热释光法在辐照食品检测中出现假阳性问题的探讨

Discussion on the problem of false positive in the detection of irradiated food by thermoluminescence method

目的探讨热释光法在辐照食品检测中出现假阳性的问题。方法按照标准EN1788-2001《食品与硅酸盐矿物隔绝的食品的辐射检验热致发光法》,采用热释光法对深海鱼加工产品进行辐照食品检测。结果与花椒粉等典型辐照样品不同,深海鱼加工产品虽然检测结果为阳性,但其谱图与典型辐照样品谱图存在一定差异。主要表现为一次发光曲线中,典型辐照样品谱图的发光峰下降舒缓,峰型符合正态分布;而深海鱼加工产品的发光峰下降陡峭,并不符合正态分布。据此,怀疑热释光法对深海鱼加工产品的检测分析结果实为假阳性。结论建议在对深海鱼产品进行辐照检测时,谨慎选用热释光法或采用其他检测方法如气相色谱分析碳氢化合物法进行复验。

Objective To explore the false positive problem in the detection of irradiated food by thermoluminescence method. Methods According to EN1788-2001 Thermoluminescence detection of irradiated food from which silicate minerals can be isolated, deep-sea fish processing products were analyzed for detection of irradiated food by thermoluminescence method. Results Deep-sea fish processing products were different from typical irradiated samples such as Chinese red pepper powder, although the results were positive, the spectrum existed some differences with typical irradiated samples mainly in thermoluminescence（TL） curves of glow 1. TL peaks of typical irradiated samples decreased slowly, and the peak patterns were in accord with the normal distribution; but TL peaks of deep-sea fish processing products were steep, and did not meet the normal distribution. Accordingly, the results of the thermoluminescence detection of irradiated food were supposed as false positive. Conclusion Thermoluminescence method should be selected carefully for the detection of deep-sea fish products, or other methods such as gas chromatographic analysis of hydrocarbons method can be used for the reinspection.