CJ Foods R&D, CJ Cheiljedang, Seoul 152-051, Korea.
J Microbiol Biotechnol. 2013 Jan;23(1):40-6. doi: 10.4014/jmb.1210.10001.
A variety of nuruk were collected from various provinces in Korea, and their microflora profiles were analyzed at the species level. A total of 42 nuruk samples were collected and when the viable cell numbers in these nuruk were enumerated, the average cell numbers of bacteria, fungi, yeast, and lactic acid bacteria from all nuruk were 7.21, 7.91, 3.49, and 4.88 log CFU/10 g, respectively. There were no significant differences in viable cell numbers of bacteria or fungi according to regions collected. Bacillus amyloliquefaciens and B. subtilis were the predominant bacterial strains in most samples. A significant portion, 13 out of 42 nuruk, contained foodborne pathogens such as B. cereus or Cronobacter sakazakii. There were various species of lactic acid bacteria such as Enterococcus faecium and Pediococcus pentosaceus in nuruk. It was unexpectedly found that only 13 among the 42 nuruk samples contained Aspergillus oryzae, the representative saccharifying fungi in makgeolli, whereas a fungi Lichtheimia corymbifera was widely distributed in nuruk. It was also found that Pichia jadinii was the predominant yeast strain in most nuruk, but the representative alcohol fermentation strain, Saccharomyces cerevisiae, was isolated from only 18 out of the 42 nuruk. These results suggested that a variety of species of fungi and yeast were distributed in nuruk and involved in the fermentation of makgeolli. In this study, a total of 64 bacterial species, 39 fugal species, and 15 yeast species were identified from nuruk. Among these strains, 37 bacterial species, 20 fungal species, and 8 yeast species were distributed less than 0.1%.
从韩国各地收集了多种 nuruk，并在物种水平上分析了它们的微生物区系图谱。共收集了 42 个 nuruk 样本，当对这些 nuruk 中的活菌数进行计数时，所有 nuruk 中的细菌、真菌、酵母和乳酸菌的平均细胞数分别为 7.21、7.91、3.49 和 4.88 log CFU/10 g。根据采集地区的不同，细菌或真菌的活菌数没有显著差异。解淀粉芽孢杆菌和枯草芽孢杆菌是大多数样品中主要的细菌菌株。有 13 种 nuruk 含有食源性致病菌，如蜡样芽胞杆菌或阪崎克罗诺杆菌。nuruk 中还存在各种乳酸菌，如屎肠球菌和戊糖片球菌。出人意料的是，在 42 个 nuruk 样本中，只有 13 个含有米酒类糖化真菌米曲霉，而广泛分布于 nuruk 中的是光柄菇属真菌。还发现，毕赤酵母是大多数 nuruk 中主要的酵母菌株，但代表性的酒精发酵菌株酿酒酵母仅从 42 个 nuruk 中的 18 个中分离出来。这些结果表明，各种真菌和酵母在 nuruk 中分布广泛，并参与了 makgeolli 的发酵。在这项研究中，从 nuruk 中总共鉴定出 64 种细菌、39 种真菌和 15 种酵母。在这些菌株中，37 种细菌、20 种真菌和 8 种酵母的分布比例低于 0.1%。
