###### Abstract  
Due to the increasing risk of chemical contaminations in the application of synthetic fungicides, the use of plant essential oils and extracts has recently been increased. In the present review, the antimicrobial potential of the most active plant-food essential oils in liquid and vapor phases has been reviewed. The volatile isothiyanates, aldehydes, and phenols, including allyl isothiamate, carvacrol, thymol, and eugenol, are considered to be the predominant components of essential oils, possessing significant antimicrobial activities. These components alone or in mixture can be effective. Overall, the antimicrobial activity of aroma compounds depends on the plant species, concentration, and method of application. This review provides useful information about the inhibitory application of the most common plant-foods' essential oils in liquid and vapor phases against the growth of pathogenic microorganisms. Essential oils (EOs) are promising natural antimicrobial alternatives in food processing facilities. Although the food industry primarily uses spices and herbs to impart flavor, aroma, and pungency to foods, potent EOs represent interesting sources of natural products for food preservation.  
functional foods; essential oils; liquid and vapor phases; antimicrobial potencies +
Footnote †: journal: Chemical Biology  
0000-0002-4891-5000]J. A. M. M.  
improve the quality and storage time of perishable food [4]. The continuous application of synthetic fungicides causes resistance in different fungal strains, while resistance to plant EOs will occur more slowly due to the different combination of compounds in EOs [5]. The synergistic effect of two or more natural compounds leads to an increase in antimicrobial potential, since the pathogens cannot easily resist all essential oil constituents [6]. The composition of EOs should be considered in their use as preservatives, because the diversity of chemical compounds may affect their biological activities. In many cases, the main constituents of EOs show bioactivity, while small amounts of EOs play an important and vital role in improving their bioactivity [7]. The type of compounds in the essential oil is one of the things that should be considered in their use as a preservative, because the variability of the chemical composition may biologically affect them. Moreover, it is very difficult to detect the exacerbating effects of some bioactive components on each other because their amounts of EOs vary. In recent decades, numerous studies have investigated the chemical composition of EOs and plant extracts which possess antimicrobial potency [8; 9; 10; 11; 12; 13] (Table S1). The susceptibility of different microbial species also differs correlating to the plant's type of EO and its different concentrations [14]. Previous studies have demonstrated that EO constituents are good microbial agents, where the microbial potency decreases in the following order: phenols > aldehydes > ketones > alcohols > esters > hydrocarbons [13]. In the present study, we comprehensively reviewed the chemical composition and antimicrobial potential of EOs by searching the keyword \"chemical composition and antimicrobial\" in the PubMed and Web of Science databases (last search: 25 September 2020).