of cereal grains. In this study the occurrence of the most commonest Fusarium toxins, namely nivalenol (NIV), deoxynivalenol (DON), deoxynivalenol-3-glucoside, fusarenon-X, 3- and 15-acetyldeoxynivalenol, HT-2 and T-2 toxins and zearalenone, in various barley cultivars harvested in 2005-2008 was monitored. The impact of weather, locality, fungicide treatment and barley cultivar (hulless or covered) on contamination was evaluated. The transfer of these mycotoxins into malt was assessed.

RESULTS

The most prevalent toxin was DON, which was found in 83% of samples (maximum level 180 µg kg(-1)), while HT-2 was detected in 62% of samples (maximum level 716 µg kg(-1)). Using analysis of covariance, weather was found to be the key factor in all years (P < 0.001). A relationship between cultivar and contamination was confirmed only for HT-2 (P < 0.001) and T-2 (P = 0.037), with higher levels of these toxins being observed in hulless cultivars. With the exception of NIV (P = 0.008), no significant relationship was found between fungicide treatment and contamination. No distinct trend regarding DON levels in malt was found, with both decreases and increases occurring.

CONCLUSION

The results show an inter-annual variation in mycotoxin occurrence in barley cultivars as well as differences in contamination of malt produced from fungicide-treated and untreated barley.

Distribution of deoxynivalenol and nivalenol in milling fractions from fusarium-infected Japanese wheat cultivars

The fate of the Fusarium mycotoxins deoxynivalenol and nivalenol during the milling of Japanese wheat cultivars artificially infected with Fusarium was investigated. Grain samples with different mycotoxin concentrations were milled using a laboratory-scale test mill to produce eight fractions: three breaking flours (1B, 2B, and 3B), three reduction flours (1M, 2M, and 3M), wheat bran, and wheat shorts. Patent flour for human consumption was made from the 1B, 2B, 1M, and 2M flours, and low-grade flour was made from 3B and 3M flours. The four resulting samples (patent flour, low-grade flour, bran, and shorts) were analyzed for deoxynivalenol and/or nivalenol with an in-house validated analytical method using high-performance liquid chromatography with UV absorbance detection. In samples with different mycotoxin concentrations, the distribution of those toxins differed among the milling fractions. Grains with a lower level of contamination produced bran and shorts samples with a high relative concentration of nivalenol. A high percentage of nivalenol was found in patent flour, followed by bran. Contrary to the less-contaminated sample, the concentration of nivalenol in moderately contaminated grain was high only in the shorts sample. The highest percentage of deoxynivalenol and nivalenol was observed in the patent flour. The results of this study indicate that the distribution of deoxynivalenol and nivalenol in milled Japanese wheat could be influenced by the contamination level of the original grain, and the milling process is not always effective for removal of toxins from wheat grains.

Less Fusarium infestation and mycotoxin contamination in organic than in conventional cereals

A total of 602 samples of cereals, consisting of organically and conventionally produced barley, oats and wheat, were collected at harvest during 2002-2004 in Norway. Organic and conventional cereals were sampled in comparable numbers regarding cereal species, localisation and harvest time, and analysed for Fusarium mould and mycotoxins. Fusarium infestation and mycotoxin content were dependent on cereal species and varied year-by-year. However, in all cereal species, Fusarium infestation and levels of important mycotoxins were significantly lower when grown organically than conventionally. Concerning the most toxic trichothecenes, HT-2 and T-2 toxin, lower concentrations were found in organic oats and barley. Wheat was not contaminated by HT-2 and T-2, but lower concentrations of deoxynivalenol (DON) and moniliformin (MON) were found when organically produced. For mycotoxins considered to constitute the main risk to humans and animals in Norwegian cereals, i.e. HT-2 in oats and DON in oats and wheat, the median figures (mean levels in brackets) were as follows: HT-2 in organic and conventional oats were <20 (80) and 62 (117) microg/kg, DON in organic and conventional oats were 24 (114) and 36 (426) microg/kg, and DON in organic and conventional wheat were 29 (86) and 51 (170) microg/kg, respectively. Concentrations of HT-2 and T-2 in the samples were strongly correlated (r = 0.94). Other mycotoxins did not show a significant correlation to each other. Both HT-2 and T-2 concentrations were significantly correlated with infestation of F. langsethiae (r = 0.65 and r = 0.60, respectively). Concentrations of DON were significantly correlated with F. graminearum infestation (r = 0.61). Furthermore, nivalenol (NIV) was significantly correlated with infestation of F. poae (r = 0.55) and MON with F. avenaceum (r = 0.37). As lower Fusarium infestation and mycotoxin levels were found in organic cereals, factors related to agricultural practice may reduce the risk of contamination with Fusarium mycotoxins. Studies of these issues will be presented separately.

