[关键词]
[摘要]
本研究对涨袋泡椒凤爪产品中的主要腐败菌及其生长特性进行了分析。采用传统的分离培养方法,筛选出主要的污染菌群,通过美兰染色镜检对细胞形态进行检测,利用26S rDNA D1/D2区序列测定及系统发育分析对分离菌株进行鉴定,采取ERIC-RAPD技术对分离菌株的分子遗传多态性进行分析,最后对优势菌株的生长特性进行研究。结果表明:从涨袋产品中共分离出40株酵母菌,分别编号为PJ1~PJ40,镜检发现所有菌株的细胞形态相同,均为椭圆形。经分子鉴定发现所分离菌株都为解脂耶氏酵母,且为两个基因分型,说明解脂耶氏酵母是该产品中的一种优势腐败菌,且污染源不同。同时,研究发现解脂耶氏酵母PJ1的最适生长pH值为4.5、最适生长温度为25 ℃、并且NaCl浓度的升高对该菌的生长起到一定的抑制作用。
[Key word]
[Abstract]
This study analyzed the dominant spoilage bacteria present in chicken feet with pickled peppers packed in inflated bags and analyzed their growth characteristics. Traditional isolation and culture methods were employed to screen the dominant spoilage bacteria; cell morphology was observed by microscopy after methylene blue staining, and the isolated strains were identified by phylogenetic analysis of the D1/D2 region of 26S rDNA sequences. Enterobacterial repetitive intergenic consensus-random amplified polymorphic DNA (ERIC-RAPD) analysis was used to characterize the genetic variation of the isolated strains. The growth characteristics of the dominant strains were also studied. Forty strains of yeast, numbered PJ1-PJ40 were isolated from the chicken feet product, and microscopic images showed that all strains had the same morphological characteristics; all were oval in shape. Molecular identification showed that all strains belonged to two genotypes of Yarrowia lipolytica, indicating that Y. lipolytica was the dominant spoilage bacteria in this product, originating from several sources of contamination. The optimal pH and temperature for growth of Y. lipolytica were found to be 4.5 and 25 ℃, respectively; increasing the NaCl concentration had an inhibitory effect on the growth of these bacteria.
[中图分类号]
[基金项目]
国家农业科技成果转化资金(2012GB2C100165);江苏省农业科技自主创新资金(CX(12)3082)