巴氏灭菌即食小龙虾特定腐败菌的16S rRNA鉴定

Molecular identification of specific spoilage organisms from ready-to-eat crayfish sterilized by pasteurization

为研究巴氏灭菌即食小龙虾食品(采用铝箔袋真空包装)的腐败菌菌相组成,采用传统分离纯化、菌落外形观察及细菌形态学镜检,并结合16S rRNA分子生物学手段和限制性内切酶消化分析的方法,选用处于货架期末(已胀袋)的小龙虾样品进行了鉴定试验。结果共从样品中分离到82株典型可培养菌,其中优势菌为苏云金芽孢杆菌(70株,占85.37%)和粘质沙雷氏菌(7株,占8.54%),另有非优势菌5株(6.09%)。研究表明,产芽孢杆菌是该小龙虾食品的优势腐败菌,常规巴氏灭菌很难将其彻底杀灭,应采用其他更有效的灭菌方法或者使用有较强针对性的防腐剂,从而延长该类食品的货架期。

To examine the spoilage microflora from aluminium-foil-vacuum-packed ready-to-eat crayfish sterilized by conventional pasteurization, species identification was made by amplified ribosomal DNA restriction analysis （ARDRA） together with 16S rRNA sequence analysis. At the same time, traditional methods of isolation, colony appearance observation and microscopic examination of the bacteria were also employed to confirm the identification. As the result, 82 typical culture-dependent strains were isolated from the ready-to-eat crayfish samples, including dominant species of Bacillus thuringiensis 70 strains （85.37%）, Serratia marcescens 7 strains （8.54%） and minority group 5 strains （6.09%）. The results indicated that bacillus is the specific spoilage organism （SSO） which is hard to be eliminated thoroughly through conventional pasteurization. Therefore, more efficient sterilization methods or targeted preservatives should be adopted to prolong the shelf life during the ready-to-eat crayfish processing and storage.