Packaging and Palatability Characteristics of Grass and Grass-Grain Fed Beef1

Sixty-three beef ribs were obtained from carcasses of known grass-grain feeding regimens. Complete carcass data and wholesale beef ribs were obtained 48 hr postmortem. Rib sections were boned and packaged in barrier bags using a chamber type vacuum machine prior to storing at 1 to 3 C for 0, 21 or 28 days. Each storage group was composed of samples which were classified as grass-fed, grain-supplemented or clover-fed beef. At the end of the storage period, three steaks (2.54 cm in thickness) were removed from each rib, wrapped in polyvinylchloride film and placed in a simulated retail case at 0 C. Individual steaks were scored for muscle color, consumer desirability, surface discoloration and odor after 0, 3 and 6 days of display time. Proximate analysis and sensory panel data were obtained for all samples. Carcasses obtained from grain-supplemented cattle exhibited higher marbling scores and quality grades than carcasses obtained from grass-fed cattle. Values for moisture were significantly (P<.05) higher in the grass-fed beef steaks. Microbial numbers determined for subcutaneous fat and lean tissue samples were not effected significantly by feeding regimes. Rib steaks obtained from carcasses of the grain-supplemented cattle exhibited less surface discoloration, higher muscle color and consumer desirability ratings in the retail case and higher sensory panel ratings for flavor and overall satisfaction than rib steaks obtained from the grass-fed beef.