Fusariummycotoxin content of UK organic and conventional wheat

Exposure estimates to Fusarium mycotoxins through cereals intake

Mycotoxins are harmful substances produced by fungi in several commodities with a widespread presence in foodstuffs. Human exposure to mycotoxins occurs mainly by contaminated food. The quantitation of mycotoxins in cereal-based food, highly consumed by different age population, is of concern. In this survey, 159 cereal-based samples classified as wheat, maize and rice-based, have been evaluated for the occurrence of patulin, deoxynivalenol, 3-acetyl-deoxynivalenol, fusarenon-X, diacetoxyscirpenol, nivalenol, neosolaniol, HT-2, T-2 and zearalenone by gas chromatography-tandem mass spectrometry. Intakes were calculated for average consumers among adults, children and infants and compared with the tolerable daily intakes (TDI). Data obtained were used to estimate the potential exposure levels. 65.4% of the samples were contaminated with at least one mycotoxin and 15.7% of the analyzed samples showed co-occurrence of mycotoxin. The dietary exposure to HT-2 and T-2 toxins was estimated as 0.010 and 0.086 μg kg(-1) bw d(-1), amounting to 10% and 86% of the TDI, for adults and infants respectively. These results back up the necessity to take a vigilant attitude in order to minimize human intake of mycotoxins.

Advanced hyphenated chromatographic-mass spectrometry in mycotoxin determination: current status and prospects

Mass spectrometric techniques are essential for advanced research in food safety and environmental monitoring. These fields are important for securing the health of humans and animals, and for ensuring environmental security. Mycotoxins, toxic secondary metabolites of filamentous fungi, are major contaminants of agricultural products, food and feed, biological samples, and the environment as a whole. Mycotoxins can cause cancers, nephritic and hepatic diseases, various hemorrhagic syndromes, and immune and neurological disorders. Mycotoxin-contaminated food and feed can provoke trade conflicts, resulting in massive economic losses. Risk assessment of mycotoxin contamination for humans and animals generally depends on clear identification and reliable quantitation in diversified matrices. Pioneering work on mycotoxin quantitation using mass spectrometry (MS) was performed in the early 1970s. Now, unambiguous confirmation and quantitation of mycotoxins can be readily achieved with a variety hyphenated techniques that combine chromatographic separation with MS, including liquid chromatography (LC) or gas chromatography (GC). With the advent of atmospheric pressure ionization, LC-MS has become a routine technique. Recently, the co-occurrence of multiple mycotoxins in the same sample has drawn an increasing amount of attention. Thus, modern analyses must be able to detect and quantitate multiple mycotoxins in a single run. Improvements in tandem MS techniques have been made to achieve this purpose. This review describes the advanced research that has been done regarding mycotoxin determination using hyphenated chromatographic-MS techniques, but is not a full-circle survey of all the literature published on this topic. The present work provides an overview of the various hyphenated chromatographic-MS-based strategies that have been applied to mycotoxin analysis, with a focus on recent developments. The use of chromatographic-MS to measure levels of mycotoxins, including aflatoxins, ochratoxins, patulin, trichothecenes, zearalenone, and fumonisins, is discussed in detail. Both free and masked mycotoxins are included in this review due to different methods of sample preparation. Techniques are described in terms of sample preparation, internal standards, LC/ultra performance LC (UPLC) optimization, and applications and survey. Several future hyphenated MS techniques are discussed as well, including multidimensional chromatography-MS, capillary electrophoresis-MS, and surface plasmon resonance array-MS.

