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Article

Natural Essential Oils as Promising Antimicrobial Agents to Improve Food Safety: Mechanistic Insights Against Multidrug-Resistant Campylobacter jejuni and Campylobacter coli Isolated from Tunisia

by
Manel Gharbi
1,2,*,
Chedia Aouadhi
1,2,
Chadlia Hamdi
1,
Safa Hamrouni
1 and
Abderrazak Maaroufi
1
1
Group of Bacteriology and Biotechnology Development, Laboratory of Epidemiology and Veterinary Microbiology, Institut Pasteur de Tunis, University of Tunis El Manar (UTM), Tunis 1002, Tunisia
2
Higher Institute of Biotechnology of Beja, University of Jendouba, Beja 9000, Tunisia
*
Author to whom correspondence should be addressed.
Foods 2026, 15(2), 308; https://doi.org/10.3390/foods15020308 (registering DOI)
Submission received: 19 December 2025 / Revised: 7 January 2026 / Accepted: 10 January 2026 / Published: 14 January 2026
(This article belongs to the Special Issue Improving Food Quality and Safety: An Exploration of Natural Antimicrobials)
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Abstract

The increasing prevalence of multidrug-resistant (MDR) Campylobacter species poses a serious threat to food safety and public health, highlighting the urgent need for natural antimicrobial alternatives to conventional antibiotics. This study investigated the antibacterial potential and mechanism of action of seven essential oils (EOs), Cymbopogon citratus, Mentha pulegium, Artemisia absinthium, Myrtus communis, Thymus algeriensis, Thymus capitatus, and Eucalyptus globulus, against multidrug-resistant Campylobacter jejuni and Campylobacter coli. The antimicrobial activity was first assessed by the agar disk diffusion and broth microdilution methods to determine inhibition zones, minimum inhibitory concentrations (MICs), and minimum bactericidal concentrations (MBCs). The most active EOs were further evaluated through time–kill kinetics, cell lysis, salt tolerance, and membrane integrity assays to elucidate their bactericidal mechanisms. Results showed that E. globulus, T. algeriensis, and M. communis exhibited the strongest inhibitory effects, particularly against C. jejuni, with MIC values ranging from 3.125% to 6.25%, while C. coli was more resistant. Time–kill and lysis experiments demonstrated rapid bacterial reduction and significant decreases in optical density, indicating cell disruption. Additionally, EO treatments reduced salt tolerance and induced leakage of cytoplasmic materials, confirming membrane damage. Overall, these findings suggest that selected essential oils exert potent antimicrobial effects through membrane disruption and osmotic imbalance, offering promising natural strategies to control MDR Campylobacter in food systems. The application of such bioactive compounds could contribute significantly to improving food quality, extending shelf life, and enhancing food safety.

1. Introduction

Campylobacter species, particularly Campylobacter jejuni and Campylobacter coli, are among the leading bacterial causes of foodborne gastroenteritis worldwide, often linked to the consumption of contaminated poultry and other animal-derived products [1,2]. In humans, infections are typically characterized by diarrhea, abdominal cramps, fever, and vomiting, but in vulnerable populations such as young children, the elderly, and immunocompromised individuals, infections can lead to severe complications including bacteremia, reactive arthritis, and, in rare cases, Guillain–Barré syndrome [3,4]. The management of Campylobacter infections is further complicated by the rising prevalence of multidrug-resistant (MDR) strains, which exhibit resistance to commonly used antibiotics such as fluoroquinolones, macrolides, and tetracyclines. This trend has become a major global concern, as it compromises the effectiveness of conventional antibiotic therapies, increases the risk of treatment failure, and poses a significant threat not only to human health but also to food production systems, where MDR Campylobacter can spread through the poultry and livestock supply chain [5,6,7]. The persistence of these resistant strains in animal reservoirs highlights the urgent need for alternative intervention strategies and comprehensive surveillance programs to mitigate their impact on public health.
The intensive and sometimes uncontrolled use of antibiotics in livestock farming has promoted the selection and spread of resistant Campylobacter strains throughout the food chain [8,9]. This contributes to the emergence of MDR populations and increases the risk of transmission to humans through contaminated animal products. Antibiotic overuse also raises concerns about environmental contamination and the persistence of resistant bacteria in agricultural settings. These challenges emphasize the pressing need for alternative approaches to control pathogenic bacteria in a manner that does not exacerbate antibiotic resistance. Plant-derived essential oils (EOs) are among the most promising options, as they exhibit broad-spectrum antimicrobial activity and are naturally biodegradable. Several EO constituents have been recognized as Generally Recognized as Safe (GRAS) by regulatory authorities; however, this designation is context-dependent and varies according to the specific compound, concentration, intended application, food matrix, and regulatory jurisdiction. In addition, sensory attributes and consumer acceptance may constrain their practical use. Despite these limitations, EOs offer considerable potential for application in food systems and animal production to reduce microbial loads, limit pathogen dissemination, and mitigate the risks associated with antibiotic overuse [10,11].
EOs are complex mixtures of volatile compounds such as terpenes, phenols, and ketones that often interact with bacterial membranes, increase permeability, and cause leakage of intracellular contents, ultimately leading to cell death [12,13]. Recent studies have demonstrated significant antibacterial activity of various essential oils against Campylobacter spp. For instance, formulations containing cinnamon, lemongrass, clove, geranium, and oregano EOs have shown strong inhibitory effects on Campylobacter strains isolated from chicken carcasses, with large inhibition zones in diffusion assays and low effective concentrations when incorporated into lipid nanocarriers [14,15,16]. Moreover, dietary supplementation with natural phenolic compounds such as eugenol and trans-cinnamaldehyde has been shown to reduce C. jejuni loads in broiler chickens and modulate virulence gene expression, demonstrating the in vivo potential of these natural antimicrobials [17].
Despite these promising findings, the precise antibacterial mechanisms of EOs against MDR Campylobacter strains remain incompletely understood. The complex mixture of bioactive compounds in EOs can act through multiple pathways, but the specific interactions that lead to bacterial inhibition or cell death are not fully characterized. Understanding these mechanisms is critical for determining optimal concentrations, delivery methods, and combinations with other antimicrobials to maximize their effectiveness. Insights into the bactericidal action of EOs will also facilitate translation of laboratory efficacy into practical applications in food production systems, ensuring both safety and consistency of antimicrobial effects [18,19].
Therefore, the present study aimed to evaluate the antibacterial activity of seven essential oils: Cymbopogon citratus, Mentha pulegium, Artemisia absinthium, Myrtus communis, Thymus algeriensis, Thymus capitatus, and Eucalyptus globulus against MDR C. jejuni and C. coli strains, and (ii) elucidate their mechanisms of action through time–-kill kinetics, cell lysis, salt tolerance, and membrane integrity assays. The findings of this work provide new insights into the bactericidal properties of EOs and support their application as natural antimicrobial agents to enhance food safety and reduce antibiotic dependence in poultry production.

