Effect of gamma radiation on fungal load decontamination of marketed spices

Abstract

In this study, the effects of gamma radiation on the decontamination of fungus, physicochemi-cal properties, and molecular analysis of Aspergillus spp. of common spices for storage were evaluated. After being irradiated with gamma doses of 0, 2, 4, and 6 kGy and sealed in glass vials, the spices were stored at room temperature for 180 days. Among the tested spice samples, chili, turmeric, and black pepper powder showed the highest presence of fungal contamination compared to cumin, coriander, garlic, and ginger samples. Microscopy was used to identify a total of 48 isolates, of which 11 were Mucor, 25 were Penicillium, and 12 were Aspergillus. By polymerase chain reaction (PCR) amplification and sequencing of the internal transcribed spacer (ITS) region, a total of 12 Aspergillus genera were identified among them: 5 in black pepper and 7 in red chili. The gamma radiation also reduced the number of microbes compared to the control group. The best gamma radiation doses were found to kill the organ-isms in the studied spices. These were 6 kGy for red chili, 4 kGy for turmeric and black pepper, and 2 kGy for cumin, coriander, garlic, and ginger. Measurements of the physicochemical parameters were not significantly impacted by the 180-day exposure to gamma radiation; however, the number of fungi drastically decreased. Gamma radiation has been explored as an effective method for decontaminating spices, offering a promising solution for ensuring food safety and quality.