食品中赭曲霉毒素A的产生机制及污染防控策略

赭曲霉毒素A(ochratoxin A,OTA)主要是由曲霉属(Aspergillus)和青霉属(Penicillium)真菌产生的有毒次级代谢产物,具有肾毒性、肝毒性、致畸性、神经毒性以及潜在致癌性,是世界范围内重点关注的真菌毒素之一。当前关于OTA产毒菌的分类、OTA合成途径及调控机制仍存在争议,制约了食品中OTA污染的高效精准控制。对曲霉属和青霉属中主要OTA产毒菌进行了系统梳理,特别是基于基因组比较数据将一度被认为是主要产毒菌的A. ochraceus中的部分菌株重新鉴定为A. westerdijkiae,介绍了主要产毒菌的产毒能力;系统介绍了OTA生物合成基因簇及关键合成与调控基因,特别是近年发现的新基因——环化酶otaY基因,其可能参与催化OTA生物合成途径初始步骤中的聚酮环化反应,基于最新研究结果进一步完善了OTA生物合成途径;针对食品生产不同环节,介绍了生物、物理和化学防控脱毒策略,重点介绍了针对产毒菌的生物防治方法,针对OTA毒素的生物降解菌及脱毒酶,并比较了不同方法的优缺点。最后,提出了食品OTA污染控制应基于“全链条控制”和“源头防控”的思路,保障食品安全、粮食安全和人民生命健康;分析了生物防治和生物脱毒技术的优缺点,指出绿色、安全的生物防控策略具有广阔的应用前景,是未来研究的重点方向。     

食品中赭曲霉毒素A检测方法研究进展

赭曲霉毒素A(ochratoxin A, OTA)是曲霉属和青霉属等有毒真菌产生的一类次级代谢产物,是常见污染食品的五大真菌毒素之一,具有较强的肾毒性、肝毒性、神经毒性和免疫毒性,以及致畸、致癌和致突变作用。OTA广泛存在于各种谷物及其制品、葡萄与葡萄酒、咖啡等多种食品原料及其成品中,严重威胁人体健康,因此有必要建立快速、准确、灵敏的OTA检测方法。针对食品中OTA的检测,目前已经拥有许多方法,如薄层色谱法,高效液相色谱法,液相-质谱联用法以及酶联免疫吸附法等。本研究对赭曲霉毒素A不同检测方法的原理、优缺点等进行归纳总结,旨在为食品中OTA的检测提供支持。     

葡萄上赭曲霉毒素A产生机制及生物检测方法研究进展

赭曲霉毒素A(Ochratoxin A,OTA)主要由赭曲霉、黑曲霉及青霉菌的某些菌株产生,具有多种毒性,葡萄及其制品中OTA污染在全球范围内普遍存在,严重影响人类和动植物的健康。控制OTA的方法已经有许多研究,其中生物方法安全环保是目前研究的热点,而认识OTA来源及产生机制是生物防治污染的基础,随着分子生物学的发展,一些新型的分子快速检测方法已经被研究出来。对OTA的毒理特性、污染及来源、产毒机制、分子生物学快速检测手段等方面进行了综述,为寻求有效的控制产毒和降解毒素方法提供理论参考,以期降低OTA污染。     

葡萄赭曲霉毒素污染及其产毒素菌株的筛选方法研究进展

赭曲霉毒素A(ochratoxin,OTA)是由曲霉属和青霉属等真菌产生的一类真菌毒素,其毒性很强,分布广泛,对人类和动植物的健康有着巨大的影响。葡萄及其制品是食品中OTA的主要来源之一,从病害的葡萄表面筛选分离产生赭曲霉毒素的菌株是最常用的研究产毒素菌株的方法。由于产毒素菌株主要分布在葡萄果实的表面,葡萄组织受损后会极大提高赭曲霉素的污染程度,研究产毒菌株分布及产毒素能力对控制赭曲霉素污染及寻找一种有效地生物防治方法提供参考。本文综述了葡萄赭曲霉毒素的污染情况及其产毒素菌株的筛选方法,为控制葡萄及其产品中的OTA污染提供依据。     

