Use of oxygen sensors for the non-destructive measurement of the oxygen content in modified atmosphere and vacuum packs of cooked chicken patties; impact of oxygen content on lipid oxidation

Samples were packaged under vacuum and modified atmosphere (70% N₂:30% CO₂) and stored at 4 °C, under 616 lux fluorescent lighting, for 25 days. Oxygen sensors attached to the inside of the lidding material in MAP packages or inserted into vacuum packages were capable of monitoring changes in oxygen levels. Lipid oxidation of samples was measured at regular intervals. Residual oxygen levels were typical of those found in MAP and vacuum-packaged meats at 0.9-1.1% and 0.11-0.15%, respectively. MAP samples contained the highest levels of oxygen and were significantly (P <0.05) more oxidised than vacuum-packaged samples. A significant (P <0.05) reduction in lipid oxidation was observed in vitamin E supplemented patties compared to unsupplemented samples. Vitamin E supplementation had an important effect in counteracting the influence of freely available oxygen on lipid oxidation. The ability to continually assess oxygen levels within packs containing cooked processed meats, through continual, non-destructive assessment using oxygen sensors, provides a far more realistic approach to determining realistic shelf-life stabilities of foods held in vacuum or modified food packing systems.