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.     

A limited survey of Fusarium mycotoxins nivalenol, deoxynivalenol and zearalenone in 1984 UK harvested wheat and barley

A limited survey for the occurrence of nivalenol (NIV), deoxynivalenol (DON) and zearalenone (ZEN) in 1984 UK-grown cereals (31 samples) have been carried out using a new procedure, which is a rapid and sensitive method for Fusarium mycotoxins. NIV, DON and ZEN were detected in 17 (55%), 20 (65%) and 4 (13%) out of 31 samples, and average levels in positive samples were 101 micrograms/kg, 31 micrograms/kg and 1 microgram/kg, respectively. Additional surveys on two wheat and eight barley samples harvested in Scotland have shown that 30%, 60% and 100% of the samples were contaminated with NIV, DON and ZEN, respectively. The contents averaged 391 micrograms/kg of NIV, 39 micrograms/kg of DON and 9 micrograms/kg of ZEN. The results of this survey show that UK-grown cereals were significantly contaminated with NIV, DON and ZEN in a similar way to that observed in Japan, Korea and China. This is the first evidence of the natural occurrence of NIV in UK cereals.     

Natural occurrence of Fusarium mycotoxins of the 1990 barley crop in Korea.

During the barley harvest in June 1990, there was a great deal of rainfall and high humidity in the southern part of Korea, and natural occurrence of Fusarium mycotoxins was suspected in barley samples. The samples of undergrade barley were obtained from four provinces and analysed for the presence of deoxynivalenol (DON) and nivalenol (NIV) by gas chromatography and zearalenone (ZEN) by high performance liquid chromatography. Of 37 samples, 33, 37 and 10 were positive for DON, NIV and ZEN, respectively. The husked barley contained 29-677 ng/g for DON, 114-1546 ng/g for NIV and 183-1416 ng/g for ZEN. The naked barley contained 38-645 ng/g for DON, 85-4569 ng/g for NIV and 40-1081 ng/g for ZEN. The average concentration of NIV in naked barley was higher than that in husked barley, but the average concentration of DON in husked barley was higher than that in naked barley. The survey indicates that the 1990 barley crop in Korea was heavily contaminated with Fusarium mycotoxins.     

Development and application of analytical methods for the determination of mycotoxins in organic and conventional wheat.

The aim of this study was to develop a multicomponent analytical method for the determination of deoxynivalenol (DON), ochratoxin A (OTA) and zearalenone (ZEN), nivalenol (NIV), 3-acetyl-DON (3-acDON), 15-acetyl-DON (15-acDON), zearalenol (ZOL) and citrinin (CIT) in wheat. It also aimed to survey the presence and amounts of DON, OTA and ZEN in Belgian conventionally and organically produced wheat grain and in wholemeal wheat flours. After solvent extraction, an anion-exchange column (SAX) was used to fix the acidic mycotoxins (OTA, CIT), whilst the neutral mycotoxins flowing through the SAX column were further purified by filtration on a MycoSep cartridge. OTA and CIT were then analysed by high-performance liquid chromatography (HPLC) using an isocratic flow and fluorescence detection, while the neutral mycotoxins were separated by a linear gradient and detected by double-mode (ultraviolet light fluorescence) detection. The average DON, ZEN and OTA recovery rates from spiked blank wheat flour were 92, 83 and 73% (RSDR = 12, 10 and 9%), respectively. Moreover, this method offered the respective detection limits of 50, 1.5 and 0.05 microg kg-1 and good agreement with reference methods and inter-laboratory comparison exercises. Organic and conventional wheat samples harvested in 2002 and 2003 in Belgium were analysed for DON, OTA and ZEN, while wholemeal wheat flour samples were taken from Belgian retail shops and analysed for OTA and DON. Conventional wheat tended to be more frequently contaminated with DON and ZEN than organic samples, the difference being more significant for ZEN in samples harvested in 2002. The mean OTA, DON and ZEA concentrations were 0.067, 675 and 75 microg kg-1 in conventional samples against 0.063, 285 and 19 microg kg-1 in organically produced wheat in 2002, respectively. Wheat samples collected in 2003 were less affected by DON and ZEN than the 2002 harvest. Organic wholemeal wheat flours were more frequently contaminated by OTA than conventional samples (p < 0.10). The opposite pattern was shown for DON, organic samples being more frequently contaminated than conventional flours (p < 0.10).     

