Antibacterial activity of Oregano, Rosmarinus and Thymus essential oils against Staphylococcus aureus and Listeria monocytogenes in beef meatballs

Abstract

Antimicrobial activity of five essential oils (EOs) was investigated up to 72h against foodborne pathogens (Staphylococcus aureus, Listeria monocytogenes, Salmonella enteritidis, Campylobacter jejuni) through disk diffusion and determination of Minimum Inhibitory Concentrations. The most active EOs were Thymus vulgaris and Origanum vulgare, followed by Cinnamomum zeylanicum, Rosmarinus officinalis, and Salvia officinalis. The antimicrobial activity of O. vulgare, Rosmarinus officinalis and T. vulgaris was investigated against five enterotoxin producers of S. aureus and five L. monocytogenes strains, for different amounts of time (up to 14 days), at 4°C, in meatballs. Concentrations of 2% and 1% restricted the growth of both the pathogens but, as a result of panel tests, altered the meat flavor. The cooked meatballs containing 0.5% of EO were acceptable in terms of taste, and the oils were able to suppress concentrations of <102CFU/g of the pathogens, revealing the potential use of R. officinalis, T. vulgaris and O. vulgare as food preservatives at this concentration.