Effects of Modified Atmosphere Packaging on Retail Color Stability in Fresh Beef

Abstract

The study aimed to evaluate the effects of different modified atmosphere packaging and different packaging styles on retail shelf life and microbial growth. Phase 1 evaluated different gas composition in modified atmosphere packaging. Ground beef and top sirloin steaks were packaged in tray overwrapped packages with 4 trays per master bag with either high oxygen (80% O2 and 20% CO2), bi-gas (70% N2 and 30% CO2), or tri-gas (69.6% N2, 30% CO2 and 0.4% CO). In addition, two treatments were packaged in barrier trays and film with either high oxygen MAP (80% O2 and 20% CO2) or low oxygen MAP (69.6% N2, 30% CO2 and 0.4% CO) gas mixture. Product was placed in dark storage for 6, 10 or 15 d. Product was color scored by a trained panel and total aerobic plate counts were measured. Tri-gas and low oxygen MAP had significantly brighter colored sirloins and ground beef and, therefore had, higher overall acceptability scores. High oxygen and bi-gas sirloins were never acceptable in terms of color or overall acceptability. For phase 2, sirloins and cube steaks were packaged in tray PVC overwrapped packages with 4 trays per master bag. All masters bag contained 69.96% N2, 29% CO2 and 0.04% CO. Three treatments were applied to the sirloins steaks and cube steaks: Single Stacked, Double Flushed (SS-DF); Double Stacked, Single Flushed (DS-SF); or Double Stacked, Double Flushed (DS-DF). Steaks were placed in dark storage for 5 or 8 d. Product was color scored by a trained panel. Aerobic Plate Counts were evaluated to determine the safety of products. No differences were observed between cube steak treatments for muscle color and overall acceptability. There were treatment differences in surface discoloration in cube steaks on d 10. The DS-SF bottom had the most (P < 0.05) surface discoloration while DS-DF top showed the least. Both DS-SF sirloin treatments had the brightest muscle color on d 6 and 7, although on d 9 and 10 DS-DF bottom had the darkest muscle color (P < 0.05). The modified atmosphere the meat in the packages does affect the color stability of beef products.