Effects of different X-ray irradiation doses on quality traits and metabolites of marinated ground beef during storage

The effect of X-ray irradiation on quality traits and metabolites identified by the H-1 nuclear magnetic resonance (NMR) of marinated ground beef was studied during 14 d of cold storage. The samples were vacuum packaged and irradiated at 2.5, 5, 7, and 10 kGy. The population of total aerobic bacteria in the samples significantly decreased as the X-ray irradiation doses increased during storage. No bacterial growth was observed in the samples irradiated at 10 kGy. The redness of the samples increased significantly as the dose levels increased. Lipid oxidation in the samples was unaffected by the irradiation doses. For volatile organic compounds, the contents of methanethiol, 2-methylfuran, and S (+)-2-butanol increased as the dose and storage period increased. X-ray irradiation at 7 kGy was effective for microbial inactivation of ground beef without compromising quality such as off-odor generation. In addition, the metabolites profile of samples can distinguish irradiation dose levels during storage.