Impact of agronomic factors on fusarium mycotoxins in harvested wheat

ABSTRACT

The aim of this study was to model fusarium mycotoxins against agronomic factors in order to identify those that have the greatest impact on mycotoxin levels in harvested wheat. To achieve this, fusarium mycotoxins levels were monitored, and associated agronomic data collected, in approximately 150 English wheat fields/year between 2006 and 2013. Results showed large seasonal variation in fusarium mycotoxin levels, with high levels in 2008 (13% and 29% exceeding legal limit for unprocessed soft wheat intended for human consumption for deoxynivalenol (DON) and zearalenone (ZON), respectively) and 2012 (10% and 15% exceeding legal limit for unprocessed soft wheat intended for human consumption for DON and ZON, respectively) and low levels in 2006 and 2011 (no samples exceeding legal limits for unprocessed soft wheat intended for human consumption for DON or ZON). Analysis of agronomic factors identified previous crop, cultivation and variety as the greatest risk factors. The greatest risk of mycotoxin development in grain was following maize as a previous crop and minimum tillage. The combined effect of these factors gave respective average DON and ZON levels 20 and 14 times higher than other previous crop and cultivation combinations. A newly quantified risk factor was harvest date. A 1-month delay in harvest resulted in a 10 and 25 times greater mean DON and ZON concentration, respectively, when compared to crops harvested around the long-term regional average harvest date. These results highlight the highly seasonal variation in fusarium mycotoxins in wheat and the agronomic factors that should be avoided to minimise fusarium mycotoxin levels in harvested wheat.     

The coexistence of the Fusarium mycotoxins nivalenol, deoxynivalenol and zearalenone in Korean cereals harvested in 1983

A survey for the occurrence of nivalenol (NIV), deoxynivalenol (DON) and zearalenone (ZEN) in Korean cereals (totalling 53 samples) harvested in 1983, showed that 96%, 72% and 57% of the samples were contaminated with NIV, DON and ZEN, respectively. Average concentrations (micrograms/kg) in unpolished barley were 546 (NIV), 117 (DON) and 110 (ZEN), and those in polished barley were 130 (NIV) and 21 (DON). The ZEN levels were below the detection limit (1 microgram/kg). Malt, wheat and rye were also heavily contaminated with these Fusarium mycotoxins. The results of this survey show that Korean cereals harvested in 1983 were significantly contaminated with NIV, DON and ZEN, and the incidence and levels, where observed, are similar to those reported in Japan.     

QuEChERS-HPLC-MS/MS法检测谷类杂粮制品中4种真菌毒素

建立了一种快速、高效的QuEChERS-高效液相色谱-质谱联用法（QuEChERS-HPLC-MS/MS）测定谷类杂粮制品中脱氧雪腐镰刀菌烯醇（DON）、3-乙酰脱氧雪腐镰刀菌烯醇（3-ADON）、15-乙酰脱氧雪腐镰刀菌烯醇（15-ADON）和玉米赤霉烯酮（ZON）共4种真菌毒素。样品前处理采用乙腈-水溶剂提取,经Florisil+C18+无水硫酸镁净化后检测。以0.10%甲酸-乙腈作为流动相,在质谱检测器的多反应监测模式下进行分析。结果表明,4种真菌毒素在各自的线性范围内线性关系良好,相关系数R2均大于0.999,回收率在85.1%～102.0%,相对标准偏差（RSD）为2.11%～6.22%。该方法具有前处理简单、净化效果好、灵敏度高和检测速度快的优点,适用于谷类杂粮制品中DON、3-ADON、15-ADON 和ZON的分析和定量检测。     

Further survey on the Fusarium mycotoxins in Korean cereals

Fifty-one samples of cereals from the 1984 harvest from Korea were analyzed for nivalenol (NIV), fusarenon-X (FX), deoxynivalenol (DON) and 3-acetyl-DON by gas chromatography (GC) utilizing a 63Ni electron capture detector (ECD), and were quantitated for zearalenone (ZEN) by high-performance liquid chromatography (HPLC) with a fluorescence detector (FD). Trichothecenes and ZEN in the positive samples were confirmed by GC-mass spectrometry (MS). Out of 51 samples, 51, 46 and 42 were positive for NIV, DON and ZEN, respectively, and one malt sample was heavily contaminated with NIV (2675 ng/g) and DON (246 ng/g), and one wheat sample was heavily contaminated with NIV (3169 ng/g). Neither FX nor 3-acetyl-DON was detected in any of the samples. The data reported here indicates that Korean cereals harvested in 1984 are simultaneously contaminated with NIV, DON and ZEN, and the incidences and levels are similar to those observed in the cereals harvested in 1983.     

