Antimicrobial activity of Cymbopogon citratus essential oil against the mycoflora of stored dried fruits of Zanthoxylum armatum

Aim : The study aimed to investigate the fungal contamination in dried fruits of Zanthoxylum armatum and the effect of essential oil of Cymbopogon citratus against the deteriorating fungi and aflatoxin production by Aspergillus flavus. Methodology : Mycoflora analysis of dried fruits of Z. armatum was done by dilution plate technique, while the antifungal assay of essential oil of C. citratus against seven isolated moulds was carried out by poisoned food technique. Aflatoxigenic potential of Aspergillus flavus and anti-aflatoxigenic activity of essential oil of C. citratus was done by spectrophotometric method. Results : A total of 17 fungal species were isolated with Aspergillus as the predominant genus. The characterization of C. citratus essential oil revealed alpha-citral and beta-citral as major components. Essential oil significantly exhibited antifungal activity against the growth of tested fungal species. The minimal inhibitory concentration of essential oil was found to be 1.5 mu l ml(-1) for Fusarium graminearum. 2.5 mu l ml(-1) for Alternaria alternata. Aspergillus flavus, A. ochraceus and Penicillium expansum and 3.0 mu l ml(-1) for A. parasiticus and P. citrinum. respectively. The essential oil completely checked the production of aflatoxin B-1 by the toxigenic strains of A. flavus. Interpretation : Both mycelial growth and aflatoxin B-1 production followed a declining trend with an increase in essential oil concentration, demonstrating its practical efficacy as a plant based antimicrobial for enhancing the shelf-life of Z. armatum.