Enzyme levels in raw meat after low dose ionizing radiation and extended refrigerated storage

Bovine semimembranosus muscle samples obtained aseptically 24 h after slaughter were irradiated at 1, 5 and 10 kGy between 0 and 4°C and stored at 2°C to determine effects of low level ionizing radiation on tissue-free enzyme levels. Samples were analyzed after 1, 7, 14 and 28 days of storage. Nonspecific proteolysis was measured using (14)C-hemoglobin as the substrate. For determination of possible effect by irradiation on lysosomal enzymes, acid phosphatase and β-glucuronidase were measured. Assays for acid phosphatase and hemoglobin proteolysis indicated negative relationship between increasing dose and enzymatic activity. At 10 kGy mean reductions in enzymatic activity were 8% and 42%, respectively, β-Glucuronidase was not affected at this or at the lower levels of radiation. Correlation between dosage and storage time with enzymatic activity was not significant.