Two blind trials on bone-in meat chunks are reported. In total 30 or 35 coded samples were analysed for irradiation treatment using electron spin resonance (ESR) spectroscopy. In the first trial 30 samples were received from other research institutes. All samples were qualitatively identified correctly. The second trial consisted of 35 samples. They were either left unirradiated or had been irradiated at doses of 1, 2.5 or 4 kGy. All samples were qualitatively identified on the basis of the ESR spectra. Using re-irradiation, the doses received by the samples were determined with linear, quadratic or exponential equations. The quadratic or exponential equations gave more successful estimates of the irradiation dose whereas linear fit equations tended to overestimate the dose.