屠宰过程中猪胴体表面及环境的细菌菌相分析

Investigation of Bacterial Flora on the Surface of Pig Carcasses and in the Environment during Slaughter

应用传统培养方法结合高通量测序技术分析屠宰分割过程中猪胴体表面微生物污染情况,并对屠宰车间刀具和分割车间接触面进行细菌菌落计数,以确定屠宰分割过程中的关键污染环节。结果表明:测序共得到881458个有效序列,864个可操作分类单元,样品共注释到了22门、33纲、79目、162科、382属和613种的微生物信息。变形菌门(Proteobacteria)、拟杆菌门(Bacteroidota)和厚壁菌门(Firmicutes)为优势菌门,不动杆菌属(Acinetobacter)和气单胞菌属(Aeromonas)为主要的优势菌属。屠宰分割过程中群落多样性的排序为放血>脱毛>分割>开膛>冲淋>冷却,冷却环节胴体表面的微生物多样性最低,分割后有所增加,表明分割是关键污染环节。传统微生物计数与测序的结果一致,从脱毛到冷却环节,猪胴体表面各类微生物数量呈下降趋势,分割后显著上升;分割车间各接触面菌落总数平均为6.11(lg(CFU/cm^(2))),高于屠宰车间刀具(平均为4.86(lg(CFU/cm^(2)))),表明分割车间各接触面是关键污染源,进一步证明猪胴体分割环节为关键污染环节。

The combination of the traditional culture-dependent method and high-throughput sequencing was used to investigate the level of microbial contamination on the surface of pig carcasses during the slaughter and segmentation process.Meanwhile,the number of microbial colonies on the slaughter knives and the contact surfaces of the segmentation workshop were counted to identify the key pollution links in the slaughter and segmentation process.The results showed that a total of 881458 valid sequences and 864 operational taxonomic units(OTUs)were obtained by sequencing.The samples were annotated to 22 phyla,33 classes,79 orders,162 families,382 genera and 613 species of microorganisms.Proteobacteria,Bacteroidota and Firmicutes were the dominant bacterial phyla.Acinetobacter and Aeromonas were the major dominant bacterial genus.The bacterial community diversity during the slaughter and segmentation process was in decreasing order as follows:bleeding>dehairing>segmentation>evisceration>final wash>chilling.The microbial diversity on the carcass surface was the lowest in the chilling stage,and increased after segmentation,indicating that the segmentation stage was the key contamination link.The results of traditional microbial counting were consistent with the results of sequencing.From dehairing to chilling,the number of each bacterial group on the surface of pig carcasses was decreased,but increased significantly after segmentation.The total number of bacterial colonies on the carcass surfaces in the segmentation workshop was 6.11(lg(CFU/cm^(2)))on average,which was higher than that on the slaughter knives(4.86(lg(CFU/cm^(2)))on average),indicating that the contact surfaces of the segmentation workshop were the key pollution source,and so the segmentation link was the key pollution link.