Comparison of 254 and 222  nm Ultraviolet‐C Light for Treatment of Wheat Flour and Infant Formula: Antimicrobial Capacity, Color Analysis, and Light Energy Efficiency

ABSTRACT

This study investigated the efficacy of ultraviolet‐C (UV‐C) light at 254 and 222 nm for inactivating Enterococcus faecium in wheat flour and powdered infant formula using a novel redistribution system to enhance particle exposure. The effects of varying UV‐C dosages (0, 0.50, 1.24, and 2.48 J/cm ² ) on microbial reduction and color changes were evaluated. Results demonstrated that 254 nm UV‐C light was more effective than 222 nm UV‐C for decontaminating the product, achieving significantly greater reductions in E. faecium across both food matrices ( p  < 0.05). In wheat flour, 254 nm treatment achieved a 4.5‐log reduction at 2.48 J/cm ² , compared to a 2.4‐log reduction at 222 nm. In infant formula, the 254 nm treatment achieved a 3.5‐log reduction, whereas the 222 nm treatment achieved a 1.5‐log reduction. While 254 nm light showed greater inactivation capacity, the electrical energy required per log reduction was comparable between the two wavelengths ( p  < 0.05). Posttreatment CIELAB color analysis found that no visibly discernible color changes occurred in wheat flour or infant formula samples ( p  > 0.05). This study suggests that UV‐C treatment, particularly at 254 nm, is a promising nonthermal decontamination method for powdered foods. It offers a potential energy‐efficient solution to enhance their safety without significantly impacting visual quality.