Color stability and reversion in carbon monoxide packaged ground beef

This study investigated the relationship between length (1, 2, 4, or 6 days) of exposure to carbon monoxide (CO) and the subsequent rate of loss of carboxymyoglobin color during display (0, 24, 48, 72 h) after repackaging in an oxygen permeable polyvinyl chloride (PVC) overwrap. In addition, the ability of CO to cause color reversion of metmyoglobin to carboxymyoglobin in brown colored, aged (4 days, PVC) or low oxygen-induced (2 days, (LOX-MAP) ground beef was studied. Extending CO exposure time increased overall mean redness. However, overall mean redness decreased after packages were opened. Day 6 exposed ground beef only maintained about 1.5 Minolta a∗ units higher than day 1 exposed after opened 72 h. The color of brown ground beef was converted to carboxymyoglobin upon exposure to carbon monoxide, regardless of how the initial brown color was formed. This color changes was relatively faster in LOX-MAP packaged ground beef compared to that formed by aging in PVC. Although color reversion is possible, consideration should be given to the microbiological status of the ground beef at the time of CO packaging.