Sanderson David C W, Carmichael Lorna A, Fisk Saffron
Scottish Universities Research and Reactor Centre, Scottish Enterprise Technology Park, Rankine Ave, East Kilbride, G75 OQF, UK.
J AOAC Int. 2003 Sep-Oct;86(5):990-7.
An interlaboratory trial was conducted to validate photostimulated luminescence (PSL) methods for herbs, spices, and seasonings. Forty products (11 herbs, 17 spices, and 12 seasonings) were purchased from a local commercial source, and randomly selected samples were irradiated with 10 kGy. Four blended products were prepared at Scottish Universities Research and Reactor Centre, mixing varying proportions of irradiated material with the untreated product. Precharacterization against a predefined threshold identified low sensitivity products (black and white peppers) and products with high natural signals (thyme, sage, parsley, and mixed herbs), both of which might be susceptible to misclassification. Precharacterization also revealed whether calibration was likely to resolve overlap between classification categories. Eight sets of screening data and 5 sets of calibrated data were returned by participants. Of the 840 samples sent, 1593 screening measurements and 788 calibrated measurements were received from 662 samples. In screening mode, participants reached definitive conclusions in 87% of cases, 99% of which were correct. Of the remaining 13%, calibration to identify low-sensitivity resolved 60% of cases. Overall, 94% of samples were correctly identified by either screening alone, or screening plus calibration; 6% remained unclassified and therefore required further investigation by thermoluminescence. The results confirm the validity of the PSL method for herbs, spices, seasonings, and blends, and emphasize the need for calibration to identify low-sensitivity samples. This method has now been adopted by the European Committee for Standardization (CEN) and the Codex Alimentarius Commission.
开展了一项实验室间试验，以验证用于草药、香料和调味料的光激发发光（PSL）方法。从当地商业渠道购买了40种产品（11种草药、17种香料和12种调味料），随机抽取的样品用10千戈瑞进行辐照。在苏格兰大学研究与反应堆中心制备了四种混合产品，将不同比例的辐照材料与未处理产品混合。针对预定义阈值进行的预表征确定了低灵敏度产品（黑胡椒和白胡椒）以及具有高天然信号的产品（百里香、鼠尾草、欧芹和混合草药），这两类产品都可能容易被误分类。预表征还揭示了校准是否可能解决分类类别之间的重叠问题。参与者返回了八组筛选数据和五组校准数据。在发送的840个样品中，从662个样品中收到了1593次筛选测量结果和788次校准测量结果。在筛选模式下，参与者在87%的案例中得出了明确结论，其中99%是正确的。在其余13%的案例中，通过校准以识别低灵敏度解决了60%的案例。总体而言，94%的样品通过单独筛选或筛选加校准被正确识别；6%仍未分类，因此需要通过热释光进行进一步调查。结果证实了PSL方法对草药、香料、调味料及混合物的有效性，并强调了进行校准以识别低灵敏度样品的必要性。该方法现已被欧洲标准化委员会（CEN）和食品法典委员会采用。
