Aims: To report fungal and aflatoxin contamination in stored tobacco leaves and the potential of Foeniculum vulgare (fennel) seed essential oil (EO) as a plant-based preservative in protection of tobacco during storage.
Methods and results: Mycological analysis of tobacco samples was done by surface sterilization and serial dilution tests. The Aspergillus flavus isolates were screened for their toxigenicity. Both in vivo and in vitro tests were done to evaluate antifungal and antiaflatoxigenic efficacy of chemically characterized EO. The mycoflora analysis revealed 108 fungal colonies belonging to five genera and nine species. All A. flavus isolates were found aflatoxigenic during screening. Gas chromatography and mass spectrometry analysis of EO identified 19 components (99·66%); estragole being the major component (47·49%). The EO showed broad fungitoxicity at 1·25 μl ml(-1) and 100% inhibition to AFB1 production as well as ergosterol synthesis at 1·0 μl ml(-1) concentration. EO showed 100% protection of stored tobacco samples from aflatoxin B1 contamination.
Conclusions: The fennel EO can thus be formulated as a plant-based preservative for food items.
Significance and impact of the study: The present investigation comprises the first report on antiaflatoxin efficacy of fennel oil and its potency in the protection of tobacco leaves from fungal and aflatoxin contamination during storage.
Keywords: Aspergillus; aflatoxin; essential oil; fennel; preservation; tobacco.
© 2015 The Society for Applied Microbiology.