| Chilled duck is a kind of safety and health y food with high nutritional value, however the quality is subjected to affect by corruption microorganism.Previous researches has shown that application of Modified Atmosphere Packaging and antistaling agents can slow the growth of microorganisms effectively. Modified Atmosphere Packaging can significantly inhibit the proliferation of corruption microorganisms in cold fresh duck,but the bacteria and growth law of the major corruption microorganisms have not yet been deeply researched on microbial.This paper researched the compositions of the bacteria of chilled duck products with different Modified Atmosphere Packaging. The results indicated that the number of Pseudomonas, Lactobacillus and Enterobacter is more than staphylococcus aureus, and compared with other duck products, small duck breast has more microorganisms. Furthermore, we compared the proliferation after inoculating with three kinds of bacteria(Pseudomonas,Enterobacterium and Lactobacillus) in duck breast with Modified Atmosphere Packaging. We found that during the 10 days of storage,proliferation of Enterobacterium and Pseudomonas were significant in the chilled duck using Modified Atmosphere Packaging,but lactic acid bacteria proliferation was relatively slow.The growth change rule on Pseudomonas and Enterobacterium in 10 days storage at 0 ℃,5 ℃,10 ℃,15 ℃ and 20 ℃were studied, respectively. We found that they growed faster in cold fresh duck as temperature rises. Using the Gompertz model, the proliferation of Pseudomonas and Enterobacterium in chilled duck with Modified Atmosphere Packaging at 0 ℃,5 ℃, 10 ℃, 15 ℃ and20 ℃were fitted and then the Gompertz model was verified., the results preliminary showed that Gompertz model could predict the proliferation of Pseudomonas and Enterobacterium in different temperatures, and the maximum specific growth rate and the LPD values were obtained under different temperatures. Using square root model we described the relationships between the temperature and the maximum specific growth rate and the LPD.Higher the coefficient of determination R2 showed that square root model could effectively predict the influence of temperature changes on the maximum specific growth rate and LPD. Further, through the determination of corrosion control values, we constructed the shelf life prediction model of cold fresh duck with Modified Atmosphere Packaging, which based on the prediction of Pseudomonas and Enterobacterium at 0-20 ℃, respectively.7 ℃, 12 ℃ and17 ℃were used to verified the model,we found that there is a smaller relative error between the measured and predicted values, which showed that the shelf life prediction model based on microbial growth forecasts could effectively predict the shelf life of chilled duck products at 0-20 ℃.The effect of the temperature fluctuation, high temperature for short time and difference number of the initial bacteria on growth prediction model were studied.. The results indicated that the temperature fluctuation made the specific growth rate of Pseudomonas decreased, the lag phase prolonged; and the specific growth rate of Enterobacteriaceae prolonged and the lag phase decreased. Number of Pseudomonas and Enterobacter were not significantly affected by 30 ℃(30min)high temperature treatment. Under different storage conditions short term high temperature number of Pseudomonas and Enterobacter of duck breast were affected significantly. The increase number of the initial bacteria made the specific growth rate of Pseudomonas and Enterobacter prolonged and the lag phase decreased; The predicted value of Pseudomonas and Enterobacter by different initial colony number forecast and the measured value was not significant in 3-8 d.,which showed that difference number of the initial bacteria had a great influence on the growth prediction model. |
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