小米乳酸菌发酵饮料胀罐微生物的分离及鉴定

目的 对小米乳酸菌饮料胀罐微生物进行分离和菌株鉴定,并对所分离菌株的产气特性进行研究。方法 使用孟加拉红琼脂培养基、营养肉汤琼脂培养基和改良MRS琼脂培养基对小米乳酸菌饮料胀罐微生物进行分离和纯化,根据菌落形态观察、菌体形态观察、16S rRNA 序列分析并结合基质辅助激光解析/电离飞行时间质谱(ALDI-TOF MS)技术对分离菌株进行鉴定。最后将分离菌株接种到无菌小米乳酸菌饮料产品中,培养观察产气现象。结果 共分离出6株细菌,编号为B001、B002、B003、B003、B005、B006,菌种鉴定结果均为副干酪乳杆菌(Lactobacillus paracasei),6株细菌均具有产气现象。结论 副干酪乳杆菌是引起本研究产品胀罐的主要原因。

Isolation and identification of spoilage microorganisms in swollen canned millet beverage fermented by lactic acid bacteria

Objective To separate and identify the spoilage microorganisms in swollen canned millet beverage fermented by lactic acid bacteria, and study the gas production of the isolated strains. Methods The spoilage microorganisms in swollen canned of the millet lactic acid bacteria fermented beverage were isolated and purified using Bangladeshi red agar medium, nutrient agar medium and modified MRS agar medium. The isolated strains were identified based on colony morphology observation, thallus morphology observation, 16S rRNA sequence analysis and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). Finally, the isolated strains were inoculated into the sterilized millet lactic acid bacteria beverage products, and cultured to observe the gas production phenomenon. Results A total of 6 strains of bacteria were isolated, numbered B001, B002, B003, B004, B005 and B006, all of which were identified as Lactobacillus paracasei, and all of the 6 strains were aerogenic. Conclusion Lactobacillus paracasei is the main cause of the product swollen can in this study.