Faces of a changing climate: semi-quantitative multi-mycotoxin analysis of grain grown in exceptional climatic conditions in Norway

Recent climatological research predicts a significantly wetter climate in Southern Norway as a result of global warming. Thus, the country has already experienced unusually wet summer seasons in the last three years (2010–2012). The aim of this pilot study was to apply an existing multi-analyte LC-MS/MS method for the semi-quantitative determination of 320 fungal and bacterial metabolites in Norwegian cereal grain samples from the 2011 growing season. Such knowledge could provide important information for future survey and research programmes in Norway. The method includes all regulated and well-known mycotoxins such as aflatoxins, trichothecenes, ochratoxin A, fumonisins and zearalenone. In addition, a wide range of less studied compounds are included in the method, e.g., Alternaria toxins, ergot alkaloids and other metabolites produced by fungal species within Fusarium, Penicillium and Aspergillus. Altogether, 46 metabolites, all of fungal origin, were detected in the 76 barley, oats and wheat samples. The analyses confirmed the high prevalence and relatively high concentrations of type-A and -B trichothecenes (e.g., deoxynivalenol up to 7230 µg/kg, HT-2 toxin up to 333 µg/kg). Zearalenone was also among the major mycotoxins detected (maximum concentration 1670 µg/kg). Notably, several other Fusarium metabolites such as culmorin, 2-amino-14,16-dimethyloctadecan-3-ol and avenacein Y were co-occurring. Furthermore, the most prevalent Alternaria toxin was alternariol with a maximum concentration of 449 µg/kg. A number of Penicillium and Aspergillus metabolites were also detected in the samples, e.g., sterigmatocystin in concentrations up to 20 µg/kg.

Inter-laboratory study of an LC-MS/MS method for simultaneous determination of deoxynivalenol and its acetylated derivatives, 3-acetyl-deoxynivalenol and 15-acetyl-deoxynivalenol in wheat

To validate an LC-MS/MS method for simultaneous determination of deoxynivalenol (DON) and its acetylated derivatives, 3-acetyl-deoxynivalenol (3ADON) and 15-acetyl-deoxynivalenol (15ADON), in wheat using a multifunctional column, an inter-laboratory study was performed in 9 laboratories using one blank wheat sample, three spiked wheat samples (10, 50, 150 µg/kg) and one naturally contaminated wheat sample. The recoveries ranged from 98.8 to 102.6% for DON, 89.3 to 98.7% for 3ADON, and from 84.9 to 90.0% for 15ADON. The relative standard deviations for repeatability (RSDR) and reproducibility (RSDR) of DON were in the ranges of 7.2-11.3% and 9.5-22.6%, respectively. For 3ADON, the RSDR ranged from 5.3 to 9.5% and the RSDR ranged from 16.1 to 18.0%, while for 15ADON, the RSDR ranged from 6.2 to 11.2% and the RSDR ranged from 17.0 to 27.2%. The HorRat values for the three analytes ranged from 0.4 to 1.2. These results validate this method for the simultaneous determination of DON and its acetylated derivatives, 3ADON and 15ADON.

Monitoring of Fusarium trichothecenes in Canadian cereal grain shipments from 2010 to 2012

A method involving dry grinding, rotary sample dividing, and gas chromatography-mass spectrometry was evaluated for the analysis of eight Fusarium trichothecenes in cereal grains. Processing of whole cereal grains by the method produced representative test portions for the analysis of deoxynivalenol (DON). Method validation data, as well as the successful participation in various international proficiency tests, demonstrated the analytical method produced accurate and precise results. The evaluated method was used to monitor DON, 3- and 15-acetyldeoxynivalenol, nivalenol (NIV), T-2 toxin, HT-2 toxin, diacetoxyscirpenol, and fusarenon-X in shipments of Canadian wheat, durum, barley, corn, rye, and oats transported between August 1, 2010, and July 31, 2012. DON was the most frequently measured trichothecene, found in 231 of the 303 samples at concentrations up to 2.34 mg/kg; NIV was the next most frequently observed trichothecene, but its occurrence was limited to barley. Concentrations of DON were significantly associated with wheat class and grade. The median DON concentration in durum (0.09 mg/kg) was lower than that for hard red spring (0.21 mg/kg). Lower grades of wheat also contained higher median concentrations of DON than higher grades, supporting the current use of Fusarium damaged kernels as a grading factor to manage DON.

