Detection of prior irradiation of dried fruits by electron spin resonance (ESR)

Dried almonds, raisins, dates and pistachio were irradiated using either ga mma radiation or electron beam, at an average absorbed dose of 5 kGy. To de tect the previous irradiation different parts of the dried fruits were anal yzed by ESR spectroscopy: almonds: skin; raisins: dried pulp; dates: dried pulp and stone; pistachio: nutshell. Analyses were carried out 2-3 months a nd 6 months after irradiation. A series of signals tentatively described as "cellulose-like", "sugar-like" and "complex" radical were observed, and so me slight differences between spectra from samples irradiated with gamma ra ys and electrons were evident. (C) 1999 Elsevier Science Ltd. All rights re served.