Distribution of deoxynivalenol and 3‐acetyldeoxynivalenol in naturally contaminated and Fusarium culmorum infected triticale samples

Eight triticale genotypes, naturally contaminated (C) and collected from heads inoculated with two separate isolates Fusarium culmorum (I₁ and I₂) kernels were analysed for accumulation ofFusarium toxins. Triticale kernels were contaminated with deoxynivalenol (DON) and 3‐acetyldeoxynivalenol (3‐AcDON). Statistical analysis revealed significant differences between naturally contaminated samples (C) and those inoculated with isolate I₁ and I₂. The following accumulation of toxins in kernels (mean mg/kg) was found: C, I₁, I₂ – DON 0.06, 14.45, 8.09; 3‐AcDON – 0.01, 0.20, 0.49. Distribution of DON and 3‐AcDON was studied in four size fractions of kernels (> 2.8 mm; ≤ 2.8–2.5 mm, < 2.5–2.2 mm and < 2.2 mm).The highest concentration of DON and 3‐AcDON was found in the smallest fraction of damaged kernels. The percentage distribution of DON and 3‐AcDON in fraction < 2.2 mm was (C) 66%, 77%, (I₁) 38%, 27%, (I₂) 46%, 40%; and in fraction < 2.5 mm: (C) 85%, 94%, (I₁) 57%, 51%, (I₂) 80%, 76%. The naturally contaminated kernel fraction < 2.2 mm (although only 2% of all) contained 33% DON and 59% 3‐AcDON, for more toxigenic isolate I₁ 10%, 15%, 14%, less toxigenic isolate I₂ 4%, 13%, 11%, respectively, calculated on dry matter basis. No significant correlation between examined characteristics was found for either I₁ or I₂ isolate. The biosynthesis mechanism of toxic metabolites was to approximate (significantly correlated) to pair objects C/I₂.     

Distribution of deoxynivalenol and 3-acetyldeoxynivalenol in naturally contaminated and Fusarium culmorum infected triticale samples

Eight triticale genotypes, naturally contaminated (C) and collected from heads inoculated with two separate isolates Fusarium culmorum (I1 and I2) kernels were analysed for accumulation of Fusarium toxins. Triticale kernels were contaminated with deoxynivalenol (DON) and 3-acetyldeoxynivalenol (3-AcDON). Statistical analysis revealed significant differences between naturally contaminated samples (C) and those inoculated with isolate I1 and I2. The following accumulation of toxins in kernels (mean mg/kg) was found: C, I1, I2--DON 0.06, 14.45, 8.09; 3-AcDON--0.01, 0.20, 0.49. Distribution of DON and 3-AcDON was studied in four size fractions of kernels (> 2.8 mm; < or = 2.8-2.5 mm, < 2.5-2.2 mm and < 2.2 mm). The highest concentration of DON and 3-AcDON was found in the smallest fraction of damaged kernels. The percentage distribution of DON and 3-AcDON in fraction < 2.2 mm was (C) 66%, 77%, (I1) 38%, 27%, (I2) 46%, 40%; and in fraction < 2.5 mm: (C) 85%, 94%, (I1) 57%, 51%, (I2) 80%, 76%. The naturally contaminated kernel fraction < 2.2 mm (although only 2% of all) contained 33% DON and 59% 3-AcDON, for more toxigenic isolate I1 10%, 15%, 14%, less toxigenic isolate I2 4%, 13%, 11%, respectively, calculated on dry matter basis. No significant correlation between examined characteristics was found for either I1 or I2 isolate. The biosynthesis mechanism of toxic metabolites was to approximate (significantly correlated) to pair objects C/I2.     

Mycotoxins in cereal grain. Part 13. Deoxynivalenol and 3-acetyl-deoxynivalenol in wheat kernels and chaff with head fusariosis symptoms

In the period of harvest at 1987 field samples of wheat heads with fusariosis symptoms were collected in 18 provinces of Poland. Subsamples of heads infected with Fusarium culmorum (W.G.Sm) Sacc. and Fusarium graminearum Schwabe were analyzed for Fusarium metabolites. In fractions of kernels with visible Fusarium-damage deoxynivalenol (DON) was present in average amount of 18.7 mg/kg (range 9.6-25.3 mg/kg) and 3-acetyl DON 1.9 mg/kg. Fractions of kernels without symptoms of visible Fusarium-damage contained only DON at average 2 mg/kg (range 0.8-3.6 mg/kg). A method of approximate calculation of DON content in a given lot of grain is proposed which may be realized during samples grading.     

