Beef ground under air and carbon dioxide (CO2) conditions were evaluated for their storage stability at 2 ± 1șC starting after 2 days in the dark to simulate transportation, followed by 7 days in lighted display by measuring color (CIE L*, a*, b*, the hue and chroma), gas headspace, microbiological content, and pigment content. AC (ground in air then packaged in 100% CO2 MAP) and CC (ground in CO2 then packaged in 100% CO2 MAP) treatments showed the highest a* and chroma values from day 3 to 9 compared with AV (ground in air then vacuum packaged) and CV (ground in CO2 then vacuum packaged) demonstrating greater color stability. CO2 grinding was effective in inhibiting total aerobic bacteria (P<0.05) and provided a 1.2 log reduction in microbial population during 9 days storage compared to meat ground in air.
Oxymyoglobin (OxyMb) content remained in an acceptable level (45- 48%) at day 9 for AC and CC ground beef packages, and surface metmyoglobin (MetMb) also remained in an acceptable range between 24 to 31% during display for all four treatments. However, ground beef in vacuum packaging (AV and CV) developed and maintained a high myoglobin (Mb) content which explains the decrease in OxyMb from 55 to 0% and 35 to 0.5% for AV and CV, respectively throughout storage.