Amenu Desalegn, Bacha Ketema
Department of Biology, College of Natural and Computational Sciences, Wollega University, P.O. Box 395, Nekemte, Oromia, Ethiopia.
Department of Biology, College of Natural Sciences, Jimma University, P.O. Box 378, Jimma, Ethiopia.
Probiotics Antimicrob Proteins. 2024 Jun 10. doi: 10.1007/s12602-024-10272-w.
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.
本研究旨在评估从埃塞俄比亚吉马镇传统发酵乳制品中分离出的产细菌素乳酸菌对生乳的抗菌活性和生物保鲜能力。对产细菌素的乳酸菌进行了针对各种食源性病原体的抗菌活性测试，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，益生菌乳酸菌分离株对食源性病原体（大肠杆菌、金黄色葡萄球菌和单核细胞增生李斯特菌）具有抑制作用，抑菌圈范围为22.00±0.57至34.13±0.57。粪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的抑菌圈为34.13±0.57毫米。这些分离株还显示出与病原体的共聚集潜力，乳酸乳球菌分离株及其组合对所研究的病原体表现出最佳的共聚集能力。生物保鲜试验表明，假定的益生菌分离株（乳酸乳球菌JULABE35、粪肠球菌JULABE 23和戊糖片球菌JULABE05）能有效降低生乳中的单核细胞增生李斯特菌。7-8天后，用这些分离株诊断的牛奶样本中单核细胞增生李斯特菌完全减少。产细菌素乳酸菌对生乳的生物保鲜能力将牛奶在4℃储存的保质期延长至10天，而没有益生菌乳酸菌的牛奶样本保质期为6天。用益生菌和产细菌素分离株保存的牛奶样本显示出良好的近似分析结果，与没有产细菌素分离株保存的牛奶有显著差异。本研究中分离出的化学物质可作为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有潜在应用。