Assessment of deoxynivalenol (DON) adsorbents and characterisation of their efficacy using complementary in vitro tests

Deoxynivalenol (DON) is a prevalent and resistant mycotoxin found in cereals and related products. Adsorbents appear to provide an opportunity to decrease DON absorption in animals but, due to their specificity, it is very difficult to evaluate their actual efficacy. It is pointless to extrapolate results obtained with one mycotoxin to another and even to extrapolate results obtained in vitro in buffer to an in vivo situation. We carried out experiments to characterize the properties of potential DON adsorbents. Initial tests in buffer pH 7 allowed us to focus on six adsorbents: activated charcoal, cholestyramin, Saccharomyces cerevisiae mannans, algal beta-glycan, fungal beta-glycan and leguminous plant. The use of equilibrium sorption models suggested a non-saturated phenomenon and involved variable mechanisms according to the specific material. Subsequent tests with a Caco-2 cell model showed a high reduction in DON cytotoxicity on proliferative intestinal cells and DON absorption by differentiated intestinal cells when adsorbent was added (except for cholestyramin). Otherwise, values were not always in accordance with those obtained in buffer. Our work allowed us to identify five potential DON adsorbents and to propose a complementary in vitro test allowing improved determination of adsorbent properties.

Survival of native Pseudomonas in soil and wheat rhizosphere and antagonist activity against plant pathogenic fungi

Survival of Pseudomonas sp. SF4c and Pseudomonas sp. SF10b (two plant-growth-promoting bacteria isolated from wheat rhizosphere) was investigated in microcosms. Spontaneous rifampicin-resistant mutants derived from these strains (showing both growth rate and viability comparable to the wild-strains) were used to monitor the strains in bulk soil and wheat rhizosphere. Studies were carried out for 60 days in pots containing non-sterile fertilized or non-fertilized soil. The number of viable cells of both mutant strains declined during the first days but then became established in the wheat rhizosphere at an appropriate cell density in both kinds of soil. Survival of the strains was better in the rhizosphere than in the bulk soil. Finally, the antagonism of Pseudomonas spp. against phytopatogenic fungi was evaluated in vitro. Both strains inhibited the mycelial growth (or the resistance structures) of some of the phytopathogenic fungi tested, though variation in this antagonism was observed in different media. This inhibition could be due to the production of extracellular enzymes, hydrogen cyanide or siderophores, signifying that these microorganisms might be applied in agriculture to minimize the utilization of chemical pesticides and fertilizers.

Mycotoxins in animal and human patients

The majority of human food and animal feed production occurs in a highly managed agroecosystem. Management decisions include variety grown, tillage and irrigation methods and practices, fertilization, pest and disease control, harvesting methods, and storage and transportation practices. This system is generally managed for optimum returns to labor and capital investments. The spores of toxigenic fungi have ubiquitous distribution and toxigenic fungi exploit food sources when conditions of moisture and temperature are above minimums for growth. The safety margins in the agroecosystem are close and are influenced by extrinsic factors such as climatic events. Control of fungal growth is important in management of raw feedstuffs, foodstuffs, condiments-spices, botanicals, and other consumable substances as they are grown, harvested, stored, and transported. The risk factors for mycotoxin production are weather conditions during crop growth and when the crop is mature, damage to seeds before, during, and after harvest, how commodities are physically handled, the presence of weed seeds and other foreign material in grain, and how commodity moisture and temperature are managed during storage and transportation. Diversion of commodities and by-products from human consumption to animal feedstuffs can increase the risk of mycotoxicoses in animals. The toxicology of selected toxigenic fungi and the mycotoxins they produce are reviewed.

