高灵敏度磁荧光免疫层析试纸模式构建及在呕吐毒素检测中的应用

构建基于磁荧光纳米材料的免疫层析试纸模式,弥补现在免疫层析技术的不足,为更灵敏的免疫学快速检测提供技术支撑。以呕吐毒素（deoxynivalenol,DON）为靶标,采用溶剂热法制备羧基修饰的超顺磁颗粒,碳二亚胺法将磁颗粒、绿色荧光蛋白及DON单克隆抗体进行偶联,一步法制备磁荧光抗体探针,以DON人工抗原（DON-BSA）为检测线建立磁荧光免疫层析试纸。同时用胶体金标记DON单克隆抗体,以DON-BSA为检测线建立胶体金免疫层析试纸;制备的磁荧光抗体探针具有很好的磁性、荧光特性及抗体反应性,基于该探针成功制备了DON磁荧光免疫层析试纸,该试纸回归方程为y=－0.562x＋0.921,R2=0.990,IC50为5.611 ng/mL,检出限为1.089 ng/mL;制备了DON胶体金免疫层析试纸,该试纸裸眼检测灵敏度为500 ng/mL;定量检测回归方程为y=－0.543x＋1.485,R2=0.991,IC50为65.16 ng/mL,检出限为11.94 ng/mL。DON磁荧光免疫层析试纸的灵敏度是胶体金免疫层析试纸的10.96 倍。本实验建立的磁荧光免疫层析试纸模式可以同时实现样品的富集及荧光信号检测,提高检测灵敏度,并成功用于DON的检测,为磁荧光纳米颗粒广泛应用于免疫层析领域提供参考。     

Development of an Immunochromatographic Test Strip for Rapid Simultaneous Detection of Enrofloxacin and Ofloxacin in Tissue of Chicken Muscle and Pork

ENR and OFL are the most consumed quinolones on livestock in China. In this work, we developed a rapid immunochromatographic lateral flow test strip for simultaneous detection of the residues of enrofloxacin and ofloxacin in chicken muscle and pork. We screened an anti-ENR and OFL monoclonal antibody. The IC₅₀ of anti-ENR and anti-OFL were 6.67 and 7.13 ng/ml, respectively. The present immunochromatographic lateral flow test strip is a one-step assay and required much less professional personnel and experimental instruments. In the present study, the decision limit (CCα) of the test strip was calculated to be 0.089 ng/mL and detection capability (CCβ) was 0.217 ng/mL with the scanner. The limit of detection was estimated to be 10 ng/mL. According to parallel HPLC analysis with 47 blind samples, coincidence rate is 100 % when the contents of ENR and OFL were more than 10 ng/mL. Results indicated that the strip test we developed had good reliability, and the strip test gave neither false positive nor false negative results. It will provide results within 20 min without special equipment. Therefore, the test strip is very useful as a screening method for semi-quantitative or qualitative detection of enrofloxacin and ofloxacin in chicken muscle and pork.     

Simultaneous detection of 12 mycotoxins in cereals using RP-HPLC-PDA-FLD with PHRED and a post-column derivatization system

A new method for the simultaneous quantification of 12 mycotoxins was developed and optimized using reverse phase high performance liquid chromatography (RP-HPLC) with a photodiode array (PDA) and fluorescence detector (FLD), a photochemical reactor for enhanced detection (PHRED) and post-column derivatization. The mycotoxins included aflatoxins (AFB(1), AFB(2), AFG(1), and AFG(2)), ochratoxin A (OTA), zearalenone (ZEA), deoxynivalenol (DON), fumonisins (FB(1), FB(2), and FB(3)), T-2 and HT-2 toxins. A double sample extraction with a phosphate-buffered saline solution (PBS) and methanol was used for co-extraction of mycotoxins, and a multifunctional immunoaffinity column was used for cleanup. Optimum conditions for separation of the mycotoxins were obtained to separate 12 mycotoxins in FLD and PDA chromatograms with a high resolution. The method gave recoveries in the range 72-111% when applied to spiked corn samples. The limits of detection (LOD) were 0.025 ng/g for AFB(1) and AFG(1), 0.012 ng/g for AFB(2) and AFG(2), 0.2 ng/g for OTA, 1.5 ng/g for ZEA, 6.2 ng/g for FB(1), FB(3) and HT-2 toxin, 9.4 ng/g for FB(2) and T-2 toxin, and 18.7 ng/g for DON. In addition, the limits of quantification (LOQ) ranged from 0.04 ng/g for AFB(2) and AFG(2) to 62 ng/g for DON. The method was successfully applied to the determination of these mycotoxins in 45 cereal samples obtained from the Malaysian market. The results indicated that the method can be applied for the multi-mycotoxin determination of cereals.     

