阿克苏地区异常生鲜乳中芽胞杆菌的分离鉴定

Isolation and identification of bacillus in abnormal raw milk in Aksu area

新疆南疆某乳品企业生产的生鲜乳偶尔会出现风味发酸、涨袋和产品货架期变短等问题,为了解该生鲜乳中是否存在芽孢杆菌感染及微生物数量超标,通过实验室常规纯培养方法对采集自该乳品企业两个奶牛场的8份异常生鲜乳样进行微生物指标检测和芽孢杆菌的分离纯化。将预处理后的奶样分别接种于PCA(37℃)、DTA(55℃)、MPC(37℃)琼脂培养基培养(48±2)h、MPC(37℃)琼脂培养基培养10 d,分别计算菌落、芽孢、嗜冷菌和耐热芽孢菌总数,并对不同形态单菌落进行分离纯化。经16S rDNA序列鉴定,从8份生鲜乳中分离出2株郭霍氏芽孢杆菌、1株枯草芽孢杆菌、1株类芽孢杆菌;8份生鲜乳中嗜冷菌总数均超过食品安全国家标准。该试验结果有助于企业分析污染源,建立科学、精确的防控微生物污染体系,为保证产品质量奠定基础。

The raw milk produced by a dairy enterprise in southern Xinjiang occasionally has problems such as sour flavor,bag swelling,and shortened product shelf life.Using the pure culture method,8 abnormal raw milk samples collected from the two dairy farms of the dairy enterprise were tested for microbial indicators and Bacllus was isolated and purified.The pretreated milk samples were inoculated in PCA(37℃),DTA(55℃),MPC(37℃)agar medium for(48±2)h,and MPC(37℃)agar medium for 10d.The total number of spores,psychrophilic bacteria and heat-resistant spore bacteria,and single colonies of different forms were isolated and purified.According to the 16S rDNA sequence identification,2 strains of Bacillus kohlrabi,1 strain of Bacillus subtilis and 1 strain of Paenibacillus were isolated from 8 fresh milks;the total number of psychrophilic bacteria in 8 fresh milks exceeded the national food safety standard.The test results wil help enterprises analyze pollution sources,establish a scientific and accurate microbial pollution prevention and control system,and lay a foundation for ensuring product quality.