P>The reduction in counts of Aspergillus spp. and aflatoxin production was assessed on hazelnuts after 254 nm UV-C treatment. A 2 log reduction in Aspergillus spp. counts was observed after 2 h reperated UV-C treatment on hazelnuts. Only one dose treatment of 6 h UV-C was sufficient to yield nearly 25% reduction in aflatoxin B1 and G1, but this dose had no effect on aflatoxin B2 and G2. SDS-PAGE of the crude extracellular protein isolated at different growth periods of A. parasiticus in liquid medium revealed production of twelve extracellular proteins starting from day 4 of inoculation, and all twelve proteins decreased after UV-C radiation. No molecular changes in macromolecular components of hazelnut with UV-C treatment were detected by Fourier Transform Infrared spectroscopy.