Detection of irradiation treatment in dried mushrooms by photostimulated luminescence, EPR spectroscopy and thermoluminescence measurements

Detection of the irradiation treatment of nine species of dried mushrooms commercially available employing photostimulated luminescence (PSL), electron paramagnetic resonance spectroscopy (EPR/ESR) and thermoluminescence (TL) is described. PSL is adaptable to six to seven species shortly after irradiation, but the PSL signal decays with storage and may render detection impossible. After 4 months of storage, six species could still be well identified by PSL if the radiation dose was higher than 5 kGy. EPR spectroscopy enabled detection with five to six species, both cellulose and crystalline sugar-like radicals being observed. For some mushrooms, hat or leg parts showed a different response and some lots could not be identified at all. TL - although being more cumbersome - allowed unequivocal identification of all species of investigated mushrooms. It is concluded that dried mushrooms exposed to ionising radiation can be successfully detected by at least one of the analytical methods investigated.