An in-vitro assessment of antifungal and antibacterial activity of cow, camel, ewe, and goat milk kefir and probiotic yogurt

Abstract

In the present study, the antimicrobial activity of kefir and probiotic yogurt produced from cow, camel, ewe, and goat milk on pathogenic bacteria (Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella enterica) and fungi (Aspergillus niger, Penicillium sp., and Fusarium sp.) during 20-day storage period at 4 oC was investigated. The carbohydrate content and pH of milk samples decreased during the fermentation process to produce probiotic yogurt and kefir, also the acidity increased significantly. The results revealed that kefir samples had stronger antifungal and antibacterial effect than probiotic yogurt samples. Among kefir samples, the ewe and cow milk kefir expressed the highest and the lowest antimicrobial activity, respectively. A. niger, S. aureus, and L. monocytogenes were the most sensitive and Penicillium sp. and E. coli were the most resistant microorganisms against treatment by kefir and probiotic yogurt.