The performance characteristics of an analytical method for cyanogenic compounds were evaluated. Specifically, we tested the trueness, repeatability and intermediate precision of the method using a spectrophotometric-based detection system for 4-pyridinecarboxylic acid and pyrazolone after steam distillation. The pH adjustment of the distillate was revealed to a#ect the trueness of the measurements. A pH of approximately 6 was found to be optimal. The targeted quantitation limit of the cyanide ion was set to 5 mg/kg. The performance of the method was evaluated using beans spiked with cyanide ion at one to two times the quantitation limit (5ῌ10 mg/kg). The trueness of the method was between 78ῌ90̮, and the repeatability and intermediate precision were between RSD 1.2̮ to 6.0̮. A surveillance of cyanogenic compounds in beans retailed in Japan was then carried out. All the results were below the quantitation limit of 5 mg/ kg.

῍ Corresponding author 2-Alkylcyclobutanones (ACBs) are specific radiolytic products in irradiated lipid-containing food and can be used to detect irradiation of foodstu#s. 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 foodstu#s 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 ῌg/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 0.5ῌ4 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 di#erent 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 100ῌ accurate. Even after the irradiated foodstu#s had been frozen for 6ῌ9 months, it was still possible to judge whether the foodstu#s had been irradiated or not using the EN1785 method.

In order to ensure compliance of raw bean paste products with the Japanese Food Sanitation Law, we examined the performance characteristics of an analytic procedure based on steam distillation followed by carbonate-pyrazolone assay to determine cyanogenic compounds in raw bean paste. The present method includes a procedure for decomposition cyanogenic glycosides using linamarase due to the possibility that cyanogenic glycoside-hydrolyzing enzymes might be deactivated in raw bean pastes. The performance of the method was evaluated using two types of bean paste spiked with a cyanogenic glycoside (linamarin) corresponding to cyanide ion concentrations of 5 and 10 mg/kg. The trueness of the method was 86-90%, and the repeatability (RSD) was 1.0-2.4%, while the intermediate precision (RSD) was 2.6% to 4.9%. A surveillance of cyanogenic compounds in 28 raw bean pastes manufactured in Japan was then carried out with the validated method. One sample contained 15 mg/kg (as hydrogen cyanide), while the other samples contained less than 5 mg/kg.