Rapid and Sensitive Immunochromatographic Strip for On‐site Detection of Sulfamethazine in Meats and Eggs

A rapid immunochromatographic (ICG) strip based on a conjugate of colloidal gold and monoclonal antibody (mAb) was developed for the rapid, sensitive, and on‐site detection of sulfamethazine in meat and egg samples. The detection limit of the ICG strip is 2 ng/mL, and the assay can be completed in 10 min. A cross‐reactivity test indicated that the ICG strip was highly specific to sulfamethazine with no cross‐reaction with sulfonamide compounds and other antibiotics. The results of the recovery test from meat and egg samples spiked with sulfamethazine were in good agreement with those obtained by the indirect competitive enzyme‐linked immunosorbent assay. These results demonstrated that the ICG strip can be used as a rapid and qualitative tool for on‐site screening of sulfamethazine in meat and egg samples.     

Effects of heating procedures on deoxynivalenol, nivalenol and zearalenone levels in naturally contaminated barley and wheat.

The influence of heating temperature and time on deoxynivalenol (DON), nivalenol (NIV) and zearalenone (ZEA) contents in naturally co-contaminated barley and wheat was investigated intending to establish the basis for a decontamination model of Fusarium mycotoxins in cereals. The standard toxins and whole barley powder samples were heated in a convection oven at 140, 160, 180, 200, or 220 degrees C, and kernel subsamples (200 g each) were roasted in an experimental rotary gas-fired roaster at 150, 180 or 220 degrees C. All treatments resulted in a time-temperature-dependent decomposition of the toxins; the logarithm of the toxin remaining % presented a linear relationship with heating time. The lines equations were used to estimate the half (H) and decimal (D) decomposition times (time required to destroy 50 or 90% of the toxin, respectively). DON and NIV H and D decomposition times were similar and 50% shorter for heated standards than for whole barley powder. ZEA standard values were considerably longer, while whole barley powder values were comparable with those of DON and NIV. At 220 degrees C, D decomposition times of DON, NIV and ZEA heated standards were 11, 10 and 85 min, respectively, while the values obtained in whole barley powder were the same for the three toxins (25 min). The determination of H and D decomposition values constitutes a basis to understand the heating stability nature of each toxin.     

Simultaneous detection of 12 mycotoxins in cereals using RP-HPLC-PDA-FLD with PHRED and a post-column derivatization system

A new method for the simultaneous quantification of 12 mycotoxins was developed and optimized using reverse phase high performance liquid chromatography (RP-HPLC) with a photodiode array (PDA) and fluorescence detector (FLD), a photochemical reactor for enhanced detection (PHRED) and post-column derivatization. The mycotoxins included aflatoxins (AFB₁, AFB₂, AFG₁, and AFG₂), ochratoxin A (OTA), zearalenone (ZEA), deoxynivalenol (DON), fumonisins (FB₁, FB₂, and FB₃), T-2 and HT-2 toxins. A double sample extraction with a phosphate-buffered saline solution (PBS) and methanol was used for co-extraction of mycotoxins, and a multifunctional immunoaffinity column was used for cleanup. Optimum conditions for separation of the mycotoxins were obtained to separate 12 mycotoxins in FLD and PDA chromatograms with a high resolution. The method gave recoveries in the range 72–111% when applied to spiked corn samples. The limits of detection (LOD) were 0.025?ng/g for AFB₁ and AFG₁, 0.012?ng/g for AFB₂ and AFG₂, 0.2?ng/g for OTA, 1.5?ng/g for ZEA, 6.2?ng/g for FB₁, FB₃ and HT-2 toxin, 9.4?ng/g for FB₂ and T-2 toxin, and 18.7?ng/g for DON. In addition, the limits of quantification (LOQ) ranged from 0.04?ng/g for AFB₂ and AFG₂ to 62?ng/g for DON. The method was successfully applied to the determination of these mycotoxins in 45 cereal samples obtained from the Malaysian market. The results indicated that the method can be applied for the multi-mycotoxin determination of cereals.     

