Effect of Electrical Stimulation on Carcass Quality and Meat Palatability of Beef from Forage- and Grain-Finished Steers

Abstract

Twenty forage-fed (FF), 20 limited grain-finished (LGF) and 19 grain-finished (GF) steers were slaughtered in a commercial meat packing firm. A randomly selected side from each carcass was electrically stimulated (ES) within 1 hr of exsanguination. All sides were chilled in a 0 C cooler, ribbed at 18 to 21 hr postmortem and evaluated for USDA quality and yield grade factors. Five short loin steaks (2.5 cm thick) were removed after 60, 120, 180 and 240 hr postmortem aging for determination of force value (SFV) and after 240 hr for palatability assessment. Quality scores for the longissimus muscle of non-ES (NES) sides of carcasses from GF steers were higher (P<.05) and more desirable for color, firmness, texture and marbling than were scores for NES sides from FF or LGF steers. Across all carcasses, ES sides had higher (P<.05) lean color, firmness and texture scores and less (P<.01) “heat-ring” than NES sides. ES had no (P>.05) effect on marbling score for longissimus muscles from FF or LGF carcasses, but increased (P<.10) marbling scores for GF beef. Steaks from FF carcasses were less (P<.05) tender and had a less desirable “moderately-dairy or grassy” flavor than loin steaks of carcasses from GF steers, which had a “slightly- to moderately-intense” beef flavor. FF and LGF loin steaks differed (P<.05) in flavor but were similar (P>.05) in all other physical, chemical and histological traits studied. ES improved (P<.05) the tenderness ratings of steaks from FF carcasses but did not (P>.05) change palatability of steaks from LGF and GF carcasses. ES decreased SFV and reduced by 5 days the cooler aging time necessary to achieve satisfactory tenderness for loins from FF, LGF and GF beef. Variability in SFV was decreased (P<.05) by ES. In general, ES increased lean quality and tenderness without creating undesirable characteristics.