Tsutsumi Tomoaki, Todoriki Setsuko, Nei Daisuke, Ishii Rika, Watanabe Takahiro, Matsuda Rieko
Division of Foods, National Institute of Health Sciences, Tokyo, Japan.
Shokuhin Eiseigaku Zasshi. 2011;52(6):321-9. doi: 10.3358/shokueishi.52.321.
2-Alkylcyclobutanones (ACBs) are specific radiolytic products in irradiated lipid-containing food and can be used to detect irradiation of foodstuffs. EN1785, a European Committee Standardization Method, can detect 2-dodecylcyclobutanone (DCB) and 2-tetradecylcyclobutanone (TCB), which are ACBs, using GC/MS, thereby allowing judgement as to whether foodstuffs have been irradiated. In this study, the performance of EN1785 as a qualitative test in a single laboratory was evaluated and its applicability to beef, pork, chicken and salmon was verified. In the performance evaluation test, lipids extracted from unirradiated food using the Soxhlet extraction method were used as negative samples. Further, negative samples, to which DCB and TCB were added at 0.05 µg/g lipid (equivalent to the amount generated in food when irradiated at 0.5 kGy or more), were used as positive samples. For each food type examined, 4 negative and 16 positive samples were analyzed by EN1785 to verify the method's ability to detect irradiation. All of the negative samples were judged negative and all of the positive samples were judged positive. Thus, the method should be able to detect irradiation in beef, pork chicken and salmon irradiated at 0.5 kGy or higher. Next, to confirm that this is the case, the same types of food examined above, both unirradiated and irradiated at doses of 0.5-4 kGy, were analyzed by the method. All of the unirradiated samples were judged negative and all of the irradiated samples were judged positive. In a laboratory different from the one where the aforementioned evaluation was conducted, a performance evaluation test was carried out. Blind coded samples, including unirradiated and irradiated samples, were then analyzed in the laboratory according to EN178S. Ten samples (2 unirradiated and 8 irradiated samples) were analyzed for each type of food and the verified method was found to be 100% accurate. Even after the irradiated foodstuffs had been frozen for 6-9 months, it was still possible to judge whether the foodstuffs had been irradiated or not using the EN1785 method.
2-烷基环丁酮（ACBs）是辐照含脂食品中特有的辐射分解产物，可用于检测食品是否经过辐照。欧洲标准化委员会的标准方法EN1785，能够使用气相色谱/质谱联用仪（GC/MS）检测作为ACBs的2-十二烷基环丁酮（DCB）和2-十四烷基环丁酮（TCB），从而判断食品是否经过辐照。在本研究中，评估了EN1785在单一实验室作为定性检测方法的性能，并验证了其对牛肉、猪肉、鸡肉和三文鱼的适用性。在性能评估测试中，使用索氏提取法从未辐照食品中提取的脂质作为阴性样品。此外，将DCB和TCB以0.05μg/g脂质的量添加到阴性样品中（相当于食品在0.5kGy或更高剂量辐照时产生的量）作为阳性样品。对于每种检测的食品类型，通过EN1785分析4个阴性样品和16个阳性样品，以验证该方法检测辐照的能力。所有阴性样品均判定为阴性，所有阳性样品均判定为阳性。因此，该方法应该能够检测出辐照剂量为0.5kGy或更高的牛肉、猪肉、鸡肉和三文鱼是否经过辐照。接下来，为了确认情况是否如此，用该方法对上述相同类型的食品进行分析，包括未辐照的和辐照剂量为0.5 - 4kGy的食品。所有未辐照样品均判定为阴性，所有辐照样品均判定为阳性。在与进行上述评估的实验室不同的另一个实验室中，开展了性能评估测试。然后，根据EN1785在该实验室对包括未辐照和辐照样品的盲编码样品进行分析。对每种食品类型分析10个样品（2个未辐照样品和8个辐照样品），发现经过验证的方法准确率为100%。即使辐照食品冷冻6 - 9个月后，使用EN1785方法仍有可能判断食品是否经过辐照。