Natural occurrence of Fusarium toxins in peanut,sorghum and maize from Mysore (India)

Peanut, sorghum and maize samples were collected from the wholesale market in Mysore, India, over a period of one year (October 1984 to September 1985). The samples were analysed for the natural occurrence of T-2 toxin (T-2), diacetoxyscirpenol (DAS) and zearalenone by thin-layer chromatography, dermal toxicity test and gas chromatography. Of the total number of peanut samples analysed, 6.9% were positive for the toxic trichothecene(s) (T-2, up to 38.89 mg kg^?1; DAS, up to 2.03 mg kg^?1); 4.8% of total sorghum samples analysed contained T-2 up to 15 mg kg^?1. Zearalenone was not found in any of the samples tested, and no toxins were detected in any of the maize samples. Samples marketed during winter and summer periods were contaminated with the toxins. All the toxin-positive samples except one peanut sample were found in produce stored for more than a week.     

Occurrence and fate of Fusarium mycotoxins during commercial processing of oats in the UK

The commercial processing of oats is different from that of other cereals, such as wheat and maize. In northwest Europe, oats also appear to be more susceptible to contamination with HT-2 and T-2 toxins than other cereals. Mycotoxins, such as deoxynivanol and zearalenone, in cereals are already controlled by EU legislation. With regard to additional, impending legislation, this study examined HT-2 and T-2 toxins together with zearalenone, deoxynivalenol and other related toxins in a commercial oat mill and how the concentrations varied from raw oats to the final prepared oat flakes. Concentrations of each Fusarium mycotoxin fell by 90-95% during the process, with the major loss being a physical distribution occurring at the de-hulling stage. Initial studies of losses occurring at other stages, such as kilning or de-branning of prepared oat groats, suggest these to be small. The use of colour sorting after kilning showed higher concentrations of each mycotoxin in the discoloured groats. The feasibility of developing a predictive tool for the oat industry is examined.     

Impact of agronomic and climatic factors on the mycotoxin content of harvested oats in the United Kingdom

ABSTRACT

A survey was conducted to determine the concentration of Fusarium mycotoxins in UK oats over three seasons (2006–8). One hundred oat samples were collected each year at harvest, together with agronomic details, and analysed for 10 Fusarium mycotoxins. The incidence and concentration of most Fusarium mycotoxins, including deoxynivalenol and zearalenone, were relatively low in oats compared with values previously reported for wheat. HT-2 toxin (HT2) and T-2 toxin (T2) levels were relatively high with an overall combined (HT2+T2) mean of 450 μg kg^?1 for 2006–8. Data were combined with a previous dataset collected from 2002–5 to determine the effects of agronomic practices and climate. There was a negative relationship with late summer rainfall, indicating that drier conditions in July and August resulted in increased HT2 and T2 in UK oats. Agronomic factors that impacted upon HT2 and T2 in harvested oats were previous crop, cultivation, and variety. Analysis of the previous cropping history showed there was a stepwise increase in HT2+T2 as the cereal intensity of the rotation increased. Variety was an important factor, with higher levels and a wider range detected on winter versus spring varieties. Indicative levels for HT2 and T2 in cereals and cereal products were introduced by the EC in 2013. The indicative level for unprocessed oats for human consumption is a combined concentration (HT2+T2) of 1000 μg kg^?1. From 2002 to 2008, between 1% and 30% of samples exceeded 1000 μg kg^?1 HT2+T2 each year (overall mean, 16%). The introduction of European legislation on HT2 and T2 mycotoxins could have serious implications for UK oat production and oat-processing industries based on the levels detected within these studies.     

