Aflatoxin B1 and sterigmatocystin in wheat and wheat products from supermarkets in China

Wheat is an important cereal but it is often contaminated with mycotoxins. The natural occurrence of aflatoxin B₁ (AFB₁) and sterigmatocystin (STC) was determined in 178 food samples (32 wheat samples and 146 wheat products) purchased from Chinese supermarkets. The methodology was validated, the wheat and wheat products samples were treated with a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) and quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). From these samples 18.8% of wheat and 8.2% of cracker samples were contaminated with AFB₁. Mean levels were 0.06 µg/kg and 0.05µg/kg, respectively. There was no AFB₁ contamination in white bread or whole meal bread. Meanwhile 53.1% of wheat, 59.2% of crackers, 20.8% of white bread and 16% of whole meal bread samples were contaminated with STC. The mean levels were 0.07, 0.79, 0.12 and 0.12 µg/kg respectively. Although the levels were low, this demonstrates the need for more comprehensive surveys for these two mycotoxins in wheat and wheat products from China.     

运用免疫亲和柱和高效液相色谱(HPLC)检测啤酒大麦中的脱氧雪腐镰刀菌烯醇

采用免疫亲和柱净化、高效液相色谱定量等方法对啤酒大麦中的脱氧雪腐镰刀菌烯醇(DON)进行检测。向啤酒大麦中加入标准品,加标的范围在0.10～2.00μg/g,加标回收率为92.04%～97.29%,相对标准偏差是0.92%～2.67%。检出限是0.01μg/g。所测样品中DON的含量范围在0.0123～0.0926μg/g,其中江浙、云南和东北产区的啤酒大麦中DON含量较高。     

脱氧雪腐镰刀菌烯醇ELISA定量检测试剂盒的研制

研制了脱氧雪腐镰刀菌烯醇ELISA试剂盒,用于检测谷物粮食中的脱氧雪腐镰刀菌烯醇(Deoxynivalenol,DON)。在抗DON单克隆抗体的基础上,用间接竞争酶联免疫吸附检测试剂盒各项指标。结果为:试剂盒最低检测浓度为20ng/mL,检测线性范围为50～400ng/mL,IC50103ng/mL。平均加标回收率>80%,批内变异系数小于10%,批间变异系数<15%。用试剂盒测定盲样,其结果与德国拜发试剂盒及免疫亲和柱-高效液相色谱检测结果无显著性差异。说明试剂盒指标符合相关技术要求,具有快速、灵敏、准确、方便等特点。     

单克隆免疫亲和柱—高效液相色谱法测定小麦中致呕毒素

研究了单克隆免疫亲和柱－高效液相色谱法测定小麦中致呕毒素的方法。样品通过水提取,提取液用免疫亲和柱净化,Spherisorb C18色谱柱分离,紫外检测器检测,外标法定量。对添加不同含量不平的致呕毒素,5次重复实验的平均回收率为69.6%-81.8%。变异系数（CV）为5.7%-8.3%。检测低限为0.02mg/kg。     

Occurrence of deoxynivalenol in wheat flour,instant noodle and biscuits commercialised in Brazil

A total of 134 samples, consisting of 58 wheat flour, 40 instant noodle and 36 biscuits, were analysed for the presence of deoxynivalenol (DON). The samples were obtained from retail markets of the city of São Paulo during the period 2010–2014. DON was determined by high performance liquid chromatography with ultraviolet detection and immunoaffinity sample clean-up. Method validation followed international guidelines. The LOD and LOQ were 60 and 200 µg kg^?1, respectively, considering the three different types of samples analysed. The lowest recovery found in this study was 91.8% with RSD 4.5% for instant noodles. DON was detected in 91.4%, 97.5% and 97.2% of samples wheat flour, instant noodles and biscuits, respectively, resulting in a total of 94.8% with levels ranging from LOD to 1720.0 µg kg^?1.     

Deoxynivalenol and ochratoxin A in German wheat and changes of level in relation to storage parameters

The occurrence of the mycotoxins deoxynivalenol (DON) and ochratoxin A (OTA) in the winter wheat of 1997 and 1998 grown under organic farming conditions was investigated using ELISAs (R-Biopharm®) for quantification. The influence of delayed drying of the grain after harvest on the development of DON and OTA was determined in storage trials (moisture: 17% and 20%; temperature: 20°C; duration: four and six weeks). The Tox5 PCR assay was used both to detect Fusarium species with the potential to produce trichothecenes and as a measure of their relative DNA content during the storage trials. The intensity of the PCR signals was correlated with the DON concentration. Fusarium species were identified microscopically by standard methods. All the freshly harvested grain samples were contaminated with DON and showed further increases in the DON concentration during storage. OTA contamination was found in 14.3% of the 1997 samples and in 24.1% of the 1998 samples. OTA increased during storage trials of the 1997 samples but not in the 1998 samples.     