Deoxynivalenol and other selected Fusarium toxins in Swedish wheat--occurrence and correlation to specific Fusarium species

Wheat is often infected by Fusarium species producing mycotoxins, which may pose health risks to humans and animals. Deoxynivalenol (DON) is the most important Fusarium toxin in Swedish wheat and has previously been shown to be produced mainly by Fusarium graminearum. However, less is known about the co-occurrence of DON and F. graminearum with other toxins and Fusarium species in Sweden. This study examined the distribution of the most important toxigenic Fusarium species and their toxins in winter wheat (2009 and 2011) and spring wheat (2010 and 2011). DNA from seven species was quantified with qPCR and the toxin levels were quantified with a multitoxin analysis method based on liquid chromatography/electrospray ionisation-tandem mass spectrometry (HPLC/ESI-MS/MS). The method enabled detection of many fungal metabolites, including DON, zearalenone (ZEA), nivalenol (NIV), T-2 toxin, HT-2 toxins, moniliformin (MON), beauvericin (BEA), and enniatins (ENNs). It was found that Fusarium poae and Fusarium avenaceum were present in almost all samples. Other common Fusarium species were F. graminearum and F. culmorum, present in more than 70% of samples. Several species occurred at lower DNA levels in 2011 than in other years, but the reverse was true for F. graminearum and Fusarium langsethiae. The most prevalent toxins were ENNs, present in 100% of samples. DON was also common, especially in spring wheat, whereas ZEA and NIV were common in 2009 and in winter wheat, but less common in 2011 and in spring wheat. Only three samples of spring wheat contained T-2 or HT-2 above LOQ. Annual mean levels of several mycotoxins were significantly lower in 2011 than in other years, but the reverse applied for DON. The strongest correlations between mycotoxin and Fusarium DNA levels were found between F. avenaceum and ENNs (r(2) = 0.67) and MON (r(2) = 0.62), and F. graminearum and DON (r(2) = 0.74). These results show that several Fusarium species and toxins co-occur in wheat. The highest toxin levels were detected in spring wheat and DON and ENNs, the latter belonging to the group of so called "emerging toxins", which were the most prevalent toxins and those occurring at the highest levels.

Fusarium damage in cereal grains from Western Canada. 1. Phylogenetic analysis of moniliformin-producing fusarium species and their natural occurrence in mycotoxin-contaminated wheat, oats, and rye

Harvest samples of common wheat (Triticum aestivum), oats (Avena sativa), and rye (Secale cereale) from producers in western Canada were analyzed for fungal infection by toxigenic Fusarium species and contamination by trichothecenes and moniliformin (MON). Fusarium graminearum and F. avenaceum were the two most frequently isolated species from samples of rye and wheat collected in 2010. F. poae and F. sporotrichioides were more commonly detected in randomly selected oat seeds. Other toxigenic Fusarium species including F. acuminatum, F. culmorum, and F. pseudograminearum as well as Phaeosphaeria nodorum (a.k.a. Septoria nodorum) were recovered primarily from fusarium-damaged kernels of wheat. Pure cultures of F. avenaceum, F. acuminatum, and other related species known to produce moniliformin were isolated from incubated seeds based on micro- and macromorphological criteria. The phylogenetic analysis inferred from partial DNA sequences of the acl1 and tef-1α genes revealed two major clades representing F. avenaceum and F. acuminatum, respectively. These clades comprised all Canadian isolates of the two species and a number of reference cultures studied earlier for their propensity to form moniliformin in vitro and in planta. However, some reference cultures previously reported to produce significant amounts of moniliformin formed minor phylogenetic lineages that represent rather distinct but closely related species. Concomitantly, cereal samples were analyzed for the presence of deoxynivalenol and moniliformin. These two Fusarium toxins were observed most frequently in common wheat, at concentrations up to 1.1 and 4.0 mg/kg, respectively. There was no apparent relationship between moniliformin concentrations and detection of F. avenaceum and F. acuminatum in rye and oat samples. Geographical analysis of the distribution of moniliformin and F. avenaceum and F. acuminatum across the Canadian Prairies also did not indicate a strong relationship.

