The interest in using natural antimicrobials instead of chemical preservatives in food products has been increasing in recent years. In regard to this, essential oils—natural and liquid secondary plant metabolites—are gaining importance for their use in the protection of foods, since they are accepted as safe and healthy. Although research studies indicate that the antibacterial and antioxidant activities of essential oils (EOs) are more common compared to other biological activities, specific concerns have led scientists to investigate the areas that are still in need of research. To the best of our knowledge, there is no review paper in which antifungal and especially antimycotoxigenic effects are compiled. Further, the low stability of essential oils under environmental conditions such as temperature and light has forced scientists to develop and use recent approaches such as encapsulation, coating, use in edible films, etc. This review provides an overview of the current literature on essential oils mainly on antifungal and antimycotoxigenic but also their antibacterial and antioxidant activities. Additionally, the recent applications of EOs including encapsulation, edible coatings, and active packaging are outlined.

Natural antimicrobials as well as essential oils (EOs) have gained interest to inhibit pathogenic microorganisms and to control food borne diseases. Campylobacter spp. are one of the most common causative agents of gastroenteritis. In this study, cardamom, cumin, and dill weed EOs were evaluated for their antibacterial activities against Campylobacter jejuni and Campylobacter coli by using agar-well diffusion and broth microdilution methods, along with the mechanisms of antimicrobial action. Chemical compositions of EOs were also tested by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The results showed that cardamom and dill weed EOs possess greater antimicrobial activity than cumin with larger inhibition zones and lower minimum inhibitory concentrations. The permeability of cell membrane and cell membrane integrity were evaluated by determining relative electric conductivity and release of cell constituents into supernatant at 260 nm, respectively. Moreover, effect of EOs on the cell membrane of Campylobacter spp. was also investigated by measuring extracellular ATP concentration. Increase of relative electric conductivity, extracellular ATP concentration, and cell constituents’ release after treatment with EOs demonstrated that tested EOs affected the membrane integrity of Campylobacter spp. The results supported high efficiency of cardamom, cumin, and dill weed EOs to inhibit Campylobacter spp. by impairing the bacterial cell membrane.

In this study, the aim was to evaluate the antimicrobial and antioxidant activities of thyme (Thymus vulgaris), oregano (Origanum vulgare), ginger (Zingiber officinale) and fennel (Foeniculum vulgare) essential oils in addition to their chemical compositions. Based on the results of gas chromatography‐mass spectrometry (GC—MS) analysis, major components were thymol andp‐cymene in thyme, carvacrol, andp‐cymene in oregano, α‐zingiberene and ar‐curcumene in ginger and (E)‐anethole in fennel essential oils. Essential oils were investigated for their antimicrobial activities by agar well diffusion and broth microdilution methods againstCampylobacter jejuniandCampylobacter coli. The inhibition zone diameters varied from 9.2 ± 0.7 to 28.7 ± 2.1 mm forC. jejuniand 14.7 ± 2.0 to 27.8 ± 2.8 mm forC. coli. While the minimum inhibitory concentrations (MICs) were lower for thyme and oregano EOs (5.65–43.20 μg/ml), the highest MIC value was obtained in fennel EO againstC. jejuni(28530 μg/ml). Total phenolic contents and antioxidant activities of these essential oils were evaluated by using Folin Ciocalteu, 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH), Cupric Reducing Antioxidant Capacity (CUPRAC) and 2, 2‐azinobis(3‐ethylbenzo‐thiazoline)‐6‐sulphonic acid (ABTS) methods. The total phenolic content of the essential oils ranged between 7.72 (ginger) to 193 (thyme) mg GAE/L. Antioxidant activities of thyme and oregano were found to be the highest according to the ABTS method, whereas thyme was found to be the highest by the CUPRAC method and ginger by the DPPH method.

It was hypothesized that inhibition zone of an essential oil (EO) in a Petri dish might be relevant to its diffusion coefficient (DC) into agar medium, which may be calculated from the Fick’s diffusion. Antibacterial activities of cumin, dill weed, fennel, ginger and oregano EOs were evaluated against Campylobacter jejuni and Campylobacter coli . DCs, zeta potential and droplet sizes of EOs were measured. The inhibition zones of EOs had in accordance with DCs whereas they had a reverse relation with droplet size. The measured DCs were in the range of 0.82–1.50 × 10 ⁻¹² m ² s ⁻¹ . The effective DC of EOs calculated from the total flux exhibited good correlations with measured DCs. Outcomes of this study may provide a pre-assessment for the antimicrobial activity of any EOs from its DC. Furthermore, it may help to understand the studies on how EOs pass through a bacterium cell and show antimicrobial effects.