Occurrence of Fusarium mycotoxins in rice and its milling by-products in Korea

A total of 201 samples of brown rice, polished rice, and two types of by-products, blue-tinged rice and discolored rice, were collected from rice stores maintained at 51 rice processing complexes in Korea. These samples were analyzed for the presence of Fusarium mycotoxins such as deoxynivalenol (DON), nivalenol (NIV), and zearalenone (ZEA). Contaminants (and their ranges) found in discolored rice samples were DON (59 to 1,355 ng g(-1)), NIV (66 to 4,180 ng g(-1)), and ZEA (25 to 3,305 ng g(-1)); those found in blue-tinged (less-ripe) rice were DON (86 to 630 ng g(-1)), NIV (50 to 3,607 ng g(-1)), and ZEA (26 to 3,156 ng g(-1)). Brown rice samples were contaminated mostly with NIV and ZEA (52 to 569 ng g(-1) and 47 to 235 ng g(-1), respectively). Polished rice samples were largely free from mycotoxins, although one sample was contaminated with NIV (77 ng g(-1)). When the fungal flora associated with each rice sample was investigated, blue-tinged rice was the most often contaminated with Fusarium graminearum (3.8%), followed by the discolored rice (2.4%) and brown rice (1.6%) samples. Using PCR, toxin genotyping of 266 isolates of F. graminearum revealed that most isolates (96%) were NIV producers. In conclusion, this survey is the first report of the cocontamination of Korean rice and its by-products with trichothecenes and ZEA. Importantly, it also provides new information on the natural contamination of rice by Fusarium mycotoxins.     

Survey of the presence of the Fusarium mycotoxins nivalenol, deoxynivalenol and T-2 toxin in Korean cereals of the 1989 harvest.

Twenty eight samples of rice, barley, millet, corn and Indian millet harvested in Korea in 1989 were subjected to assay for contamination of nivalenol (NIV), deoxynivalenol (DON) and T-2 toxin by using gas chromatography and gas chromatography-mass spectrometry. Seven samples were found to be positive for NIV and DON in the ranges of 189-624 micrograms/kg and 168-506 micrograms/kg, respectively. Of the contaminated samples, three samples, one barley, one Indian millet and one corn sample were contaminated simultaneously with both NIV and DON. T-2 toxin was not detected in any samples.     

Determination of Deoxynivalenol and Nivalenol in Wheat by Ultra-Performance Liquid Chromatography/Photodiode-Array Detector and Immunoaffinity Column Cleanup

An ultra-performance liquid chromatography (UPLC®) method has been developed for the simultaneous determination of deoxynivalenol (DON) and nivalenol (NIV) in wheat. Ground sample was extracted with water and the filtered extract was cleaned up through an immunoaffinity column containing a monoclonal antibody specific for DON and NIV. Toxins were separated and quantified by UPLC® with photodiode-array detector (λ?=?220 nm) in less than 3 min. Mean recoveries from blank wheat samples spiked with DON and NIV at levels of 100–2,000 μg/kg (each toxin) ranged from 85 to 95 % for DON and from 81 to 88 % for NIV, with relative standard deviations less than 7 %. Similar recoveries were observed from spiked samples when methanol/water (80:20, v/v) was used as extraction solvent. However, by using a wheat sample naturally contaminated with DON and NIV, the one-way analysis of variance (Student–Newman–Keuls test) between different extraction solvents and modes showed that water extraction provided a significant increase (P?<?0.001) in toxin concentrations (mean values of six replicate analyses) with respect to methanol/water (80:20, v/v). No significant difference was observed between shaking (60 min) and blending (3 min). The limit of detection (LOD) of the method was 30 μg/kg for DON and 20 μg/kg for NIV (signal-to-noise ratio 3:1). The immunoaffinity columns showed saturation of DON/NIV binding sites at levels higher than 2,000 ng in blank wheat extracts spiked with the corresponding amount of mycotoxin, as single mycotoxin or sum of DON and NIV. The range of applicability of the method was from LOD to 4,000 μg/kg, as single mycotoxin or sum of DON and NIV in wheat. The analyses of 20 naturally contaminated wheat samples showed DON contamination in all analyzed samples at level ranging from 30 to 2,700 μg/kg. NIV was detected in two samples at negligible toxin levels (up to 46 μg/kg). This is the first UPLC® method using immunoaffinity column cleanup for the simultaneous and sensitive determination of DON and NIV in wheat.     

