Antimicrobial Activity of Some Spices against Potential Probiotic Bacteria Isolated from Raw Sheep Milk

Abstract

Probiotics have several beneficial effects for human health. These probiotic bacteria in the human gut prevent harmful bacteria from adhering to the intestinal mucosa. Some studies report that the secondary metabolites of spices have an effect on common pathogenic bacteria, but their impact on beneficial probiotic bacteria is still not entirely understood. In this view, the present study aimed at the isolation of probiotic microorganisms from sheep milk, the screening of these organisms for a few probiotic characterizations, and an evaluation of the effect of several spices on the development of probiotic bacteria. A total of 26 bacterial strains were isolated from raw sheep milk samples. Five goat isolates, SMH12, SMH15, SMB16, SMB24, and SMB26, displayed acid and bile resistance, responses to simulated stomach and duodenum passage, and antibiotic susceptibility. An antibacterial activity study of these potential probiotic bacterial isolates revealed that bacterial isolate SMB16 was more effective at inhibiting the growth of both gram-positive and gram-negative pathogenic bacteria, viz., Escherichia coli (MTCC118), Staphylococcus aureus (MTCC7443), Pseudomonas aeruginosa (MTCC424), Listeria monocytogenes (MTCC657), and Salmonella typhimurium (MTCC733). Screening of the antimicrobial activity of different spices, such as garlic (Allium sativum), ginger (Zingiber officinale), and onion (Allium cepa), against selected probiotic bacterial isolates. The bacterial isolate SMB16 was tolerant of these spices, while other isolates were sensitive. This strain, SMB16, was identified as Enterococcus hirae by 16S rRNA gene sequence analysis.