Assessment of Cymbopogon citratus (DC.) stapf essential oil as herbal preservatives based on antifungal, antiaflatoxin, and antiochratoxin activities and in vivo efficacy during storage.

Thirty-five randomly collected samples of stored table grapes (Vitis vinifera L.) from different markets of Gorakhpur city, Uttar Pradesh, India, revealed occurrence of 11 types of fungi. Of which, Aspergillus flavus, Aspergillus niger, and Aspergillus ochraceus were dominant causing severe decay of grapes with 58%, 52%, and 67% incidence, respectively. On screening of 15 essential oils at 0.33 μL/mL, Cymbopogon citratus oil caused 100% mycelial inhibition against aforesaid dominant fungi. Oil was fungistatic at 0.29 μL/mL and exhibited broad fungitoxicity against other fruit rotting fungi associated with collected samples. C. citratus oil completely inhibited the growth and mycotoxin (AFB1 and OTA) secretion of the aflatoxigenic and ochratoxigenic strains of A. flavus, A. niger, and A. ochraceus at 0.8 μL/mL. E-Citral (52.9%) and Z-Citral (39.38%) were the major components of C. citratus oil during gas chromatography and gas chromatography-mass spectrometry analysis. Application of 200 and 300 μL of C. citratus oil on 1 kg of stored grapes showed enhancement of shelf life up to 10 d. The oil did not exhibit any phytotoxic effect on fruits. These results confirm that C. citratus oil could be a natural alternative to commercial fungicide for control of fruit rotting fungi of stored grapes.