Enhancing safety and quality of red pepper powder using chlorine dioxide washing

This study assessed the efficacy and practical applicability of chlorine dioxide (ClO₂) washing technology for reducing pesticide residues and microbial contamination in red peppers and red pepper powder. Laboratory trials evaluated pesticide removal, microbial inactivation, and quality attributes (color, vitamin C, capsaicinoids under various ClO₂ concentrations(0–50 mg/L) and exposure durations(1–5 min). At 25 mg/L, ClO₂ reduced pesticide residues by 8–11 % in red peppers and 54–62 % in red pepper powder, and decreased total bacterial counts by approximately 1.0 Log CFU/g (p < 0.05). Using the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method integrated with gas exposure monitoring, 25 mg/L was identified as the optimal concentration balancing reduction efficiency and worker safety. Field validation using red peppers from three farms confirmed that the developed ClO₂ washing device maintained stable concentrations and was effective under practical farm-level conditions. Cluster analysis revealed distinct patterns in pesticide reduction depending on their physicochemical stability. Overall, ClO₂ washing demonstrated effective and safe removal of pesticide residues and microorganisms while maintaining product quality, supporting its use as a practical post-harvest management strategy for red pepper powder production.