A survey on the occurrence of Fusarium mycotoxins in Bavarian cereals from the 1987 harvest

Bavarian cereals and wheat flour from the 1987 harvest were analysed for nivalenol (NIV) and deoxynivalenol (DON) using high performance liquid chromatography (HPLC) and for T-2 toxin and zearalenone (ZEA) by enzyme-linked-immunosorbent assay (ELISA). The study included 190 field samples of wheat, barley, rye and oat with visibly damaged ears, 45 samples of wheat intended for feed production and two series of wheat flour (type 550) and whole wheat flour collected in October 1987 and June 1988. The field samples examined showed a high DON contamination of wheat (87%) with an average of 3.96 mg/kg and a maximum of 43.8 mg/kg. Mean levels between 0.33 mg/kg and 0.27 mg/kg DON could be detected in barley, rye and oat. Of the wheat samples, 58% contained ZEA with a maximum of 1.560 mg/kg. The highest levels of ZEA were detected in samples which also showed high concentrations of DON. The NIV and T-2 toxin levels were comparatively low. Thirty percent of the samples showed NIV concentrations between 0.04 mg/kg and 0.29 mg/kg and 38% contained between 0.005 and 0.60 mg/kg of T-2. In the wheat samples for feed production, only DON was detected with an average of 0.190 mg/kg and a maximum of 0.75 mg/kg. The highest DON levels (0.58 mg/kg) from October 1987 were found in the wheat flour samples which were lower than the highest DON concentration (3.24 mg/kg) detected in the samples collected during June 1988. This fact was probably due to a substantial amount of non-contaminated wheat from 1986. The toxin concentrations in the whole wheat flour were not higher than in the type 550 flour.(ABSTRACT TRUNCATED AT 250 WORDS)     

A survey on the occurrence of Fusarium mycotoxins in Bavarian cereals from the 1987 harvest

Summary Bavarian cereals and wheat flour from the 1987 harvest were analysed for nivalenol (NIV) and deoxynivalenol (DON) using high performance liquid chromatography (HPLC) and for T-2 toxin and zearalenone (ZEA) by enzyme-linked-immunosorbent as say (ELISA). The study included 190 field samples of wheat, barley, rye and oat with visibly damaged ears, 45 samples of wheat intended for feed production and two series of wheat flour (type 550) and whole wheat flour collected in October 1987 and June 1988. The field samples examined showed a high DON contamination of wheat (87%) with an average of 3.96 mg/kg and a maximum of 43.8 mg/kg. Mean levels between 0.33 mg/kg and 0.27 mg/kg DON could be detected in barley, rye and oat. Of the wheat samples, 58% contained ZEA with a maximum of 1.560 mg/kg. The highest levels of ZEA were detected in samples which also showed high concentrations of DON. The NIV and T-2 toxin levels were comparatively low. Thirty percent of the samples showed NIV concentrations between 0.04 mg/kg and 0.29 mg/kg and 38% contained between 0.005 and 0.60 mg/kg of T-2. In the wheat samples for feed production, only DON was detected with an average of 0.190 mg/kg and a maximum of 0.75 mg/kg. The highest DON levels (0.58 mg/kg) from October 1987 were found in the wheat flour samples which were lower than the highest DON concentration (3.24 mg/kg) detected in the samples collected during June 1988. This fact was probably due to a substantial amount of non-contaminated wheat from 1986. The toxin concentrations in the whole wheat flour were not higher than in the type 550 flour. The regional distribution of the mean DON concentrations showed the highest levels in Middle and Lower-Franconia.

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Vorkommen von Fusarium Mykotoxinen in bayerischem Getreide der Ernte 1987

Zusammenfassung Cerealien und Weizenmehle der bayerischen Ernte 1987 wurden mittels hochauflösender Flüssigchromatographie (HPLC) auf Nivalenol (NIV) und Deoxynivalenol (DON) Bowie mit Enzymimmunoassay auf T-2 Toxin und Zearalenon (ZEA) analysiert. Die Untersuchungen umfaßten 190 Feldproben von Weizen, Gerste, Roggen und Hafer, die alle optisch erkennbaren Fusarienbefall aufwiesen, 45 Futterweizenproben Bowie zwei Probenserien von Weizenmehlen der Type 550 und Vollkornweizenmehlen, die im October 1987 und im Juni 1988 gezogenwurden. — Die Untersuchungen der Feldproben ergaben eine hohe DON-Kontamination des Weizens (87%) mit einem durchschnittlichen Gehalt von 3,96 mg/kg und einem Maximalgehalt von 43,8 mg/kg. In Gerste, Roggen und Hafer konnten durchschnittlich zwischen 0,33 mg/kg und 0,27 mg/kg DON-nachgewiesen werden. 58% der Winterweizenproben wiesen Zearalenon mit einem Maximalgehalt von 1,56 mg/kg auf. Die höchsten ZEA-Werte wurden in Proben ermittelt, die gleichzeitig einen hohen DON-Gehalt aufwiesen. Die Konzentrationen von NIV und T-2 Toxin waren vergleichsweise niedrig. 30% der Proben hatten NIV-Gehalte zwischen 0,04 mg/kg und 0,29 mg/kg und 38% enthielten T-2 Toxin zwischen 0,005 mg/kg und 0,06 mg/kg. In den Futterweizenproben konnte DON als einziges Toxin mit einem Gehalt von durchschnittlich 0,19 mg/kg und maximal 0,75 mg/kg festgestellt werden. Die Weizenmehle, die im October 1987 gezogen wurden, wiesen maximal 0,58 mg/kg DON auf. Die Gehalte lagen damit medriger als die der Mehlproben vom Juni 1988, die maximal 3,24 mg/kg und durchschnittlich 0,26 mg/kg DON enthielten. Dieser Sachverhalt könnte auf Anteile von nicht kontaminiertem Weizen der Ernte 86 an den im October gezogenen Mehlproben zurückgeführt werden. Die Toxingehalte der Vollkornmehle waren nicht höher als die der Weizenmehle der Type 550. Die höchsten Durchschnittsgehalte von DON wurden in Mittel- und Unterfranken festgestellt.