Estimating deoxynivalenol contents of wheat samples containing different levels of Fusarium-damaged kernels by diffuse reflectance spectrometry and partial least square regression

Fusarium head blight is a fungal disease causing yield losses and mycotoxin contamination in wheat and other cereals. Wheat kernels (cultivar Ritmo) were sampled in 2001, 2002, 2003, and 2006 and Fusarium-damaged kernels were separated from sound grain based on visual assessment. Subsequently, grain lots containing 0, 20, 40, 60, 80, and 100% of damaged kernels were compiled. Each lot was split and the spectrometric reflectance (wavelengths 350-2500 nm) was measured using subgroup one, while the concentration of the mycotoxin deoxynivalenol (DON) was determined by high-performance liquid chromatography in subgroup two. DON concentrations in batches classified as sound were not significantly different from 0. Estimating DON contents from the percentage of Fusarium-damaged kernels was impeded by vast variability, resulting in a coefficient of determination of 0.49. Using spectrometric data subjected to partial least square regression allowed estimating DON contents with higher accuracy, in particular at elevated percentages of damaged kernels. The coefficient of determination was 0.84 for the relationship between DON contents estimated based on spectrometric data and the DON contents measured. The intercept of a regression line fitted through a plot of estimated versus measured DON contents was 0.89 ± 3.61 mg/kg. Since intercept + standard error was larger than the actual legal limit (1.25 mg DON per kg dry grain in the European Union), the spectrometric procedure was still not precise enough to allow a reliable separation of grain samples with DON contents below 1.25 mg/kg from samples with DON contents above the limit. However, spectrometric data also allowed estimating the DON content of the average damaged kernel within a given lot composed of sound and damaged kernels, which is probably the reason for the reduction of the fraction of unexplained variance by 35% compared to the visual approach and illustrates that spectrometric approaches can make a contribution to reducing DON contents of wheat grain.     

NIR spectroscopy and chemometric tools to identify high content of deoxynivalenol in barley

ABSTRACT

Deoxynivalenol (DON) is one of the mycotoxins produced mainly by the Fusarium graminearum species complex in small grain cereals, including barley. This toxin can cause alimentary disorders, immune function depression and gastroenteritis. The negative health effects associated with DON coupled to the increasing concern about green and rapid methods of analysis motivated this study. In this context, near infrared (NIR) spectroscopy data were applied for exploratory analysis to distinguish barley with high and low levels of DON contamination (> or <1250 µg/kg according to the European Union threshold), by Partial Least Squares-Discriminant Analysis (PLS-DA), and to verify the performance of Partial Least Squares-Regression (PLS-R) to predict DON concentration in barley samples. Maximum values of specificity and sensitivity were achieved in the calibration set; 90.9% and 81.9% were observed in the cross-validation set for the PLS-DA classification model. PLS-R quantification of DON in barley presented low values of error (RMSEC = 101.94 µg/kg and RMSEP = 160.76 µg/kg). Thus, we found that NIR in combination with adequate chemometric tools could be applied as a green technique to monitor DON contamination in barley.     

A survey of the occurrence of deoxynivalenol in wheat from 1986-1988 harvests in the USSR

The occurrence of deoxynivalenol (DON; vomitoxin) in wheat from 1986-1988 harvests in the USSR was surveyed. A significant frequency of DON contamination (81.3% of samples analyzed) was observed. A correlation between levels of DON contamination and percentage of Fusarium-damaged kernels was demonstrated. It was shown that DON contamination did not exceed the maximum tolerated level (MTL) established in the USSR (1.0 mg/kg) if samples contained no more than 0.6% of Fusarium-damaged kernels.     

Natural occurrence of scirpentriol in cereals infected by Fusarium species.

Wheat, barley and oat grain samples naturally contaminated with Fusarium spp. were analysed for the presence of scirpentriol (STO). This toxin was detected in 1, 37 and 8% of 248 wheat, 32 barley and 99 oat grain samples, respectively, and the maximum concentration was 83 microg x kg(-1). Samples of wheat and oat grain with visible scab symptoms were also analysed, and STO (mean level 255 microg x kg(-1)) was detected only in oat samples infected with F. sporotrichioides and F. poae as the dominant species. We analysed 15 barley samples that were subdivided based on seed size into fractions of <2.5 and > 2.5 mm in diameter. The smaller kernels contained an average 94% of the STO in the samples (in kernel fraction > 2.5 mm 28 microg x kg(-1), <2.5 mm 297 microg x kg(-1)). In oats, STO levels were highest in the chaff, lower in the stalk's apical internode and lowest in the grain.     