Natural co-occurrence of fungi and mycotoxins in poultry feeds from Entre Ríos, Argentina

A total of 120 pelleted poultry feed samples from Entre Ríos Province, Argentina, were evaluated. The aims were to investigate (1) the presence of relevant toxigenic fungi, as well as to determine the ability to produce aflatoxins (AFs) by Aspergillus section Flavi isolated strains; and (2) the natural co-occurrence of AFs, fumonisins (FBs), gliotoxin, diacetoxyscirpenol (DAS), HT-2 and T-2 toxin by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Total fungal counts were below the established value (1 × 10⁴ CFU g⁻¹). Aspergillus flavus and A. parasiticus were the only aflatoxigenic species isolated. Co-occurrence of fumonisin B₁ (FB₁), HT-2 and T-2 toxin was detected in 100% of the feeds, with mean levels from 4502 to 5813; 6.7 to 21.6 and 19.6 to 30.3 µg kg⁻¹, respectively. A large number of starter samples were co-contaminated with aflatoxin B₁ (AFB₁), FB₁, HT-2 and T-2 toxins. Gliotoxin and DAS were not found in this survey.

Single laboratory evaluation of a planar waveguide-based system for a simple simultaneous analysis of four mycotoxins in wheat

The accuracy and precision of a commercially available system based on an indirect competitive immunoassay and planar waveguide technology was evaluated for the analysis of deoxynivalenol (DON), ochratoxin A (OTA), zearalenone (ZEAR), and T-2 toxin in wheat. The system generally performed well at the tested concentrations that were close to the regulatory limits of DON and OTA in wheat. The mean percent recovery of OTA from certified and in-house reference materials ranged from 90 to 111 %, with a relative standard deviation of 8-16 % (at 4.2, 4.9, and 7.0 μg/kg). Mean percent recoveries of DON ranged from 75 to 103 %, with a relative standard deviation of 14-20 % (at 610, 940, and 1300 μg/kg). As analyte concentrations approached the lower limits of the working range of 3 μg/kg OTA and 400 μg/kg DON, the mean percent recoveries and relative standard deviation increased for both DON and OTA. A lack of reference materials precluded a thorough evaluation of the method for the analysis of ZEAR and T-2. The particular strength of the technology was that multiple mycotoxins were analyzed simultaneously.

Synthetic routes to isotopologues of acetylated derivatives of deoxynivalenol to be used in stable isotope dilution assays

The isomers 3-O-acetyl- and 15-O-acetyldeoxynivalenol (3-ADON and 15-ADON) are intermediates of deoxynivalenol (DON) biosynthesis. Both compounds are present along with DON in contaminated food and feed, but they are not analysed routinely. This review describes synthetic routes to stable isotope labelled 3-ADON and 15-ADON that can be used as internal standards in stable isotope dilution assays. The label was introduced either as [2H3]-acetyl or [13C2]-acetyl group in all protocols. Regioselective acetylation can be obtained by the use of protection groups or stepwise acetylation and hydrolysis. Advantages and disadvantages of both strategies are discussed.

Development of a purification method for simultaneous determination of deoxynivalenol and its acetylated and glycosylated derivatives in corn grits and corn flour by liquid chromatography-tandem mass spectrometry

We developed a purification method based on liquid chromatography-tandem mass spectrometry for the identification of deoxynivalenol (DON), its acetylated derivatives (3-acetyl-deoxynivalenol and 15-acetyl-deoxynivalenol), and a glycosylated derivative (deoxynivalenol-3-glucoside [D3G]) in corn-based products. The analytes were extracted from samples with acetonitrile-water (85:15, vol/vol) and then purified with multifunctional columns. Evaluation of five kinds of multifunctional columns revealed that DON and its acetylated derivatives were recovered well (96 to 120%) by all columns, but D3G was recovered adequately (93.5%) by only one column, InertSep VRA-3. Samples of corn grits and corn flour were analyzed using the purification method with InertSep VRA-3. DON, D3G, and 15-acetyl-deoxynivalenol were the major contaminants in the samples harvested in 2009, but only DON was detected in the samples harvested in 2010. These results suggest that the purification method using InertSep VRA-3 is effective for identification of DON and its derivatives in corn-based products.

