2015 Volume 62 Issue 8 Pages 382-393
In this study, electron spin resonance (ESR) techniques were employed for the detection of gamma-irradiated spices after long-term storage. Results obtained by the two methods were compared with respect to measurement conditions and determination criteria. Method 1 was based on EN1787. In method 2, the measurement conditions were appropriate for the detection of S signals (S1 and S2), which are radiation-induced radicals. Determination criteria for irradiation were characterized by the S1 signal intensity at lower magnetic field and its distance to the main signal. When the same sample was assessed by the two methods, method 2 exhibited a higher accuracy for irradiated sample detection. Moreover, while the S signals decayed during storage, the method was capable of detecting gamma-irradiated black pepper and cumin stored for 4 years. Thus, the ESR technique can be used for these screening tests. On the other hand, the PSL technique could detect irradiated basil, parsley, oregano, coriander, and cumin but not black and white peppers. The ESR and PSL techniques as screening tests were found to complement each other for the detection of maladaptive samples. In particular, as a confirmed inspection method for irradiated spices, the TL technique was found to be applicable.
