The residual concentration of CO2 and O2 in the headspace of the packageswas assessed for each of the three treatments at seven-day intervals. A constant increase in the percentage of CO2 and a simultaneous reduction in the O2 concentrationwere noted for the vacuumtreatment (Fig. 1), an environment that enabled the development of anaerobic microorganisms. This behavior occurred likely due to the consumption of O2 by muscle respiration, which is higher in the first days following the slaughter and which decreases during the storage period and