Prediction model for the shelf-life of chilled pork stored at different temperatures

In order to validate model for the shelf-life of chilled pork, mixed specific microorganisms were inoculated to the non-contamination longissimus muscle. The samples were tray-packaged at 0℃, 4℃, 7℃, 10℃, 14℃ and 20℃, and their total aerobic psychrotrophic counts were determined. Simultaneously, the characteristics of chilled pork purchased from different corporations stored at 4℃ were analyzed in order to determine the average number of specific spoilage microorganisms when the shelf-life was ended. Gompertz type model and Belehradek (square root) model were used to establish the prediction model for shelf-life of chilled pork. Results show that the average number of specific spoilage microorganisms is 7.23 lg(cfu/g) at the end of shelf-life. The kinetics models of specific spoilage microorg- anisms were developed and the growth dynamics of this organism could be well described by a Gompertz type model. And six growth models were established for chilled pork. The temperature dependence of specific spoilage microorg- anisms kinetic parameters-μmax (maximum specific growth rate) and λ(lag phase) were modeled using Belehradek (square root) model. The correlation coefficient can finely describe the influences of temperature on μmax and λ. The absolute values of model residuals are all less than 0.1 and they all fluctuate around zero. The model for describing temperature with μmax and λ is credible. Therefore, the prediction model for the shelf-life of chilled pork stored aerobically from 0℃ to 20℃ were validated.