Development of a method based on ESR spectroscopy for the identification of irradiated beef, pork, and chicken meats

The electron spin resonance (ESR) spintrapping method for the detection of irradiated beef, pork, and chicken was studied using a α-(4-pyridyl-1-oxide)-N-tert-butylnitrone (POBN) spin trapper in the dose of 0.5-7 kGy. Irradiation caused a significant increase in the ESR signal intensity of samples with hyperfine coupling constants of a∨N=1.57 mT and a∨H=0.25 mT, which correspond to lipid-derived radicals. In contrast, un-irradiated samples exhibited a weak ESR signal with no hyperfine coupling constants. The irradiation-induced lipid radical stability vs. temperature was also studied at room temperature, -4 and -18℃ using 3 kGy irradiated beef. Temperature did not affect ESR signal intensity or the hyperfine coupling constants. To investigate the applicability of the proposed procedure for pork and chicken, a comparison of the spectra at the hyperfine coupling constants confirmed the presence of lipid-derived radicals in the samples.