Shelf life of modified atmosphere packed cooked meat products: a predictive model

The effect of temperature, concentration of dissolved CO2 and water activit y on the growth of Lactobacillus sake was investigated by developing predic tive models for the lag phase and the maximum specific growth rate of this specific spoilage organism for gas-packed cooked meat products. Two types o f predictive model were compared: an extended Ratkowsky model and a respons e surface model. In general, response surface models showed a slightly bett er correlation, but the response surface model for the maximum specific gro wth rate showed illogical predictions at low water activities. The concentr ation of dissolved CO2 proved to be a significant independent variable for the maximum specific growth rate as well as for the lag phase of L. sake. S ynergistic actions on the shelf life-extending effect were noticed between temperature and dissolved CO2, as well as between water activity and dissol ved CO2. The developed models were validated by comparison with the existin g model of Kant-Muermans et al. (1997) and by means of experiments in gas-p acked cooked meat products. Both developed models proved to be useful in th e prediction of the microbial shelf life of gas-packed cooked meat products . (C) 1999 Elsevier Science B.V. All rights reserved.