Inhibition of Fungal Strains Isolated from Cereal Grains via Vapor Phase of Essential Oils.

Tereza Střelková,David Novotný,Anett Kovács,Bence Nemes,Matěj Božik,Pavel Klouček

doi:10.3390/molecules26051313

Tereza Střelková, David Novotný + Show 4 more

Open Access

https://doi.org/10.3390/molecules26051313

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Abstract

Fungal contamination in stored food grains is a global concern and affects food economics and human and animal health. It is clear that there is a need to develop new technologies with improved performances that are also eco-friendly in nature. Due to the bioactivity of essential oils (EOs) in the vapor phase, their low toxicity for humans, and their biodegradability and antifungal properties, EOs could be a suitable solution. In this study, we explored the potential of thyme, oregano, lemongrass, clove, and cajeput EOs in the vapor phase. For 17 days, inhibitory activity was assessed against five strains of postharvest pathogens—Aspergillus spp., Fusarium s. l. spp., and Penicillium ochrochloron—isolated from cereal grains. A modified disc volatilization method was used, which is more effective in comparison to traditional screening methods. Three concentrations were tested (250, 125, and 62.5 μL/L). The two highest concentrations resulted in complete inhibition of fungal growth; however, even 62.5 μL/L showed a significant antifungal effect. The efficiency of EOs followed this order: thyme > oregano > lemongrass > clove > cajeput. From our findings, it appears that the use of EOs vapors is a better option not only for laboratory experiments, but for subsequent practice.

Highlights

Food grains constitute a vital part of the daily diet of the population worldwide [1], and the most cultivated crop is wheat [2]
The main aims of the present study were to determine the antifungal activities of thyme, oregano, clove, lemongrass, and cajeput essential oils (EOs) in the vapor phase, and their suitability for use as disinfectants against Aspergillus spp., Fusarium spp., and Penicillium ochrochloron isolated from cereal grains
Mycotoxins are produced by fungal species such as Aspergillus, Penicillium, and Fusarium that colonize the plants in a field and can spread during the post-harvest period [22]

Summary

Introduction

Food grains constitute a vital part of the daily diet of the population worldwide [1], and the most cultivated crop is wheat [2]. Cereal grains contain a large number of microorganisms that deteriorate the products’ nutritive value and are dangerous to human and animal health [3]. Fungal contamination in stored food grains is a global concern and affects food economics both directly and indirectly [1]. 20% of wheat that would otherwise be available each year is lost due to diseases [2,4]. The mycotoxins secreted by different seed-borne fungi cause qualitative losses of commodities, and potentially induce various health problems in consumers [5].

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