2. Materials and Methods

2.1. Essential Oils

In the present study, seven commercially obtained EOs, Cymbopogon citratus, Mentha pulegium, Artemisia absinthium, Myrtus communis, Thymus algeriensis, Thymus capitatus, and Eucalyptus globules, were purchased from the company “Carthago Essences Sousse, Tunisia”, and evaluated for their antibacterial activity against MDR C. jejuni and C. coli strains isolated from poultry in Tunisia. The oils were supplied with a purity ≥ 98% according to the manufacturer’s specifications. Detailed information on the composition and concentration of specific active compounds was not provided by the supplier.

2.2. Selected Bacteria and Growth Conditions

Ten multidrug-resistant Campylobacter strains (Table 1), including five C. jejuni and five C. coli isolates, were used to evaluate the antibacterial activity of the essential oils. The strains were obtained from poultry sources. Their antibiotic susceptibility profiles had been previously determined by [20,21]. All strains were cultured on Karmali agar (Oxoid, Basingstoke, UK) and incubated under microaerophilic conditions (5% O2, 10% CO2, 85% N2) at 42 °C for 48 h.

2.3. Preliminary Assessment of the Antimicrobial Activity of Essential Oils

The antibacterial activity of the seven EOs was initially screened using the disc diffusion method, as described by Aouadhi et al. [22], with minor modifications. Briefly, Mueller-Hinton agar (Oxoid, Ltd., Basingstoke, UK) plates (without any supplementation) were inoculated by uniformly surface spreading 100 µL of each strain suspension standardized to 0.5 McFarland (108 CFU/mL; OD600 = 0.08–0.1). Sterile filter paper discs (6 mm diameter) were impregnated with 15 µL of each EO and placed onto the inoculated agar surface. To reduce EO volatilization, plates were left at room temperature for 30 min to allow pre-diffusion before incubation. The plates were incubated in sealed bags filled with a microaerophilic gas mixture (5% O2, 10% CO2, and 85% N2) for 18 to 19 h at 42 °C. The diameter of the growth inhibition zone (including disc diameter of 6 mm) was used to estimate the qualitative antimicrobial activity of tested EOs. Erythromycin (15 µg/disc) was used as a positive reference. Negative control corresponds to disc without sample.

2.4. Quantitative Evaluation of the Antibacterial Efficacy of Essential Oils

The quantitative antibacterial activity of the seven EOs was assessed by determining their minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs). The broth microdilution method described by Aouadhi et al. [22] was employed. Bacterial suspensions were prepared by inoculating Bolton broth with three to four freshly isolated colonies, followed by incubation at 42 °C for 24 h. EOs were dissolved in dimethyl sulfoxide (DMSO) (Biomatik, ON, Canada).to achieve final concentrations ranging from 0.07% to 50% (v/v). Cultures without EOs served as positive growth controls, while negative controls contained the test EO but no bacteria. After 24 h of incubation at 42 °C, the MIC was defined as the lowest EO concentration that completely inhibited visible bacterial growth. To determine MBCs, 100 µL aliquots from each well were plated onto Karmali agar and incubated at 42 °C to evaluate cell viability. All experiments were conducted in triplicate to ensure reliability and reproducibility of the results.

2.5. Investigation of the Mechanism of Action of Thymus Capitatus Essential Oil

2.5.1. Time–Kill Kinetics Assay

The bactericidal kinetics of T. algeriensis and E. globulus EOs were evaluated against only the five C. jejuni, selected based on their higher susceptibility to these oils, in order to characterize their time-dependent antibacterial activity. Each strain was tested separately and displayed a similar kinetic trend; therefore, the results are presented as the mean response of the five strains. This assay quantifies the reduction in viable bacterial counts in the presence of each EO at its minimum inhibitory concentration (MIC) [23]. Briefly, three to five colonies from an 18 h culture were suspended in 2 mL of peptone water (Oxoid, Ltd., Basingstoke, UK) to obtain a working suspension adjusted to 105 CFU/mL (OD600 = 0.01). The EOs were added at their respective MICs, and bacterial suspensions with or without EO (growth control) were incubated at 42 °C under continuous agitation for 24 h. Aliquots (100 µL) were collected at predetermined time points (0, 2, 4, 6, 8, and 24 h) to determine bacterial survival [24].

2.5.2. Bacteriolytic Activity Assay

The potential bacteriolytic effect of T. algeriensis and E. globulus EO was evaluated by monitoring the optical density of bacterial suspensions at 620 nm over time [23,24]. Two colonies from an 18 h culture of the five C. jejuni strains were inoculated into 9 mL of nutrient broth and incubated at 42 °C for 18 h under shaking conditions. Cells were harvested by centrifugation (10,000 rpm, 12 min, 4 °C), washed twice with phosphate-buffered saline (PBS) (Biomatik, ON, Canada), and resuspended in PBS containing Tween 80 (0.01%, v/v). The resulting suspension was standardized to 1010 CFU/mL (OD600 = 1.0) and divided into two tubes: one containing EO at its MIC (treated) and another without EO (untreated control). Suspensions were stirred for 120 min, homogenized, diluted (1:100), and their absorbance was immediately measured at 620 nm. Results were expressed as the percentage ratio of OD620 at each time point relative to that at 0 min.

2.5.3. Determination of Cytoplasmic Material Leakage

The release of intracellular materials absorbing at 280 nm from the five C. jejuni strains cells following exposure to EOs of T. algeriensis, E. globulus, and M. communis was quantified to evaluate loss of membrane integrity. The assay was performed according to the method described by Carson et al. [25].

2.5.4. Evaluation of Salt Tolerance Impairment

The impact of the EOs of T. algeriensis, E. globulus, and M. communis on the salt tolerance of the five C. jejuni strains was assessed according to the method described by Carson et al. [22]. Bacterial suspensions were treated or left untreated with the respective EOs at their MICs for 30 min, then plated onto nutrient agar (Oxoid, Ltd., Basingstoke, UK) supplemented with increasing concentrations of NaCl (0–100 g/L). After incubation at 42 °C for 24 h, colony-forming units (CFU/mL) were enumerated. Salt tolerance was determined by comparing CFU counts obtained on NaCl-supplemented media with those on NaCl-free agar.

