超高效液相色谱-质谱联用法检测地理标志产品松江大米中8种真菌毒素的含量

建立超高效液相色谱-三重四极杆质谱法同时检测大米基质中8种真菌毒素的方法,对地理标志产品松江大米中真菌毒素的污染情况进行监测。大米样品经提取液乙腈水混合液（84:16,v:v）超声提取后,取部分提取液加入内标溶液,混匀后过多功能净化柱MycoSep229净化,采用Waters Acquity UPLC?BEH?C18色谱柱 (2.1 mm×50 mm, 1.7 μm),以0.1%（v:v）甲酸水溶液-乙腈作为流动相进行梯度洗脱,分离黄曲霉毒素B1（Aflatoxin B1, AFB1）、黄曲霉毒素B2（Aflatoxin B2, AFB2）、黄曲霉毒素G1（Aflatoxin G1,AFG1）、黄曲霉毒素G2（Aflatoxin G2, AFG2）、伏马毒素B1（FumonisinsB1, FB1）、伏马毒素B2（FumonisinsB2, FB2）、伏马毒素B3（FumonisinsB3, FB3）、赭曲霉毒素A（Ochratoxin A, OTA） 8种真菌毒素化合物,该方法采用电喷雾离子化正离子模式,以多反应监测方式进行。AFB1、AFG1、FB1、FB2、FB3、OTA 6种真菌毒素在0.5-15μg/L范围内线性良好,AFB2、AFG2在0.125-3.75μg/L范围内线性良好,线性相关系数r均大于0.999;8种化合物定量限(limit of quantifications, LOQs)范围为0.01-0.25 μg/kg,比国标中相同方法的定量限降低2-80倍不等;在低、中、高三水平加标,其回收率均在95%~120%范围内,相对标准偏差(relative standard deviations, RSDs)为1.5%~8.9% (N=6)。本方法前处理简单,方法利用率高,结果准确可靠,利用该方法检测的20批新上市松江大米中真菌毒素污染情况比较乐观,对人体的健康危害较低。     

利用液相色谱对原粮的真菌毒素检测——HPLC法测定玉米赤霉烯酮

<正>真菌毒素是一种真菌产生的有毒代谢产物。常见的污染粮食的真菌毒素包括:玉米赤霉烯酮(zearalenone,ZEN)、赭曲霉毒素A(ochratoxin A,OTA)、黄曲霉毒素B1(aflatoxins,AFB1)、黄曲霉毒素B2(AFB2)、黄曲霉毒素G1(AFG1)、黄曲霉毒素G2(AFG2)、呕吐毒素(deoxynivalenol,DON)以及T-2毒素等。根据大量研究文献及实验室的长期监测数据,出现很多粮食中同时遭到多种真菌毒素污染的情况。在基层实验室检测仪器配置情况的基础上,我国     

高效液相色谱法同时检测粮食中常见8 种真菌毒素的含量

建立免疫亲和柱净化-高效液相色谱法同时测定粮食中黄曲霉毒素B1（aflatoxins,AFB1）、黄曲霉毒素B2（AFB2）、黄曲霉毒素G1（AFG1）、黄曲霉毒素G2（AFG2）、赭曲霉毒素A（ochratoxin A,OTA）、玉米赤霉烯酮（zearalenone,ZEN）、呕吐毒素（deoxynivalenol,DON）和T-2毒素的检测方法。样品经乙腈-水提取后,用免疫亲和柱净化,Agilent Elipse Plus C18（100 mm×4 mm,3.5 μm）色谱柱分离,以甲醇-乙腈-水-乙酸为流动相,流速1 mL/min,柱温35 ℃,进样量20 μL,检测系统为可变波长检测器串联光化学衍生器串联荧光检测器。根据信噪比为3的峰响应值,确定各真菌毒素的检出限为：AFB1 0.446 ng/mL、AFB2 0.152 ng/mL、AFG1 0.523 ng/mL、AFG2 0.334 ng/mL、ZEN 7 ng/mL、OTA 0.7 ng/mL、DON 200 ng/mL、T-2毒素100 ng/mL。样品中各真菌毒素的平均加标回收率,玉米为80.0%～104.5%,小麦为83.2%～102.8%,方法精密度为2.6%～10.2%。从样品前处理到分析整个过程耗时约2 h。本方法简便、快速、灵敏度高,适用于粮食中多种真菌毒素的快速测定。     