Estimating mycotoxin contents of Fusarium-damaged winter wheat kernels

Winter wheat (Triticum aestivum L., cultivars Ritmo and Dekan) grain was sampled in Northern Germany between 2001 and 2006. Kernels damaged by fungi of the genus Fusarium were separated from sound grain by visual assessment. Samples containing 0%, 20%, 40%, 60%, 80% and 100% of Fusarium-damaged kernels were compiled and analyzed for the Fusarium type B trichothecenes deoxynivalenol (DON, 2001-2006), nivalenol (NIV, 2006), 3-acetyl-deoxynivalenol (3AcDON, 2006) and 15-acetyl-deoxynivalenol (15AcDON, 2006). The relationship between mycotoxin contents and the percentage of Fusarium-damaged kernels was calculated for each lot of grain. Apart from one exception, relationships between the percentage of Fusarium-damaged kernels and NIV, 3AcDON or 15AcDON were non-significant. In contrast, close relationships between the percentage of Fusarium-damaged kernels and the DON content were observed (r(2)=0.93-0.99). The y-axis intercepts were not significantly different from zero, but the DON content of the damaged kernels varied by a factor of 11.59 between years and by a factor of 1.87 between cultivars. Fusarium-damaged kernels contained between 0.21 and 2.39 microg DON kernel(-1). The overall average DON content of a Fusarium-damaged wheat kernel was 1.29 +/- 0.11 microg. The DON content of diseased kernels was affected by environment and wheat genotype but not by genotype x environment interaction. On average, Fusarium-damaged kernels contained 9.7-fold more DON than 15AcDON, 19.5-fold more DON than NIV, and 26.9-fold more DON than 3AcDON. 3AcDON and 15AcDON contents per wheat kernel were not significantly different between cultivars. On average, 4.27% of Fusarium-damaged kernels were sufficient to reach the 1.25 mg DON kg(-1) grain limit for unprocessed cereals in the EU. Given the low percentages of Fusarium-damaged kernels that are equivalent to current legal DON limits, grading accuracies >96% would be needed when using automatic grading systems for separating sound from damaged kernels.     

Carry-over of Fusarium toxins (deoxynivalenol and zearalenone) from naturally contaminated wheat to pigs.

The frequent contamination of grain with the Fusarium toxins, deoxynivalenol (DON) and zearalenone (ZON), is an important issue in animal and human nutrition. However, data on the exposure of humans to these toxins through consumption of animal tissues exposed to Fusarium toxins (carry-over) are fragmentary. Therefore, residues of DON, ZON and their metabolites were determined in tissues and body fluids of pigs (female and castrated male) from a fattening trial. Pigs were fed a control (n = 6, 0.24 mg DON and 0.009 mg ZON per kg diet as fed) or a Fusarium toxin-contaminated diet (n = 12, 6.68 mg DON and 0.056 mg ZON per kg diet as fed) either ad libitum or for restrictive consumption for 12 weeks. After slaughter (96.3 +/- 11.6 kg live weight), the concentrations of DON and its metabolite, de-epoxy-DON, were measured in serum, bile, liver, kidney, musculus longissimus and back fat, while ZON and its metabolites, alpha- and beta-zearalenol (alpha-/beta-ZOL), were determined in serum, bile and liver. The mean carry-over factor of DON + de-epoxy-DON, defined as the concentration of both substances in the tissue/fluid divided by the DON concentration in the diet, for all pigs decreased from bile (0.1046 +/- 0.0653) > kidney (0.0151 +/- 0.0070) > liver (0.0057 +/- 0.0043) > serum (0.0023 +/- 0.0018) > muscle (0.0016 +/- 0.0016) > back fat (0.0002 +/- 0.0004). The time interval between the end of feeding and slaughter had no consistent effect on DON + de-epoxy-DON concentrations in the analysed specimen of Fusarium toxin-exposed pigs fed restrictively. No transfer of ZON and its metabolites could be observed into serum of pigs, while the mean carry-over factors of ZON + alpha-ZOL + beta-ZOL were 0.0094 +/- 0.0123 and 4.0 +/- 2.2 for liver and bile, respectively. Therefore, it can be concluded that serum is a reliable indicator for DON exposure, but an inappropriate parameter to deduce ZON exposure, which is better represented by bile concentration of ZON + alpha-ZOL + beta-ZOL. However, the exposure risk to humans by consumption of edible tissues of animals exposed to Fusarium toxins is negligible compared to the direct consumption of grain-based food.     