2.6. Statistical Analysis

All experiments were conducted in triplicate and results are expressed as mean ± standard deviation (SD). Data normality was assessed using the Shapiro–Wilk test [26] and homogeneity of variances was verified using Levene’s test [27]. One-way analysis of variance (ANOVA) followed by [28]. Tukey’s honestly significant difference (HSD) post hoc test [28] was used to compare inhibition zone diameters, MIC and MBC values, and NaCl tolerance among essential oils. Two-way ANOVA was applied to assess the effects of EO type and bacterial strain, as well as their interaction, on inhibition diameters and growth reduction. Differences were considered statistically significant at p < 0.05. All statistical analyses were performed using GraphPad Prism version 9.5.1 (GraphPad Software, San Diego, CA, USA) and IBM SPSS Statistics version 26.0 (IBM Corp., Armonk, NY, USA).

3. Results and Discussion

3.1. Antibacterial Activity of Essential Oils (Disk Diffusion Assay)

The disk diffusion assay revealed notable variability in the antibacterial activity of the seven essential oils (EOs) tested against C. coli and C. jejuni, highlighting both strain-specific and oil-specific effects (Table 2). Two-way ANOVA confirmed that the type of EO type (p < 0.001) and the bacterial strain (p < 0.01) significantly influenced inhibition diameters, with a significant interaction between the two factors (p < 0.05), indicating that the effectiveness of a given EO depends on the target strain. Among the oils tested, A. absinthium EO showed the most potent activity (p < 0.05) against C. coli, producing the largest inhibition zone (37.6 ± 0.6 mm). In contrast, C. citratus and M. pulegium EOs displayed moderate activity against C. coli (28.6 ± 0.3 and 31 ± 0.2 mm, respectively) but were almost inactive against C. jejuni. Interestingly, the EO of T. algeriensis demonstrated comparable inhibitory effects against both C. coli and C. jejuni, indicating a broad antibacterial spectrum. This property could be advantageous for the development of EO-based interventions intended to control multiple Campylobacter strains in food production or clinical settings. Similarly, E. globulus showed strong activity against C. jejuni but lower efficacy against C. coli.
These variations in EO activity are consistent with the concept that the chemical composition of EOs, typically containing 20–60 bioactive constituents, plays a central role in their antimicrobial effects. The synergistic or additive interactions among major components such as thymol, carvacrol, and linalool, along with minor constituents, can significantly influence bacterial susceptibility [23,29,30]. Mechanistically, these compounds are reported to disrupt bacterial membranes, increase permeability, and induce leakage of intracellular contents, ultimately leading to cell death [31,32].

3.2. Minimum Inhibitory and Bactericidal Concentrations (MIC and MBC)

The broth microdilution assay provided a quantitative assessment of the antibacterial efficacy of the EOs against C. jejuni and C. coli. The MIC and MBC values revealed marked differences in potency among the oils and between the two Campylobacter species (p < 0.05) (Table 3). Notably, E. globulus EO exhibited the strongest inhibitory and bactericidal activity against C. jejuni, with MIC and MBC values of 3.13% and 1.56% v/v, respectively. T. algeriensis and M. communis also demonstrated strong activity, with MIC values of 6.25% v/v against C. jejuni, highlighting their potential as natural antimicrobials. In contrast, T. capitatus showed the weakest activity, with MICs of 25% and 50% v/v against C. jejuni and C. coli, respectively. These differences may reflect variations in EO chemical composition, particularly in the concentration and types of phenolic and monoterpene constituents, which are known to influence membrane permeability, cytoplasmic leakage, and disruption of metabolic processes in bacteria [1,2,7,29].
Interestingly, C. coli consistently exhibited higher MIC and MBC values compared to C. jejuni across most EOs (p < 0.01, two-way ANOVA; Table 3), indicating greater intrinsic tolerance. This trend may be related to differences in cell membrane composition, efflux pump activity, or stress response mechanisms, which could reduce the susceptibility of C. coli to EO components. The higher resistance of C. coli underscores the importance of considering species-specific responses when designing EO-based antimicrobial interventions. The observed patterns align with previous studies, including Ozogul et al. [33], which reported differential susceptibility of Campylobacter strains to Thymus spp. and Eucalyptus oils. The strong antimicrobial activity of these oils is generally attributed to their bioactive terpenes, including thymol, carvacrol, and 1,8-cineole, which act synergistically to destabilize the bacterial cytoplasmic membrane, disrupt membrane potential, and induce leakage of intracellular contents [23,34,35]. These mechanisms are consistent with the results of both disk diffusion and microdilution assays, reinforcing the potential of these EOs as effective natural agents against Campylobacter spp. Overall, the quantitative data from MIC and MBC assays confirm the species- and oil-dependent variability in antimicrobial potency and highlight E. globulus, T. algeriensis, and M. communis as promising candidates for further investigation.

3.3. Time–Kill Kinetics

The time–kill kinetics of T. algeriensis and E. globulus EOs against five C. jejuni strains were assessed to evaluate their bactericidal activity. Data shown in Figure 1 represent the mean viable counts (log CFU/mL) ± SD of the five strains, each tested individually, which all exhibited similar trends. Both EOs achieved complete inhibition of bacterial growth by the first sampling point at 1 h, indicating rapid bactericidal effects. Due to the sampling interval, it is not possible to determine whether one oil acted faster than the other; nonetheless, these results demonstrate that both oils are highly effective in rapidly reducing C. jejuni populations upon exposure. The rapid onset of killing suggests that the primary mechanism is likely membrane disruption rather than interference with slower biosynthetic processes, such as protein or nucleic acid synthesis. This interpretation is supported by previous studies demonstrating that monoterpenes and phenolic compounds, commonly present in these EOs, can integrate into lipid bilayers, alter membrane fluidity, induce depolarization, and cause leakage of intracellular contents, leading to cell death within minutes [31,36].
The rapid bactericidal activity observed here has several important implications. First, it supports the potential use of these EOs as effective interventions in food safety, where rapid reduction in C. jejuni populations is critical to prevent contamination and infection. Second, the speed of action reduces the likelihood of bacterial adaptation or development of resistance, which is a major concern with conventional antibiotics. Moreover, the differences in killing kinetics between E. globulus and T. algeriensis may reflect variations in their chemical profiles, with specific bioactive constituents such as 1,8-cineole, α-pinene, linalool, or carvacrol contributing to the observed potency and rapid membrane-targeted activity.
Interestingly, the bactericidal kinetics of these EOs resemble those reported for other plant-derived antimicrobials. For instance, Daucus carota EO was previously shown to eliminate Campylobacter populations within 30 min, further supporting the idea that essential oils can act as rapid, membrane-active bactericidal agents [31,36,37]. These results highlight the importance of selecting oils not only based on MIC values but also considering kinetic parameters, which provide a more comprehensive understanding of their antimicrobial potential under dynamic conditions.

