摘要:  随着我国经济发展，超市和连锁企业的逐步推广，质量更好，更加健康的冷鲜肉也逐步占领了老百姓的餐桌，走进千家万户。本文研究冷鲜肉在储存过程中的菌群变化，目的在于更好的保证其品质、延长其货架期，为其长期储存提供新的思路。实验方法使用酚氯仿异戊醇法提取冷鲜肉中菌群的基因组DNA，并通过PCR扩增及DGGE电泳技术探讨其随保存时间延长，菌群结构变化情况。通过努力，实验成功扩增了菌群基因组DNA，为230bp，DGGE电泳结果发现，DGGE分子指纹图谱上条带存在显著的差异，用bionumberics软件分析DGGE结果，发现新鲜样本和第一天样本的相似度最高，为0.97，其次是第三天和第四天，为0.86，而第二天同第三天、第四天相比有下降，为0.78，表明冷鲜肉在储存过程中有的菌种一直存在，并且还不断有新的菌种出现，但是当时间延长一定时间后，菌群结构趋于稳定。

关键词：菌群结构； 基因组DNA ； PCR扩增技术； 变性梯度凝胶电泳

Abstract：The chilled meat which has better quality and more healthy is gradually occupied the dinning-tables of the common people and entered every household during the economic development of our country and the gradual popularization of the supermarkets and chain enterprises. This report is focus on researching the changing law of Flora structure in chilled meat in process of storage in order to better ensure its quality, extend its shelf life and provide new thinking for long-term storage. [Method] The changing law of Flora structure in chilled meat sample in process of storage with the increase of time was studied after extracting Genomic DNA, PCR amplification technologies and Denaturing gradient gel electrophoresis（DGGE). [Result] after Gene amplification, the strip of the Denaturing gradient gel electrophoresis Fingerprint show significant differences. To use the bionumberics software analyses the results of Denaturing gradient gel electrophoresis（DGGE),it found that the first day has very high similarity with the fresh sample by 0.97, after that is the similarity of third day and the fourth day are the second higher by 0.86. However, for the second day, its similarity comes down when compared with the third day and the fourth day by 0.78.The results illustrated that some of the bacterias of chilled meat in process of storage are exist, also there are some of the new bacterias appeared but the Flora structure tend to stabilize when time extension. But it is needed to recover and test in order to know the specific kinds of the bacterias. 

Key words：Flora structure; genome DNA ; PCR amplification technologies; gradient gel electrophoresis（DGGE）