A survey of the natural occurrence of Fusarium mycotoxins in cereals grown in New Zealand in 1986-1989.

Fusarium mycotoxins, principally trichothecenes, occurred commonly in grain from crops in the North Island of New Zealand, but were much less common and also at the much lower levels in grains from South Island regions. The principal contaminants were trichothecenes of the nivalenol (NIV) and deoxynivalenol (DON) types. Trichothecenes derived from scirpentriol and T-2 tetraol were not common. Moniliformin occurred very rarely, while zearalenone contamination was not uncommon, but the levels were generally low. Maize kernels were commonly contaminated by moderate levels of both NIV- and DON-type trichothecenes, with levels up to 3.6 mg/kg and 11.95 mg/kg respectively recorded. The occurrence of NIV-type trichothecenes as a general contaminant in the range of 0.3-0.8 mg/kg, and frequently as the main contaminant, is unusual.     

Production of mycotoxins byFusarium species isolated in Germany

Summary Cultures ofFusarium tricinctum 434 formed large amounts of the trichothecene mycotoxins deoxynivalenol (DON) and 3-acetyldeoxynivalenol (AcDON), as well as the macrocyclic secondary metabolite zearalenone on moistened, autoclaved maize, rice and oats. The formation of zearalenone was low, with levels from 15 to 72 mg/kg as compared to the trichothecene production with maximum quantities of 917 mg/kg of AcDON on rice and 750 mg/kg DON on oats. In the cultures ofF. graminearum 183, total mycotoxin amounts found were lower, with maximum levels of zearalenone up to 150 mg/kg and AcDON up to 160 mg/kg on rice. DON, however, was produced in quantities of about 740 mg/kg on rice.

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Produktion von Mykotoxinen durch in Deutschland isolierte Fusarium-Arten1. Zeitverlauf der Deoxynivalenol-, 3-Acetyldeoxynivalenol-, und Zearalenon-Bildung auf festen Substraten

Zusammenfassung Kulturen vonFusarium tricinctum 434 bildeten auf feuchtem, autoklaviertem Mais, Reis bzw. Hafer relativ hohe Mengen der Trichothecen-Mykotoxine Deoxynivalenol (DON) und 3-Acetyldeoxynivalenol (AcDON) sowie das zu den makrocyclischen Lactonen zählende Mykotoxin Zearalenon. Die Zearalenonbildung war mit Werten von 15 bis 72 mg/kg gegenüber der Trichothecenproduktion mit maximal 917 mg/kg AcDON auf Reis und 750 mg/kg DON auf Hafer deutlich niedriger. In den Kulturen vonF. graminearum 183 wurden insgesamt geringere Toxinmengen gefunden mit maximalen Zearalenon-konzentrationen bis zu 150 mg/kg sowie AcDON Mengen bis zu 160 mg/kg auf Reis. Dagegen erreichte die DON-Bildung auf Reis 740 mg/kg.

     

Comparison of sensory properties of popcorn from various types and sizes of kernel

Three rice‐type popcorns (red, white and yellow) and one pearl‐type popcorn (yellow) were used in this study. All types were sized into three fractions (5 < D < 6 mm, 6 < D < 7 mm and D > 7 mm) by screening with round‐hole sieves. Samples were tested for popping quality and suitability for popping, and the sensory properties of the popcorns were evaluated. A popcorn popper with a maximum operating temperature of 226 °C was used for popping the samples (25 g). Both kernel type and size affected the expansion volume and the number of unpopped kernels. Yellow pearl‐type (YPT) and white rice‐type (WRT) popcorns showed good popping performance. The popping properties of the smallest‐sized kernels were better than those of the other fractions. Popcorn type significantly affected the flake size uniformity, flake shape uniformity, flake colour, crispness and taste of the products. Analysis of variance (ANOVA) and principal component analysis (PCA) showed that that kernel size was of great importance for the expansion volume, which was negatively correlated with number of unpopped kernels, 1000‐kernel weight and diameter ratio and positively correlated with flake size, kernels per 25 g, crispness and tenderness. © 2001 Society of Chemical Industry     