3.4. Cell Lysis Assay

The cell lysis assay provided quantitative evidence of membrane damage and disruption of bacterial cell integrity induced by the essential oils (EOs) of T. algeriensis, E. globulus, and M. communis. All five C. jejuni strains were tested separately, and similar trends were observed across strains. Data are presented as the mean values of these five strains. A time-dependent decrease in optical density (OD620) was observed in all EO-treated samples, indicating progressive lysis of C. jejuni cells. Statistical analysis confirmed that OD620 values at each time point were significantly lower than the untreated control (p < 0.05; one-way ANOVA followed by Tukey’s post hoc test) (Figure 2). Specifically, OD620 decreased to 86.6%, 82.9%, and 69% of the initial absorbance for T. algeriensis, E. globulus, and M. communis, respectively, while the control remained stable, confirming that these effects were EO-mediated rather than due to spontaneous cell death or aggregation [30,38,39].
These results suggest that the primary antibacterial action of the tested EOs involves disruption of the bacterial cell envelope, resulting in leakage of intracellular contents and loss of turgor. The greater reduction in OD observed for M. communis indicates a more pronounced lytic effect compared to the other oils, likely reflecting differences in chemical composition, particularly the presence of membrane-active compounds such as phenolic monoterpenes (thymol, carvacrol) and oxygenated terpenes (1,8-cineole, linalool). These compounds are known to intercalate into phospholipid bilayers, perturb membrane structure, and destabilize lipid–protein interactions, ultimately causing cell rupture and lysis [10,11,12,13,30,35,36,38,39].
The relative differences in lytic activity among the oils are consistent with the MIC, MBC, and time–kill kinetics data, supporting a mechanism of rapid, membrane-targeted bactericidal action. For instance, E. globules EOs, which exhibited the lowest MIC and fastest killing kinetics, also induced substantial cell lysis, confirming that its antimicrobial potency is closely linked to membrane disruption. Similarly, the slightly lower lysis observed for T. algeriensis may indicate a strong but more gradual membrane-targeted effect, while M. communis’s pronounced OD decrease suggests an aggressive lytic action, possibly due to synergistic effects among its multiple bioactive components.

3.5. Effect on Salt Tolerance

The evaluation of C. jejuni growth on Karmali agar containing increasing NaCl concentrations (Table 4) revealed that essential oils (EOs) significantly affected bacterial tolerance to osmotic stress. Two-way ANOVA confirmed that both NaCl concentration (p < 0.001) and EO treatment (p < 0.001) had a significant impact, with a notable interaction between the two factors (p < 0.05). As expected, higher salt concentrations alone reduced bacterial growth, reflecting the inherent sensitivity of C. jejuni to osmotic stress. Interestingly, the presence of EOs amplified this effect, with E. globulus EOs completely inhibiting growth even at 2.5% NaCl, whereas M. communis and T. algeriensis allowed partial survival under the same conditions. These findings suggest that EO treatment interferes with the bacteria’s ability to adjust to salty conditions, likely by impairing the mechanisms responsible for maintaining ion balance and osmotic homeostasis. Disruption of osmotic regulation can prevent the cell from accumulating compatible solutes or adjusting internal solute concentrations, which is critical for survival under hyperosmotic conditions.
The differential effects of the three EOs indicate that specific chemical constituents may influence how C. jejuni responds to osmotic pressure. For example, E. globulus may contain components that either destabilize membrane-associated ion channels or inhibit stress response pathways, thereby enhancing sensitivity to NaCl. In contrast, the partial growth observed with M. communis and T. algeriensis suggests that these oils exert milder interference with osmotic adaptation mechanisms, allowing some cells to survive low to moderate salt concentrations.
These results provide additional insight into the antibacterial potential of EOs by demonstrating that, beyond direct growth inhibition, they compromise bacterial stress tolerance, which could reduce survival in challenging environments such as food matrices with high salt content. This effect could be particularly valuable for food preservation strategies, where combining EOs with mild osmotic stress may synergistically limit C. jejuni survival and proliferation.
Overall, the salt tolerance assay highlights a secondary mode of action for EOs: interference with bacterial adaptive responses to environmental stress, complementing their direct bactericidal activity. This dual effect reinforces the potential of EOs as multifunctional antimicrobials capable of reducing pathogen survival under diverse conditions [32,39].

3.6. Membrane Integrity

The measurement of cytoplasmic material leakage at 260 nm provided direct evidence that T. algeriensis, E. globulus, and M. communis essential oils (EOs) compromise C. jejuni cell membrane integrity. The significant increase in OD620 values after EO treatment (p < 0.05) (Figure 3), particularly with T. algeriensis (OD260 = 14.7 after 90 min), indicates the release of nucleic acids and other intracellular components into the surrounding medium. This release is a feature of severe membrane disruption, confirming that the bacterial envelope is a primary target of EO action. The differences in leakage among the oils likely reflect variations in their chemical composition and the presence of highly active compounds such as thymol, carvacrol, and 1,8-cineole, which are known to integrate into lipid bilayers, destabilize membranes, and increase permeability [10,11,12,13,35]. T. algeriensis caused the greatest leakage, suggesting a particularly strong membrane-targeted effect, while E. globulus and M. communis were slightly less aggressive but still highly effective. These observations align with previous reports showing EO-induced leakage of cytoplasmic contents and oxidative stress in bacterial cells [14,38,39].
When integrated with the broader dataset, the cytoplasmic leakage results corroborate other indicators of membrane-targeted bactericidal activity. The low MIC and MBC values, rapid killing kinetics, decreased NaCl tolerance, and OD620-based lysis all point to the cell membrane as the primary site of EO action. This multi-parameter evidence reinforces the conclusion that C. jejuni cells are killed not simply by metabolic inhibition but through physical compromise of membrane integrity, resulting in uncontrolled leakage of essential intracellular materials and cell death.
The observed strain-dependent differences, with C. coli showing higher MIC values, suggest that membrane composition or associated stress-response mechanisms may confer relative tolerance to EO-induced membrane damage. Nonetheless, the consistent effectiveness of E. globulus, T. algeriensis, and M. communis across multiple assays highlights their strong and reproducible antibacterial activity, supporting their potential use as natural antimicrobials in food safety applications.
In general, the cytoplasmic material leakage assay provides direct mechanistic evidence that complements inhibition, MIC/MBC, time–kill, and salt tolerance results. Together, these findings demonstrate that selected EOs exert rapid, potent, and membrane-targeted bactericidal effects against C. jejuni, confirming their suitability as alternative interventions to control foodborne pathogens and reduce the risk of antibiotic-resistant Campylobacter strains.

