Effects of excess dietary sulfur on beef carcass characteristics and quality after aging

Abstract Text: To test the effects of excess dietary S on beef carcass characteristics and quality (color shelf-life, oxidative stability, and sensory attributes) 20 steers (initial BW = 279 ± 60.4 kg) were blocked by BW and assigned randomly to 1) no additional S (~ 0.15% S) or 2) high S (0.40% S). Steers grazed fall pastures and were offered corn and soybean meal supplements for 114 d. Steers were moved to the feedlot, remained on prior dietary treatments, and received corn and soybean meal rations for 123 d. Steers were slaughtered at an average BW of 565 ± 38.4 kg. Boneless rib sections were obtained and aged 14 d at 4°C before fabrication into 2.54-cm-thick steaks. Steaks were overwrapped with oxygen permeable film and stored in open-topped, coffin-chest display cases (2.8°C) under continuous warm-white, fluorescent lighting (1600 lx) for 7 d of simulated retail display. Trained panelists (n = 11) evaluated raw LM color on d 0, 1, and 7. Instrumental (L*, a*, and b*) color was evaluated on d 0, 1, 4, and 7. Thiobarbituric acid reactive substances (TBARS) were measured on d 0 and 7 from LM cross-sections. Consumer sensory panel (n = 151) assessed cooked LM sensory attributes. Steer growth did not differ (P = 0.58) between dietary S levels. Dietary S did not affect HCW (P = 0.50), dressing percentage (P = 0.44), USDA yield grade (P = 0.56), LM area (P = 0.36), or 12th rib fat thickness (P = 0.66). Although TBARS were greater (P<0.0001) on d 7 than 0 of simulated retail display, values did not (P = 0.19) differ between dietary S levels. No differences were observed in total color (P = 0.27) or percent discoloration (P = 0.42); however, LM from steers fed 0.40% S were perceived to display greater worst-point color (P<0.05; treatment × day) on d 1 of simulated retail display. Dietary S did not effect a* (P = 0.50), b* (P = 0.61), or L* (P = 0.64). Furthermore, consumers failed to perceive a difference in tenderness (P = 0.26), juiciness (P = 0.61), overall impression (P = 0.37), beef flavor (P = 0.40), or off-flavor (P = 0.79) between the 2 dietary S levels. These results suggest that supplementing beef cattle diets with 0.40% S had no appreciable effects on steer performance or beef carcass characteristics, objective color, oxidative stability, and sensory attributes.

Keywords: beef, quality, sulfur