光学适配体传感器在赭曲霉毒素A检测中的应用研究进展

赭曲霉毒素A(ochratoxin A,OTA)是一类主要由曲霉属和青霉属等真菌产生的次级代谢产物。毒理学研究表明,OTA具有强烈的肝毒性和肾毒性,并有致畸、致癌、致突变等危害。OTA作为一种天然污染物,对食品污染的范围较广,主要包括谷类、咖啡、葡萄等及其相关产品,因此,开发高灵敏、高准确性的OTA检测技术对于预防控制其危害具有重要的意义。传统的OTA检测方法通常耗时费力且价格昂贵,限制了它们的应用范围。新兴的光学适配体传感器在检测OTA方面具有灵敏度高、选择性好和操作简单等优点,引起了人们的广泛关注。该文综述了近年来光学适配体传感器在OTA快速检测领域的应用及不同类型的OTA适体传感器的优缺点,并对该领域未来的发展方向进行了讨论和展望。     

控制葡萄及其制品中赭曲霉毒素A的研究进展

赭曲霉毒素A(OTA)是一种有毒的真菌次级代谢产物,在葡萄及其制品中经常被检出。本文综述了控制葡萄及其制品中OTA的主要措施,包括抑制OTA产生菌的生长及其产毒和去除已产生的OTA两方面。葡萄中的致病菌主要是青霉和曲霉,而炭黑曲霉是其中最主要OTA产生菌,通过模拟葡萄生长及葡萄制品的生产过程,发现温度、光照、湿度等因素是影响OTA产生菌的生长及其产毒的重要因素。去除OTA的方法概括的分为物理方法、化学方法、生物方法,其中生物降解OTA是目前研究的热点。     

赭曲霉素A污染及毒性研究进展

赭曲霉素A(Ochratoxin A)是曲霉属和青霉属一些产毒菌株次级代谢产物,是一种重要食品污染物,具有强烈肾毒性和一定肝毒性、神经毒性及免疫毒性,并具有致癌、致畸、致突变性。该文介绍赭曲霉素常见产生菌及其对食品污染,毒理学特性及检测方法。     

茶叶中赭曲霉毒素A安全性风险研究进展

茶叶是世界上消费量最大的饮品之一,其品饮安全性对消费者健康及茶产业发展尤为重要。近年来关于茶叶是否存在真菌毒素污染的问题引起了社会的广泛关注和消费者的诸多疑虑,如何科学客观地对待这个问题十分关键。赭曲霉毒素A(OTA)是一种危害性较大的真菌毒素,其产生菌种类繁多,污染广泛,能溶于水且不易降解,具有较强的肝肾毒性和致畸、致突变、致癌和免疫抑制作用。本文在检索研读国内外相关文献的基础上,综述了OTA的理化特性、危害与致毒机理、主要产毒菌及产毒条件、茶叶中可能产OTA的微生物、OTA的检测方法和检测结果等,分析探讨了茶叶中的OTA潜在风险,并提出建议,为茶叶中的OTA污染风险评估和防控提供参考依据。     

葡萄中产赭曲霉毒素A炭黑曲霉的控制方法

炭黑曲霉(Aspergillus carbonarius)属曲霉属黑色曲霉菌,是葡萄中赭曲霉毒素A(ochratoxin A,OTA)主要产生菌,广泛存在于许多国家和地区的葡萄及其制品中,是造成葡萄酒中OTA污染的主要来源。控制这些霉菌的生长与产毒是从源头上减少葡萄原料及其制品OTA污染的关键环节,有关炭黑曲霉的污染规律及其控制方法方面的研究成为近年来的国际研究热点。根据已有研究,紫外线照射、杀菌剂、二氧化硫、纳他霉素、多酚、香精油、天然提取物和挥发性化合物等都能够在一定条件下对炭黑曲霉的生长与产生OTA的能力产生一定的抑制作用。最新研究发现,酵母、细菌和一些非产毒真菌及其代谢产物也对炭黑曲霉的生长和OTA产生具有良好抑制作用,而且具有无毒无害,安全性好等优点,在实际应用中展示出很好的应用潜力,越来越受到相关科研工作者和应用者的重视。本文主要围绕上述研究内容,对国内外近年来的相关研究进展进行综述。     

