Inactivation of <i>Bacillus cereus</i> Spores on Red Chili Peppers Using a Combined Treatment of Aqueous Chlorine Dioxide and Hot‐Air Drying

Abstract

Abstract The effect of a combined treatment using aqueous chlorine dioxide (ClO 2 ) and hot‐air drying to inactivate Bacillus cereus spores on red chili peppers was evaluated. Ten washed and dried pepper samples, each comprising half of a single pepper ( Capsicum annuum L .), were inoculated with B. cereus spore suspension. The inoculated samples were washed with sodium hypochlorite (NaOCl; 50, 100, or 200 μg/mL) or ClO 2 (50, 100, or 200 μg/mL) solution for 1 min and then air‐dried (25 ± 1 °C, 47 ± 1% relative humidity), which was followed by drying with hot air at 55 °C for up to 48 h. The spore populations on the samples were enumerated and their a w and chromaticity values were measured. The spore numbers immediately after treatment with NaOCl and ClO 2 were not significantly different. A more rapid reduction in spore numbers was observed in the samples treated with ClO 2 than those treated with NaOCl during drying. A combined treatment of ClO 2 and hot‐air drying significantly reduced the spore populations to below the detection limit (1.7 log CFU/sample). B. cereus spores on chili peppers were successfully inactivated by washing with ClO 2 solution followed by hot‐air drying whereas the pepper color was maintained.