Antimicrobial Potential of Selected Essential Oils and Essential Oil’s Active Components Against Food Spoilage Bacteria and Foodborne Pathogens and Antibiofilm Potential Against Multidrug-Resistant <i>Staphylococcus aureus</i> and <i>Pseudomonas aeruginosa</i>

The rising concern of multidrug-resistant pathogens and the unavailability of new antibiotics in the discovery pipeline has generated the need for alternative approaches for their control. Essential oils (EOs) and essential oil’s active components (EoCs) have been reported for their antimicrobial effect since long. In this study, we evaluated 11 EOs and 4 EoCs for their antimicrobial and antibiofilm activity. Among EOs, oregano (zone of inhibition [ZOI] = 24.62 ± 8.10 mm), cinnamon (ZOI = 18.38 ± 5.88 mm), cassia (ZOI = 20.23 ± 4.61 mm), and thyme (ZOI = 13.77 ± 5.67 mm), and among EoCs, cinnamaldehyde (ZOI = 24.69 ± 5.83 mm), carvacrol (ZOI = 24.38 ± 7.76 mm), and thymol (ZOI = 22.92 ± 7.43 mm) demonstrated the higher antimicrobial activity against the targeted pathogens. Only cinnamon (ZOI = 16.62 ± 2.58 mm) and cassia (ZOI = 15.24 ± 1.90 mm) were found to be effective as antimicrobial against Pseudomonas aeruginosa strains. Cinnamaldehyde (ZOI = 9.02 ± 2.68 mm) demonstrated weak antimicrobial activity. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and antibiofilm assays were performed in triplicate. Statistical analysis using the Kruskal–Wallis test revealed a significant overall difference between treatments ( p < 0.05) against both P. aeruginosa and Staphylococcus aureus . Specifically, Dunn’s multiple comparisons test showed significant differences ( p < 0.05) in MIC values between cinnamaldehyde and eugenol for P. aeruginosa with no significant difference in their MBC. For S. aureus , significant variations ( p < 0.05) in MIC and MBC were observed between carvacrol and thymol, and between thyme and other oils like tea tree, cumin, and lemongrass. Antibiofilm effect of EOs and EoCs against P. aeruginosa and S. aureus was found at concentration of 0.031% for cinnamon EO and cinnamaldehyde and at 0.015 − 0.007% for carvacrol. Gas chromatography–mass spectrometry analysis of EOs and EoCs was performed to determine their bioactive compounds. The study highlights that EOs and EoCs can be used as alternative antimicrobials against food spoilage bacteria and drug-resistant pathogens.