Abstract:

During storage at 0, 4, 7, 10 or 15 ℃, tray-packaged pork was periodically measured for its total bacteria count and Brochothrix thermosphacta count, sensory quality and total volatile basic nitrogen. The maximum Brochothrix thermosphacta count for keeping pork from spoilage was 5.316 lg(CFU/g). The average of Brochothrix thermosphacta counts in chilled pork at the end of shelf-life at different temperatures was 7.519 lg(CFU/g). SAS9.1 statistical software was used to fit Gompertz type models for the growth dynamics of Brochothrix thermosphacta at different temperatures, and these models were found to be able to do well. Two Belehradek models that describe the relationships between temperature and maximum specific growth rate or lag phase were set up and their determination coefficients were both more than 0.99, which indicates that there is a quiet good relationship between temperature and maximum specific growth rate or lag phase. Based on these investigations, a predictive model for the shelf-life of chilled pork stored at a temperature ranging from 0 to 15 ℃ was set up. Comparison between the observed shelf-life of pork stored at 3 ℃ and its predictive counterpart was carried out, and a relative error was found. This demonstrates that the predictive model is reliable in predicting the shelf-life of chilled pork stored a temperature ranging from 0 to 15 ℃.

Key words: chilled pork, Brochothrix thermosphacta, growth model, shelf-life