赭曲霉毒素A分析方法进展

赭曲霉毒素A(OchratoxinA,OTA)是曲霉属和青霉属的某些菌种产生的一种具有致癌、致畸、免疫抑制和肝肾毒性的有毒代谢产物,世界上许多国家已制定了食品中OTA的相关法规和标准,而准确、可靠、灵敏的分析OTA方法是法规标准实施的重要依据。有机溶剂与酸(或碳酸氢钠)的混合溶液是提取食品中OTA的常用溶剂系统;含有OTA提取液的净化手段包括液液分配、固相柱萃取和免疫亲和层析等;反相液相色谱配荧光检测器、酶联免疫吸附法和液相色谱质谱联机是分析OTA的常用方法,本文就OTA的检测方法进行综述。     

Simultaneous determination of ochratoxin A, B and citrinin in foods by HPLC-FL and LC/MS/MS

Methods using high-performance liquid chromatography with fluorescence detection (HPLC-FL) and using liquid chromatography with tandem mass spectrometry (LC/MS/MS) were developed for simultaneous determination of ochratoxin A (OTA), ochratoxin B (OTB) and citrinin (CIT) in cereal, fruit, and coffee products. The samples were extracted with ethyl acetate under an acidic condition, and then cleaned up with liquid-liquid separation. The test solutions were analyzed by reverse-phase HPLC-FL and LC/MS/MS. Mass spectral acquisition was performed in positive ion mode by applying multiple reaction monitoring. The performances of both detectors were almost equivalent. The recoveries of OTA and OTB were 87-111%, and that of CIT were 70-88%. The limits of quantification (S/N> or =10) of OTA, OTB and CIT was 0.1 mug/kg or less. These methods were considered to be useful for the determination of the three mycotoxins at low levels (0.1 microg/kg).     

Fluorescence polarization immunoassay based on a monoclonal antibody for the detection of ochratoxin A

A fluorescence polarization immunoassay (FPIA) based on a monoclonal antibody for the determination of ochratoxin A (OTA) was developed. Fluorescein‐labelled OTA derivative (tracer) was synthesized and purified by thin‐layer chromatography. The optimized OTA FPIA had a dynamic range from 5 to 200 ng mL^?1 with IC₅₀ value of 30 ng mL^?1 and a detection limit of 3 ng mL^?1. The method developed was characterized by high specificity and reproducibility. Cross‐reactivity with other mycotoxins (zearalenone, aflatoxins, patulin and T‐2 toxin) was negligible (<0.1%). Methanol extracts of barley samples were used for the analysis. The results of OTA determination in barley were compared with those determined by indirect competitive enzyme‐linked immunosorbent assay (ELISA). Recoveries for the samples spiked at 50, 100 and 500 ng g^?1 levels were 91, 90 and 97%, respectively, for FPIA, and 98, 98 and 102%, for ELISA. Naturally contaminated barley samples were analysed by these methods but some disagreement was observed between the results. The FPIA method can be applied for screening of food samples for OTA residues without a complicated clean‐up.     

Occurrence of ochratoxin A in cocoa beans: Effect of shelling

The aim of this study was to investigate the influence of the shelling process on the presence of ochratoxin A (OTA) in cocoa samples. Twenty-two cocoa samples were analysed for the determination of OTA before (cocoa bean) and after undergoing manual shelling process (cocoa nib). In order to determine OTA contamination in cocoa samples, a validated high-performance liquid chromatography (HPLC) method with fluorescence detection was used for the quantitative analysis of ochratoxin A (OTA). In both types of samples, OTA was extracted with methanol-3% sodium hydrogen carbonate solution and then purified using immunoaffinity columns prior to HPLC analysis. Due to the fact that different recovery values were obtained for OTA from both types of samples, a revalidation of the method in the case of cocoa nibs was needed. Revalidation was based on the following criteria: Selectivity, limits of detection and quantification (0.03 and 0.1 µg kg^-1, respectively), precision (within-day and between-day variability) and recovery 84.2% (RSD = 7.1%), and uncertainty (30%). Fourteen of the twenty-two cocoa bean samples (64%) suffered a loss of OTA of more than 95% due to shelling, six samples suffered a loss of OTA in the range 65-95%, and only one sample presented a reduction of less than 50%. The principal conclusion derived from this study is that OTA contamination in cocoa beans is concentrated in the shell; therefore, improvements of the industrial shelling process could prevent OTA occurrence in cocoa final products.     