A comparison of contents of group A and B trichothecenes and microbial counts in different cereal species

Concentrations of trichothecenes and the amounts of microbial biomass were compared in grain of bread wheat, durum wheat, triticale, rye, oat and barley. Grain samples came from lines regionalised in Poland grown under identical climatic and agricultural conditions in 2007. Among the six analysed cereals, the highest mean concentration of toxic metabolites of 151.89 µg/kg was found for grain of Triticum durum, whereas the lowest was for barley grain (25.56 µg/kg). The highest contamination with microscopic fungi was recorded in case of barley and rice grain (mean concentrations of ergosterol were 12.53 mg/kg and 11.24 mg/kg, respectively). In case of the analysed cereals, the total microbial biomass expressed in the amount of ATP turned out to be the highest (4.7 × 10⁵ relative light units [RLU]) for rye and oat (3.2 × 10⁵ RLU). The results of the applied classical discrimination analysis indicate a significant diversification of species in terms of all the 11 analysed metabolites.

Fusarium species, zearalenone and deoxynivalenol content in preharvest scabby wheat heads from Poland

High incidence of Fusarium head blight occurred in Northern and Southern Poland in the 2009 season. Head samples from 106 wheat fields were collected before harvest from Northern, Central and Southern Poland in August 2009. Fusarium species were identified in 1,311 heads with visible scab symptoms and the collected material was subjected to mycotoxin analyses. Fusarium graminearum was identified as the most frequently occurring species on wheat, present in 48% of all samples examined. This species prevailed in Northern and Southern Poland, with the frequencies of 53% and 55%, respectively, and its frequency has increased over five-fold after two decades. In the central part of the country, Fusarium culmorum was the major pathogen of wheat, with a frequency of 43%, although in this region the incidence of infected heads in wheat fields was lower than 1%. Several other species, including Fusarium avenaceum, Fusarium cerealis and Microdochium nivale, occurred with lower frequencies. Microscopic identification of species was confirmed using species-specific markers in DNA extracted directly from sporodochia. For the first time, glucosylated deoxynivalenol was identified in Polish cereals, in amounts of 1.6 to 7.4 mg/kg. Deoxynivalenol (DON) content was estimated between 1.7 and 11.9 mg/kg for the healthy looking kernels (HLK) fraction, while the Fusarium-damaged kernels (FDK) were contaminated with high amounts of DON, from 57.3 to 312.3 mg/kg, and zearalenone, from 0.035 to 4.48 mg/kg. The HLK fractions contained about 20 times less DON and zearalenone (ZEA) than the FDK fractions. ZEA accumulated in both FDK kernels and chaff fractions at a similar level. DON was accumulated in the chaff fraction in much lower amounts than in the FDK fraction.

Distribution of T-2 and HT-2 toxins in milling fractions of durum wheat

The effect of processing on mycotoxin content in milling fractions has been investigated in 10 samples of durum wheat contaminated with T-2 and HT-2 toxins at levels ranging from 97 to 5,954 μg/kg (sum of T-2 and HT-2 toxins). Either naturally contaminated samples or samples artificially inoculated with Fusarium sporotrichioides under field conditions were used. A method based on liquid chromatography-tandem mass spectrometry coupled with immunoaffinity column cleanup was validated in-house for the simultaneous analysis of both toxins in a variety of matrices, including uncleaned wheat, cleaned wheat, screenings, bran, red dog, fine middlings, and semolina. Mean recoveries from samples spiked with T-2 and HT-2 toxins at levels of 100 μg/kg ranged from 85 to 107%, with relative standard deviations (RSDs) lower than 14%. The milling process led to an increase of T-2 and HT-2 toxin contents up to 13- and 5-fold in screenings and bran, respectively, compared with occurrence in the uncleaned wheat; however, an overall reduction of T-2 and HT-2 toxins by 54% (RSD, 20%) and 89% (RSD, 3%) was observed in cleaned wheat and in semolina, respectively.