山东省玉米真菌毒素污染状况调查及分析

为掌握山东省玉米的真菌毒素污染状况,评估污染带来的安全风险,为加强真菌毒素污染防控提供依据,采集了山东省玉米主产县2013年~2014年收获和储藏的玉米样品共520批次,采用液相色谱—飞行时间质谱联用仪(UPLC-Q-TOF)方法检测了玉米中黄曲霉毒素(AFB_1、AFB_2、AFG_1、AFG_2)、伏马毒素(FB_1、FB_2、FB_3)、呕吐毒素(DON)和玉米赤霉烯酮(ZEN)的污染水平。结果表明,AFB1、AFB2、AFG1在玉米中检出率分别为18.08%、7.88%、0.77%,平均含量分别为7.62、0.60、0.05μg/kg;FB1、FB2、FB3检出率分别为92.50%、88.08%、83.85%,平均含量分别为1 798.69、531.83、197.71μg/kg;DON检出率为26.35%,平均含量为240.44μg/kg;ZEN检出率为14.62%,平均含量为74.90μg/kg;AFG2未检出。调查结果还表明,伏马毒素在所测样品中污染最为严重,超标率达33.46%;单一样品受多种毒素混合污染的情况较严重。     

QuEChERS-超高效液相色谱串联质谱法测定发酵黑茶中的10种真菌毒素

建立了云南普洱茶、湖南黑茶、广西六堡茶和湖北老青茶等发酵黑茶黄曲霉毒素B1（AFB1）、黄曲霉毒素B2（AFB2）、黄曲霉毒素G1（AFG1）、黄曲霉毒素G2（AFG2）、脱氧雪腐镰刀菌烯醇（DON）、3-乙酰基脱氧雪腐镰刀菌烯醇（3-AcDON）、玉米赤霉烯酮（ZEN）、T-2毒素（T-2）、HT-2毒素（HT-2）、赭曲霉毒素A（OTA）等10种真菌毒素的简单、快速、高灵敏度超高效液相色谱-串联质谱检测方法。样品采用乙腈/水溶液（84+16）提取试样、QuEChERS净化,试样以C18柱分离,多反应监测（MRM）模式进行定量与定性分析,采用外标法定量。结果表明,在优化的条件下,10种真菌毒素在各自的线性响应范围内线性关系良好,相关系数（r）均不小于0.9995,定量限（LOQ）为0.1~10 μg/kg,在三个不同加标水平下平均回收率为61.9%~120.3%,相对标准偏差（RSD）为3.2%~16.1%。采用建立的方法对市面上销售的黑茶中的10种真菌毒素进行了筛查,数批产品检出真菌毒素。该方法简单、准确、可靠,可适用于发酵黑茶中多种真菌毒素的快速分析。     

粮油中黄曲霉毒素检测研究

正黄曲霉毒素(AFT)是由黄曲霉和寄生曲霉在温度、湿度合适的条件下产生的真菌毒素,其存在对人体具有极强的致癌、致畸等危害,包括AFB1、AFB2、AFG 1、AFG 2等~([1,2])。全世界每年约有1/4的食品会受到黄曲霉毒素的污染,花生、玉米等原料在生产、运输中易受黄曲霉毒素的污染~([3])。现有免疫亲和柱净化-高效液     

高效液相色谱法测定食用植物油中6种真菌毒素

建立了基于分散液液微萃取技术（DLLME）的高效液相色谱法同时测定食用植物油中6种真菌毒素的方法。样品经石油醚脱脂，乙腈-水-乙酸（体积比84∶ 15∶ 1）超声提取，CHCl3为萃取剂液液萃取净化及柱前衍生化后，以Agilent XDB-C18色谱柱（4.6 mm×150 mm, 3.5 μm）分离，梯度洗脱，经荧光检测器检测。结果表明：食用植物油中6种真菌毒素的线性关系良好，相关系数均大于0.999，方法检出限为0.2~0.5 μg/kg，样品的平均加标回收率为75.88%~105.25%，相对标准偏差为0.5%~9.5%。该方法可用于食用植物油中黄曲霉毒素（AFB1、AFB2、AFG1、AFG2）以及赭曲霉毒素（OTA、OTB）6种真菌毒素的同时检测。     

