Construction Of Predictive Growth Model Of Pseudomonas And Escherichia Coli In Chilled Pork

Chilled pork has been the main form of the fresh pork consumption in the recent years. However,the growth of microorganism that lead to the spoilage of product has been the great barrier for producer during slaughter,transportation and preservation.In virtue of predictive microbiology,we can make a quick evaluation for shelf life and quality of product without traditional test.We invested the original microflora of pork after slaughter and segmentation,and obtained the main spoilage strains in chilled meat.The predictive growth models of Pseudomonas and Escherichia Coli in chilled meat were constructed,and then were packaged to computer software.This software can make a quick evaluation for meat quality so as to provide directions for meat factories.The results were described as follows.1,The main microflora of chilled meat after slaughter and segmentation were isolated and identified.The results indicted that the diversity of original microflora of chilled meat were very different.The dominant bacteria were Enterbacteriaceae and Pseudomonas spp..2,The aseptic longissimus dorsi muscle was inoculated by Pseudomonas,and then was tray-packaged at 4,7,10,13 and 16℃for storage.The status of growth at different temperatures was compared to linear model with the Statistica program,the results showed that growth dynamics of Pseudomonas in pork at different temperatures could be well described by Gompertz model.The correlation regression of Belehradek model finely described the influence of temperature on growth.Validation of built kinetic model under isothermal was carried out by comparing with experimental development of Pseudomonas grown at temperatures 8℃,12℃,using concept of EGT to validate the model under fluctuating temperature conditions.Bias and accuracy factors were calculated respectively, it suggested in the range of temperature 4-16℃,the model we built can predict the growth of Pseudomonas in pork effectively.3,The aseptic longissimus dorsi muscle was inoculated by Escherichia coli,and then was tray-packaged at 4,7,10,13 andl6℃for storage.The status of growth at different temperatures was compared to linear model with the Statistica program,the results showed that growth of Escherichia coli in pork could be well described by Gompertz model in the range of temperature 7-16℃.The correlation regression of Belehradek model finely described the influence of temperature on growth.Validation of built model was carried out by comparing with experimental development of Escherichia coli grown in pork at temperatures 8℃,12℃.It suggested the model we built is effective by bias and accuracy factors.4,Based on primary and secondary models,tertiary model "Microbial Predictor" was built by forming a computer software package.Microbial Predictor include two systems: search system and prediction system.There are four modeds in Microbial Predictor: predictive model of Pseudomonas,predictive model of Escherichia coli,predictive model of Yersinia enterocolitica and predictive model of mixture organisms.