The present invention relates to the use of carbon monoxide as a process aid to reduce the curing time of ground beef. Ground beef must presently go through a curing stage of 24 hours to 8 days for the oxymyoglobin to transform to deoxymyoglobin, which presents a desirable purple color for the raw meat. In the present invention the curing process is interrupted when some of the ground beef is not completely cured, i.e., still in the metmyoglobin stage, and the ground beef is packaged in a treatment gas containing carbon monoxide. The carbon monoxide converts the myoglobin into carboxymyoglobin, which has a desirable bright-red cherry color.