Abstract
The color of the longissimus dorsi (LD) muscles from 7695 beef carcasses was evaluated following carcass grading at a commercial abattoir in the Central Alberta Region. Darker-than-normal beef was found in 3.7% of steer and heifer carcasses. However, the incidence of true dark-cutting beef (i.e., dark in color and with a pH greater than 6.0) was estimated to be only 0.5%. The length of time between stunning and the measurement of color had a major impact on color. The incidence of dark-colored beef was three times higher at 15–18 h than at 23–26 h poststunning, apparently because of incomplete development of muscle color at the earlier times. Carcass fat cover, weight and conformation affected muscle color, with smaller and leaner carcasses yielding higher frequency of dark-colored beef. Other factors influenced muscle color, including: (1) gender, (2) nutritional regime, (3) transit distance, (4) lairage time at the abattoir and (5) weather conditions. All of these could be explained by their effect on the time of color measurement or on carcass size and fatness. These findings indicate that if meat color is evaluated during the first 24 h postslaughter, it may be affected by many factors not related to preslaughter stress. During this time period accurate assessment of ultimate muscle color of the dark-cutting condition of conventionally-handled carcasses is not possible. Key words: Beef, color, dark cutting, stress