Influence of roasting and different brewing processes on the ochratoxin A content in coffee determined by high-performance liquid chromatography-fluorescence detection (HPLC-FLD)

A rapid and reliable procedure has been developed for the determination of ochratoxin A (OTA) in green and roasted coffee. The method consists of extraction of the sample with methanol-5% aqueous sodium hydrogen carbonate/1% PEG8000 (20:80), followed by immunoaffinity column (IAC) clean-up and, finally, high-performance liquid chromatography (HPLC) determination with fluorimetric detection. Mean recoveries for green and roasted coffee spiked at different levels ranging from 94 and 105% were obtained. The limit of determination (S/N = 3) was 0.032 ng g(-1) and the precision (within-laboratory relative standard deviation) was 6%. The method described has been used to assess the influence of roasting and different brewing processes on OTA content in commercial lots of green and roasted coffee. The results provided evidence that roasting led to a significant drop on OTA levels (65-100%). Also, the way coffee is prepared affects the OTA content: brewing using a Moka Express (Italian coffee) led to a significant reduction of OTA concentration (50-75%) since hot water stays in contact with coffee for a short time. On the contrary, Turkish coffee-making (infusion for about 10 min) cause poor reduction in OTA.     

Influence of roasting and different brewing processes on the ochratoxin A content in coffee determined by high-performance liquid chromatography-fluorescence detection (HPLC-FLD)

A rapid and reliable procedure has been developed for the determination of ochratoxin A (OTA) in green and roasted coffee. The method consists of extraction of the sample with methanol–5% aqueous sodium hydrogen carbonate/1% PEG8000 (20:80), followed by immunoaffinity column (IAC) clean-up and, finally, high-performance liquid chromatography (HPLC) determination with fluorimetric detection. Mean recoveries for green and roasted coffee spiked at different levels ranging from 94 and 105% were obtained. The limit of determination (S/N = 3) was 0.032 ng g^?1 and the precision (within-laboratory relative standard deviation) was 6%. The method described has been used to assess the influence of roasting and different brewing processes on OTA content in commercial lots of green and roasted coffee. The results provided evidence that roasting led to a significant drop on OTA levels (65–100%). Also, the way coffee is prepared affects the OTA content: brewing using a Moka Express (Italian coffee) led to a significant reduction of OTA concentration (50–75%) since hot water stays in contact with coffee for a short time. On the contrary, Turkish coffee-making (infusion for about 10 min) cause poor reduction in OTA.     

A rapid high-performance liquid chromatography with fluorescence detection method developed to analyze ochratoxin A in wine

A rapid, sensitive, reproducible, and inexpensive method of high-performance liquid chromatography with fluorescence detection (HPLC-FLD) for the analysis of ochratoxin A (OTA) in wine was developed. It is characterized by direct injection of the wine into the HPLC apparatus, with no need of extraction or cleanup. The method uses acetonitrile, water, and acetic acid (49:49:2, vol/vol/vol, respectively) as the isocratic mobile phase and a 5-microm monolithic C18 column (100 by 3 mm inside diameter). The relative standard deviation obtained in the OTA determination varied between 0.22 and 1.76%, with a mean value of 0.89%, in samples with concentrations between 0.10 and 100 ng/ml. The recovery of OTA ranged from 102% in samples spiked with 1 ng/ml OTA to 120% in samples with 0.10 ng/ml OTA. The method compared favorably with a published method based on an immunoaffinity column cleanup and a chromatographic assay with a C18 conventional HPLC column.     

