## 4 Antimicrobial Activities of Plant-Food EOs in Liquid and Vapor Phases
### Antibacterial Activities of EOs in Liquid and Vapor Phases  
Many studies have shown that EOs possess antibacterial properties against a wide range of bacterial strains [35; 36; 37] (Table S1). The \(D\)-values on exposure to _Mentha piperita_ EO were analyzed as 2.14 and 2.8 min and 1.4 and 12.8 min, against _Escherichia coli_ and _Staphylococcus aureus_, respectively; in this study, the antimicrobial potency of _M. piperita_ EO was correlated with its major constituents, such as \(\upalpha\)-terpinene (19.7%), isomenthone (10.3%), piperitone oxide (19.3%), and \(\upbeta\)-caryophyllene (7.6%). In a study carried out by [PERSON] et al. (2006) on _Origanum vulgare_ EO, among 22 identified compounds pulegone (31.54%), 1,8-cineole (15.89%), menthofuran (11.8%), and _cis_-isopulegone (9.74%) were the major constituents, and the MIC values against _Staphylococcus aureus_ was ranged from 75 to 1200 \(\upmu\)g/mL.  
In an investigation of _Lavandula tenuisecta_ EO, 38 components (88.6%) were characterized, where the major constituents were identified as camphor (26.9%), fenchone (22.7%), and 1,8-cineole (18.1%); the EO was effective against almost all studied bacteria, including _Staphylococcus aureus_, _Escherichia coli_, _Pseudomonas aeruginosa_, and _Enterobacter cloaceae_, with MIC and MBC values ranging from 6.25 to 50 \(\upmu\)g/mL [38]. In a study carried out on _Tanucatum walteri_ EO, thymol (22.5%), 1,8-cineole (8.2%), umbellulone (6.9%), \(\upalpha\)-bisabolol (6.3%), and camphor (5.3%) were characterized as the principal constituents; the highest antimicrobial activity of the EO was observed against _Staphylococcus aureus_, _Enterococcus faecalis_, and _Klebsiella pneumoniae_ with MIC values of 0.63 mg/mL [39].  
[PERSON] et al. (2010) showed that the EO of _Cuminum cyninum_ mostly contains cuminaldehyde (39.48%), \(\gamma\)-terpinene (15.21%), \(\upalpha\)-cymene (11.82%), \(\upbeta\)-pinene (11.13%), 2-caren-10-al (7.93%), _trans_-carveol (4.49%), and myrrtenal (3.5%), indicating MIC values of 0.078 mg/mL for Gram-positive bacteria and from 0.078 to 0.15 mg/mL for Gram-negative bacteria [8]. In one study, the major constituents of fennel (_Foeniculum vulgare_) EO were identified as _trans_-anethole (63.16%), I-fenchone (15.53%), estragole (6.43%), limonene (4.69%), and \(\alpha\)-pinene (4.33%). In this experiment, the MIC amounts were determined by the microbroth dilution method and were in the range of 50-100 \(\upmu\)L/mL, depending on the studied bacteria and the tested yeast _C. albicans_[40]. The antibacterial activities of _Satureja_ species (_S. hortensis, S. spicicera_, and _S. khuzistanica_) EOs against Gram-positive and Gram-negative bacteria was studied by [PERSON] et al. (2016), and the MIC value was determined to be 0.031 and 0.062 \(\upmu\)L/mL, respectively [36]. The antibacterial effects of _Mentha piperita_ EOs against _Staphylococcus aureus_ and _Escherichia coli_ microorganisms were in agreement with those of linalool, carvone, and \(p\)-menthan-1-ol contents, while the MIC value was analyzed as 0.1% [41].  
The stronger activity of cinnamon (_Cinnamomum verum_) EO on _Escherichia coli_ and _Staphylococcus aureus_ may be due to cinnaldehyde, the major identified constituent in its EO (92.40%). The MIC value was similar for both bacteria (1.0 mg/mL), while the MBC values were found to be 4.0 and 2.0 mg/mL against _E. coli_ and _Staphylococcus aureus_, respectively [42]. Other research revealed that the EOs of garlic (_Allium sativum_), onion (_Allium cepa_), and cinnamon (_Cinnamom cassia_) show an effective activity against _Listeria monocytogenes_. Sulfides (80%) were the most abundant compounds present in onion and garlic essential oils, while cinnamaldehyde (76.54%) is rich in cinnamon EO. In this study, the MIC values were 0.025 mg/mL for onion EO and 0.100 mg/mL for cinnamon and garlic [43].