Production and characterization of a monoclonal antibody that cross-reacts with the mycotoxins nivalenol and 4-deoxynivalenol.

Nivalenol is a mycotoxin produced by certain fungi that are pathogenic to important cereal crops, in particular maize, wheat, and barley. This toxin, 3alpha,4beta,7alpha,15-tetrahydroxy-12,13-epoxytrichothec-9-en-8-one, is found worldwide and is closely related to 4-deoxynivalenol (DON or vomitoxin), a mycotoxin associated with outbreaks of Fusarium head blight in North America. The literature on the toxicity of nivalenol suggests it is similar, if not more toxic, than DON. Despite the development of rapid immunologically based assays for detecting DON, such assays have not existed for detecting nivalenol without chemical modification of the analyte. This paper describes the development of a monoclonal antibody using a nivalenol-glycine protein conjugate. The monoclonal antibody was most specific for an acetylated form of DON (3-Ac-DON), but it exhibited sensitivity and cross-reactivity that were useful for detecting nivalenol and DON at relevant levels without the need to modify either toxin chemically. In an competitive indirect ELISA format, the concentrations of toxins able to inhibit colour development by 50% (IC50) were 1.7, 15.8, 27.5, 68.9, and 1740 ng ml(-1) for the mycotoxins 3-Ac-DON, DON, nivalenol, 15-Ac-DON, and fusarenon-X, respectively. The antibody was also used to develop a competitive direct ELISA for DON and nivalenol, with IC50's of 16.5 ng ml(-1) (DON) and 33.4 ng ml(-1) (nivalenol). These assays are capable of detecting both DON and nivalenol simultaneously, a property that may be useful in regions where these toxins co-occur or in formats, such as immunoaffinity columns, where co-isolation of both toxins is desirable.     

Development of an Ultrasensitive Immunochromatographic Assay (ICA) Strip for the Rapid Detection of Phenylethanolamine A in Urine and Pork Samples

In this study a one‐step immunochromatographic assay based on competitive format was developed for the rapid detection of phenylethanolamine A (PEAA) residues in urine and pork samples. A monoclonal antibody against PEAA was produced from BALB/c mice immunized with the PEAA‐BSA conjugate. The results of this qualitative test strip were to be interpreted visually. The visual detection limit (VDL) and threshold level of the optimized immunochromatographic assay for PEAA were 0.1 ng/mL and 0.5 ng/mL, respectively. Cross‐reactions with other β‐agonists were not significant inhibitions to the performance of the test strip assay. The results from the test strip were in a good agreement with those obtained using a high performance liquid chromatography‐tandem mass spectrometry (HPLC‐MS/MS) assay. The immunochromatographic assay developed here was a useful on‐site screening tool that is rapid to use, low in cost, and extremely convenient for the detection of PEAA in urine samples and pork samples.     

Natural occurrence of Fusarium toxins in soy food marketed in Germany

A total of 45 samples of soy food including whole beans, roasted soy nuts, flour and flakes, textured soy protein, tofu, proteinisolate including infant formulas and fermented products (soy sauce) were randomly collected in food and health food stores and analysed for Fusarium toxins. A spectrum of 13 trichothecenes of the A-type as well as of the B-type were determined by gas chromatography/mass spectrometry, zearalenone (ZEA), alpha- and beta-zearalenol (alpha- and beta-ZOL) by high performance liquid chromatography (HPLC) with fluorescence and UV-detection. Detection limits ranged between 1 and 19 microg/kg. At least one of the toxins investigated was detected in 11 out of a total of 45 samples of soy food belonging to different commodities. Scirpentriol (SCIRP), 15-monoacetoxyscirpenol, 4,15-diacetoxyscirpenol, T-2 tetraol, HT-2 toxin, deoxynivalenol (DON), 15- and 3-acetyldeoxynivalenol, ZEA, alpha- and beta-ZOL were detected in at least one sample, T-2 triol, T-2, NEO, NIV and FUS-X were not detected in any sample. Five out of 11 samples were positive for one toxin, one sample for two, three, six or seven toxins, two samples for 5 toxins, demonstrating the possibility of a contamination of soy food with a spectrum of Fusarium toxins. SCIRP, DON and ZEA were found up to 108, 260 and 214 microg/kg, the other toxins did not exceed 61 microg/kg. A first insight into the contamination of soy food with a broad spectrum of Fusarium toxins is provided.     

