Does the treatment of dried herbs with ozone as a fungal decontaminating agent affect the active constituents?

Abstract

Herbs and spices are food crops susceptible to contamination by toxigenic fungi. Ozone, as a decontamination approach in the industry, has attractive benefits over traditional food preservation practices. A contribution to the studying of ozone as an antifungal and anti-mycotoxigenic agent in herbs and spices storage processes is achieved in this research. Nine powdered sun-dried herbs and spices were analyzed for their fungal contamination. The results indicate that licorice root and peppermint leaves were found to have the highest population of fungi while black cumin and fennel record the lowest population. The most dominant fungal genera are Aspergillus, Penicillium, Fusarium, and Rhizopus. Ozone treatment was performed at a concentration of 3 ppm applied for exposure times of 0, 30, 90, 150, 210, and 280 min. After 280 min of exposure to ozone, the reduction of fungal count ranged from 96.39 to 98.26%. The maximum reduction in spore production was achieved in the case of A. humicola and Trichderma viride exposed for 210 min ozone gas. There was a remarkable reduction in the production of the total mycotoxin, reaching 24.15% in aflatoxins for the 150 min-treated inoculum in the case of A. flavus. The total volume of essential oil of chamomile and peppermint was reduced by 57.14 and 26.67%, respectively, when exposed to 3 ppm. For 280 min. In conclusion, fumigation with ozone gas can be used as a suitable method for achieving sanitation and decreasing microbial load in herbs and spices. Still, it is crucial to provide precautions on ozone's effect on major active constituents before recommending this method for industrial application.

Keywords: Dried herbs and spices; Essential oil constituents; Fungal contamination; Mycotoxins; Ozone.