Determination of ochratoxin A in red wine and vinegar by immunoaffinity high-pressure liquid chromatography

A method is described for the determination of ochratoxin A (OTA) in red wine and vinegar using an acidic chloroform extraction, an immmunoaffinity clean-up step, and a high-performance liquid chromatographic determination with fluorescence detection. The detection limit was estimated at 0.002 microg/liter. The mean recovery factors were found at 91.3 and 96.6% for wine and vinegar, respectively. Thirty-one samples of red wine originating from Mediterranean sea countries and 15 samples of vinegar were examined for the presence of OTA. All red wine samples contained OTA. Seventy-two percent of these samples were found to be contaminated over 0.1 microg/liter. Among them, nine samples contained ochratoxin A in the range of 0.5 to 3.4 microg/liter, 12 samples in the range of 0.10 to 0.50 microg/liter (median: 0.176 microg/liter), and 9 samples in the range of 0.010 to 0.100 microg/liter (median: 0.041 microg/liter). All 15 vinegar samples showed the presence of OTA. The most contaminated ones were three balsamic vinegar samples containing 0.156 microg/liter, 0.102 microg/liter, and 0.252 microg/liter of OTA. In the remaining 12 samples, ochratoxin A levels ranged from 0.008 microg/liter to 0.046 microg/liter (median: 0.012 microg/liter). These data are in good agreement with the hypothesis that wine originating from Southern countries might contain significant OTA concentration and showed the possible occurrence of traces of OTA in vinegar.     

药食两用类食品中赭曲霉毒素A的高效液相色谱-荧光检测方法

目的:采用免疫亲和净化和高效液相色谱技术,建立淀粉、糖类药食两用食品中赭曲霉毒素A的测定方法。方法:样品粉末经甲醇-水(8:2,V/V)涡旋、超声及振摇提取,提取液以磷酸盐缓冲液稀释后,用商品免疫亲和柱净化,含有赭曲霉毒素A的甲醇洗脱液用高效液相色谱技术分析,C18反相色谱柱分离,荧光检测器测定。结果:赭曲霉毒素A的最低检出浓度为1.0μg/kg(RSN=3);在0.5～100ng/mL范围内,峰面积与质量浓度呈线性关系(r=0.9995);以不含赭曲霉毒素A的太子参、莲子、薏苡、麦冬和龙眼肉为加标基质,加标水平为1～8μg/kg时,平均回收率在81.8%～107%之间,RSD为1.66%～15.0%(n=3)。结论:免疫亲和柱能和高效液相色谱-荧光检测相结合取得较为满意的结果,准确度高、精密度好,满足欧盟对食品饲料中OTA检测方法的要求,适合于淀粉、糖类药食两用食品中赭曲霉毒素A的测定。     

High levels of ochratoxin A in licorice and derived products

The ochratoxin A (OTA) content of 30 samples of licorice root and derived products (licorice-confectionery, licorice block, and licorice extract) was analyzed by a standard HPLC-fluorescence technique and confirmed by methyl-ester formation. All analyzed samples of licorice and derived products were found to contain ochratoxin A, and some of them showed extremely high concentrations up to 252.8 ng/g of OTA. Highest levels of ochratoxin A were found in dry licorice root, averaging 63.6 ng/g, while mean contents in fresh licorice root were 9.2 ng/g. Licorice-confectionery (sweets) contained 3.8 ng/g of OTA. Ochratoxin A was also abundant in two licorice derivatives, liquid licorice extract (16.0 ng/g) and solid licorice block (39.5 ng/g). The ochratoxin levels found in licorice and derived products are higher than those reported in the literature for other food commodities. The experiments of OTA transfer into the tea beverages showed that almost 5% of the OTA present in dry licorice root is transferred to the corresponding decoction tea, whereas only 1% of OTA remains in infusion tea. The significance of the levels of ochratoxin A in licorice and its derivatives is discussed in the context of existing data on ochratoxin contamination in foods.