     

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 µg 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 µg 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.     

Fate of Fusarium mycotoxins in maize flour and grits during extrusion cooking

Extrusion technology is used widely in the manufacture of a range of breakfast cereals and snacks for human consumption and animal feeds. To minimise consumer exposure to mycotoxins, the levels of deoxynivalenol (DON) and zearalenone (ZON) in cereals/cereal products and fumonisins B₁ and B₂ (FB₁ and FB₂) in maize are controlled by European Union legislation. Relatively few studies, however, have examined the loss of Fusarium mycotoxins during processing. The behaviour of FB₁, FB₂ and fumonisin B₃ (FB₃), DON and ZON during extrusion of naturally contaminated maize flour and maize grits is examined using pilot-scale equipment. DON and ZON are relatively stable during extrusion cooking but the fumonisins are lost to varying degrees. There is some loss of ZON when present in low concentrations and extruded at higher moisture contents. The presence of additives, such as reducing sugars and sodium chloride, can also affect mycotoxin levels. Moisture content of the cereal feed during extrusion is important and has a greater effect than temperature, particularly on the loss of fumonisins at the lower moistures. The effects are complex and not easy to explain, although more energy input to the extruder is required for drier materials. However, on the basis of these studies, the relationship between the concentration of Fusarium toxins in the raw and finished product is toxin- and process-dependent.     

Monoclonal-based enzyme-linked immunosorbent assay for the detection of zearalenone in cereals

A monoclonal antibody against zearalenone (ZEA) was produced and used successfully to develop a direct competitive enzyme-linked immunosorbent assay (DC-ELISA) for the analysis of ZEA in cereals. This DC-ELISA had a limit of detection of 0.15?±?0.02 µg l^?1 and an IC₅₀ value of 1.13?±?0.16 µg l^?1. Matrix interference was minimized by dilution of the sample extract before ELISA assays. Aqueous methanol (80%) gave good extraction efficiencies, and the recovery from spiked rice, barley, and corn samples averaged between 87 and 112%. Although ZEA was detected in seven (9%) of 80 rice samples and in eight (16%) of 50 barley samples, the concentration of ZEA in samples was around or below the limit of detection of DC-ELISA. Among 38 corn samples, ZEA was detected in nine (24%) samples in the range 41.0–909.8 µg kg^?1. Re-analysis of the ELISA-positive corn samples by high-performance liquid chromatography (HPLC) confirmed that seven (18%) corn samples were positive. The ZEA results for corn showed very good agreement between DC-ELISA and a commercial AgraQant® zearalenone kit (r ²?=?0.98). Thus, the monoclonal antibody-based DC-ELISA could be applied to the preliminary screening of ZEA contamination when analysis of a large sample number is needed.     