西南地区辣椒干制品中黄曲霉毒素污染状况及风险评估

为分析来自西南地区（四川、重庆和云南）辣椒干制品中黄曲霉毒素（AFB1、AFB2、AFG1和AFG2）的污染情况和暴露风险,购自西南地区的超市、农贸市场和零售店的干辣椒和辣椒粉样品经研碎、过筛、提取、衍生等前处理后,采用高效液相色谱（HPLC）法测定黄曲霉毒素含量。结果表明,该方法的精密度及准确度较好,AFB1、AFG1的检出限和定量限均分别为0.05 ng/mL、0.15 ng/mL;AFB2、AFG2的检出限和定量限均分别为0.03 ng/m L、0.10 ng/mL。四川、重庆和云南地区辣椒干制品中黄曲霉毒素的阳性率分别为15%、10%和5%;干辣椒和辣椒粉中黄曲霉毒素的阳性率均分别为6.67%和13.33%;来自农贸市场和零售店的辣椒干制品阳性率（分别为15%、10%）比超市（5%）高。样品中黄曲霉毒素的膳食暴露量为0.001 455 ng/（kg体质量·d）,西南地区人群暴露率为0.15%,表明存在一定的暴露风险。     

发酵茶中多种真菌毒素超高效液相色谱-串联质谱法的测定

采用乙腈/水溶液(84+16)提取试样、Myco Spin 400多功能柱净化,建立了发酵茶(普洱茶、湖南黑茶和红茶)中黄曲霉毒素B1(AFB1)、黄曲霉毒素B2(AFB2)、黄曲霉毒素G1(AFG1)、黄曲霉毒素G2(AFG2、赭曲霉毒素A(OTA)五种真菌毒素的简单、快速超高效液相色谱-串联质谱检测方法。试样以Agilent Zorbax Rrhd SB-C18柱分离,多反应监测(MRM)模式进行定量与定性分析,外标法定量。结果表明,在优化的条件下,五种真菌毒素在各自的线性响应范围内线性关系良好,相关系数(r)不低于0.9983,定量限(LOQ)为0.1~0.5μg/kg,低、中、高3个加标水平的平均回收率(n=3)为63.5%~125.0%,相对标准偏差(RSD)为3.9%~17.2%。该方法前处理简单、检测速度快、净化效果好、结果准确、可靠,适合发酵茶中多种真菌毒素的快速检测。     

免疫亲和柱净化-超高效液相色谱串联质谱法同时测定火锅底料中的5种真菌毒素

目的：建立复合免疫亲和柱净化、超高效液相色谱串联质谱检测火锅底料中的黄曲霉毒素B1(Aflatoxins B1,AFB1)、黄曲霉毒素B2(Aflatoxins B2,AFB2)、黄曲霉毒素G1(Aflatoxins G1,AFG1)、黄曲霉毒素G2(Aflatoxins G2,AFG2)、赭曲霉毒素A(Ochratoxin A, OTA)的方法。方法：样品提取后,经复合免疫亲和柱净化,以0.1%甲酸水和甲醇为流动相梯度洗脱,用Agilent EclipsePlus C18 RRHD色谱柱分离,ESI+进行多反应监测,内标法定量。结果：5种真菌毒素的线性范围在0.1～10.0 ng/mL,相关系数(r)>0.999,检出限0.1μg/kg,定量限0.3μg/kg。3个加标水平下(0.2、5.0、10.0μg/kg)的回收率在81.38%～97.87%之间,相对标准偏差为0.79%～6.18%。结论：该方法快速准确,可用于火锅底料中5种真菌毒素的定性、定量检测。     

Co-occurrence of aflatoxins,ochratoxin A and zearalenone in Capsicum powder samples available on the Spanish market

The aim of this study was to determine the co-occurrence of aflatoxins (AFs), ochratoxin A (OTA) and zearalenone (ZEA) in paprika and chilli samples purchased in Spain, using HPLC with fluorescence detection. The occurrence of mycotoxin in 64 paprika samples was 59% for AFs, 98% for OTA and 39% for ZEA, whereas in the 35 chilli samples, the contamination was 40% for AFs, 100% for OTA and 46% for ZEA. None of the samples had AFs levels higher than the legally allowable limits. Regarding the co-occurrence of mycotoxins, 75% of paprika samples and 65% of chilli samples contained more than one mycotoxin. Chilli samples generally had lower concentrations of AFB1, AFB2, total AFs and OTA than had paprika samples. The high incidence of OTA contamination suggests that additional legislation may be required to for these kinds of spices.     

