Factors Affecting the Formation of a Dark, Coarse Band ("Heat-Ring") in Bovine Longissimus Muscle
Journal of Animal Science
Alternate right or left sides of eight Holstein-Friesian steer carcasses were electrically stimulated (ES, 550 V) approximately 40 min postmortem, with the nonstimulated (NS) sides serving as the experimental control. Temperature and pH of the longissimus muscle (LM) from both sides were monitored at 1, 3, 6, 12, 24 and 48 h poststimulation. At 12, 24 and 48 h, the LM was sectioned for visual evaluation and for measurements of pH and temperature at three locations across the muscle surface and for measurements of color using a Hunter Color Difference Meter. A significant correlation (r=.792, P<.0001) was found between the pH of the dorsal surface of the muscle [the position at which a dark, coarsely textured outer band (DCB) or "heat-ring" is normally located] and DCB score; pH was elevated in those muscle areas where the DCB was most pronounced. Electrical stimulation lowered (P<.05) both the incidence and severity of the DCB at 12 h postmortem, and totally eliminated this phenomenon by 24 h. At 24 h, however, the DCB severity in NS sides was less than at 12 h. Muscle color, as measured objectively and visually, was brighter in the stimulated muscles through 24 h postmortem.
Orcutt, M.W., Dutson, T.R., Cornforth, D.P. and Smith, G.C. 1984. Factors affecting the formation of a dark, coarse band ("Heat-Ring") in bovine Longissimus muscle. J. Animal Sci. 58:1366.