Thyme Essential Oil as a Potential Tool Against Common and Re-Emerging Foodborne Pathogens: Biocidal Effect on Bacterial Membrane Permeability

Over the past decade, foodborne diseases have become a significant public health concern, affecting millions of people globally. Major pathogens like <i>Salmonella</i> spp., <i>Escherichia coli</i>, <i>Listeria monocytogenes</i>, and <i>Staphylococcus aureus</i> contaminate food and cause several infections. This study investigates the potential of thyme essential oil (Thy-EO) as a natural antimicrobial agent against most common and re-emerging foodborne bacteria, including <i>S. enterica</i>, <i>Yersinia enterocolitica</i>, and <i>L. monocytogenes</i>. Preliminary tests provided qualitative evidence of Thy-EO's efficacy by evaluating its antibacterial activity through direct contact and vapor phase exposure. Then, the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were defined to quantitatively evaluate the bacteriostatic and bactericidal effects of Thy-EO, revealing a strong inhibitory effect against <i>S. enterica</i>, <i>Y. enterocolitica</i> and <i>L. monocytogenes</i>. Additionally, Thy-EO exerted rapid bactericidal kinetics characterized by the disruption of bacterial cell membrane integrity over time. Results highlight Thy-EO's potential as an alternative antimicrobial agent, demonstrating that treatment with Thy-EO significantly and irreversibly affects the growth of the tested foodborne pathogens.