Survey of T-2 and HT-2 toxins in soybean and soy meal from Argentina using immunoaffinity clean-up and high performance liquid chromatography

Soybean and soy meal samples collected during the harvest season 2008-2009 in the soybean-growing area of Córdoba Province in Argentina were analysed for T-2 and HT-2 toxins occurrence. These mycotoxins were detected using HPLC analysis with fluorescence detection after derivatisation with 1-anthronylnitrile and immunoaffinity column clean-up. Characteristics of in-house validated method such as accuracy, precision, detection and quantification limits were defined by means of recovery test with spiked soybean and soy meal samples. Mean recoveries for T-2 within the spiking range 125-500 µg/kg, were 90.9 and 81.3% for soybean and soy meal, respectively with a withinlaboratory relative standard deviation <10%. Analysis of samples spiked with HT-2 in the same range gave a mean recovery of 70.2 and 77.5% for soybean and soy meal, respectively, with relative standard deviations <12%. The limit of detection for the method was 25 µg/kg for T-2 and HT-2, based on a signal-to-noise ratio 3:1 and the limit of quantification was established as three times the detection limit. Out of 64 samples, only two soybean samples showed contamination with A-type trichothecenes evaluated. Confirmatory analyses of the contaminated samples were performed by LC-MS/MS. This study demonstrated low incidences and levels of T-2 and HT-2 in soybean harvested among the areas in the Cordoba Province.

Influence of barley malting operating parameters on T-2 and HT-2 toxinogenesis of Fusarium langsethiae, a worrying contaminant of malting barley in Europe

The fungus Fusarium langsethiae, exclusively described in Europe at present, seems to have taken the place of other Fusarium species in barley fields over the last 5 years. It has proved to be a highly toxic type-A trichothecene producer (T-2 and HT-2 toxins). The aim of this work was to study the ecotoxinogenesis of this fungus the better to identify and manage the health risk it may pose during the beer manufacturing process. The influence of temperature and water activity on its growth rate and production of toxins are particularly assessed from a macroscopic point of view. Different cultures were grown on sterilized rehydrated barley with a water activity between 0.630 and 0.997 and a temperature ranging from 5 to 35 degrees C. Biomass specific to F. langsethiae and T-2 and HT-2 toxins were quantified by real-time polymerase chain reaction and liquid chromatography-mass spectrometry, respectively. It appears that the optimal temperature and water activity for F. langsethiae toxinogenesis are 28 degrees C and 0.997. This fungus was able to produce 2.22 g kg(-1) of these toxins in 16 days on barley in optimal production conditions. The malting process seems to be a critical step because, in its temperature range, specific production was six times higher than under optimal temperatures for fungus growth. In the short-term, this work will help redefine the process conditions for malting. In the medium-term, the results will contribute to the development of a molecular tool to diagnose the presence of this contaminant and the detection of the toxins in barley, from fields to the end product.

Health effects of moniliformin: a poorly understood Fusarium mycotoxin

The contamination of the food and feed chain with mycotoxins and the subsequent threat to human health and animal welfare is evident. Today mycotoxin research is still strongly focused on mycotoxins such as aflatoxins, ochratoxin A and for Fusarium fungi mainly the trichothecenes deoxynivalenol (DON) and T-2 and HT-2 toxins. However, fungi of the Fusarium genus are clearly capable of synthesising other mycotoxins as well, including moniliformin (MON). The occurrence of MON is worldwide and the levels in grains vary from below the limit of quantification to the highest detected value in maize intended for human consumption being close to 20 mg/kg. In Finland and Norway, the reported levels are typically a few hundreds of micrograms per kilogram. The toxicology of MON is not well understood. It is characterised by major species differences but typically MON evokes myocardiac damage. For MON, No Observed Adverse Effect Level (NOAEL) has not been established and a provisional Tolerable Daily Intake (pTDI) value has not been proposed. In our risk assessment, we applied a NOAEL value of 10 mg/kg bw/day which is based on our unpublished subchronic exposure experiments. By applying this value in the risk assessment combined with the estimated intakes from food in Finland and Norway, it seems that MON per se does not pose a clear threat to human health at current levels. On the other hand, one needs to bear in mind the concurrent exposure to other mycotoxins and the fact that the risk assessment of mycotoxin mixtures are in their infancy.