Toxicity profile of commercially produced indigenous banana beer

Mycotoxins, together with endotoxins, represent important classes of naturally occurring contaminants in food products, posing significant health risks to consumers. The aim of this study is to investigate the occurrence of both Fusarium mycotoxins and endotoxins in commercially produced traditional banana beer. Two brands of commercially produced traditional banana beer were collected from a local retail market in Kigali, Rwanda. Beer samples were analysed for the presence of deoxynivalenol (DON), fumonisin B(1) and zearalenone (ZEA), using an enzyme-linked immuno-sorbent assay (ELISA) method. The quantification of bacterial endotoxin using Limulus amoeboecyte lysate (LAL) assay was also conducted. The contamination levels were 20 and 6.7?μg?kg(-1) for DON; 34 and 31.3?μg?kg(-1) for FB(1); 0.66 and 2.2?μg?kg(-1) for ZEA in brands A and B of the beers, respectively. Results indicate that the levels of Fusarium toxins and bacterial endotoxin reported in this study did not pose adverse human health effects as a result of drinking/consuming banana beer. However, exposure to low/sub-threshold doses or non-toxic levels of endotoxins magnifies the toxic effect of xenobiotic agents (e.g. fungal toxins) on liver and other target organs. Considering Fusarium toxins and/or endotoxin contamination levels in other agricultural commodities intended for human consumption, health risks might be high and the condition is aggravated when beer is contaminated by mixtures of the mycotoxins, as indicated in this study.     

Effects of proanthocyanidins,dehulling and removal of pericarp on digestion of barley grain by ruminal micro‐organisms

The effects of proanthocyanidins (PA), dehulling, and removal of the pericarp on the rate and extent of barley digestion by ruminal micro‐organisms were studied using a control barley (cv Harrington) and three PA‐free barley lines (Caminant, Ca504316 and Ca802711). Each barley was studied in five preparations: whole grain (W); dehulled kernels (DH); kernels with pericarp removed (DP); dry‐rolled grain (DR), and the pericarp‐testa fraction (PT) produced during preparation of DP. Vanillin‐HCl staining and chemical analysis confirmed that PA were present only in the Harrington barley, and localised in the pericarp‐testa layer. Whole kernels, DH and DP were incubated with diluted ruminal fluid in vitro, and all five preparations were incubated in situ (nylon bag technique). Harrington DR and all four PT fractions were also incubated in vitro in the presence (0.074% w/v) and absence of polyethylene glycol (PEG), which specifically binds PA. The four barleys did not differ in in vitro dry matter disappearance (DMD) or gas production from W, DH or DP preparations, nor in in situ DMD rates from W, DH or DP (P > 0.05). In vitro DMD and gas production among PT fractions from the four barleys were also similar (P > 0.05), as were in vitro DMD from PEG‐present and PEG‐absent DR Harrington. With Harrington PT, in vitro ammonia concentrations were higher (P < 0.05) with PEG than without. For each barley line, in vitro DMD rates were highest (P < 0.01) with DP, followed by DH, and then by W (P < 0.01). In in situ incubations also, DMD rates and effective degradabilities of DR samples exceeded (P < 0.05) those of DH samples. It was concluded that the presence of proanthocyanidins did not affect ruminal digestion of barley grain, and that abrasive milling to breach the hull and pericarp may be a promising method by which to regulate the rate of barley digestion in the rumen. © Minister of Public Works and Government Services Canada 1999     

制麦和酿造过程中脱氧雪腐镰刀菌烯醇的初步研究

2008年江苏某农场的赤霉病感染相对严重的KA-4B大麦中,脱氧雪腐镰刀茵烯醇（DON）的含量为1．91mg/kg。以此大麦为原料,实验室规模下进行制麦和酿造实验,结果表明,浸麦可以洗去大麦本身含有的绝大部分DON;而大麦内部没有被洗掉的镰孢霉属真菌孢子在发芽阶段重新萌发、生长代谢,形成并积累大量的DON;焙燥阶段不能破坏DON,成品麦芽和麦根中DON的含量分别是原大麦中DON含量的51％和89％。麦芽中的DON可以经过糖化和发酵过程流入到啤酒中,啤酒中DON的总含量是麦芽粉中DON总量的86％。而同一年份相邻农场的基本未感染赤霉病的KA-4B大麦中,DON含量低于0．1mg/kg,绿麦芽和麦根中均检测到低于0．1mg／kg的DON,而成品麦芽、麦汁和啤酒中均未检测到DON。制麦及酿造实验表明,与基本未感染赤霉病的KA-4B大麦相比,赤霉病感染程度严重的KA-4B大麦微生物污染严重,DON含量相对高,大麦品质较差,发芽率较低,麦芽浸出率低,所制得麦汁的过滤速度快,麦汁和啤酒的色度均较高。     

