Safety Evaluation and Probiotic Characteristics of Enterococcus faecalis EF-ZA1107-06

Enterococcus was isolated from 1-month-old baby feces in Guangzhou and the strain was identified as Enterococcus faecalis by molecular biology and was named Enterococcus faecalis EF-ZA1107-06. The strain was evaluated for its safety and some probiotic potential properties. The results show that the strains does not produce nitroreductase and has no hemolytic activity. It is highly sensitive to many kinds of antibiotics, does not contain plasmids, and has no acute toxicity to the mice. EF-ZA1107-06 was proved as an edible safe strain. High tolerance was observed by EF-ZA1107-06 strain for simulated gastrointestinal condition. After continuous exposure to simulated saliva for 10 min, simulated gastric juice for 2 h, and simulated intestinal juice for 3 h, the survivability was still above 65%, which was comparable to that of Lactobacillus rhamnosus GG (LGG). EF-ZA1107-06 can inhibit the growth of Escherichia coli, Salmonella, Pseudomonas aeruginosa, Candida albicans, Listeria monocytogenes, Staphylococcus aureus. The inhibitory effect of its supernatant on Escherichia coli is significantly stronger than that of LGG. The supernatant, lysate and suspension of the EF-ZA1107-06 strain all have certain DPPH free radical scavenging capacity and hydroxyl radical scavenging ability. DPPH free radical scavenging rate of 2×10⁸ CFU/mL EF-ZA1107-06 suspension is (93.16±0.17)%. The hydroxyl radical scavenging rate of the suspension is (90.48±1.12)%. The cholesterol removal rate of 2×10⁸ CFU/mL EF-ZA1107-06 fermentation broth is (44.29±0.30)%. The EF-ZA1107-06 strain has high cholesterol scavenging ability.