T-2 toxin and HT-2 toxin in grain and grain-based commodities in Europe: occurrence, factors affecting occurrence, co-occurrence and toxicological effects

This paper presents an overview of the occurrence of T-2 toxin and HT-2 toxin in cereals in Europe and derived food products, factors influencing the occurrence, co-occurrence with other trichothecenes, and toxicological effects of T-2 and HT-2 in human. Of all cereals, oats showed to be most susceptible to T-2/HT-2 contamination. Particularly, oats grown in Scandinavia and UK in the period 2003-2007 were highly contaminated. This contamination has reduced in 2008 and 2009. In raw cereals, T-2 and HT-2 levels were highly correlated with each other in most instances, with the HT-2 level being two to seven times higher than the T-2 level. The toxin levels showed not to be correlated with levels of deoxynivalenol and nivalenol. The occurrence of T-2 and HT-2 in the field varied between years, regions, cereal grain varieties, sowing time, and precrop. Organically produced cereals contained lower T-2 and HT-2 levels as compared to conventionally grown cereals. Little or no effects from using fungicides was seen. Processing cereals resulted in low T-2 and HT-2 levels in food products, although oat products contained some T-2 and HT-2. The by-products from food processing, often used for animal feeding, frequently were highly contaminated. T-2 and HT-2 showed to have high acute and subacute toxicity, as they caused haematotoxic, immunotoxic, cytotoxic, and dermal effects. Carcinogenicity of T-2 and HT-2 in human has not been proven. Outbreaks of human toxicosis caused by trichothecenes, including T-2 and HT-2, have been reported. The present overview is deemed to be valuable for risk assessments at the European level, planned to be held by EFSA. It also provides directions for further research, including the ecology of the fungi responsible for T-2 and HT-2, and agronomical practices to reduce the contamination in the field.

Reaction of winter wheat (Triticum aestivum L.) cultivars to infection with Fusarium spp.: mycotoxin contamination in grain and chaff

This study compares the susceptibility of winter wheat (Triticum aestivum L.) cultivars to Fusarium head blight (FHB) and accumulation of mycotoxins in kernels and chaff under different climatic conditions in two locations-Cerekwica near Poznan (Central West Poland) and Sitaniec, near Zamosc, Lublin region (South East Poland). Very high variations were found in the concentrations of mycotoxins (zearalenone, ZEA; nivalenol, NIV; deoxynivalenol, DON; moniliformin, MON) in examined fractions: Fusarium-damaged kernels (FDK) and healthy looking kernels (HLK) and in chaff for individual cultivars in both locations. In most cases, significantly higher concentrations of investigated toxins were recorded in wheat from the area of Lublin than from Poznan (p < 0.05). The highest Fusarium infection rates and mycotoxin biosynthesis levels were observed in the Lublin location, with the percentage of the FDK fraction ranging 8.1-81.6. In this region, ZEA concentration (microg g(-1)) after inoculation with F. culmorum and F. graminearum ranged from 0.02-0.48 and 0.32-1.04, respectively. In the Poznan area, the toxin concentrations were considerably lower, ranging 0.01-0.10 and 0.03-0.13 microg g(-1) for both isolates, respectively. The concentration of DON was significantly higher than ZEA or NIV levels. The levels of MON accumulation (microg g(-1)) in the FDK fraction were between 0.14 and 1.73 (Poznan area) and ND (not detected) to 2.51 (Lublin area). F. avenaceum infection rate ranged 7-35% in samples where the toxin was detected.

