Journal Article

Synergistic antibacterial effect of hydroxyl radicals generated by the combination of hypochlorous acid and UV irradiation

Lee, Hwa Yong, Lee, Han Bit, Kim, Younghee

2025

Overview

Livestock farms are at risk of exposure to various environmental pollutants, particularly airborne viruses that can cause infectious diseases. Hydroxyl radicals (•OH) are well-known for their strong bactericidal and virucidal properties and are widely applied in disinfection processes. However, their efficacy is significantly diminished in the presence of organic substances. This study investigated the bactericidal effects of hydroxyl radicals generated from hypochlorous acid (HOCl) under UV irradiation and evaluated their resistance to quenching by airborne organic matter. Rose Bengal (RNO) dye was used as a probe to detect •OH radical generation, while yeast extract served as a representative organic contaminant. RNO bleaching efficiency increased in a concentration-dependent manner under UV irradiation, confirming the formation of hydroxyl radicals. However, in the presence of yeast extract, this bleaching effect was drastically reduced, indicating that organic compounds can interfere with radical activity. The bactericidal effects of UV light and HOCl were independently evaluated using Salmonella as a model organism. The presence of organic matter significantly reduced the bactericidal efficacy of both UV and HOCl treatments when applied separately. In contrast, combined exposure to HOCl and UV irradiation demonstrated a 10% increase in bacterial reduction and halved the required exposure time, regardless of HOCl concentration. These findings highlight the synergistic bactericidal potential of HOCl and UV irradiation and support their applicability in airborne bacterial disinfection under realistic environmental conditions.

• Publisher: Public Library of Science,PLOS,Public Library of Science (PLoS)
• Subject: Air pollution / Amino acids / Anti-Bacterial Agents - chemistry / Anti-Bacterial Agents - pharmacology / Antibacterial activity / Antibacterial agents / Antimicrobial agents / Biology and Life Sciences / Bleaching / Chlorine / Contaminants / Disinfection / Disinfection & disinfectants / Disinfection - methods / Drug Synergism / Effectiveness / Efficiency / Environmental conditions / Environmental quality / Exposure / Farms / Foot & mouth disease / Free radicals / Hydrochloric acid / Hydroxyl Radical - chemistry / Hydroxyl Radical - pharmacology / Hydroxyl radicals / Hypochlorous acid / Hypochlorous Acid - chemistry / Hypochlorous Acid - pharmacology / Infection control / Infectious diseases / Irradiation / Livestock / Livestock farming / Livestock farms / Medicine and Health Sciences / Organic compounds / Organic contaminants / Organic matter / Outdoor air quality / Physical Sciences / Proteins / Rose Bengal - chemistry / Salmonella / Salmonella - drug effects / Salmonella - radiation effects / Ultraviolet radiation / Ultraviolet Rays / Yeast