Purpose: In this work, three different essential oils were evaluated for their anti-ochratoxigenic effect against two toxigenic A. carbonarius isolates that originated from Greek vineyards.
Methods: Grapes were inoculated with 103 spores and treated with 200 ppm EOs of Eugenia cariophyllus (clove), Cinnanomum cassia (cinnamon) and Cymbopogon flexuosus (lemongrass) in a contact assay and a volatile assay. Grapes were incubated at 25oC and removed for OTA determination by HPLC after 5 days.
Results: The analysis led to diverse differences within the different EOs but also between the two isolates. In contact assay, similar results were observed for both isolates, even though EOs efficacy differed by approximately 40% of toxin reduction by clove, 73% by cinnamon and 58% by lemongrass. On the contrary, volatile assay revealed an isolate dependent effect. Clove oil reduced OTA production by 44% and 90% and cinnamon by 41% and 98%, in Ac29 and Ac28, respectively. Lemongrass had a strong effect in both isolates amounting to 92% and 98%. In conclusion, all EOs used in this study had a great influence on toxin production. However, in comparison of the two EOs treatments, volatiles showed the highest impact on A. carbonarius growth and eventually on OTA production.
Significance: The above findings suggest that natural compounds such as essential oils could be a promising approach to control mycotoxin production against chemical protection strategies.