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.

Birds select conventional over organic wheat when given free choice

BACKGROUND

Global demand for organic produce is increasing by euro4 billion annually. One key reason why consumers buy organic food is because they consider it to be better for human and animal health. Reviews comparing organic and conventional food have stated that organic food is preferred by birds and mammals in choice tests.

RESULTS

This study shows the opposite result-that captive birds in the laboratory and wild garden birds both consumed more conventional than organic wheat when given free choice. There was a lag in preference formation during which time birds learnt to distinguish between the two food types, which is likely to explain why the present results differ from those of previous studies. A further experiment confirmed that, of 16 potential causal factors, detection by birds of consistently higher levels of protein in conventional seeds (a common difference between many organic and conventional foodstuffs) is the likely mechanism behind this pattern.

CONCLUSION

The results of this study suggest that the current dogma that organic food is preferred to conventional food may not always be true, which is of considerable importance for consumer perceptions of organically grown food.

Fusarium mycotoxin content of UK organic and conventional oats

Every year between 2002 and 2005 approximately 100 samples of oats from fields of known agronomy were analysed by GC/MS for 10 trichothecenes: deoxynivalenol (DON), nivalenol, 3-acetylDON, 15-acetylDON, fusarenone X, T-2 toxin (T2), HT-2 toxin (HT2), diacetoxyscirpenol, neosolaniol and T-2 triol. Samples were also analysed for moniliformin and zearalenone by HPLC. Of the 10 trichothecenes analysed from 458 harvest samples of oat only three, 15-acetylDON, fusarenone X and diacetoxyscirpenol, were not detected. Moniliformin and zearalenone were absent or rarely detected, respectively. HT2 and T2 were the most frequently detected fusarium mycotoxins, present above the limit of quantification (10 microg kg(-1)) in 92 and 84% of samples, respectively, and were usually present at the highest concentrations. The combined mean and median for HT2 and T2 (HT2 + T2) was 570 and 213 microg kg(-1), respectively. There were good correlations between concentrations of HT2 and all other type A trichothecenes detected (T2, T2 triol and neosolaniol). Year and region had a significant effect on HT2 + T2 concentration. There was also a highly significant difference between HT2 + T2 content in organic and conventional samples, with the predicted mean for organic samples five times lower than that of conventional samples. This is the largest difference reported for any mycotoxin level in organic and conventional cereals. No samples exceeded the legal limits for DON or zearalenone in oats intended for human consumption. Legislative limits for HT2 and T2 are currently under consideration by the European Commission. Depending on the limits set for unprocessed oats intended for human consumption, the levels detected here could have serious consequences for the UK oat-processing industry.

Fusarium head blight of wheat: pathogenic species and their mycotoxins

Fusarium head blight is a wheat disease of global importance and devastating impact in some years, especially in regions with high cereal production. Wheat grain contamination with mycotoxins is the result of head infection with several Fusarium pathogens. Among all metabolites accumulated in grain of wheat and other cereals infected with Fusarium culmorum and Fusarium graminearum, deoxynivalenol (DON) and other trichothecenes as well as zearalenone (ZEA) are accumulated with the highest levels and frequencies. Furthermore, moniliformin and enniatins were identified in several countries, where Fusarium avenaceum frequency was high. Several other species occurring with lower frequency have been reported. The chemotypes of individual isolates were established with the use of specific PCR markers. This review summarises the information on toxigenic Fusarium species infecting wheat heads, the morphological and molecular identification methods, toxic metabolites accumulated in the infected grain and on recent Fusarium genomic research. The interaction between the aggressive Fusarium pathogens and wheat host plant is discussed, particularly concerning the level of accumulation of DON and ZEA in grain samples. Various types of plant resistance against Fusarium head blight are described, together with wheat quantitative trait loci and DNA markers for their identification, that are useful for resistance breeding. Taking into account the risk of increased occurrence of several Fusarium mycotoxins, regulatory limits of DON, ZEA and fumonisins were established in EU, USA, Canada and other countries.