As storage time increased, pH decreased (P b 0.05) for MAP and VP and increased (P b 0.05) for PVC. TBARS varied (P b 0.05) among MAP and VP treatments. Except for day 1, CO headspace concentrations were similar among fat concentrations, and residual CO absorption in meat increased (P b 0.05) for all MAP treatments. In all treatments, degree of lightness was similar, redness decreased and brown discoloration increased during storage. As psychrotrophic bacteria counts increased, panelists detected color and off-odor deterioration in all systems. The CO treatment had no effect on maintaining the carboxymyoglobin “cherry red” fresh meat color during meat spoilage.