Antimicrobial effects of the essential oils of basil populations (Ocimum basilicum l.) in Serbia

Since pathogen microorganisms can be found in food, natural antimicrobial compounds, like ethereal oils, are of great interest in food preservation. The aim of the study was to evaluate antimicrobial activity of ethereal oils extracted from 10 basil species in Serbia against food borne microorganisms. In studying antimicrobial effects of essential oils the following microorganisms were used: Gram negative bacteria-Escherichia coli ATCC 25922 and Salmonella enteritidis ATCC 31806, Gram positive bacteria-Bacillus cereus ATCC 11788 and Staphylococcus aureus ATCC 25923, yeasts-Candida albicans ATCC 24433 and Saccharomyces cerevisiae ATCC 9763 and mold Aspergillus niger. Screening of essential oils antimicrobial activity was done using the disk diffusion method with various concentrations of oil (pure oil, suspensions with alcohol in concentrations 2:1, 1:1, 1:2 and 1:3, 1:4 and 1:5). The best antimicrobial effect was observed in the essential oil from basil T-10 which exerted microbistatic effect on bacteria Escherichia coli ATCC 25922 (inhibitory zone 7mm) and Bacillus cereus ATCC 11788 (inhibitory zone 4.66mm) when applied in suspension with alcohol in concentration 1:5 (1ml essential oil:5ml 96% C2H5OH). Significant microbistatic effects on yeast Candida albicans ATCC 24433 was observed in tests with essential oils from basil T-8 (suspension 1:1 with alcohol, inhibitory zone 41.67mm) and basil T-6 (suspension 1:1 with alcohol, inhibitory zone 41mm). .