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 meat discoloration. Supplementation of
cattle diets with enough vitamin E to achieve about 4 /lg g-t 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 (Escherichin coli 0157:H7; Listeriu 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.