Assessment of the Effect of Satureja montana and Origanum virens Essential Oils on Aspergillus flavus Growth and Aflatoxin Production at Different Water Activities

Abstract

Aflatoxin contamination of foodstuffs poses a serious risk to food security, and it is essential to search for new control methods to prevent these toxins entering the food chain. Several essential oils are able to reduce the growth and mycotoxin biosynthesis of toxigenic species, although their efficiency is strongly influenced by the environmental conditions. In this work, the effectiveness of Satureja montana and Origanum virens essential oils to control Aspergillus flavus growth was evaluated under three water activity levels (0.94, 0.96 and 0.98 aw) using a Bioscreen C, a rapid in vitro spectrophotometric technique. The aflatoxin concentrations at all conditions tested were determined by HPLC-FLD. Aspergillus flavus growth was delayed by both essential oil treatments. However, only S. montana essential oil was able to significantly affect aflatoxin production, although the inhibition percentages widely differed among water activities. The most significant reduction was observed at 0.96 aw, which is coincident with the conditions in which A. flavus reached the highest levels of aflatoxin production. On the contrary, the treatment with S. montana essential oil was not effective in significantly reducing aflatoxin production at 0.94 aw. Therefore, it is important to study the interaction of the new control compounds with environmental factors before their application in food matrices, and in vitro ecophysiological studies are a good option since they provide accurate and rapid results.

Phytochemical Evaluation of Tinctures and Essential Oil Obtained from Satureja montana Herb

“…Therefore, currently there are known some chemotypes, based on the chemical composition of the essential oil analysis of S. montana [ 6 , 10 , 20 ]. Among them are chemotype with thymol and carvacrol domination [ 4 ], carvacrol [ 1 , 2 , 17 ], chemotype of linalool, p -cymene and α-terpineol [ 4 ], chemotype of linalool [ 6 , 10 ], intermediate chemotype of p -cymene/linalool [ 6 ], chemotype of p -cymene, thymol and carvacrol [ 6 ], chemotype of p -cymene and carvacrol [ 19 ], chemotype of myrcene and viridiflorol [ 6 ], chemotype of linalool, thymol and carvacrol [ 10 ], chemotype of p -cymene, linalool, thymol and carvacrol [ 3 ], chemotype of carvacrol, γ-terpinene, and p -cymene [ 20 ].…”

“…S. montana shows antiviral activity against several types of viruses, including human immunodeficiency virus type-1 (HIV-1) and Cucumber mosaic virus (CMV) [ 5 ]. Essential oil of S. montana significantly decreased the aflatoxin production by Aspergillus flavus [ 20 ]. Additionally, S. montana aqueous extracts did not show antibacterial activity.…”

Comparative Growth Inhibition of Bread Spoilage Fungi by Different Preservative Concentrations Using a Rapid Turbidimetric Assay System

“…Lambert), which used linear interpolation between successive OD readings. These TTD OD values were chosen because they more accurately represented the initiation of growth before the filamentous development for these fungi ( Carbó et al, 2018 ; García-Díaz et al, 2020 ).…”

“… Medina et al (2012) showed that the Bioscreen C system, which has been previously used for bacteria and yeast studies, could also be used for filamentous growth assays by subtle modifications of the liquid broth medium. This has allowed the rapid screening of the efficacy of novel compounds, the ecology of growth and mycotoxin production by mycotoxigenic spoilage fungi, and the comparison of formulations of biocontrol agents ( Medina et al, 2012 ; Aldars-García et al, 2018 ; Carbó et al, 2018 ; Debonne et al, 2020 ; García-Díaz et al, 2020 ).…”

Proof of concept: could snake venoms be a potential source of bioactive compounds for control of mould growth and mycotoxin production

“…2020; García‐Díaz et al . 2020). However, there have been few new lead compounds which have been found for use in food and feed chains to reduce mould growth and mycotoxin contamination, without impacting on the organoleptic properties of the final product.…”