within these trays using a low O2 permeable (3 cm3/m2/24 h) lidding film (20 mm of a laminate orientated polypropylene (OPP) and a co-extrusion layer (50 mm) of PE/EVOH/ PE) for modified atmosphere packaging using a gas mixture containing either 80:20:0, 60:20:20, 60:40:0 or 40:40:20/O2, CO2, N2 and a gas volume ratio to meat of either 1:1 or 3:1.