A comparison of modified atmosphere and vacuum skin packing for the storage of red meats

Abstract

Summary The performances of two commercially available packaging systems for prolonging the shelf‐life of fresh meat were compared at 1°C and during simulated retail display. Beef and pork loin steaks in modified atmosphere packs (MAP), containing 75% O2 and 25% CO2, developed an initial bright red (beef) or pink (pork) colour, which gradually changed to brownish‐red or ‐pink after 12 days; similar samples in vacuum skin packs (VSP) remained purple‐red throughout the storage period. Off‐odours developed more rapidly in MAP (8–12 days), possibly due to more extensive growth of Brochothrix thermosphacta and the effects of aerobic conditions on the metabolites of lactic acid bacteria, which predominated in both types of packs. Evidence of rancidity, using thiobarbituric acid assay, was demonstrated in MAP beef after approximately 8 days, but not in VSP. Drip losses in MAP increased after 6 days' storage, but remained generally low in VSP. Physical texture (shear force values of cooked samples) of beef was unaffected by packaging method, but pork in VSP was significantly more tender ( P < 0.001) than in MAP.