Effect of several packaging conditions on the microbiological, physicochemical and sensory properties of ostrich steaks during refrigerated storage.

A total of 365 ostrich steaks were packaged in air (AIR), vacuum (VAC), MAP1 (70% O2  + 30% CO2 ), MAP2 (30% O2  + 30% N2  + 40% CO2 ), MAP3 (20% O2  + 30% N2  + 50% CO2 ), MAP4 (50% N2  + 50% CO2 ), MAP5 (20% N2  + 80% CO2 ) or MAP6 (100% CO2 ). Microbial counts (10 groups), pH, Aw and sensory properties (nine-point hedonic scale) were determined on days 0, 1, 3, 7 and 15 of storage (4 °C). On day 0, microbial counts (log10  cfu/g) ranged from undetectable levels (Brochothrix thermosphacta, enterococci) to 3.21 ± 0.63 (total aerobic counts -TAC-). The highest and the lowest microbial loads throughout storage were observed in AIR and MAP6, respectively. On day 15 TAC as high as 9.96 ± 0.20 log10  cfu/g were found in AIR. The shelf-life (time until overall acceptability score fell below 5) was 3 days (MAP1, MAP2), 7 days (MAP3, AIR) or 15 days (MAP4, MAP5, MAP6). Only for VAC the shelf-life limit extended beyond 15 days.