reported that packaging ground beef in a low-oxygen-carbon monoxide (0.4% CO, 30% CO2 and 69.6% N) system resulted in formation of the stable carboxymyoglobin pigment and prevention of surface discoloration. The growth of psychrotrophic aerobic bacteria, total aerobic bacteria and Lactobacillus counts were significantly decreased when compared to the conventional PVC packaging system. The lower microbial counts could also be attributed to the presence of CO2 in the package. Dixon and Kell (1989) determined that lowering of meat pH is a result of CO2 absorption and production of carbonic acid that dissociates to bicarbonate and hydrogen ions. A decrease in meat pH has been shown to negatively affect the rate of oxidation processes such as pigment and lipid oxidation as well as water holding capacity (WHC) of meat