本文以豆汁源屎肠球菌DZ为研究对象，从生长曲线、产酸能力、产粘能力及模拟人体胃肠道耐受性等方面探究其特性；通过吲哚实验，溶血实验，硝酸还原酶检测等实验探究其安全性，并进一步探究其发酵产品的安全性。结果表明，屎肠球菌DZ在1 h-4 h时菌落生长较快；在pH 3.0的人工胃液中可存活，之后进入肠道可增殖；豆汁接菌发酵16 h时，酸度值达43.69 °T，接菌发酵的豆汁酸度值差异极显著（p<0.01）；发酵时间为16 h时，粘度值达5.50 mPa·s且差异极显著（p<0.01）；在安全性探究实验中，硝酸还原酶检测及吲哚实验均为阴性，溶血性实验表明屎肠球菌DZ为γ-溶血；其发酵产品均未检出黄曲霉毒素、呕吐毒素等有害物质。结论说明，屎肠球菌DZ具备在极低pH值情况下存活的能力，产酸能力良好，且具备一定的产粘能力；该菌不分解色氨酸，不溶血，其代谢产物中不含硝酸还原酶，具有一定安全性。

The features of growth curve, acid-producing capacity, viscosity-producing capacity and stimulated human gastrointestinal tolerance of Enterococcus faecium DZ from fermented soya-bean milk were studied. The safety of Enterococcus Faecium DZ was explored using indole test, hemolysis test and nitrate reductase assay, and the safety of its fermented product was further investigated. The results showed that the colony growth of Enterococcus faecium DZ was rapid in 1 h-4 h. It could survive in simulated gastric juice with pH of 3.0, and then enter the intestine for proliferation. The acidity of fermented soya-bean milk by bacterial inoculation for 16 h was 43.69 °T. The acidity of fermented soya-bean milk by bacterial inoculation presented a significant difference (p<0.01). After fermentation for 16 h, the viscosity was 5.50 mPa·s and its difference was extremely significant (p<0.01). In the exploration of safety, nitrate reductase assay showed negative results. Indole test presented negative results. Hemolysis test showed that Enterococcus faecium DZ was γ-hemolysis. The results demonstrates that Enterococcus faecium DZ has the capacity to survive at very low pH, good acid-producing capacity, and certain viscosity-producing capacity; it does not decompose tryptophan, does not hemolyze, and its metabolites does not contain nitrate reductase, which has certain safety.

北京市教委科技项目（KM201812448001）；万人计划教学名师特殊支持项目（20181215）；教育部食品营养与安全应用技术协同创新中心（XM-16-H23）；北京市财政支持特高校建设专项（PXM2020-157102-000025）