Microbial quality of gamma-irradiated dried Roselle (Hibiscus sabdariffa L.) calyx powder

The influence of gamma irradiation on the microbial shelf life of Hibiscus sabdariffa (Roselle) calyx powder was determined in this study. Roselle calyx powder samples were procured from a local market, packaged in high-density polyethylene bag, irradiated at 0, 2, 4, 6, 8 and 10 kGy and then stored at ambient temperature (27 ± 3 °C) for 3 months. During the storage period, samples were taken at 0, 1, 2 and 3 months for microbial analysis. Gamma irradiation doses (2, 4 and 6 kGy) significantly reduced the microbial load of the dried calyx powder. Microbial counts were not detected in samples irradiated at 8 and 10 kGy. This implies that gamma irradiation doses of 8 and 10 kGy completely eliminated microorganisms in the samples. Decontamination using gamma irradiation improves the microbial shelf life of Roselle calyx powder. •Irradiation doses of 2, 4 and 6 kGy reduced microbial load of dried calyces powder.•No microbial count was detected in samples irradiated at 8 and 10 kGy.•Radiation decontamination improves microbial shelf life of Roselle calyces powder.