4. Conclusions

This study demonstrates that selected EOs possess significant antibacterial activity against MDR C. jejuni and C. coli strains isolated from poultry in Tunisia. Among the seven EOs evaluated, those of E. globulus, T. algeriensis, and M. communis consistently exhibited the strongest inhibitory and bactericidal effects, as evidenced by large inhibition zones, low MIC and MBC values, and rapid killing kinetics. The other EOs, T. capitatus, A. absinthium, and M. pulegium, also demonstrated measurable antibacterial activity, although to a lesser extent, highlighting variability in EO potency and species-specific susceptibility. Notably, C. coli generally showed higher tolerance than C. jejuni, emphasizing the need to consider species-dependent differences when designing EO-based interventions
Mechanistic investigations revealed that the antibacterial action of these EOs is primarily membrane-targeted. The rapid bactericidal effects observed in time–kill assays, together with significant cell lysis, cytoplasmic material leakage, and impaired salt tolerance, indicate severe disruption of cell envelope integrity and loss of osmotic homeostasis. These complementary findings provide strong, multi-level evidence that EO constituents act predominantly through physical damage to bacterial membranes rather than solely through metabolic inhibition.
Importantly, the ability of EOs to compromise stress adaptation mechanisms, such as tolerance to elevated NaCl concentrations, suggests an additional mode of action that could reduce Campylobacter survival in food-related environments. This multifunctional activity strengthens their potential value as natural antimicrobials, particularly in food safety applications where rapid pathogen control and mitigation of antibiotic resistance risks are critical.
Nevertheless, it should be acknowledged that the EO concentrations required for antimicrobial efficacy may exceed sensory acceptance thresholds in certain food matrices, potentially limiting their direct application due to strong organoleptic effects. To address this limitation, future strategies should explore delivery systems such as micro- or nano-encapsulation, incorporation into edible coatings or active packaging, and integration within hurdle technology approaches, which may enable effective microbial control at reduced, sensory-acceptable concentrations.
Overall, the present work supports the use of E. globulus, T. algeriensis, and M. communis EOs as promising alternative or complementary agents for controlling antibiotic-resistant Campylobacter spp. in poultry production and food systems. Future studies should also focus on chemical characterization of active components, evaluation of synergistic effects with conventional preservation methods, assessment of sensory impact, and validation under real food matrix conditions to facilitate practical application.

Author Contributions

Conceptualization, M.G. and A.M.; methodology, M.G., S.H., C.A. and C.H.; validation, M.G. and A.M.; formal analysis, M.G.; investigation, M.G., S.H., C.A. and C.H.; data curation, M.G.; writing—original draft preparation, M.G.; writing—review and editing, M.G.; visualization, M.G., S.H., C.A., C.H. and A.M.; supervision, A.M.; project administration, M.G. and A.M. All authors have read and agreed to the published version of the manuscript.

Funding

This work was financed by funding provided to the Laboratory of Epidemiology and Veterinary Microbiology (LR16IPT03) by the Tunisian Ministry of Higher Education and Scientific Research.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The original contributions presented in the study are included in the article. Further inquiries can be directed to the corresponding author.

Conflicts of Interest

The authors declare no conflicts of interest.

Abbreviations

The following abbreviations are used in this manuscript:
MICMinimum Inhibitory Concentration
MBCMinimum Bactericidal Concentration
EOsEssential Oils

