| In order to analyze the corruption microorganisms of native-chicken soup, streak plate separation method was used to classify and identify the primary bacterial flora according to colony characters, bacterial shape, physio-biochemical tests as well as16S rDNA sequence analysis. The results indicated that the primary bacteria in native-chicken soup were Enterobacter aerogenes, Pantoea agglomerans, Pseudomonas, Pseudomonas fluorescens, Bacillus cereus and Paenibacillus.The antibacterial activity of fructus mume extract and the effect of pH value, temperature on the antibacterial activity were studied in this paper. And its major antibacterial compositions were preliminary analyzed by thin layer chromatography-bioautography and high performance liquid chromatography. The results showed that the extract of fructus mume has strong inhibition effect on Bacillus cereus, Pseudomonas, and so on. The minimum inhibitory concentration (MIC) was between2.5and5.5mg/mL, the optimum medium pH was5～6, and it was stable for temperature. Developing agent was chloroform:methanol=5:1(v:v). Compared with citric acid and alkali neutralized fructus mume, organic acids were initially identified as its major antibacterial composition. The result of high performance liquid chromatography showed that the major antibacterial composition of fructus mume extract was citric acid.Bacillus cereus was used as a target to study the possible antibacterial mechanism of the fructus mume extract by electron microscopy, SDS-PAGE and by the measurement of electrical conductivity, alkaline phosphatase (AKP) content and proteins released. The results indicated that fructus mume extract could damage the structure of cell wall and cell membrane, which resulted in the increase of permeability of cell membrane and release of cell components. Fructus mume alcohol extract could also affect the synthesis of bacteria protein, blocking the protein expression in bacteria.Fructus mume extract, Nisin and lysozyme were used to combine in order to get stronger inhibited effect. The optimum proportion was25μL/100mL fructus mume extract,0.03%lysozyme,0.03%nisin. And its applied research in native-chicken soup was studied, taking total bacteria counts, TVB-N value, TBA value, pH value and sense organ evaluation as the index to appraise its anticorrosion effect. The results showed that the compound antiseptic could prolong the shelf-life of native-chicken soup four days, and have significantly (P<0.05) antimicrobial effect compared with the control. |
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