Improved microwave-mediated synthesis of 3-(3-aryl-1,2,4-oxadiazol-5-yl)propionic acids and their larvicidal and fungal growth inhibitory properties

The synthesis of 3-(3-aryl-1,2,4-oxadiazol-5-yl)propionic acids from arylamidoximes and succinic anhydride under focused microwave irradiation conditions is described. The new synthetic method furnished the desired products in 2-3 min and good yields. Furthermore, the previously complicated purification procedure has been simplified in a manner which is quick, eco-friendly and cost-effective. Larvicidal bioassay and fungal growth inhibitory tests were performed using several 3-(3-aryl-1,2,4-oxadiazol-5-yl)propionic acids. These acids presented strong larvicidal activity against L4 larvae of Aedes aegypti. The results suggest that larvicidal activity might be correlated with the presence of electron-withdrawing substituents in the para position of the phenyl ring except the fluorine atom. The alterations observed in the larvae spiracular valves of the siphon and anal papillae by 1,2,4-oxadiazoles in the larvicidal bioassay are responsible for larvae's death. Furthermore, all acids inhibited the fungal growth of five different types of fungi, viz., Fusarium solani, F. oxysporum, F. moniliforme, F. decemcellulare and F. lateritium in a preliminary evaluation. Both of these activities are being disclosed for the first time for 1,2,4-oxadiazole-5-yl ring linked at C-3 of propionic acid.

Climate change and food safety: an emerging issue with special focus on Europe

According to general consensus, the global climate is changing, which may also affect agricultural and livestock production. The potential impact of climate change on food security is a widely debated and investigated issue. Nonetheless, the specific impact on safety of food and feed for consumers has remained a less studied topic. This review therefore identifies the various food safety issues that are likely to be affected by changes in climate, particularly in Europe. Amongst the issues identified are mycotoxins formed on plant products in the field or during storage; residues of pesticides in plant products affected by changes in pest pressure; trace elements and/or heavy metals in plant products depending on changes in their abundance and availability in soils; polycyclic aromatic hydrocarbons in foods following changes in long-range atmospheric transport and deposition into the environment; marine biotoxins in seafood following production of phycotoxins by harmful algal blooms; and the presence of pathogenic bacteria in foods following more frequent extreme weather conditions, such as flooding and heat waves. Research topics that are amenable to further research are highlighted.

Influence of agricultural practices on the contamination of maize by fumonisin mycotoxins

The objective of the present work was to investigate the effect of different agricultural practices on the contamination of maize by fumonisin mycotoxins. Corn samples were collected from 16 maize fields located in Aragón (northeastern Spain) during the 2007 crop year. Corn samples were collected from each field five times at different maturation stages: F1, day 0 (milky corn); F2, day 15; F3, day 30 (yellow corn); F4, day 45; and F5, ripe corn at harvest. The agricultural practices evaluated were type of seed (conventional and transgenic), planting method (dry and wet planting), tillage system (plowing and minimum tillage), type of irrigation (flood and sprinkler), residue management of preceding crop (removal and burial), nitrogen fertilization level (kg N per ha), and harvest date. Mycotoxin analysis was carried out with the ROSA Fumonisin test, which measures both fumonisin B1 and B2 by lateral flow immunoassay. No fumonisins were detected in milky corn (F1 and F2 stages). Only one field had fumonisins in F3 yellow corn (1,037 microg/kg); this field was part of the only farm affected by borer insects. One-third of fields had fumonisins at the F4 stage (363 microg/kg), and 62.5% of the fields were positive for fumonisins at the F5 harvest stage (520 microg/kg). Wet planting and the removal of debris from the previous crop significantly lowered the risk of fumonisin in corn. The use of insect-resistant maize seeds tended to reduce fumonisin levels. However, higher levels of nitrogen fertilizer had a tendency to increase fumonisin levels in corn. Tillage system, type of irrigation, and harvest date had no clear effect on fumonisin levels.

A small protein that fights fungi: AFP as a new promising antifungal agent of biotechnological value

As fungal infections are becoming more prevalent in the medical or agricultural fields, novel and more efficient antifungal agents are badly needed. Within the scope of developing new strategies for the management of fungal infections, antifungal compounds that target essential fungal cell wall components are highly preferable. Ideally, newly developed antimycotics should also combine major aspects such as sustainability, high efficacy, limited toxicity and low costs of production. A naturally derived molecule that possesses all the desired characteristics is the antifungal protein (AFP) secreted by the filamentous ascomycete Aspergillus giganteus. AFP is a small, basic and cysteine-rich peptide that exerts extremely potent antifungal activity against human- and plant-pathogenic fungi without affecting the viability of bacteria, yeast, plant and mammalian cells. This review summarises the current knowledge of the structure, mode of action and expression of AFP, and highlights similarities and differences concerning these issues between AFP and its related proteins from other Ascomycetes. Furthermore, the potential use of AFP in the combat against fungal contaminations and infections will be discussed.

