Laboratory Chemical Engineering, Department Bioprocess & Microbial System, UMR CNRS/INPT/UPS 5503, ENSA Toulouse, France.
Toxins (Basel). 2010 Aug;2(8):1928-42. doi: 10.3390/toxins2081928. Epub 2010 Jul 28.
The OTA content of 30 roasted coffees purchased in French supermarkets was evaluated by two validated different methods: one using immunoaffinity column (IAC) clean-up after alkaline extraction; the second using toluene extraction under acidic conditions. OTA recoveries (0.5 to 5 µg/kg) ranged from 16-49% with the alkaline extraction method and 55-60% with the acidic method. OTA recoveries from prepared beverages were similar with all methods (75-80%). All samples containing OTA ranged from trace (<LOQ) to 11.9 µg/kg. About 20 to 140% of OTA passed through the beverages. Recoveries of over 100% of OTA in beverages were due to three types of interferences: (i) formation of open-ring OTA (OP-OA) during alkaline extraction, (ii) isomerization of OTA during roasting, and (iii) presence of the nonchlorinated analogue OTB. The first two types of interference generate OTA derivatives that are not recognized by OTA antibodies, while OTB cross-reacts with OTA-antibodies. These analytical problems will seriously impact the amount of OTA detected, especially at the levels close to the limits from the EU legislation. Underestimation of OTA could be highly dangerous for health.
评估了在法国超市购买的 30 种烘焙咖啡中的 OTA 含量，使用了两种经过验证的不同方法：一种是碱性提取后使用免疫亲和柱（IAC）净化；另一种是酸性条件下使用甲苯提取。碱性提取方法的 OTA 回收率（0.5 至 5μg/kg）在 16-49%之间，酸性方法的回收率在 55-60%之间。所有方法从制备的饮料中回收的 OTA 相似（75-80%）。所有含有 OTA 的样品含量均痕量（<LOQ）至 11.9μg/kg。约 20%至 140%的 OTA 通过饮料。饮料中 OTA 的回收率超过 100%是由于三种类型的干扰：（i）碱性提取过程中形成开环 OTA（OP-OA），（ii）烘焙过程中 OTA 的异构化，和（iii）非氯化类似物 OTB 的存在。前两种类型的干扰会生成 OTA 衍生物，这些衍生物不能被 OTA 抗体识别，而 OTB 与 OTA 抗体发生交叉反应。这些分析问题将严重影响 OTA 的检测量，尤其是在接近欧盟法规规定的限量的水平下。对 OTA 的低估可能对健康造成极大的危害。
