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

This study assessed the efficacy and practical applicability of chlorine dioxide (ClO 2 ) 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 ClO 2 concentrations(0–50 mg/L) and exposure durations(1–5 min). At 25 mg/L, ClO 2 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 ClO 2 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, ClO 2 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. • TOPSIS found 25 mg/L ClO₂ optimal, cutting pesticides and microbes effectively while maintaining overall product quality. • Confirmed pesticide and microbial reduction under real farm conditions, with no adverse effects on product quality. • Cluster analysis grouped pesticides by reduction patterns and stability, offering predictive insights for ClO 2 washing effectiveness before and after drying.