The objective of this study was to investigate the effects of carbon dioxide (CO2) concentration (100mlCO(2)/100 ml pack gas, 50mlO(2):20mlCO(2):30mlN(2)/100 ml pack gas, 70mlO(2):30mlCO(2)/100 ml pack gas and 80mlO(2):20mlCO(2)/100 ml pack gas) on the sensory quality of modified atmosphere packed (MAP) beef steaks (M. longissimus thorasis). Steaks were stored at 4 degrees C for 15 days and tested for CO2 off flavour, lipid oxidation flavour, juiciness and tenderness (up to day 12) of the resulting cooked meat as well as pH, colour, drip loss, and cooking loss. One steak from each of the experimental treatments was taken immediately from the respective MA packs and cooked before serving straight to panellists. A second steak from each of the pack was treated similarly, but left in ambient air for 30 min to let dissolved CO2 dissipate from the meat prior to cooking and serving. The 50mlO(2):20mlCO(2):30mlN(2)/100 ml pack gas treatment displayed a significantly (P <= 0.05) and negative correlation to CO2 flavour which was even more pronounced for samples where the CO2 was allowed to dissipate (Dis, P <= 0.001). Thus this packaging gas combination could be used to optimise the sensory quality of MAP steak. Additionally opening retail MAP packs up to 30 min prior to cooking has a benefit towards the perceived sensory quality of the cooked product. (C) 2011 Elsevier Ltd. All rights reserved.