Comparisons of the number of viable cells (A) and heating energy (B) for peeled potatoes when using steam or microwave heating. ST: no treatment, CS: conventional steam, SHS: superheated steam, MW: microwave heating, TC: total cell count, HR: heat-resistant microorganism. Bar data are mean and standard-deviation values; those marked with different letters differ significantly by ANOVA with Duncan’s multiple-range test at p < 0.05