Interlaboratory study of LC-UV and LC-MS methods for the simultaneous determination of deoxynivalenol and nivalenol in wheat

To evaluate LC methods with UV or MS detection for simultaneous analysis of deoxynivalenol (DON) and nivalenol (NIV) in wheat, an interlaboratory study was conducted in 11 laboratories. DON and NIV were purified using a multifunctional column, and their concentrations were determined using LC-UV or LC-MS(/MS). No internal standards were used. Three fortified wheat samples (0.1, 0.5 and 1 mg/kg), one naturally contaminated wheat sample, and one blank wheat sample were used. The recoveries ranged from 90% to 110% for DON and from 76% to 83% for NIV. For DON, the relative standard deviations for repeatability (RSDr) ranged from 1.1% to 7.6%. The relative standard deviations for reproducibility (RSDr) ranged from 7.2% to 25.2%. For NIV, the RSDr ranged from 2.0% to 10.7%, and the RSDr ranged from 7.0% to 31.4%. Regardless of sample and detector, the HorRat values for DON and NIV ranged from 0.4 to 1.4. Both LC-UV and LC-MS(/MS) methods were considered to be suitable for application as an official method.     

Contents of Fusarium toxins in Finnish and imported grains and feeds

The aim of the present study was to investigate the levels of trichothecenes in representative samples of Finnish and imported cereals and feeds from the 1987 and 1988 crops. Trichothecene concentrations were determined in samples as trimethylsilylether derivatives by a gas chromatograph equipped with a mass selective detector (GC-MSD) using selected ion monitoring (SIM) which proved to be a reliable and sufficiently sensitive technique. Representative samples of Finnish and imported oats, wheat, barley, rye, maize gluten, soy granules, rapeseed, turnip rapeseed, fish meal, poultry feed and pig feed were analysed employing 19-nortestosterone as an internal standard. Almost all grain and feed samples contained deoxynivalenol (DON) from 7 to 300 micrograms/kg and smaller amounts (13-120 micrograms/kg) of 3-acetyldeoxynivalenol (3-AcDON). The most toxic trichothecenes, T-2, HT-2 toxins and nivalenol (NIV) and also zeralenone (ZEN) were found at low concentrations in some samples. Six lots of oats containing 1.3-2.6 mg/kg of DON and 0.2-0.6 mg/kg of 3-AcDON were found in the Finnish grain samples. Silo samples of almost all imported grains contained DON but at levels below 50 micrograms/kg. Imported grains contained no other trichothecenes. DON, 3-AcDON and ZEN were found in imported feedstuffs at low concentrations.     

Fusarium mycotoxin content of UK organic and conventional wheat

Each year (2001–2005), 300 samples of wheat from fields of known agronomy were analysed for ten trichothecenes by gas chromatography-mass spectrometry (GC/MS) including deoxynivalenol (DON), nivalenol, 3-acetyl-DON, 15-acetyl-DON, fusarenone X, T2 toxin, HT2 toxin, diacetoxyscirpenol, neosolaniol and T-2 triol and zearalenone by high-performance liquid chromatography (HPLC). Of the eleven mycotoxins analysed from 1624 harvest samples of wheat, only eight were detected, and of these only five–deoxynivalenol, 15-acetyl-DON, nivalenol, HT-2 and zearalenone–were detected above 100 µg kg^?1. DON was the most frequently detected Fusarium mycotoxin, present above the limit of quantification (10 µg kg^?1) in 86% of samples, and was usually present at the highest concentration. The percentage of samples that would have exceeded the recently introduced legal limits varied between 0.4% and 11.3% over the five-year period. There was a good correlation between DON and zearalenone concentrations, although the relative concentration of DON and zearalenone fluctuated between years. Year and region had a significant effect on all mycotoxins analysed. There was no significant difference in the DON concentration of organic and conventional samples. There was also no significant difference in the concentration of zearalenone between organic and conventional samples, however organic samples did have a significantly lower concentration of HT2 and T2. Overall, the risk of UK wheat exceeding the newly introduced legal limits for Fusarium mycotoxins in cereals intended for human consumption is low, but the percentage of samples above these limits will fluctuate between years.