不同乳粉中优势芽孢杆菌的检测与分析

Detection and Analysis of Dominant Bacillus in Different Milk Powder

为研究乳粉中菌落总数和芽孢杆菌种属的组成,分析乳粉在运输、销售、贮藏过程中的风险菌,该研究以国内某品牌的6种不同产地的乳粉为研究对象,采用传统的平板培养方法结合非热处理和热处理两种处理方式对6种乳粉中菌落总数、芽孢菌数量进行统计分析,并通过形态学、革兰氏染色镜检结合16S rDNA鉴定样品中的优势芽孢杆菌。6种样品中的菌落总数主要在10^(2)~10^(3) CFU/g范围内,均小于国家标准5.0×10^(4) CFU/g,符合GB 19644—2010的安全范围。芽孢杆菌在6种样品中均有检出,检出值在10^(1)~10^(2) CFU/g范围内。根据形态学观察分类得到7种革兰氏阳性芽孢杆菌,经16S rDNA和BLAST比对鉴定,芽孢杆菌分别为Bacillus licheniformis、Bacillus amyloliquefaciens、Bacillus circulans、Bacillus paramycoides、Bacillus subtilis、Bacillus velezensis和Bacillus cereus。不同乳粉的菌落总数符合国家标准要求范围,但其中芽孢杆菌种类繁多,是乳粉中微生物的主要优势菌。该研究为我国乳粉质量的监督与监测提供了数据支撑,为乳粉的安全风险评估提供了科学依据。

To study the total bacterial count and the composition of Bacillus species in milk powder and analyze the risk bacteria during the transportation,sales and storage of milk powder,in this study,with six kinds of milk powder from different places of origin of a domestic brand as the research object,the total bacterial count and the number of Bacillus in six kinds of milk powder are statistically analyzed by traditional plate culture method combined with non-heat treatment and heat treatment,and the dominant Bacillus in the samples is identified by morphology,Gram staining microscopy combined with 16S rDNA.The total bacterial count in the six samples is mainly in the range of 10^(2)~10^(3) CFU/g,which is all less than the national standard of 5.0×10^(4) CFU/g,and meets the safety range of GB 19644—2010.Bacillus is detected in all the six samples,with the detection value in the range of 10^(1)~10^(2) CFU/g.According to morphological observation,seven kinds of Gram-positive Bacillus are classified.After 16S rDNA and BLAST comparison,Bacillus is identified as Bacillus licheniformis,Bacillus amyloliquefaciens,Bacillus circulans,Bacillus paramycoides,Bacillus subtilis,Bacillus velezensis and Bacillus cereus respectively.The total bacterial count of different milk powder meets the requirements of national standards,but there are many kinds of Bacillus,which are the main dominant bacteria in milk powder.This study has provided data support for supervision and monitoring of milk powder quality in China and scientific basis for safety risk assessment of milk powder.