ESR method for detecting irradiated fresh mangoes

Kikuchi, Masahiro; Hussain, M. S.*; Morishita, Norio; Sakashita, Tetsuya; Funayama, Tomoo; Ukai, Mitsuko*; Shimoyama, Yuhei*; Kobayashi, Yasuhiko

When tropical fruits are imported, quarantine treatments are required for preventing plant pests. The irradiation is a choice of the quarantine treatments for tropical fruits in the world. When the irradiation is utilized as the treatment, detection methods are required to endorse the reliability of labels for consumers. To distinguish the irradiated fresh mangoes from non-irradiated ones, radical detection was carried out using ESR. After freeze-drying mangoes, the ESR main peak was observed but the signal intensity was affected by ripeness and period of storage. We found that the existence of side peaks is an effective indicator to detect fresh mangoes irradiated to dose range of quarantine treatment. Since ESR method is able to measure without complicate preparation, this technique is useful to detect the irradiation treatment against a wide variety of foods.