The performance of several oxygen scavengers in varying oxygen environments at refrigerated temperatures: implications for low-oxygen modified atmosphere packaging of meat

The oxygen scavenging capacity of four commercially available iron-based oxygen scavengers was studied. Individual oxygen scavenger sachets were placed in pouches and filled with 1%, 2%, 6%, 12% or 22% oxygen, 40% carbon dioxide and balance nitrogen, and stored at 3 °C or 10 °C, with or without a drip pad infused with water and monitored over 24 h. The four scavengers all reduced oxygen from the packs at the oxygen concentrations and temperatures tested. However, for all of the conditions measured, the scavengers did not absorb their nominal capacity in the 24-h period. In anoxic modified atmosphere packaging of beef steaks, it is essential to reduce residual oxygen levels to below 0.05% as quickly as possible to minimise the formation of metmyoglobin. While the scavengers tested were effective in removing oxygen, the rate of removal would appear not to be fast enough to create the anoxic conditions required to prevent metmyoglobin formation in beef steaks, particularly in those cuts, which are highly susceptible to metmyoglobin formation. Reproducibility was also a critical issue for the scavengers, particularly at low oxygen concentrations. None of the scavengers had a coefficient of variation of less than 20% at the low oxygen concentrations. Therefore, to obtain consistent results, it is recommended that multiple scavengers be used.