食用植物油中黄曲霉毒素和赭曲霉毒素的污染状况及特征分析北大核心CSCD

针对市场在售的调和油、玉米油、大豆油、花生油和菜籽油等食用植物油,随机购买20种共290份食用植物油样品。采用液相色谱法测定AFB_(1)、AFB_(2)、AFG_(1)、AFG_(2)以及OTA、OTB真菌毒素的含量,对食用植物油中黄曲霉毒素和赭曲霉毒素的污染水平和分布特征进行分析。结果表明:20种290份食用植物油样品中,有16种共67份样品存在不同程度的真菌毒素污染,总污染率达到23.1%,不同种类食用植物油污染呈现“多种类、共分布”的特点,其中AFG_(1)污染率(14.8%)最高,其次为OTA(13.4%)。绝大多数阳性样本受1~4种真菌毒素污染,仅有少数阳性样本受真菌毒素污染数量达到5种。总体上食用植物油样品受到多种真菌毒素的混合污染情况比较严重,应引起一定的重视。     

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.     

Aflatoxin and ochratoxin A content of spices in Hungary

In October and November 2004, 91 spice samples (70 ground red pepper, six black pepper, five white pepper, five spice mix and five chilli samples), the majority of which originated from commercial outlets, were analysed for aflatoxins B₁, B₂, G₁ and G₂ (AFB1, AFB2, AFG1, AFG2) and ochratoxin A (OTA) content by high-performance liquid chromatography (HPLC) after immunoaffinity column clean-up. Eighteen of the 70 ground red pepper samples contained AFB1, seven of them in a concentration exceeding the 'maximum level' of 5 µg kg^-1 (range 6.1-15.7 µg kg^-1). Of the other spices assayed, the AFB1 contamination of one chilli sample exceeded 5 µg kg^-1 (8.1 µg kg^-1). Thirty-two of the 70 ground red pepper samples contained OTA, eight of them in a concentration exceeding the 10 µg kg^-1 'maximum level' (range 10.6-66.2 µg kg^-1). One chilli sample was contaminated with OTA at 2.1 µg kg^-1. The AFB1 and OTA contamination of ground red pepper exceeding the 'maximum level' (5 and 10 µg kg^-1, respectively) was obviously the consequence of mixing imported ground red pepper batches heavily contaminated with AFB1 and OTA with red pepper produced in Hungary. This case calls attention to the importance of consistently screening imported batches of ground red pepper for aflatoxin and ochratoxin A content and strictly prohibiting the use of batches containing mycotoxin concentrations exceeding the maximum permitted level.     

自贡冷吃兔主要原辅料中细菌的鉴定及溯源分析

通过对冷吃兔生产所用冷鲜兔、辣椒、花椒、八角、芝麻、孜然、山奈、香料、桂皮、生产用水中的微生物数量进行测定并采用传统培养法结合16S rDNA测序技术鉴定,确定了原料和各种辅料中细菌的主要种属,最后通过构建系统发育树进行溯源分析。结果表明,原辅料中共分离76株菌,分布于20个属;不同原辅料菌落总数从大到小为：兔肉>孜然>辣椒>香料>生产用水>山奈>八角>桂皮>花椒>芝麻;不同原辅料含细菌属水平数量排序为：原料肉>辣椒、孜然>香料、生产用水>花椒、八角、芝麻、桂皮>山奈;不同原辅料含细菌种水平数量排序为：香料>原料肉>桂皮>辣椒>八角>山奈>孜然、花椒>芝麻、生产用水。在冷吃兔原辅料中细菌多样性高,芽孢杆菌属在原辅料中普遍存在,原料肉所含的细菌量最多。本研究深入了解了冷吃兔原辅料中的污染情况并能为从源头控制细菌种类与数量提供理论依据,更好的控制管理生产过程,使其安全性提升。     

Aflatoxins and ochratoxin A and their Aspergillus causal species in Tunisian cereals

ABSTRACT

Occurrence of aflatoxins (AFs) AFB1, AFB2, AFG1, AFG2 and ochra toxin A (OTA) was studied in 65 samples of stored and freshly harvested wheat, barley and maize collected in Tunisia. The mycotoxins were simultaneously extracted and quantified by high performance liquid chromatography. Determination of AF-producing (section Flavi) and OTA-producing Aspergillus species (sections Nigri and Circumdati) was conducted in these samples by species-specific polymerase chain reaction (PCR). Results showed that most of maize samples were contaminated with AFs, data after storage showing lower values than those collected at harvest. All contaminated maize samples contained AFG1 and AFG2, among which 27.78% also had AFB1 and AFB2. This AFs pattern was consistent with the A. parasiticus toxin profile. A. flavus however showed the highest frequency in maize but was also found in barley and wheat where no AFs were detected. In contrast, OTA was neither found in maize nor in barley and only one wheat sample contained OTA. A. niger was the only OTA-producing species detected.     

