Radicidation of Frozen Grated-Yam and Change of Its Viscosity

Abstract

The use of a gamma radiation process for the elimination of coliform in frozen grated yam seasoned and beaten was investigated. The number of coliform was detected from 9 to 365 per gram, and total number of bacteria were counted from 3.3×10⁴ to 5.6×10⁵ per gram. The coliform group was composed of both Escherichia coli and Intermediate type, and also Arizona like organism and Proteus were isolated considerably. The D₁₀ values of coliform and Salmonella in the frozen grated yam were 35krad and 40krad respectively, and these organisms could be reduced below a detectable limitation by a dose of 150 to 200krad irradiation. The sterilization of coliform and Salmonellae in frozen grated yam could be achieved by a dose of 300 to 500krad irradiation. However viscosity of grated yam, which have an effect on organoleptic quality, was decreased extremely when irradiated with a dose more than 200krad, and so it could be concluded that the irradiation of 150 to 200krad would be desirable for elimination of coliform and Salmo-nellae from frozen grated yam without remarkable change of organoleptic qualities.