Quality deterioration in meat occurs because of oxidation of lipids and muscle pigments. Lipid oxidation causes development of off-odors and off-flavors; muscle-pigment oxidation negatively affects color, appearance and acceptability. Lipid and muscle-pigment oxidation are closely associated such that delaying lipid breakdown will delay meal discoloration. Supplementation of cattle diets with enough vitamin E to achieve about 4 μg g−1 of alpha-tocopherol in muscle extended the time beef was of acceptable quality. Feeding supplemental vitamin E to feedlot steers and heifers produced beef with higher tissue alpha-tocopherol, slower metmyoglobin formation, fewer oxidation products and 24–48 h longer acceptable appearance during display. Growth of spoilage and pathogenic (Escherichia coli 0157:H7; Listeria monocytogenes) bacteria did not differ on beef cuts from cattle fed vs. not-fed supplemental vitamin E. Field studies documented that supplementing diets of feedlot cattle with 500–1000 IU per head per day of vitamin E for 90–100 days prior to harvest was efficacious for beef marketed in both domestic and export trades.