A Review on Mycotoxins in Food and Feed: Malaysia Case Study

Fungi are distributed worldwide and can be found in various foods and feedstuffs from almost every part of the world. Mycotoxins are secondary metabolites produced by some fungal species and may impose food safety risks to human health. Among all mycotoxins, aflatoxins (AFs), ochratoxin A (OTA), trichothecenes, deoxynivalenol (DON and T‐2 toxin), zearalenone (ZEN), and fumonisins (FMN) have received much attention due to high frequency and severe health effects in humans and animals. Malaysia has heavy rainfall throughout the year, high temperatures (28 to 31 °C), and high relative humidity (70% to 80% during wet seasons). Stored crops under such conditions can easily be contaminated by mycotoxin‐producing fungi. The most important mycotoxins in Malaysian foods are AFs, OTA, DON, ZEN, and FMN that can be found in peanuts, cereal grains, cocoa beans, and spices. AFs have been reported to occur in several cereal grains, feeds, nuts, and nut products consumed in Malaysia. Spices, oilseeds, milk, eggs, and herbal medicines have been reported to be contaminated with AFs (lower than the Malaysian acceptable level of 35 ng/g for total AFs). OTA, a possible human carcinogen, was reported in cereal grains, nuts, and spices in Malaysian market. ZEN was detected in Malaysian rice, oat, barley, maize meal, and wheat at different levels. DON contamination, although at low levels, was reported in rice, maize, barley, oat, wheat, and wheat‐based products in Malaysia. FMN was reported in feed and some cereal grains consumed in Malaysia. Since some food commodities are more susceptible than others to fungal growth and mycotoxin contamination, more stringent prevention and control methods are required.     

Validation of the procedure for the simultaneous determination of aflatoxins ochratoxin A and zearalenone in cereals using HPLC-FLD

Method validation for quantitative analysis of aflatoxins (AFs), ochratoxin A (OTA) and zearalenone (ZEA) in cereals using HPLC with fluorescence detector (FLD) is described. Mycotoxins were extracted with methanol?:?water (80?:?20) and purified with a multifunctional AOZ immunoaffinity column before HPLC analysis. The validation of the analytical method was performed to establish the following parameters: specificity, selectivity, linearity, limits of detection (LOD) and quantification (LOQ), accuracy, precision (within- and between-day variability), stability, robustness, measurement of performance, and measurement of uncertainty. Calibration curves were linear (r?>?0.999) over the concentration range, from the LOQ to 26, 40 and 400?ng/g for AFs, OTA and ZEA, respectively. LOD and LOQ were 0.0125 and 0.05?ng/g for aflatoxin B1 (AFB1) and G1 (AFG1), 0.0037 and 0.015?ng/g for aflatoxin B2 (AFB2) and G2 (AFG2), as well as 0.05 and 0.2?ng/g for OTA and 0.5 and 2?ng/g for ZEA, respectively. The mean recovery values were 77–104% for different concentrations of AFs, OTA and ZEA in spiked cereal samples. Both intra- and inter-day accuracy and precision were within acceptable limits. This method was successfully applied for the simultaneous determination of mycotoxins for 60 cereal samples collected from Malaysian markets. Fifty per cent of the cereal samples were contaminated with at least one of these mycotoxins, at a level greater than the LOD. Only one wheat sample and two rice samples were contaminated with levels greater than the European Union regulatory limits for AFs and OTA (4 and 5?ng/g). The means and ranges of mycotoxins obtained for the cereal samples were 0.4?ng/g and 0.01–5.9?ng/g for total AFs; 0.18?ng/g and 0.03–5.3?ng/g for OTA; and 2.8?ng/g and 2.4–73.1?ng/g for ZEA, respectively. The results indicate that the method is suitable for the simultaneous determination of AFs, OTA and ZEA in cereals and is suitable for routine analysis.     

