Investigating the effects of plant essential oils on post-harvest fruit decay.

Essential oils are one of the most important natural products derived from plants, due to their various biological properties and their medicinal and nutritional uses. This chapter provides an overview of several different aspects relating to essential oils including a historical perspective, the uses of essential oils, their main sources and antifungal activity, their bioactive single constituents and their modes of action. The chapter will also give an insight into the chemical measures necessary for controlling plant pathogens and their negative impact on human health and/or the environment. It will also review the different sources of essential oils such as sage, oregano, thyme and marjoram from the Lamiaceae family, vervain from the Verbanacae family, and magnolia from the Magnoliaceae family. The antimicrobial activity of essential oils is reviewed, with particular emphasis on the antifungal properties exhibited against some serious pathogenic fungi and postharvest disease. Moreover, various antimicrobial tests and techniques, such as various kill-time studies, killing time determination, LD-50 and growth curve recording, poisoned food techniques, spore germination and measurement of metabolic CO2 are included. Finally, five case studies relating to the antifungal activity of some plant essential oils, either in vitro or in vivo, against post-harvest pathogenic fungi are reviewed at the end of this chapter.