References

  1. Kovačević, Z.; Čabarkapa, I.; Šarić, L.; Pajić, M.; Tomanić, D.; Kokić, B.; Božić, D.D. Natural solutions to antimicrobial resistance: The role of essential oils in poultry meat preservation with focus on Gram-negative bacteria. Foods 2024, 13, 3905. [Google Scholar] [CrossRef]
  2. Pires, H.M.; Bastos, L.M.; da Silva, E.F.; Fonseca, B.B.; Sommerfeld, S.; de Oliveira Junior, R.J.; Ribeiro, L.N.M. Antimicrobial activity of essential-oil-based nanostructured lipid carriers against Campylobacter Spp. isolated from chicken carcasses. Pharmaceutics 2024, 16, 922. [Google Scholar] [CrossRef]
  3. Aljazzar, A.; Abd El-Hamid, M.I.; El-Malt, R.M.S.; El-Gharreb, W.R.; Abdel-Raheem, S.M.; Ibrahim, A.M.; Abdelaziz, A.M.; Ibrahim, D. Prevalence and antimicrobial susceptibility of Campylobacter species with particular focus on the growth promoting, immunostimulant and anti-Campylobacter jejuni activities of eugenol and trans-cinnamaldehyde mixture in broiler Chickens. Animals 2022, 12, 905. [Google Scholar] [CrossRef] [PubMed]
  4. Sharafutdinov, I.; Linz, B.; Tegtmeyer, N.; Backert, S. Therapeutic and protective approaches to combat Campylobacter jejuni infections. Front. Pharmacol. 2025, 16, 1572616. [Google Scholar] [CrossRef] [PubMed]
  5. Micciche, A.; Rothrock, M.J., Jr.; Yang, Y.; Ricke, S.C. Essential oils as intervention strategies to reduce Campylobacter levels in food production systems. Front. Microbiol. 2019, 10, 1058. [Google Scholar] [CrossRef] [PubMed]
  6. Arsi, K.; Donoghue, A.M.; Venkitanarayanan, K.; Kollanoor-Johny, A.; Fanatico, A.C.; Blore, P.J.; Donoghue, D.J. The Efficacy of the natural plant extracts, thymol and carvacrol against Campylobacter colonization in broiler Chickens. J. Food Safety 2024, 34, 321–325. [Google Scholar] [CrossRef]
  7. Soulaimani, B. Comprehensive review of the combined antimicrobial activity of essential oil mixtures and synergism with conventional antimicrobials. Nat. Prod. Commun. 2025, 20, 1934578X251328241. [Google Scholar] [CrossRef]
  8. Kaakoush, N.O.; Castaño-Rodríguez, N.; Mitchell, H.M.; Man, S.M. Global epidemiology of Campylobacter infection. Clin. Microbiol. Rev. 2015, 28, 687–720. [Google Scholar] [CrossRef]
  9. Van Boeckel, T.P.; Brower, C.; Gilbert, M.; Grenfell, B.T.; Levin, S.A.; Robinson, T.P.; Teillant, A.; Laxminarayan, R. Global trends in antimicrobial use in food animals. Proc. Natl. Acad. Sci. USA 2015, 112, 5649–5654. [Google Scholar] [CrossRef]
  10. Burt, S. Essential oils: Their antibacterial properties and potential applications in foods: A review. Int. J. Food Microbiol. 2004, 94, 223–253. [Google Scholar] [CrossRef]
  11. Marchese, A.; Barbieri, R.; Coppo, E.; Orhan, I.E.; Daglia, M.; Nabavi, S.F.; Izadi, M.; Nabavi, S.M. Antimicrobial activity of essential oils: A review. Trends Food Sci. Technol. 2017, 61, 36–48. [Google Scholar]
  12. Lambert, R.J.W.; Skandamis, P.N.; Coote, P.J.; Nychas, G.J.E. Study of the MIC and mode of action of oregano essential oil, thymol and carvacrol. J. Appl. Microbiol. 2001, 91, 453–462. [Google Scholar] [CrossRef] [PubMed]
  13. Cristani, M.; D’Arrigo, M.; Mandalari, G.; Castelli, F.; Sarpietro, M.G.; Micieli, D.; Venuti, V.; Bisignano, G.; Saija, A.; Trombetta, D. Interaction of four monoterpenes contained in essential oils with model membranes: Implications for their antibacterial activity. J. Agric. Food Chem. 2007, 55, 6300–6308. [Google Scholar] [CrossRef] [PubMed]
  14. Ramić, D.; Bucar, F.; Kunej, U.; Dogša, I.; Klančnik, A.; Smole Možina, S. Antibiofilm potential of Lavandula preparations against Campylobacter jejuni. Appl. Environ. Microbiol. 2021, 87, e0109921. [Google Scholar] [CrossRef]
  15. Gahamanyi, N.; Song, D.G.; Cha, K.H.; Yoon, K.Y.; Mboera, L.E.G.; Matee, M.I.; Mutangana, D.; Amachawadi, R.G.; Komba, E.V.G.; Pan, C.H. Susceptibility of Campylobacter strains to selected natural products and frontline antibiotics. Antibiotics 2020, 9, 790. [Google Scholar] [CrossRef]
  16. Kurekci, C.; Padmanabha, J.; Bishop-Hurley, S.L.; Hassan, E.; Al Jassim, R.A.; McSweeney, C.S. Antimicrobial activity of essential oils and five terpenoid compounds against Campylobacter jejuni in pure and mixed culture experiments. Int. J. Food Microbiol. 2013, 166, 450–457. [Google Scholar] [CrossRef]
  17. Angelini, P. Plant-derived antimicrobials and their crucial role in combating antimicrobial resistance. Antibiotics 2024, 13, 746. [Google Scholar] [CrossRef]
  18. Dai, L.; Sahin, O.; Grover, M.; Zhang, Q. New and alternative strategies for the prevention, control, and treatment of antibiotic-resistant Campylobacter. Transl. Res. 2020, 223, 76–88. [Google Scholar] [CrossRef]
  19. Jubair, N.; Rajagopal, M.; Chinnappan, S.; Abdullah, N.B.; Fatima, A. Review on the antibacterial mechanism of plant-derived compounds against multidrug-resistant bacteria (MDR). Evid.-Based Complement. Altern. Med. 2021, 2021, 3663315. [Google Scholar] [CrossRef]
  20. Gharbi, M.; Kamoun, S.; Hkimi, C.; Ghedira, K.; Béjaoui, A.; Maaroufi, A. Relationships between virulence genes and antibiotic resistance phenotypes/genotypes in Campylobacter spp. isolated from layer hens and eggs in the North of Tunisia: Statistical and computational insights. Foods 2022, 11, 3554. [Google Scholar] [CrossRef]
  21. Gharbi, M.; Béjaoui, A.; Hamrouni, S.; Arfaoui, A.; Maaroufi, A. Persistence of Campylobacter spp. in poultry flocks after disinfection, virulence, and antimicrobial resistance traits of recovered isolates. Foods 2023, 12, 890. [Google Scholar] [CrossRef] [PubMed]
  22. Aouadhi, C.; Jouini, A.; Maaroufi, K.; Maaroufi, A. Antibacterial effect of eight essential oils against bacteria implicated in bovine mastitis and characterization of primary action mode of Thymus capitatus essential oil. Foods 2024, 13, 237. [Google Scholar] [CrossRef] [PubMed]
  23. Viljoen, A.; van Vuuren, S.; Ernst, E.; Klepser, M.; Demirci, B.; Başer, H.; van Wyk, B.E. Osmitopsis asteriscoides (Asteraceae)-the antimicrobial activity and essential oil composition of a Cape-Dutch remedy. J. Ethnopharmacol. 2003, 88, 137–143. [Google Scholar] [CrossRef] [PubMed]
  24. Guinoiseau, E.; Luciani, A.; de Rocca Serra, D.; Quilichini, Y.; Berti, L.; Lorenzi, V. Primary mode of action of Cistus ladaniferus L. essential oil active fractions on Staphyloccocus aureus strain. Adv. Microbiol. 2015, 5, 881–890. [Google Scholar] [CrossRef]
  25. Carson, C.F.; Mee, B.J.; Riley, T.V. Mechanism of action of Melaleuca alternifolia (Tea Tree) oil on Staphylococcus aureus determined by time-kill, lysis, leakage, and salt tolerance assays. J. Antimicrob. Chemother. 2002, 50, 195–201. [Google Scholar]
  26. Shapiro, S.S.; Wilk, M.B. An analysis of variance test for normality (complete samples). Biometrika 1965, 52, 591–611. [Google Scholar] [CrossRef]
  27. Levene, H. Robust tests for equality of variances. In Contributions to Probability and Statistics: Essays in Honor of Harold Hotelling; Stanford University Press: Stanford, CA, USA, 1960; pp. 278–292. [Google Scholar]
  28. Tukey, J.W. Comparing individual means in the analysis of variance. Biometrics 1949, 5, 99–114. [Google Scholar] [CrossRef]
  29. Falleh, H. Demystifying the power of essential oils: A review of their antibacterial properties and potential as natural food preservatives. EXCLI J. 2025, 24, 828–850. [Google Scholar]
  30. Kalemba, D.; Kunicka, A. Antibacterial and antifungal properties of essential oils. Curr. Med. Chem. 2003, 10, 813–829. [Google Scholar] [CrossRef]
  31. da Silva, A.T.; Cândido, A.E.C.M.; Júnior, E.D.C.M.; do É., G.N.; Moura, M.P.S.; Souza, R.F.S.; Guimarães, M.L.; Peixoto, R.M.; de Oliveira, H.P.; da Costa, M.M. Bactericidal and synergistic effects of Lippia origanoides essential oil and its main constituents against multidrug-resistant strains of Acinetobacter baumannii. ACS Omega 2024, 9, 43927–43939. [Google Scholar] [CrossRef]
