Abstract：
This study aimed to assess the antibacterial activity and bio-preservation capability of bacteriocin-producing LAB isolated from Ethiopian traditional fermented dairy products in raw milk from Jimma town. Bacteriocin-producing LAB were tested for their antimicrobial activity against various foodborne pathogens, including Staphylococcus aureus, Escherichia coli, Listeria monocytogenes, and Salmonella typhimurium. The results showed that probiotic LAB isolates inhibited foodborne pathogens (E. coli, S. aureus, and L. monocytogenes), with inhibition zones ranging from 22.00 ± 0.57 to 34.13 ± 0.57. Enterococcus faecium and Lactococcus lactis demonstrated possible antagonistic effects against E. coli, while Pediococcus pentosaceus had a 34.13 ± 0.57 mm inhibitory zone against Pseudomonas aeruginosa. The isolates also showed co-aggregation potential with the pathogens, with Lactococcus lactis isolates and their combinations demonstrating the best co-aggregation capabilities against the investigated pathogens. The bio-preservative assay showed that putative probiotic isolates (L. lactis JULABE35, E. faecium JULABE 23, and P. pentosaceus JULABE05) were efficient in decreasing Listeria monocytogenes in raw milk. After 7-8 days, milk samples diagnosed with these isolates showed complete reduction of Listeria monocytogenes. The bio-preservation capability of bacteriocin-producing LAB on raw milk extended the shelf life of milk at 4 °C storage for ten days, compared to six days for milk samples without probiotic LAB. The milk samples preserved with probiotic and bacteriocin-producing isolates showed good proximate analysis, showing significant variation with milk kept without bacteriocin-producing isolates. The isolated chemicals employed in this study can be used as food additives or food preservatives, indicating potential applications in Ethiopian traditional fermented dairy products.
摘要：
这项研究旨在评估从埃塞俄比亚传统发酵乳制品中分离的产生细菌素的LAB在Jimma镇的原料奶中的抗菌活性和生物保存能力。测试了产生细菌素的LAB对各种食源性病原体的抗菌活性，包括金黄色葡萄球菌,大肠杆菌,单核细胞增生李斯特菌,和鼠伤寒沙门氏菌.结果表明，益生菌LAB分离株抑制食源性病原体(E。大肠杆菌金黄色葡萄球菌，和单核细胞增生李斯特菌），抑制区范围为22.00±0.57至34.13±0.57。屎肠球菌和乳酸乳球菌对大肠杆菌表现出可能的拮抗作用，而戊糖片球菌对铜绿假单胞菌有34.13±0.57毫米的抑制区。分离株还显示出与病原体的共同聚集潜力，乳酸乳球菌分离株及其组合证明了针对所研究病原体的最佳共聚集能力。生物防腐剂分析表明，推定的益生菌分离株(L.乳酸JULABE35，屎肠球菌JULABE23和戊糖假单胞菌JULABE05）可有效降低原料乳中的单核细胞增生李斯特菌。7-8天后,诊断为这些分离物的牛奶样本显示单核细胞增生李斯特菌完全减少。生产细菌素的LAB在原料奶上的生物保存能力延长了牛奶在4°C储存10天的保质期，与不含益生菌LAB的牛奶样品相比，为6天。用产生益生菌和细菌素的分离物保存的牛奶样品显示出良好的近似分析，在没有产生细菌素的分离株的情况下，牛奶显示出明显的变化。本研究中使用的分离化学物质可用作食品添加剂或食品防腐剂，表明在埃塞俄比亚传统发酵乳制品中的潜在应用。
