U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.


Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Main content area

Aqueous chlorine dioxide generated with organic acids have higher antimicrobial efficacy than those generated with inorganic acids

Lianger Dong, Marisa Wall, Yong Li
International journal of food microbiology 2022 v.369 pp. 109632
Escherichia coli O157, Listeria monocytogenes, Salmonella Typhimurium, antimicrobial properties, chlorine dioxide, chlorites, citric acid, food microbiology, hydrochloric acid, lactic acid, malic acid, models, pH, peptones, romaine lettuce, sodium sulfate
Chlorine dioxide (ClO₂) is commonly generated by mixing sodium chlorite and acid. This study aimed to evaluate how acid affects the release kinetics and antimicrobial property of ClO₂. Solutions made with weak acids released ClO₂ more slowly and had higher stability than those made with hydrochloric acid. Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes were treated with 1, 2.5, and 5 ppm ClO₂ for 3 or 5 min. Lettuce inoculated with the pathogenic bacteria were treated with 2.5 and 5 ppm ClO₂ for 5 min. The effects of peptone load at 0.01% and 0.02% on the antimicrobial efficacy of ClO₂ were investigated in S. Typhimurium cell suspensions. The contribution of acids alone at the pH of the ClO₂ solutions to bacterial reduction was also evaluated. The 2.5 ppm ClO₂ solutions made with citric acid, lactic acid, and malic acid showed higher reductions in all three bacteria than ClO₂ made with hydrochloric acid and sodium bisulfate. The 5 ppm ClO₂ solutions produced with organic acids reduced populations of all bacterial strains from 7 log CFU/mL to undetectable level in 3 min, except S. Typhimurium treated by ClO₂ produced with lactic acid. On inoculated Romaine lettuce model, 5 ppm ClO₂ produced with lactic acid and malic acid resulted in the highest reduction of E. coli O157:H7, S. Typhimurium, and L. monocytogenes of approximately 1.4, 1.7, and 2.4 log CFU/g, respectively. The antimicrobial efficacy of ClO₂ made with HCl and NaHSO₄ were affected by 0.01% and 0.02% peptone load, respectively. Food-grade organic acids produced aqueous ClO₂ solutions with stronger antimicrobial properties than inorganic acids. The acids alone at the pH of ClO₂ did not show significant bacterial reductions.