Biocontrol and PGPR Features in Native Strains Isolated from Saline Soils of Argentina

A bacterial collection of approximately one thousand native strains, isolated from saline soils of Cordoba province (Argentina), was established. From this collection, a screening to identify those strains showing plant growth promotion and biocontrol activities, as well as salt tolerance, was performed. Eight native strains tolerant to 1 M: NaCl and displaying plant growth promotion and/or biocontrol features were selected for further characterization. Strains MEP(2 )18, MRP(2 )26, MEP(2 )11a, MEP(3 )1, and MEP(3 )3b significantly increased the growth of maize seedlings under normal and saline conditions, whereas isolates ARP(2 )3, AEP(1 )5, and ARP(2 )6 were able to increase the root dry weight of agropyre under saline conditions. On the other hand, strains MEP(2 )18 and ARP(2 )3 showed antagonistic activity against phytopathogenic fungi belonging to Sclerotinia and Fusarium genus. Antifungal activity was found in cell-free supernatants, and it was heat and protease resistant. Strains MEP(2)18 and ARP(2)3 were identified as Bacillus sp. and strains MEP(2)11a and MEP(3)3b as Ochrobactrum sp. according to the sequence analysis of 16S rRNA gene.

Transepithelial transport of fusariotoxin nivalenol: mediation of secretion by ABC transporters

Mycotoxin nivalenol (NIV) is a natural contaminant of various cereal crops, animal feed and processed grains throughout the world. Human and animal contamination occurs mainly orally, and the toxin must traverse the intestinal epithelial barrier before inducing potential health effects. In this study, we investigated the mechanisms involved in NIV transepithelial transfer. The human intestinal Caco-2 cell line showed a basal-to-apical polarized transport of NIV. Using metabolic inhibitors and temperature-dependent experiments, we demonstrated that basolateral-apical (BL-AP) transfer of NIV involved an energy-dependent transport whereas apical-basolateral (AP-BL) transfer was governed by passive diffusion. NIV efflux was significantly decreased in the presence of the P-glycoprotein (P-gp) inhibitor valspodar, the multi-drug resistance-associated proteins (MRPs) inhibitor MK571, but was not modified by the breast cancer resistance protein (BCRP) inhibitor Ko143. Intracellular NIV accumulation was investigated using epithelial cell lines transfected with either human P-glycoprotein or MRP2. This accumulation was significantly decreased in LLCPK1/MDR1 and MDCKII/MRP2 cells, compared to wild-type cells, and this effect was reversed by valspodar and MK571, respectively. These in vitro results suggested that NIV was a substrate for both P-glycoprotein and MRP2. This interaction may play a key role in weak intestinal absorption of NIV and the mainly predominant excretion of NIV in faeces in animal studies.

Strategies to Prevent Mycotoxin Contamination of Food and Animal Feed: A Review

Mycotoxins are fungal secondary metabolites that have been associated with severe toxic effects to vertebrates produced by many important phytopathogenic and food spoilage fungi including Aspergillus, Penicillium, Fusarium, and Alternaria species. The contamination of foods and animal feeds with mycotoxins is a worldwide problem. We reviewed various control strategies to prevent the growth of mycotoxigenic fungi as well as to inhibit mycotoxin biosynthesis including pre-harvest (resistance varieties, field management and the use of biological and chemical agents), harvest management, and post-harvest (improving of drying and storage conditions, the use of natural and chemical agents, and irradiation) applications. While much work in this area has been performed on the most economically important mycotoxins, aflatoxin B(1) and ochratoxin A much less information is available on other mycotoxins such as trichothecenes, fumonisin B(1), zearalenone, citrinin, and patulin. In addition, physical, chemical, and biological detoxification methods used to prevent exposure to the toxic and carcinogenic effect of mycotoxins are discussed. Finally, dietary strategies, which are one of the most recent approaches to counteract the mycotoxin problem with special emphasis on in vivo and in vitro efficacy of several of binding agents (activated carbons, hydrated sodium calcium aluminosilicate, bentonite, zeolites, and lactic acid bacteria) have also been reviewed.

