The Effect of Different Packaging Systems on the Shelf Life of Refrigerated Ground Beef

Abstract: The aim of this study was to investigate the effects of different packaging systems on the shelf life of refrigerated ground beef. The ground beef samples were packaged as follows: AA (100% ambient air), 90O₂:10CO₂ (90% O₂ and 10% CO₂), 80O₂:20CO₂ (80% O₂ and 20% CO₂), 70O₂:30CO₂ (70% O₂ and 30% CO₂), 60O₂:40CO₂ (60% O₂ and 40% CO₂), 50O₂:50CO₂ (50% O₂ and 50% CO₂), 100O₂ (100% O₂), and VP (vacuum packaging). All treatments were analyzed daily for O₂ and CO₂ levels, pH, filtration time, total volatile basic nitrogen (TVB-N), aerobic mesophilic heterotrophic bacteria (AMHB), and aerobic psychrotrophic heterotrophic bacteria (APHB) over 20 days at 2 °C. All MAP systems had a decrease of O₂ and an increase of CO₂ levels during storage period (p < 0.05). Overall, the MAP systems were similarly able to decrease the pH and retard the increase of TVB-N and filtration time over the storage period (p > 0.05). Moreover, the MAP systems increased the lag phase and/or the generation time of both AMHB and APHB, extending the shelf life by 3 (90O₂:10CO₂), 4 (70O₂:30CO₂ and 100O₂), and 5 days (80O₂:20CO₂, 60O₂:40CO₂, 50O₂:50CO_2, and VP). All MAP systems were equally effective in retarding physicochemical degradation; however, 80O₂:20CO₂, 60O₂:40CO₂, 50O₂:50CO_2, and VP were the most effective in impairing bacterial growth and extending the shelf life of ground beef stored under refrigeration.