Post-mortem physicochemical and biochemical changes in scientifically slaughtered and cold slaughtered broiler chicken meat

Cold slaughtered broiler chicken meat is a food safety and meat authenticity concern because it is obtained from birds that die before slaughter and are processed without proper exsanguination. The present study compared early post-mortem physicochemical and biochemical changes in scientifically slaughtered (SS) and cold slaughtered (CS) broiler chicken meat. A total of 100 broiler chickens, comprising 50 SS and 50 CS birds, were evaluated. Breast and leg muscle samples were collected during 0-2, 2-4 and 4-6 h post-mortem intervals and analysed for carcass temperature, pH, R-value, lactic acid concentration and malachite green test reaction. Muscle temperature declined significantly during the first 6 h post-mortem in both groups. The pH of breast and leg muscles decreased progressively with time, with CS samples showing lower pH than SS samples. At 4-6 h, breast muscle pH was 5.83±0.04 in SS and 5.63±0.04 in CS, while leg muscle pH was 6.02±0.02 in SS and 5.81±0.02 in CS. R-value increased significantly with post-mortem time in both groups, indicating progressive ATP degradation. Lactic acid concentration also increased with time and was higher in CS meat, particularly during the early post-mortem period. The malachite green test revealed imperfect bleeding in 68 per cent of breast and 70 per cent of leg muscle samples from CS carcasses, whereas all SS samples showed normal bleeding. The findings indicate that cold slaughtered meat undergoes altered post-mortem biochemical changes and shows greater residual blood retention. Combined assessment of pH, R-value, lactic acid and malachite green test may provide useful supportive indicators for detecting cold slaughtered broiler chicken meat.