An investigation into gamma‐ray treatment of shellfish using electron paramagnetic resonance spectroscopy

Abstract

Gamma irradiation is a safe method for the decontamination of shellfish, and its technical feasibility and safety have been endorsed (FAO/IAEA/WHO). In order to implement proper food-processing regulations, the identification of radiation treatment is required. In this study, electron paramagnetic resonance (EPR) spectroscopy was employed to identify the irradiation of seven different types of commonly consumed shellfish. Characteristics (g factor and signal intensity) of the EPR spectra of control and irradiated samples were recorded in order to clarify the gamma-ray treatment of shellfish. Radiation-specific signals around g = 2.0038 ± 0.0006 (g₁) and g = 1.9996 ± 0.0002 (g₂ and g₃) were observed for all shellfish samples irradiated with absorbed doses of 3 and 6 kGy. The X-ray diffraction (XRD) spectra of some shellfish samples were recorded to investigate their mineral profiles. The EPR spectroscopic results indicated that carbonate minerals were the source of the paramagnetic species that were produced upon irradiation, entrapped in the shellfish and showed radiation-specific asymmetric signals whose intensities increased quantitatively with the absorbed radiation dose. The XRD analysis revealed that aragonite and calcite minerals were present in the shells of shellfish.