Study On Spoilage Character Of Chilled Pork Under Different Package Conditions

With the advantage of delicious taste,safe,hygiene and nutritious of the chilled pork,it is gradually replacing the traditional frozen and flesh meat,and which will be a new consumption pattern that represent the future development direction of the production and consumption of the raw pork.Package as an important external environment factor,affect the diversity of the microorganism distribution and the shelf life of meat.So it is necessary to grasp the distribution and variation of the microbial of the chilled pork under different packaging and its effect on the quality.Besides finding out the common corruption index of the different packaging form can provide a theoretical basis for objectively reflecting pork spoilage process,and can also provide a technical support for safety control and monitoring system of meat.In this paper,molecular biology technique was used to study the changes in the structure of microbial of chilled pork in tray,vacuum and modified atmosphere package stored at 5°C.The change of the quality indicators and correlation analysis of the three package form were studied during the storage of the chilled pork.The common quality indicators which can reflect the change of the quality of different package form were also determined.The results showed that:(1)The microbial flora of tray,vacuum and modified atmosphere were varied during the storage.During the early period of the tray packaging,the bands were rich and the microbial flora was complex.And the diversity of microbial reduced with the storage time prolonged.The microbial flora of vacuum packaging were also complex in the early period,the bands of lactic acid bacteria were gradually bright,well the bands of B.thermosphacta were first weak then brighten.The lactic acid bacteria as well as B.thermosphacta were dominant spoilage bacteria at last.Well,the bands were few and weak of the modified atmosphere packaging at the early period,the bands of Enterobacter was always bright,and the pesusomonad and lactic acid bacteria were present until the end of the storage time.(2)The change of microbial number,biogenic amine,conductivity,p H and TVB-N value of the three packaging were different.(3)The correlation of quality indicators of the three packaging form was studied,the result showed that putrescine and pentamethylene diamine of tray packaging were significantly related to microbial number,p H and TVB-N value at 0.01 level,and Aw and conductivity were related to microbial number,p H and TVB-N value,remarkably;The putrescine,pentamethylene diamine,tyramine,a* and conductivity of the vacuum packaging were significantly related to microbial number,p H and TVB-N value as well as each other at 0.01level;Well,under the modified atmosphere packaging form significantly related to microbial number,p H and TVB-N value at 0.01 level were putrescine,pentamethylene diamine,tyramine,L* and conductivity,and b* was also significantly related to microbial number,p H and TVB-N value.So the correlation of quality indicators of the chilled pork under the three packaging form showed a big discrepancy.(4)The electronic nose fingerprint was applied to analysis the change of odor of chilled pork under different packaging form during the storage time.And from the result,something in common was found in the chilled pork spoilage process under the three packaging form.(5)Through the analysis of the quality indicators under the three packaging form,the putrescine,pentamethylene diamine and conductivity were significantly related to microbial number,p H and TVB-N value under different packaging form.So,except the normal microbial number,p H and TVB-N value,the putrescine,pentamethylene diamine and conductivity can also used to as the indicators of the spoilage of chilled pork,and the change of its number can reflect the process of the spoilage of chilled pork,objectively.