Advanced electron paramagnetic resonance spectroscopy for the identification of irradiated food

Electron paramagnetic resonance (ESR) spectroscopy can be utilized for the identification of irradiated fruits and vegetables. For ESR measurements, the sample is placed in a quartz ESR tube, the tube is sealed with paraffin film and stored in the dark in a desiccator at 40 ± 5% relative humidity. The sample is subjected to the simultaneous action of a magnetic field and an electromagnetic microwave of very high frequency. Effective drying techniques are required as pretreatments to reduce the moisture content in order to obtain clear or improved ESR spectral features. A number of research studies have reported the radiation-induced signals in plant materials containing cellulose with two side peaks having g values linked with a central signal. The technique has also been used successfully for herbs, nuts, spices, and meat.