  32. Yasir, M.; Nawaz, A.; Ghazanfar, S.; Okla, M.K.; Chaudhary, A.; Al, W.H.; Ajmal, M.N.; AbdElgawad, H.; Ahmad, Z.; Abbas, F.; et al. Anti-bacterial activity of essential oils against multidrug-resistant foodborne pathogens isolated from raw milk. Braz. J. Biol. 2022, 84, e259449. [Google Scholar] [CrossRef]
  33. Ozogul, Y.; Kuley, E.; Ucar, Y.; Ozogul, F. Antimicrobial impacts of essential oils on food borne-pathogens. Recent Pat. Food Nutr. Agric. 2015, 7, 53–61. [Google Scholar] [CrossRef]
  34. da Silva, E.F.; Bastos, L.M.; Fonseca, B.B.; Ribas, R.M.; Sommerfeld, S.; Pires, H.M.; Dos Santos, F.A.L.; Ribeiro, L.N.M. Lipid nanoparticles based on natural matrices with activity against multidrug resistant bacterial species. Front. Cell. Infect Microbiol. 2024, 13, 1328519. [Google Scholar] [CrossRef]
  35. Álvarez-Martínez, F.J.; Barrajón-Catalán, E.; Herranz-López, M.; Micol, V. Antibacterial plant compounds, extracts and essential oils: An updated review on their effects and putative mechanisms of action. Phytomedicine 2021, 90, 153626. [Google Scholar] [CrossRef] [PubMed]
  36. Friedman, M.; Henika, P.R.; Mandrell, R.E. Bactericidal activities of plant essential oils and some of their isolated constituents against Campylobacter jejuni, Escherichia coli, Listeria monocytogenes, and Salmonella enterica. J. Food Prot. 2002, 65, 1545–1560. [Google Scholar] [CrossRef] [PubMed]
  37. Dedieu, L.; Brunel, J.M.; Lorenzi, V.; Muselli, A.; Berti, L.; Bolla, J.M. Antibacterial mode of action of the Daucus carota essential oil active compounds against Campylobacter jejuni and efflux-mediated drug resistance in Gram-negative bacteria. Molecules 2020, 25, 5448. [Google Scholar] [CrossRef] [PubMed]
  38. Mutlu-Ingok, A.; Karbancioglu-Guler, F. Cardamom, cumin, and dill weed essential oils: Chemical compositions, antimicrobial activities, and mechanisms of action against Campylobacter spp. Molecules 2017, 22, 1191. [Google Scholar] [CrossRef]
  39. Bakkali, F.; Averbeck, S.; Averbeck, D.; Idaomar, M. Biological effects of essential oils: A review. Food Chem. Toxicol. 2008, 46, 446–475. [Google Scholar] [CrossRef]
Foods 15 00308 g001
Figure 1. Time–kill kinetics of T. algeriensis and E. globulus essential oils against C. jejuni. Curves represent mean viable counts (log CFU/mL) ± SD of five independently tested C. jejuni strains exposed to each essential oil at its MIC.
Figure 1. Time–kill kinetics of T. algeriensis and E. globulus essential oils against C. jejuni. Curves represent mean viable counts (log CFU/mL) ± SD of five independently tested C. jejuni strains exposed to each essential oil at its MIC.
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Foods 15 00308 g002
Figure 2. Percentage of cell lysis of five C. jejuni strains following treatment with selected essential oils, expressed as (A620(T)/A620(T0)) × 100. Values represent the mean of the five strains.
Figure 2. Percentage of cell lysis of five C. jejuni strains following treatment with selected essential oils, expressed as (A620(T)/A620(T0)) × 100. Values represent the mean of the five strains.
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Foods 15 00308 g003
Figure 3. Effect of T. algeriensis, E. globulus, and M. communis essential oils on the release of cytoplasmic components from C. jejuni, measured at 260 nm. Values represent mean ± SD of five independently tested C. jejuni strains (n = 5). Statistical differences were determined using two-way ANOVA followed by Tukey’s post hoc test (p < 0.05).
Figure 3. Effect of T. algeriensis, E. globulus, and M. communis essential oils on the release of cytoplasmic components from C. jejuni, measured at 260 nm. Values represent mean ± SD of five independently tested C. jejuni strains (n = 5). Statistical differences were determined using two-way ANOVA followed by Tukey’s post hoc test (p < 0.05).
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Table 1. Characteristics of used C. jejuni and C. coli strains [20,21].
Table 1. Characteristics of used C. jejuni and C. coli strains [20,21].
StrainsSpeciesPhenotype of ResistanceResistance Genes Detected
I208E17P48C. jejuniAmp, Amc, Cip, Chl, Nal, Ery, Tet, Chl, Lintet(O), cmeB, blaOXA-61, 23S rRNA, gyrA, fexB, optrA, aac(6′)-Ib-cr, blaVIM, blaOXA-48, NDM
I201E17P48C. jejuniAmp, Amc, Cip, Chl, Nal, Ery, Tet, Chl, Lintet(O), cmeB, blaOXA-61, 23S rRNA, gyrA, blaVIM, aac(6′)-Ib-cr, blaOXA-48
I245E17P48C. jejuniAmp, Amc, Cip, Chl, Nal, Ery, Tet, Chl, Lintet(O), cmeB, blaOXA-61, 23SrRNA, gyrA, blaVIM, aac(6′)-Ib-cr, blaOXA-48
I255E17P48C. jejuniAmp, Amc, Cip, Chl, Nal, Ery, Tet, Chl, Lintet(O), cmeB, blaOXA-61, 23SrRNA, gyrA, blaVIM, aac(6′)-Ib-cr, blaNDM
I260E17P48C. jejuniAmp, Amc, Cip, Chl, Nal, Ery, Tet, Chl, Lintet(O), cmeB, blaOXA-61, 23SrRNA, gyrA, blaVIM, aac(6′)-Ib-cr, blaNDM
I1E17P1C. coliAmp, Cip, Chl, Ery, Tet, Chl, Gentet(O), cmeB, blaOXA-61, 23SrRNA, gyrA, blaVIM, aac(6′)-Ib, blaNDM
I267E30D10C. coliAmc, Cip, Chl, Nal, Ery, Tet, Chl, Lintet(O), cmeB, blaOXA-61, 23S rRNA, gyrA, blaVIM, aac(6′)-Ib-cr, blaOXA-48, blaNDM
I234E30A12C. coliAmp, Amc, Cip, Chl, Nal, Ery, Tet, Chl, Lintet(O), cmeB, blaOXA-61, 23S rRNA, gyrA, blaVIM, aac(6′)-Ib, blaNDM
I179E17P19C. coliAmp, Amc, Cip, Chl, Ery, Tet, Chl, Lintet(O), cmeB, blaOXA-61, 23S rRNA, gyrA, blaVIM, aac(6′)-Ib, blaNDM
I292E21P2C. coliAmp, Amc, Cip, Chl, Nal, Ery, Tet, Chl, Lintet(O), cmeB, blaOXA-61, 23S rRNA, gyrA, blaVIM, aac(6′)-Ib-cr, blaNDM
Table 2. Inhibition zone diameters (mm) of seven EOs against C. coli and C. jejuni strains.
Table 2. Inhibition zone diameters (mm) of seven EOs against C. coli and C. jejuni strains.
EOsC. jejuniC. coli
C. citratus6.0 ± 0.0 d28.6 ± 0.3 b
M. pulegium6.0 ± 0.0 d31.0 ± 0.2 b
A. absinthium18.3 ± 0.6 c37.6 ± 0.6 a
M. communis25.0 ± 0.5 b29.6 ± 0.3 b
T. algeriensis29.3 ± 0.3 b29.3 ± 0.5 b
T. capitatus20.3 ± 0.7 c31.3 ± 0.4 b
E. globulus34.6 ± 0.4 a23.3 ± 0.6 c
ERY6.0 ± 0.0 d6.0 ± 0.0 d
Values represent mean ± SD (n = 3). Within each column, values with different superscript letters are significantly different (p < 0.05; one-way ANOVA followed by Tukey’s HSD test). ERY: erythromycin (control).
Table 3. Minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of essential oils against Campylobacter spp. (% v/v).
Table 3. Minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of essential oils against Campylobacter spp. (% v/v).
Tested Campylobacter SpeciesEssential oils
E. globulusT. capitatusT. algeriensisM. communisA. absinthiumM. pulegium
MIC (% v/v)
C. jejuni3.13 ± 0.0 b25.0 ± 0.0 a6.25 ± 0.0 b6.25 ± 0.0 b25.0 ± 0.0 a–
C. coli12.5 ± 0.0 a50.0 ± 0.0 a25.0 ± 0.0 a25.0 ± 0.0 a–12.5 ± 0.0 a
MBC (% v/v)
C. jejuni1.56 ± 0.0 b12.5 ± 0.0 a3.13 ± 0.0 b3.13 ± 0.0 b12.5 ± 0.0 a–
C. coli6.25 ± 0.0 a25.0 ± 0.0 a12.5 ± 0.0 a12.5 ± 0.0 a–6.25 ± 0.0 a
Values are mean ± SD (n = 3). Different superscript letters within each column indicate significant differences (p < 0.05; one-way ANOVA, Tukey’s test). “–”: no activity detected.
Table 4. Effect of NaCl concentration on C. jejuni growth (%) in the presence of EOs of M. communis, M. communis, and E. globulus at their MIC levels.
Table 4. Effect of NaCl concentration on C. jejuni growth (%) in the presence of EOs of M. communis, M. communis, and E. globulus at their MIC levels.
NaCl (%)ControlEssential oils
M. communisT. algeriensisE. globulus
0.0100.0 ± 0.0 a66.4 ± 1.3 b67.4 ± 0.8 b1.0 ± 0.2 c
2.591.2 ± 0.6 a58.4 ± 0.9 b66.4 ± 1.1 b0.8 ± 0.1 c
Values represent mean ± SD (n = 3). Different letters within the same row indicate significant differences (p < 0.05; two-way ANOVA, Tukey’s test). No growth was observed at 5% and 10% NaCl for any sample, so these values are not reported.
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MDPI and ACS Style

