Oregano (O vulgare subsp hirtum) is one of the foremost subspecies of the O vulgare species, mostly used for culinary purposes. 1 Essential oil (EO) of oregano species has been the focus of numerous researchers because of its potential in the food and pharmaceutical industry. Terpenes are the main bioactive compounds of the volatile fraction. Although the quantitative and the qualitative content of the EO varies, depending on many parameters (eg geographical origin, environmental conditions), the monocyclic and oxygenated monoterpenes carvacrol and its isomer thymol are the main characteristic compounds. 2 Oregano species are also rich in bicyclic monoterpenes such as thujene, camphene, α-pinene and β-pinene. Other monoterpenes found in the EO are γ-terpinene and p-cymene. Moreover, oxygenated sesquiterpenes, such as β-caryophyllene oxide, usually exist 3 in the volatile fraction of the species.Among several biological properties of the EOs, antimicrobial activity has attracted intensive research as a natural antimicrobial that could replace synthetic food additives. 4 The effectiveness of EO from O vulgare against pathogenic bacteria, such as Salmonella enterica subsp enterica ser. typhimurium, Escherichia coli, Listeria monocytogenes Staphylococcus aureus, Pseudomοnas aeruginosa and Micrococcus luteus, has been studied, and most researchers have concluded that estimates of minimal inhibitory concentration (MIC)

Nowadays, essential oils (EOs) have a wide use in many applications such as in food, cosmetics, pharmaceutical and animal feed products. Consumers’ preferences concerning healthier and safer foodstuffs lead to an increased demand for natural products, in replacement of synthetic substances, used as preservatives, flavourings etc. EOs, besides being safe, are promising alternatives as natural food additives, and much research has been carried out on their antioxidant and antimicrobial activity. The initial purpose of this review is to discuss conventional and ‘green’ extraction techniques along with their basic mechanism for the isolation of EOs from aromatic plants. This review aims to provide a broad overview of the current knowledge about the chemical constitution of EOs while considering the existence of different chemotypes, since bioactivity is attributed to the chemical composition – qualitative and quantitative – of EOs. Although the food industry primarily uses EOs as flavourings, an overview on recent applications of EOs in food systems and active packaging is provided. EOs exhibit poor solubility in water, oxidation susceptibility, negative organoleptic effect and volatility, restricting their use. Encapsulation techniques have been proven to be one of the best approaches to preserve the biological activities of EOs and minimize their effects on food sensory qualities. Herein, different encapsulation techniques and their basic mechanism for loading EOs are discussed. EOs are highly accepted by consumers, who are often under the misconception that ‘natural’ means safe. This is, however, an oversimplification, and the possible toxicity of EOs should be taken into consideration. Thus, in the final section of the current review, the focus is on current EU legislation, safety assessment and sensory evaluation of EOs. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.