Occurrence of deoxynivalenol and T-2 toxin in bread and pasta commercialised in Spain

Deoxynivalenol and T-2 toxin were extracted from wheat-based bread (n = 75) and pasta (n = 75) samples using a mixture of acetonitrile:water (86:14 v/v); for analysis, gas chromatography/mass spectrometry after derivatisation with trifluoroacetic anhydride was utilised. The recovery of deoxynivalenol and T-2 toxin from both food matrixes ranged from 90.1 to 94.0%. The occurrence of these mycotoxins in bread was 28.0% and 2.6% for deoxynivalenol and T-2 toxin, respectively, whereas in pasta, the occurrence of both mycotoxins was higher, varying from 9.3 to 62.7%. The mean content of deoxynivalenol (42.5 μg/kg) in bread was lower than the content of T-2 toxin (68.37 μg/kg), while in pasta the content of deoxynivalenol (137.1 μg/kg) was superior. The estimated daily intake of deoxynivalenol and T-2 toxin from the consumption of these products represents 8.4% and 0.2% of the tolerable daily intake, respectively. These results back up the necessity to take a vigilant attitude in order to prevent human intake of trichothecenes. This information is necessary and of high priority in order to protect the consumer’s health from the risk of exposure to these toxins.     

Fate of the fusarium mycotoxins, deoxynivalenol, nivalenol and zearalenone, during extrusion of wholemeal wheat grain

In the European Union, deoxynivalenol in cereals and cereal products is controlled by recent legislation with the objective of minimizing consumer exposure to this mycotoxin. Relatively few studies have examined the loss of Fusarium mycotoxins during processing and whether this is accurately reflected by the processing factors. The behaviour of deoxynivalenol, nivalenol and zearalenone during extrusion of naturally contaminated wholemeal wheat flour has been examined using pilot-scale equipment. Factors examined were temperature and moisture content. Concentrations of the three mycotoxins were little changed by extrusion although the amount of deoxynivalenol decreased at the lowest moisture content. However, this effect did not appear to be temperature-dependent, suggesting that the apparent loss is either due to binding or inability to extract the residue. Under some conditions, concentrations of the mycotoxins, particularly nivalenol, were higher after extrusion.     

Stable isotope dilution analysis of the Fusarium mycotoxins deoxynivalenol and 3-acetyldeoxynivalenol

Trichothecenes are secondary metabolites produced by several fungi of the Fusarium genus during their growth period. They inhibit protein biosynthesis in eukaryotic cells resulting in numerous toxic effects such as diarrhea, vomiting, and gastro-intestinal inflammation. Considering its occurrence in food and feedstuff, deoxynivalenol (DON) is one of the most important trichothecenes. We report the synthesis of stable isotope labeled 15-d(1)-deoxynivalenol (15-d(1)-DON) from its natural precursor 3-acetyldeoxynivalenol (3-AcDON) as starting material. Furthermore, a method for the analysis of DON and 3-AcDON using HPLC-MS/MS with stable isotope labeled 15-d(1)-DON and 3-d(3)-AcDON as internal standards has been developed. In total, 18 cereal product samples were analyzed with contamination levels ranging from 10-301 microg/kg for DON and 5-14 microg/kg for 3-AcDON. This is the first report of an isotope dilution MS method for the analysis of type B-trichothecenes.     

Fusarium species (section Liseola) and its mycotoxins in maize harvested in northern Argentina

Maize and maize products harvested in small fields and stored by farmers in northern Argentina were assayed for Fusarium and fumonisin and beauvericin contamination. Fumonisins were present in six of the 18 samples. The levels of fumonisins ranged from 603 to 1888ng/kg. Fumonisin B₃ (FB₃) and beauvericin were not detected in the samples evaluated. Fusarium subglutinans was one of the most prevalent species isolated. Twenty-five strains of F. subglutinans isolated from maize kernels and belonging to Gibberella fujikuroi mating population E were beauvericin-producers in culture. Seven of these strains also produced moniliformin. This is the first report on beauvericin-production by maize isolates of F. subglutinans from Argentina.     

Stability of the Fusarium mycotoxins nivalenol, deoxynivalenol and zearalenone in ground maize under typical cooking environments

The effects of moisture, pH and heat on the stability of nivalenol (NIV), deoxynivalenol (DON) and zearalenone (ZEN) present as natural contaminants of ground maize were measured for different periods. Standard solution tests were also performed to measure pH, salt and temperature effects on NIV and DON. The solution tests showed NIV and DON to be relatively stable in buffer solutions over the pH range 1-10. Quite harsh conditions (pH 12, high salt concentration, 80°C, prolonged exposure) were needed to give substantial breakdown. In the ground maize substrate, these toxins were further stabilized relative to the solution tests. NIV and DON were both reduced (range 60-100%) by treatment with aqueous bicarbonate solution at 10, 20 or 50% of the ground maize dry weight, and subsequent heating at 80 or 110°C for 2 and 12 days. There was no measurable reduction at lower test temperatures (20, 40°C). NIV (but not DON) also showed some reduction following addition of water and heating at 80 or 110°C for 12 days. ZEN content was not reduced even by 12 days of heating at 110°C after treatment with a sodium bicarbonate solution.     

