Antibacterial activity of Thymus capitatus and Thymus algeriensis essential oils against four food-borne pathogens inoculated in minced beef meat
Résumé
The antibacterial activity of the essential oils extracted from Thymus capitatus and Thymus algerien-sis was studied against Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, and Pseudomonas aeruginosa. In this study, the disk method showed that T. capitatus EO has a strong antibacterial effect, whereas T. algeriensis EO showed a moderate activity. In addition, the inhibi-tory effect of both EOs was evaluated against four pathogenic strains inoculated experimentally (10 8 CFU/g) in the minced beef meat, mixed with different concentrations of EOs, and stored for 15 days. Both EOs at low concentrations (0.01 and 0.05% [vol/wt]) exerted a bacteriostatic effect (p < .001), only against E. coli and S. typhimurium. However, at higher concentrations (1 and 3% [vol/wt]), the bactericidal activity was pronounced (p < .0001), in particular in the case of T. capita-tus EO against all strains, except P. aeruginosa. The latter was still present after 15 days of storage, which explains its resistance.
Practical applications : Results from this study were confirmed that both thyme EOs could be considered as a very promising natural preservatives for foods from microbial spoilage in the food industries, also they can serve to inhibit or prevent the growth of food-borne pathogens.