Sensory comparison of commercial low and high oxygen modified atmosphere packed sirloin beef steaks

The objectives of this study were to investigate the effects of using commercially low and high modified atmosphere packaging (MAP) on quality characteristics of sirloin beef steaks. Gas mixtures used included 80% O(2):20% CO(2) (O(2)80), 70% O(2)/30% CO(2) (O(2)70) and 50% O(2)/30% CO(2):20% N(2) (O(2)50) and for commercial packs O(2)75 ± 5%, CO(2)25 ± 5%, <5% N(2)-(O(2)Com). All samples were packed in similar tray and packaging film formats. The experimental parameters monitored included microbiological, physiochemical and sensory measurements (naïve assessors). Microbial counts did not exceed the recommended legal ranges over the storage period. However the numbers of LAB (lactic acid bacteria) were the highest for commercially-packed samples (O(2)Com) in comparison to laboratory packaged samples (O(2)80, O(2)70 and O(2)50). Commercially-packaged samples eventually spoiled due to the occurrence of off-flavours and off-odours and subsequently were the least acceptable to sensory naïve assessors.