切达干酪成熟过程中细菌群落结构的分析

Analysis of Bacterial Community Structure of Cheddar Cheese During Ripening

【目的】研究切达干酪成熟过程(6℃,180 d)中细菌群落的动态变化和组成多样性。【方法】用选择性培养基计数,并对菌落进行总DNA提取和PCR-DGGE分析。【结果】随着切达干酪成熟时间的延长,发酵剂嗜热链球菌的数量显著下降,非发酵剂乳杆菌种类明显增多。对DGGE图谱条带重扩增、测序,并进行BLAST对比分析得出,增多的乳杆菌主要为植物乳杆菌、干酪乳杆菌、副干酪乳杆菌、瑞士乳杆菌和鼠李糖乳杆菌。【结论】切达干酪成熟过程中细菌群落的组成和数量处于动态变化之中,PCR-DGGE用作选择性培养基计数菌落的后续分析,可以明确培养基上长出的菌落属于哪一种或哪一亚种,进而客观和真实地分析出干酪内细菌群落的组成和动态变化。

[ Objective] The diversity and dynamics of cheddar cheese bacterial community were studied at 6℃ for 180 d. [Method] The selective medium was used for bacteria isolation and counting, then the colonies in the plate were collected and the total DNA was extracted for polymerase chain reaction （PCR）-DGGE analysis. [Result] As the cheddar cheese ripening, the population of the starter Streptococcus thermophilus decreased significantly, to the contrary, the species of non-starter Lactobacillus had an obvious increase. The amplification, sequencing, and BLAST comparative analysis of DGGE profiles bands showed that the main increasing Lactobacillus were Lactobacillus plantarum, Lactobacillus casei. Lactobacillus paracaseL Lactobacillus helveticus and Lactobacillus rhamnosus. [Conclusion] Dynamic changes of bacterial community composition and quantity exist in cheddar cheese ripening period. PCR-DGGE as a follow-up analysis of selective medium analysis could define the kind of species and subspecies, and then could help us to get an objective and realistic analysis of the composition and dynamics of cheese bacterial community.