The interaction of the variety microorganisms is the important way to the proper flavor of Sichuan bacon and Sichuan sausage under natural conditions. It's necessary to study the micro-ecosystem of fermented meat for improving traditional processing technology and controlling product quality.Sichuan bacon and Sichuan sausage were used as the experimental materials in this study. The change of micro- ecosystem was analyzed during the processing and storage of Sichuan sausage and Sichuan bacon with culture-dependant method and RAPD molecular marker technology. Some factors were analyzed by comparison, such as microbial community DNA sequence diversity index, richness index and evenness index of samples by analyzing electrophoresis picture with gel imaging system and image analysis software. The major researches and experimental results were as follows:1. The dominant microorganisms in Sichuan bacon were lactic acid bacteria and Staphylococcus. Smoking had significant effect on microflora especially yeast. The microbial property displayed that the predominant microorganisms in Sichuan sausage were Staphylococcus, Micrococcus and Lactobacillus. During the storage, the changes of counts of yeasts and moulds were few.2. DNA was extracted from microorganisms in fermented meat by SDS (sodium dodecyl sulfate) method, lysozyme method, benzyl chloride method, bacteria DNA extraction kit method and improved CTAB(cetyl trimethyl ammonium bromide) method respectively. Results showed that the benzyl chloride method was the most suitable for extracting genomic DNA from microorganisms in fermented meat.3. Single factor gradient method was carried out to optimize the reaction system of RAPD-PCR. The results showed that, in 25μl RAPD-PCR reaction system of total microbial from fermented meat, the most suitable concentration of MgCl2, dNTPs, primer,template DNA, Taq DNA polymerase were 2.5 mmol/L,0.15 mmol/L,15 pmol 50 ng and 1.0 U respectively.4. The richness, abundance index correction, diversity index and evenness index of the microbial community DNA sequence of Sichuan bacon and Sichuan sausage were changed with storage time. The abundance index was to a maximum value after 30d, the variation trend of amendment richness and abundance index was consistent. There was some difference between bacon and sausage in the variation and magnitude of diversity index and evenness index and microbial community DNA sequence. The abundance index was to a maximum value and the evenness index is the highest during the smoked days after 30 d.5. In comparison with the results from classic microbiological methods reported, the results from RAPD were not completely consistent. The microbial diversity of Sichuan sausage and Sichuan bacon during the processing and storage by these two methods were inconsistent. |