安徽河南粮食中脱氧雪腐镰刀菌烯醇和玉米赤霉烯酮的污染调查

目的：调查安徽、河南两省粮食中镰刀菌毒素污染情况。方法：以玉米、小麦为材料,分别采用酶联免疫吸附法(ELISA)和高效液相色谱法(HPLC)检测了脱氧雪腐镰刀菌烯醇(DON)和玉米赤霉烯酮(ZEN)的含量,采用SPSS软件对检测结果进行统计学分析。结果：安徽河南两省玉米、小麦中的DON和ZEN含量平均值分别为424.0μg/kg和187.2μg/kg,检出率分别为76.7%和75.3%。其他省份的玉米、小麦中DON和ZEN含量的平均值为52.2μg/kg和24.1μg/kg,检出率分别为60%和70%。结论：和其他省份相比,安徽、河南两省的粮食受镰刀菌毒素污染程度更严重。根据现有的国家限量标准,ZEN的超标率比DON更高。     

Deoxynivalenol and nivalenol in commercial wheat grain related to Fusarium head blight epidemics in southern Brazil

A three-year (2006-2008) survey on commercial wheat grain was conducted aimed at quantifying the intensity of Fusarium head blight epidemics related to kernel quality and levels of deoxynivalenol (DON) and nivalenol (NIV). Grain samples, obtained from 38 municipalities throughout the state of Rio Grande do Sul, Brazil, were assessed visually for Fusarium-damaged kernels (FDK) and chemically using liquid chromatography-mass spectrometry (LC-MS/MS). Overall FDK mean levels were 15.5%, not differing among the years. Co-contamination was predominant (59/66) across samples and overall mean levels of DON and NIV were 540 and 337 μg/kg, respectively. When the levels of both mycotoxins were added together (DON + NIV), a higher correlation with FDK was found (R = 0.36, P < 0.01), compared to single toxin data. For the first time, the presence of NIV in levels comparable to DON is reported from a multi-year regional epidemiological survey in the country which should be of concern to the small grains industry.     

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.

     

Determination of deoxynivalenol in wheat-based breakfast cereals marketed in Portugal.

Deoxynivalenol (DON), also known as vomitoxin, is one of a group of closely related secondary fungal metabolites--the trichothecenes--and is produced predominantly by several species of the genus Fusarium, especially Fusarium graminearum. The present study was carried out to evaluate the natural occurrence of DON in different kinds of wheat-based breakfast cereals widely consumed by the population. A total of 88 commercially available samples of wheat-based breakfast cereals were randomly collected from different supermarkets in Lisbon, Portugal. The samples were analyzed using immunoaffinity column, and DON was quantified by liquid chromatography. Detection limit was 100 microg/kg. Average recovery of DON was 80%. Of 88 analyzed samples, 72.8% contained levels of DON between 103 and 6,040 microg/kg, with mean level of 754 microg/kg, and 24 samples (27.2%) were not contaminated (< 100 microg/kg). These results indicate an incidence of this mycotoxin in these products, and the authors suggest a monitoring for the prevention of molds and mycotoxins. This is the first report in Portugal on natural contamination with DON in wheat-based breakfast cereals.     

Utilization of highly deoxynivalenol-contaminated wheat via extrusion processing

Deoxynivalenol (DON) is a toxic natural metabolite produced by Fusarium graminearum. In this study we investigated the effects of sodium bisulfite and extrusion cooking under high temperature and pressure on DON levels in wheat grain and mill fractions. Samples of highly naturally DON-contaminated soft winter wheat were soaked for 1 h in water or aqueous sodium bisulfite (SB) solutions (0.5, 1.5, 2.5, or 5% SO2 equivalent) and extruded. The soaking treatment with SB solution (5% SO2 equivalent) lowered DON from 7.3 microg/g to 0.8 microg/g without extrusion and to 0.3 microg/g with an extrusion process. When the contaminated kernels were tempered with water or SB solutions (5 or 10% SO2 equivalent) and milled, the flour samples, as expected, showed lower levels of DON (from 7.3 to 3.1 microg/g). Extrusion of milled flour and whole meal samples, both obtained from SB-tempered wheat, did not change DON levels significantly under the studied extrusion conditions as compared to the nonextruded milled flour and whole meal samples. However, the extrusion process can be utilized to remove moisture and/or odor of chemicals used in the soaking solutions and to produce potentially useful extruded products.