Perilla essential oil: a natural antimicrobial agent against Listeria monocytogenes

Foodborne infections caused by Listeria monocytogenes are increasing. Chemical antimicrobials are the primary control measure in the food industry; however, prolonged use of these agents may pose health risks, highlighting the need for natural antimicrobial alternatives. Perilla essential oil (PEO) has shown potential as a natural antibacterial agent but its efficacy against L. monocytogenes remains underexplored. The aim of this study was to explore the antibacterial characteristics of PEO against L. monocytogenes.

Perilla essential oil was extracted from dried perilla leaves by hydrodistillation, with 50 compounds identified by gas chromatography-mass spectrometry (GC-MS). This essential oil exhibited strong antibacterial activity, with a minimum inhibitory concentration/minimum bactericidal concentration (MIC/MBC) of 1/4 mg mL^-1. Observation using scanning electron microscopy (SEM) showed that bacteria treated with PEO were deformed and ruptured. Treatment with PEO increased bacterial surface hydrophobicity from 2.1% to 10.8% as the concentration rose from 0 to 4 mg mL^-1. Biofilm biomass decreased from 2.13 to 0.55 over the same concentration range. Perilla essential oil also disrupted the cell wall and membrane of L. monocytogenes, leading to higher leakage of nucleic acids and proteins in comparison with untreated cells. Gel electrophoresis confirmed that PEO reduced bacterial protein content. Furthermore, the respiratory-chain dehydrogenase of PEO-treated (1, 2, 4 mg mL^-1) L. moncytogenes decreased by 45.91%, 64.56% and 68.41%, respectively, compared to untreated bacteria.

These findings suggest that PEO exhibited good antibacterial effects, making it a potential natural antimicrobial agent for food contaminated with L. monocytogenes. © 2025 Society of Chemical Industry.