College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, Shaanxi, 712100, China.
Department of Biological Systems Engineering, Washington State University, Pullman, WA, 99164-6120, USA.
Sci Rep. 2017 Aug 30;7(1):10054. doi: 10.1038/s41598-017-10138-y.
Walnuts (Juglans regia) have been associated with foodborne illness outbreaks in recent years. Thus, the purpose of this study was to investigate the distribution of bacteria on in-shell walnut surfaces from six representative provinces in China. The bacterial populations on walnut surfaces were investigated by high-throughput sequencing based on the bacterial 16 S rRNA hypervariable region V4. Twenty-eight samples were collected from fourteen regions in six provinces and harvested in different periods (the fresh in 2016 and the old in 2015). Proteobacteria was the most dominant phylum in all samples except for XJ1. In XJ1, and the most abundant phylum was Cyanobacteria, which also accounted for a large proportion of the abundance in YN1, YN11, XJ2 and SC11. In addition, Firmicutes and Actinobacteria were also the abundant phyla in the given samples. Some genera belonging to the opportunistic pathogens were detected, such as Pseudomonas, Acinetobacter, Burkholderia and Bacillus. The results revealed that the composition and abundance of bacterial consortiums on walnut surfaces varied among the geographical sites where they were harvested. Moreover, the storage time of samples also had impact on the abundance of bacteria. This study may provide a better understanding of the bacterial communities' diversity on in-shell walnut surfaces.
近年来，胡桃（Juglans regia）已与食源性疾病爆发有关。因此，本研究的目的是调查中国六个代表性省份带壳核桃表面细菌的分布情况。通过基于细菌 16S rRNA 高变区 V4 的高通量测序，研究了核桃表面的细菌种群。从六个省份的十四个地区采集了 28 个样本，并在不同时期（2016 年新鲜样本和 2015 年老样本）进行了采集。除 XJ1 外，所有样本中最主要的菌门都是变形菌门。在 XJ1 中，最丰富的菌门是蓝藻门，在 YN1、YN11、XJ2 和 SC11 中也占很大比例。此外，厚壁菌门和放线菌门也是这些样本中的丰富菌门。检测到一些属于机会性病原体的属，如假单胞菌、不动杆菌、伯克霍尔德菌和芽孢杆菌。结果表明，收获地的地理位置不同，核桃表面细菌联合体的组成和丰度也不同。此外，样本的储存时间也对细菌的丰度有影响。本研究可能有助于更好地了解带壳核桃表面细菌群落的多样性。