Development and application of a method for the analysis of two trichothecenes: deoxynivalenol and T-2 toxin in meat in China by HPLC-MS/MS

A reliable and sensitive method was developed and successfully applied for the determination of deoxynivalenol and T-2 toxin simultaneously in pig dorsal muscle, pig back fat and chicken muscle by high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) analysis. Limit of detection of deoxynivalenol and T-2 was 0.02 μg/kg and 0.007 μg/kg, and limit of quantification of deoxynivalenol and T-2 was 0.07 μg/kg and 0.02 μg/kg, respectively. Sixty-six meat samples were analyzed and deoxynivalenol was detected in the samples of pig back fat, with concentrations lower than 0.5 μg/kg, and T-2 toxin was detected in the samples of pig dorsal muscle, pig back fat and chicken muscle, with concentrations lower than 0.5 μg/kg. The results of sample analysis show that only trace residues of deoxynivalenol and T-2 toxin were detected in the samples analyzed.     

International interlaboratory study for the determination of the Fusarium mycotoxins zearalenone and deoxynivalenol in agricultural commodities

Twenty-eight laboratories from 12 different countries participated in an interlaboratory study for the determination of the Fusarium mycotoxin zearalenone (ZON) in maize and deoxynivalenol (DON) in maize and wheat employing their usual in-house methods. The aim of this study was to obtain information about the state-of-the-art of ZON and DON analysis in cereals and to support a knowledge and experience exchange between the participating laboratories in the field of mycotoxin analysis. Eight different sample types were distributed to the participants, 'blank' materials, spiked samples (102 mu g/kg ZON in maize and 475 mu g/kg DON in wheat) and naturally-contaminated maize and wheat. For the final separation and quantification either gas chromatography (GC), high performance liquid chromatography (HPLC), thin layer chromatography (TLC) or enzyme linked immunosorbent assays (ELISA) were employed by the participating laboratories. Coefficients of variation (CV) between laboratory mean results (outliers rejected) ranged from 28 to 41% for ZON and from 32 to 38% for DON. The results are close to the between laboratory CV criteria of 40% for DON and ZON at concentration levels of > 100 mu g/kg established by the CEN in 1999. A good trueness was obtained for the wheat samples spiked at 475 mu g/kg DON. However, a significant deviation at p = 0.01 from the respective target value was observed for the maize samples spiked at 102 mu g/kg ZON. The high CVs can be traced back to problems occurring by determination of the concentration of the participants' own calibrant solutions. Additionally, the variability of the results is strongly influenced by the use of different final separation and quantification procedures.     

Recent advances on the use of adsorbent materials for detoxification of Fusarium mycotoxins

The extensive use of adsorbents in the livestock industry has led to the introduction of a wide range of new products on the market, most of them claiming high in vitro mycotoxin adsorption capacity. However, adsorbents that may appear effective in vitro do not necessarily retain their efficacy when tested in vivo. Studies performed in our laboratory during the past few years aiming to evaluate the efficacy of various adsorbent materials in binding Fusarium mycotoxins are reported. Adsorption experiments were performed in in vitro screening tests for Fusarium mycotoxins at different pHs; by in vivo tests using the increase of the sphinganine to sphingosine ratio in rat urine and tissues as a biomarker of fumonisin exposure; and by a dynamic, computer-controlled, gastrointestinal model simulating the gastrointestinal tract of healthy pigs. Most of the commercially available mycotoxin-binders failed in sequestering in vitro Fusarium mycotoxins. Only for a small number of adsorbent materials was the ability to bind more than one mycotoxin demonstrated. Cholestyramine was proven to be an effective binder for fumonisins and zearalenone in vitro, which was confirmed for zearalenone in experiments using a dynamic gastrointestinal model and for fumonisins in in vivo experiments. No adsorbent materials, with the exception of activated carbon, showed relevant ability in binding deoxynivalenol and nivalenol. The in vitro efficacy of activated carbon toward fumonisins was not confirmed in vivo by the biomarker assay. The dynamic gastrointestinal model was a reliable tool to study the effectiveness of adsorbent materials in reducing the bioaccessibility of Fusarium mycotoxins, as an alternative to the more difficult and time-consuming studies with domestic livestock.