Evaluation of animal age and muscle type on beef log juice colour and residual GOT activity when cooked to target end-point temperature of 79.4 degrees

The effectiveness of the pink-juice test to determine 79.4 degrees C end-po int temperature (EPT) of cooked beef logs was appraised. Logs made from fiv e cuts of meat from three animal age groups were fabricated in triplicate t o simulate products received at ports of entry and then cooked to EPTs of 7 8.0-81.8 degrees C. CIELAB L*, a*, b*, C and h degrees values of internal s urfaces of freshly sliced meat and pressed juices from samples were determi ned. Sensory ratings were made by six trained panelists to determine intens ities of residual red color of the juices. Animal age and cut of meat had little effect on the CIELAB color values. Re sidual red color was apparent in all samples by both sensory and a* values analysis. Sensory ratings did not vary significantly (P < 0.05) by animal a ge or cut of meat. Average values of 3.2 (intensity range, 1-9) corresponde d to an EPT slightly greater than 80 degrees C; absence of red color in the juices would therefore indicate an EPT in excess of the target temp of 79. 4 degrees C. Residual glutamic-oxaloacetic transaminase activity (GOT) acti vity, used as a collateral test for EPT, ranged from 482.5 to 1641.8 SFU ml (-1) of juice and differed significantly by cut of meat (P < 0.05), but not by animal age. (C) 1999 Society of Chemical Industry.