荧光微球免疫层析法定量检测牛乳中酪蛋白

目的研究用荧光微球免疫层析法定量检测牛乳中的酪蛋白。方法本文以酪蛋白为抗原,免疫新西兰大白兔制备抗酪蛋白的多克隆抗体,将纯化后的多克隆抗体通过EDC介导法与荧光微球进行偶联,将滤纸、样品垫、结合垫、NC膜和吸水纸组装成试纸条,用此荧光微球免疫层析法定量检测牛乳中的酪蛋白。结果试纸条在25 min内就能判定结果,最低检测限为100 ng/mL,该方法与BSA、OVA均无交叉反应,具有很好的特异性。检测酪蛋白浓度为100.0、500.0、1000.0 ng/mL的样品,试纸条的批内回收率分别为(89.03±5.2)%、(93.47±6.9)%和(91.2±7.8)%,批间回收率分别为(87.69±6.2)%、(92.73±8.3)%、(89.82±8.5)%。结论初步建立了一种快速、方便、高灵敏度的荧光微球免疫层析方法用以检测牛乳制品中的过敏原——酪蛋白。     

Development and Application of a Method for the Analysis of 9 Mycotoxins in Maize by HPLC‐MS/MS

A reliable and sensitive liquid chromatography/tandem mass spectrometry (LC‐MS/MS) method was developed for the simultaneous determination of aflatoxins (AFB₁, AFB₂, AFG₁, and AFG₂), ochratoxin A (OTA), deoxynivalenol (DON), zearalenone (ZEA), fumonisin B₁ (FB₁), and T2‐toxin in maize. The samples were first extracted using acetonitrile: water: acetic acid (79 : 20 : 1), and then further cleaned‐up using OASIS HLB cartridge. Optimum conditions for the extraction and chromatographic separation were investigated. The mean recoveries of mycotoxins in spiked maize ranged from 68.3% to 94.3%. Limits of detection and quantification ranged from 0.01 to 0.64 μg/kg and from 0.03 to 2.12 μg/kg, respectively. The LC‐MS/MS method has also been successfully applied to 60 maize samples, which were collected from Shaanxi Province of China. Twenty‐four of the total 60 samples (40%) were contaminated with at least 1 of these 9 mycotoxins. Occurrence of mycotoxins were 6.7%, 1.7%, 3.3%, 6.7%, 1.7%, 23.3%, and 3.3% for AFB₁, AFB₂, OTA, ZEA, DON, FB₁, and T2‐toxin, respectively. The results demonstrated that the procedure was suitable for the simultaneous determination of these mycotoxins in maize matrix.     

高效液相色谱-串联质谱法测定3种水产品中的T-2毒素与HT-2毒素

建立高效液相色谱-串联质谱定量快速检测罗非鱼、南美白对虾和黄金贝中的T-2毒素与HT-2毒素方法。以10 mL乙酸乙酯作为提取溶剂,振荡提取,无水硫酸钠除水,定量移取5 mL提取液氮气吹干后用1 mL含有0.1%甲酸的甲醇-5 mmol/L乙酸铵溶液（3∶7,V/V）复溶,正己烷脱脂净化,基质匹配法外标定量。3 种水产品中T-2毒素和HT-2毒素的检出限分别为2 μg/kg和4 μg/kg。T-2毒素质量浓度为2～100 ng/mL,HT-2毒素质量浓度为4～200 ng/mL,范围内线性良好。在3 种样本中进行3 个水平添加实验（n=6）,T-2毒素回收率为84.3%～109.9%,HT-2毒素的回收率为90.9%～103.2%。T-2毒素的相对标准偏差为2.0%～8.7%,HT-2毒素的相对标准偏差为2.6%～10.6%。本方法简便快速、准确度好、精密度高,适用于3 种代表性水产品中T-2与HT-2毒素的同时检测。     