Effects of industrial processing on the distributions of deoxynivalenol, cadmium and lead in durum wheat milling fractions

The aim of this work was to investigate the distributions of deoxynivalenol, cadmium and lead in durum wheat milling fractions from industrial milling plants. The study focused on two milling technologies: conventional milling and debranning before milling. Initial analyses of samples of all raw materials showed contamination levels considerably lower than the limits imposed by the European Commission. Deoxynivalenol, cadmium and lead showed rather similar patterns of distribution. Semolina had lower, although not significant levels of these undesirable substances than unprocessed wheat grain; in contrast, marked concentration factors were found for the contaminants in shorts (middlings) and flour shorts. Debranning technology resulted in higher contamination levels in products intended for animal feed than conventional milling. The difference was statistically significant for deoxynivalenol and lead contamination of the shorts (middlings) fraction. As the outer parts of the kernel are generally considered richer in inorganic elements and moulds, Pearson's correlation was performed to investigate the relationship between the crude fibre contents of the different fractions, adopted as bran marker, and contaminant levels. Positive correlations were found for each of the three contaminants, although the correlation coefficients were not very high, demonstrating that crude fibre likely does not constitute a good marker for describing contaminants repartitioning in milling fractions when the levels of these substances are low.     

Detection and quantification of adulteration of durum wheat flour by flour from common wheat using reverse phase HPLC

When common wheat (Triticum aestivum L) gliadins were separated by RP-HPLC, a major doublet peak eluted at 47.20 and 47.94 min. This peak was consistently found to be absent in Durum wheat (Triticum durum Desf) gliadins separated under identical conditions. In Durum wheat gliadins a characteristic small peak eluted at 48.30 min followed at 50.47, 510.37, 52.80 min by larger peaks. The peak area ratio of the peaks eluting at 50.47 and 51.37 min was found to be 2.18 (±0.14). This ratio was found to decrease proportionally on contamination of Durum wheat flour with flour from some common wheat varieties. This ratio alone was not enough to detect and quantify adulteration by all varieties of common wheat. An alternative method was found whereby the peak emerging between 47 and 49 min in the Durum wheat gliadin elution profile was expressed as a ratio of the total protein applied. This ratio was shown to increase when Durum wheat flour was adulterated with flour from common wheat thus enabling quantitative estimation of the level of adulteration. A third method of detecting adulteration of Durum wheat flour is also proposed in which the peak emerging between 47 and 49 min is collected and the protein separated by PAGE. The presence of more than one band of γ/β-gliadins is indicative of adulteration.     

粮谷中呕吐毒素管式化学发光免疫分析法的研究与应用

目的:建立一种准确度高、重复性优的快速检测粮谷中呕吐毒素（DON）的管式化学发光免疫分析法（CLIA）。方法:本研究基于抗原抗体的特异性反应,选择磁性微粒为固相载体,通过优化磁微粒的稀释度、反应时间等工作条件,建立了高准确度、重复性良好的DON-CLIA。结果:本研究建立的DON-CLIA的检测范围为5¹85 ng/m L;最低检测限为3.82 ng/m L（样本检测限为0.076μg/g）;准确度相对偏差为6.64%,重复性变异系数为2.32%,均小于10%;DON的添加回收率在90%¹10%之间。结论:本研究建立的DON-CLIA的检测范围、检测限、准确度、重复性、回收率,均符合实际工作的要求,是一种快速、高效、准确的化学发光免疫分析法,适用于大量样本的DON含量的测定。      

Deoxynivalenol and its acetyl derivatives in bread and biscuits in Shandong province of China

In the present study, 100 commercial breads and biscuits were investigated for the occurrence of deoxynivalenol (DON) and its acetylated derivatives 3-acetyldeoxynivalenol (3-Ac-DON) and 15-acetyldeoxynivalenol (15-Ac-DON). The target mycotoxins were determined by isotope dilution ultrahigh performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS). DON was determined in 95% of the test samples with a mean value of 153.3 µg/kg. Compared with DON, 3-Ac-DON and 15-Ac-DON were far less frequently detected, with mean values of 1.14 and 0.37 µg/kg, respectively. The estimated daily intakes of the sum of DON and its derivatives in breads and biscuits were 0.0059 and 0.0313 µg/kg bw/day, respectively, which was within the group provisional tolerable daily intake of 1.0 µg/kg bw/day set by the Joint FAO/WHO Expert Committee on Food Additives. In the future, systematic monitoring programmes of DON and its derivatives in relevant foodstuffs are still necessary for food safety and human health.     