Gharbi, M.; Aouadhi, C.; Hamdi, C.; Hamrouni, S.; Maaroufi, A. Natural Essential Oils as Promising Antimicrobial Agents to Improve Food Safety: Mechanistic Insights Against Multidrug-Resistant Campylobacter jejuni and Campylobacter coli Isolated from Tunisia. Foods 2026, 15, 308. https://doi.org/10.3390/foods15020308

AMA Style

Gharbi M, Aouadhi C, Hamdi C, Hamrouni S, Maaroufi A. Natural Essential Oils as Promising Antimicrobial Agents to Improve Food Safety: Mechanistic Insights Against Multidrug-Resistant Campylobacter jejuni and Campylobacter coli Isolated from Tunisia. Foods. 2026; 15(2):308. https://doi.org/10.3390/foods15020308

Chicago/Turabian Style

Gharbi, Manel, Chedia Aouadhi, Chadlia Hamdi, Safa Hamrouni, and Abderrazak Maaroufi. 2026. "Natural Essential Oils as Promising Antimicrobial Agents to Improve Food Safety: Mechanistic Insights Against Multidrug-Resistant Campylobacter jejuni and Campylobacter coli Isolated from Tunisia" Foods 15, no. 2: 308. https://doi.org/10.3390/foods15020308

APA Style

Gharbi, M., Aouadhi, C., Hamdi, C., Hamrouni, S., & Maaroufi, A. (2026). Natural Essential Oils as Promising Antimicrobial Agents to Improve Food Safety: Mechanistic Insights Against Multidrug-Resistant Campylobacter jejuni and Campylobacter coli Isolated from Tunisia. Foods, 15(2), 308. https://doi.org/10.3390/foods15020308

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