Fusarium toxins in corn food products: a survey of the Serbian retail market

This paper presents data on the occurrence of Fusarium toxins – zearalenone (ZEA), deoxynivalenol (DON) and fumonisins (FUMs) B1 and B2 – in corn flours and corn flakes marketed in Serbia. A total of 71 samples were collected over 2013–2016 and analysed using HPLC with UV or fluorescence detection. In the case of corn flours, none of the samples taken in 2013 exhibited the presence of ZEA or DON, whereas 90% were positive for FUMs. In 2015, occurrence was very high: ZEA 93%, DON 86% and FUMs 100% (mean 43.3, 322.6 and 323.0 μg kg^?1, respectively), with 21% of the samples exceeding the maximum level for ZEA and 7% for DON and FUMs. In 2016, a lower occurrence was recorded in the case of ZEA (75%) and DON (38%), with drastically lower mean contamination levels (six- and 10-fold, respectively), while FUMs stayed at 97%, with twofold lower mean. The maximum level was exceeded only for ZEA (3%). The frequency of ZEA–DON–FB1 co-occurrence was 86% in 2015 and 25% in 2016. Regarding corn flakes, occurrence summarised for the study period was 87% ZEA, 73% FUMs and 40% DON. One sample (7%) exceeded the maximum levels for both ZEA and DON. Observed occurrence changes were in agreement with the climatic conditions during corn growing seasons preceding the market release of the processed products.     

Survey of Fusarium toxins in foodstuffs of plant origin marketed in Germany

A total of 219 samples of foodstuffs of plant origin, consisting of grain-based food, pseudocereals and gluten-free food as well as vegetables, fruits, oilseeds and nuts, were randomly collected during 2000 and 2001 in food and health food stores. A spectra of 13 trichothecene toxins including diacetoxyscirpenol (DAS), 15-monoacetoxyscirpenol (MAS), scirpentriol (SCIRP), T-2 and HT-2 toxins (T-2, HT-2), T-2 triol, T-2 tetraol, neosolaniol (NEO) of the A-type as well as deoxynivalenol (DON), 3- and 15-acetyl-DON (3-, 15-ADON), nivalenol (NIV), and fusarenon-X (FUS-X) of the B-type were determined by gas chromatography/mass spectrometry. Analysis of zearalenone (ZEA), alpha- and beta-zearalenol (alpha- and beta-ZOL) was made by high-performance liquid chromatography with fluorescence and UV-detection. Detection limits ranged between 1 and 19 microg/kg. Out of 84 samples of cereal-based including gluten-free foods, 60 samples were positive for at least one of the toxins DON, 15-ADON, 3-ADON, NIV, T-2, HT-2, T-2 tetraol and ZEA, with incidences at 57%, 13%, 1%, 10%, 12%, 37%, 4% and 38%, respectively, whereas SCIRP and its derivatives MAS and DAS, T-2 triol, Fus-X as well as alpha- and beta-ZOL were not detected in any sample of this subgroup. Contents of DON ranged between 8 and 389 microg/kg, for all other toxins determined concentrations were below 100 microg/kg. The pseudocereals amaranth, quinoa and buckwheat were free of the toxins investigated. Ten of 85 samples of vegetables and fruits were toxin positive. ZEA and the type A trichothecenes MAS, SCIRP, DAS, HT-2 were detected in 7, 3, 2, 1 and 1 samples, respectively. Out of 35 samples of oilseeds and nuts, 7 samples were toxin positive. HT-2, T-2 and ZEA were detected in 4, 3 and 4 samples, respectively. In vegetables and fruits as well as in oilseeds and nuts, toxin levels were below 50 microg/kg. None of the B-type trichothecenes analysed was found for both subgroups.     

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).     

