Microbial decontamination of dried cassava (Manihot esculenta) chips using gamma irradiation

Abstract

This study presented an evaluation of the impact of gamma irradiation as a decontaminating tool in improving microbial quality of dried cassava chips. Thirteen (13) month old white-flesh cassava roots were purchased from an experimental farm of the Council for Scientific and Industrial Research-Crops Research Institute (CSIR-CRI) at Pokuase in the Greater Accra Region of Ghana. The cassava roots were cleaned, peeled, washed and processed into chips, and then oven-dried. The dried cassava chips were gamma irradiated to target doses of 2.5, 5.0, 7.5 and 10.0 kGy at a dose rate of 0.75 kGy/h. Un-irradiated chips were used as controls. Total Viable Count (TVC), Total Coliform Count (TCC), Yeast and Mould Count (YMC), Staphylococcus aureus count (SAC), Bacillus species count (BSC) and Salmonella count (SC) of the dried cassava chips were determined using standard methods. Coliform, Staphylococcus aureus, Bacillus spp, yeast and moulds were detected in the dried cassava chips, except Salmonella. Gamma irradiation significantly reduced the microorganisms recorded on the surfaces of the dried cassava chips in dose-dependent manner. Radiation decontamination has the potential to improve microbial quality of dried cassava chips.