Coupling the dynamics of diffused gases and microbial growth in modified atmosphere packaging

Coupling microbial dynamics with the complete dynamics of the packaging gases is still a challenge. In this work the microbial growth kinetic parameters for Pseudomonas and Lactic Acid Bacteria (LAB) in MAP are identified based on accurate estimation of diffusivity of gases and parameter scaled sensitivity approaches. The microbial dynamics are also compared with those estimated based on partial pressure measurement. Scaled sensitivity coefficient analysis using dissolved gases as variable inputs, shows that in most cases the only coefficients large enough for estimation were those for CO_2max-diss, and for μ_max. The current data showed that dissolved gases led significant differences on the microbial parameter of CO_2max values when compared with the headspace gases. On the other hand, the (so-called) dissolved specific growth rate follows a clear trend down for both microorganisms in relation to the increase of the initial headspace CO₂. Finally, current results indicate a possible correlation between CO_2max-diss, CO_{2max-headspace}, and μ_max as functions of CO_2init.