Fusarium toxins in wheat flour collected in an area in southwest Germany

A total of 60 samples of wheat flour were collected during the first 6 months of 1999 from mills and food stores in an area in southwest Germany. Samples included whole-grain and two types of white flour with these three groups characterized by a high, medium and low ash content. The contents of deoxynivalenol (DON), nivalenol (NIV), 3- and 15-acetyldeoxynivalenol, HT-2 toxin (HT-2), T-2 toxin (T-2) and fusarenon-X (FUS-X) were determined by gas chromatography/mass spectrometry, and those of zearalenone (ZEA), alpha- and beta-zearalenol (alpha- and beta-ZOL) by high performance liquid chromatography with fluorescence detection. FUS-X, alpha- and beta-ZOL were not detected in any sample. Based on incidence and level, DON was the predominant toxin followed by NIV and ZEA for all three flour types. The overall degree of toxin contamination was lower with decreasing ash content. This suggests a localization of the toxins analyzed primarily in the outer parts of the original wheat kernels. The median DON content was significantly (P<0.05) higher for wheat flour originating from wheat of conventional than of organic production.     

胶体金免疫层析法快速定量检测猪肝中喹乙醇残留

本文研究了胶体金免疫层析试纸条快速定量检测猪肝中喹乙醇残留的方法。利用胶体金免疫层析技术,制备了喹乙醇胶体金试纸条,检测了其特异性,并建立了T/C比值法进行定量检测猪肝中喹乙醇的残留。制备的试纸条可以在15min内完成定性和定量检测,与卡巴氧、乙酰甲喹和3-甲基-喹噁啉-2-羟酸几乎无交叉反应。当肝中喹乙醇质量浓度在1²00ng/mL范围内,试纸条有较好的线性关系,最低检测限为6.83ng/mL。阴性加标实验结果表明,喹乙醇浓度在25、50、100ng/mL时,试纸条的回收率在90.9%¹05.0%之间。      

Detection of deoxynivalenol in foods and indoor air using an array biosensor

Deoxynivalenol (DON), a mycotoxin produced by several Fusaruim species, is a worldwide contaminant of foods and feeds. Because of the potential dangers due to accidental or intentional contamination of foods with DON, there is a need to develop a rapid and highly sensitive method for easy identification and quantification of DON. In this study, we have developed and utilized a competitive immunoassay technique to detect DON in various food matrixes and indoor air samples using an array biosensor. A DON-biotin conjugate, immobilized on a NeutrAvidin-coated optical waveguide, competed with the DON in the sample for binding to fluorescently labeled DON monoclonal antibodies. To demonstrate a simple procedure amenable for on-site use, DON-spiked cornmeal, cornflakes, wheat, barley, and oats were extracted with methanol-water (3:1) and assayed without cleanup or preconcentration. The limits of detection ranged from 0.2 ng/mL in buffer to 50 ng/g in oats. The detection limit of DON spiked into an aqueous effluent from an air sampler was 4 ng/mL.     

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.     

Natural occurrence of Fusarium toxins in oats harvested during five years in an area of southwest Germany.

A total of 56, 56, 54, 51, and 55 oats samples used for feed production were collected randomly after the 1987, 1989, 1990, 1991 and 1992 crops, respectively, from farms located in an area of southwest Germany. Deoxynivalenol (DON), 3- and 15-acetyl-deoxynivalenol (3-, 15-ADON), nivalenol (NIV), fusarenon-X (FUS-X), T-2 toxin (T-2), HT-2 toxin (HT-2) and diacetoxyscirpenol (DAS) were determined by gas chromatography with mass selective detection (GC-MS), zearalenone (ZEA), alpha and beta-zearalenol (alpha-, beta-ZOL) by GC-MS or by HPLC. DON was the major toxin with incidences at 49-85% and mean levels in positive samples of 52-302 micrograms/kg. Incidences of ZEA, 3-ADON, NIV, HT-2, and T-2 were at 20-37, 0-30, 18-67, 0-29, and 27-61%, respectively, with mean levels in positive samples at 8-25, 5-63, 11-192, 205-296, and 20-244 micrograms/kg, respectively. alpha- and beta-ZOL and DAS were not detected in any sample. 15-ADON and FUS-X were assayed in samples from 1987, 1991 and 1992. 15-ADON was detected in 9, 4 and 0% of samples, with an average of 9 and 18 micrograms/kg, respectively; FUS-X was not detected. The incidence and levels of toxins varied from year to year. The correlation between the occurrence of toxins and precipitation is discussed.