中国主要小麦种植区雨养条件下水分胁迫发生规律模拟--测试文章

运用EPIC（Environmental Policy Integrated Climate）作物生长模型模拟了1961—2011年中国各小麦种植区小麦生长过程,对中国各小麦种植区小麦生育期内水分胁迫规律进行了分析。结果表明：雨养条件下,全国11个小麦种植区的水分胁迫程度可分为3个等级;冬麦区（新疆冬麦区除外）和东北春麦区水分胁迫均值、发生频率均明显低于其他春麦区;南方的3个冬麦区（华南、西南、长江中下游）,水分胁迫的程度、发生频率均低于其他麦区;黄淮、北部冬麦区水分胁迫规律相似,在1、2月和5、6月较高,而北部冬麦区水分胁迫程度和发生频率略高于黄淮冬麦区;北部、西北、北疆春麦区、新疆冬麦区在雨养条件下水分胁迫最为严重,如果没有灌溉,小麦几乎绝收,尤其是新疆冬麦区。     

2009年干旱半干旱地区小麦品质状况研究

在2009年,选取河北、山东、山西、陕西四个省干旱半干旱地区节水高产小麦样品114份,对籽粒感官性状、质量指标、品质性状进行全面分析和评价。结果表明,达到优质强筋小麦国家标准样品占样品总数15.8%,达到优质弱筋小麦国家标准样品占样品总数0.9%;通过试验筛选推荐适合该区域种植的节水高产优质多抗小麦新品种。     

高效液相色谱法测定小麦中脱氧雪腐镰刀菌烯醇含量的不确定度评定

对高效液相色谱法测定小麦中脱氧雪腐镰刀菌烯醇含量的测量不确定度进行评定。依据JJF 1135-2005《化学分析测量不确定度评定》及CNAS-GL06-2006《化学分析中不确定度的评估指南》中不确定度评定的基本程序,建立数学模型,分析高效液相色谱法测定小麦中脱氧雪腐镰刀菌烯醇含量过程中引入的各测量不确定度分量,计算得到测量结果的合成标准不确定度和扩展不确定度。评定结果表明：影响检测结果不确定度的因素主要是质量浓度因素,其次是体积因素及样品非均匀性因素,相对标准不确定度分别为0.040 3、0.019 7、0.019 6。     

高效液相色谱法测定小麦胚中的棉籽糖

研究了采用高效液相色谱法测定小麦胚中的棉籽糖。样品经粉碎、振荡、萃取、过滤等前处理,通过色谱柱进行分离,流动相为64％的乙腈和36％的重蒸馏水。棉籽糖的浓度在10－50μg/mL的范围内能被定量测定,其回收率为99．71％,变异系数为1．89％。     

啤酒中脱氧雪腐镰刀菌烯醇含量的测定

采用高效液相色谱法对啤酒中脱氧雪腐镰刀菌烯醇(DON)进行分析检测。选用色谱柱Zorbax Eclipose XDB-C18(4.6mm×250mm,5μm),流动相为甲醇-0.05%磷酸水溶液(体积比20∶80),柱温30℃,流速1.0mL/min,检测波长210nm。在此条件下,DON得到很好分离,在0.75～100mg/L范围内线性关系良好,R2=0.999 3,外加标回收率在85.36%～96.92%之间,RSD为4.21%,该方法可以简便、准确地测定啤酒中DON含量。     

固相萃取柱净化-高效液相色谱法测定小麦中脱氧雪腐镰刀菌烯醇

建立固相萃取-高效液相色谱对小麦中脱氧雪腐镰刀菌烯醇（deoxynivalenol,DON）进行测定的方法。从提取溶剂、净化方式、流动相组成以及流动相流速等条件优化DON检测方法。结果表明,当样品提取溶剂为乙腈-水（84∶16,V/V）,Bond Elut Mycotoxin固相萃取柱净化,流动相组成为乙腈-水（6∶94,V/V）,流速为0.9 mL/min时,DON检测结果最好,该检测方法的DON回收率达到90.12%～106.25%,日内和日间相对标准偏差分别为4.51%和6.12%。该方法快速、准确,重复性好,稳定性高,适合DON污染小麦样品的大批量检测。     

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.     

液相色谱法测定谷物中脱氧雪腐镰刀菌烯醇

建立检测谷物中脱氧雪腐镰刀菌烯醇(DON)的液相色谱方法,通过不同提取方法的比对来确定最佳的DON提取方案,并最终确定使用乙腈-水(体积比V/V,84/16)提取,经过DON专用净化柱的净化处理后,采用紫外检测器(λ=220 nm)及C18亲水分离柱测定。结果表明,用高速均质机均质4 min提取,可大幅度提高方法回收率,回收率达到90.7%~98.9%,方法最低检出限为50μg/kg。     

Inhibitory Effect of Fusarium Mycotoxins on Growth of Brewing Yeasts. 2. Deoxynivalenol and Nivalenol*

The effect of the trichothecene mycotoxins deoxynivalenol (DON) and nivalenol (NIV) on growth of Saccharomyces cerevisiae lager and ale strains has been studied. The toxins were added into the growth medium in low and high concentrations. Yeast growth was assessed by measurement of dry weight or relative growth, cell number, viability and conductance change of the growth medium using direct and indirect methods. The inhibitory effect of both DON and NIV on yeast growth was dependent on toxin concentration. Additionally, when the extent of inhibition of yeast growth caused by high concentrations of both toxins was observed, it was subject to yeast strain, length of incubation and method used to assess yeast growth. The lowest concentrations of mycotoxin causing significant inhibition on growth of brewing yeasts were: 100 μg/ml DON for the lager strain and 50 μg/ml for the ale strain, and 50 μg/ml NIV for the ale strain.