Validation of the procedure for the simultaneous determination of aflatoxins ochratoxin A and zearalenone in cereals using HPLC-FLD

Method validation for quantitative analysis of aflatoxins (AFs), ochratoxin A (OTA) and zearalenone (ZEA) in cereals using HPLC with fluorescence detector (FLD) is described. Mycotoxins were extracted with methanol : water (80 : 20) and purified with a multifunctional AOZ immunoaffinity column before HPLC analysis. The validation of the analytical method was performed to establish the following parameters: specificity, selectivity, linearity, limits of detection (LOD) and quantification (LOQ), accuracy, precision (within- and between-day variability), stability, robustness, measurement of performance, and measurement of uncertainty. Calibration curves were linear (r > 0.999) over the concentration range, from the LOQ to 26, 40 and 400 ng/g for AFs, OTA and ZEA, respectively. LOD and LOQ were 0.0125 and 0.05 ng/g for aflatoxin B1 (AFB1) and G1 (AFG1), 0.0037 and 0.015 ng/g for aflatoxin B2 (AFB2) and G2 (AFG2), as well as 0.05 and 0.2 ng/g for OTA and 0.5 and 2 ng/g for ZEA, respectively. The mean recovery values were 77-104% for different concentrations of AFs, OTA and ZEA in spiked cereal samples. Both intra- and inter-day accuracy and precision were within acceptable limits. This method was successfully applied for the simultaneous determination of mycotoxins for 60 cereal samples collected from Malaysian markets. Fifty per cent of the cereal samples were contaminated with at least one of these mycotoxins, at a level greater than the LOD. Only one wheat sample and two rice samples were contaminated with levels greater than the European Union regulatory limits for AFs and OTA (4 and 5 ng/g). The means and ranges of mycotoxins obtained for the cereal samples were 0.4 ng/g and 0.01-5.9 ng/g for total AFs; 0.18 ng/g and 0.03-5.3 ng/g for OTA; and 2.8 ng/g and 2.4-73.1 ng/g for ZEA, respectively. The results indicate that the method is suitable for the simultaneous determination of AFs, OTA and ZEA in cereals and is suitable for routine analysis.     

Aflatoxins and ochratoxin A in stored barley grain in Spain and impact of PCR-based strategies to assess the occurrence of aflatoxigenic and ochratoxigenic Aspergillus spp

Contamination of barley by moulds and mycotoxins results in quality and nutritional losses and represents a significant hazard to the food chain. The presence of aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1) and G2 (AFG2) and ochratoxin A (OTA) in stored barley in Spain has been studied. Species-specific PCR assays were used for detection of Aspergillus flavus, A. parasiticus, A. ochraceus, A. steynii, A. westerdijkiae, A. carbonarius and A. niger aggregate in mycotoxin-positive barley samples at different incubation times (0, 1 and 2 days). Classical enumeration techniques (CFU/g) in different culture media for evaluation of Aspergillus in sections Flavi, Circumdati and Nigri were also used. One hundred and five barley kernel samples were collected in Spanish grain stores from 2008 to 2010, and analyzed using a previously optimized method involving accelerated solvent extraction, cleanup by immunoaffinity column, liquid chromatographic separation, post-column derivatization with iodine and fluorescence detection. Twenty-nine samples were contaminated with at least one of the studied mycotoxins. AFB1, AFB2, AFG1, AFG2, and OTA were detected in 12.4%, 2.9%, 4.8%, 2.9%, and 20% of the samples, respectively. Aflatoxins and OTA co-occurred in 4.8% of the samples. Maximum mycotoxin levels (ng/g) were 0.61 (AFB1), 0.06 (AFB2), 0.26 (AFG1), 0.05 (AFG2), and 2.0 (OTA). The results of PCR assays indicated the presence of all the studied species, except A. westerdijkiae. The PCR assays showed high levels of natural contamination of barley with the studied species of Aspergillus which do not correspond to the expected number of CFU/g in the cultures. These results suggest that a high number of non-viable spores or hyphae may exist in the samples. This is the first study carried out on the levels of aflatoxins and OTA in barley grain in Spain. Likewise, this is the first report on the presence of aflatoxigenic and ochratoxigenic Aspergillus spp. in barley grain naturally contaminated with those mycotoxins using a species-specific PCR approach.