The antifungal protein AFP secreted by Aspergillus giganteus does not cause detrimental effects on certain mammalian cells

The antifungal protein AFP is a small, cystein-rich protein secreted by the imperfect ascomycete Aspergillus giganteus. The protein efficiently inhibits the growth of filamentous fungi, including a variety of serious human and plant pathogens mainly of the genera Aspergillus and Fusarium, whereas AFP does not affect the growth of yeast and bacteria. This restricted susceptibility range makes it very attractive for medical or biotechnological use to combat fungal infection and contamination. We, therefore, analyzed whether AFP affects the growth or function of a number of mammalian cells. Here we show that the protein neither provokes any cytotoxic effects on human endothelial cells isolated from the umbilical vein nor activates the immune system. Moreover, potassium currents of neurons and astrocytes do not change in the presence of AFP and neither excitatory processes nor the intracellular calcium homeostasis of cultured skeletal muscle myotubes are affected by AFP. Our data, therefore, suggest that AFP is indeed a promising candidate for the therapeutic or biotechnological use as a potential antifungal agent.

Natural occurrence of 16 fusarium toxins in grains and feedstuffs of plant origin from Germany

A total of 220 samples comprising cereals, cereal byproducts, corn plants and corn silage as well as non-grain based feedstuffs was randomly collected during 2000 and 2001 from sources located in Germany and analysed for 16 Fusarium toxins. The trichothecenes scirpentriol (SCIRP), 15-monoacetoxyscirpenol (MAS), diacetoxyscirpenol (DAS), T-2 tetraol, T-2 triol, HT-2 and T-2 toxin (HT-2, T-2), neosolaniol (NEO), deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-ADON), 15-acetyldeoxynivealenol (15-ADON), nivalenol (NIV) and fusarenon-X (FUS-X) were determined by gas chromatography/mass spectrometry. Zearalenone (ZEA) and alpha- and beta-zearalenol (alpha- and beta-ZOL) were analysed by high performance liquid chromatography with fluorescence and UV-detection. Detection limits ranged between 1 and 19 microg/kg. Out of 125 samples of a group consisting of wheat, oats, corn, corn byproducts, corn plants and corn silage only two wheat samples did not contain any of the toxins analysed. Based on 125 samples the incidences were at 2-11% for DAS, NEO, T-2 Triol, FUS-X, alpha- and beta-ZOL, at 20-22% for SCIRP, MAS, T-2 tetraol and 3-ADON, at 44-74% for HT-2, T-2, 15-ADON, NIV and ZEA, and at 94% for DON. Mean levels of positive samples were between 6 and 758 microg/kg. Out of 95 samples of a group consisting of hay, lupines, peas, soya meal, rapeseed meal and other oil-seed meals, 64 samples were toxin negative. DAS, T-2 triol, NEO and FUS-X were not detected in any sample. The incidences of DON and ZEA were at 14 and 23% respectively, those of the other toxins between 1-4%, mean levels of positive samples were between 5 and 95 microg/kg.

Fusariotoxin transfer in animal

Mycotoxin fusariotoxins, essentially represented by trichothecenes, zearalenone and fumonisins, are widely scattered in cereals and their products. Human and animals are particularly concerned by toxicity consecutive to oral chronic exposure. Human exposure can be direct via cereals or indirect via products of animals having eaten contaminated feed. As this alimentary risk is considered as a major problem in public health, it is thus of great importance to determine bioavailability, metabolic pathways and distribution of these mycotoxins in animal and human organism. Most studies indicate that fusariotoxins can be rapidly absorbed in the small intestine but the mechanisms involved remain unclear. Except NIV, fusariotoxins can be partly metabolised into more hydrophilic molecules in digestive tract or liver. Fumonisins present different behaviour as they seem very few and slowly absorbed and metabolised. The main part of absorbed fusariotoxins shows a rapid elimination within 24h after ingestion, followed by a slower excretion of small amounts. However, traces of fusariotoxins or their derivates can be found in animal products. This manuscript, reviewing literature published on fusariotoxin transfer, highlights that too little data are available to correctly appreciate fusariotoxin transfer in organism. Further studies focusing on mechanisms involved in the transfer are needed before clarifying risk assessment for human health.