Chlorine dioxide as water disinfectant during fresh-cut iceberg lettuce washing: Disinfectant demand, disinfection efficiency, and chlorite formation. (January 2017)

• Record Type: Journal Article
• Authors: Van Haute, S.; Tryland, I.; Escudero, C.; Vanneste, M.; Sampers, I.
• Is Part Of: Lebensmittel-Wissenschaft + Technologie =. Volume 75(2017)
• Page Start: 301
• Page End: 304
• Publication Date: 2017-01
• Subjects: Fresh-cut lettuce -- Chlorine dioxide -- Water disinfection -- Microbial cross-contamination -- Disinfection by-products; Food industry and trade -- Periodicals; Food -- Composition -- Periodicals; Microbiology -- Periodicals; Nutrition -- Periodicals; 664.005
• DOI: 10.1016/j.lwt.2016.09.002
• Languages: English
• ISSNs: 0023-6438

Abstract

Abstract: The use of chlorine dioxide (ClO2 ) as water disinfectant during fresh-cut iceberg lettuce washing was studied concerning three key issues: i) disinfectant demand, ii) disinfection efficiency, and iii) production of chlorite (ClO2 − ). Standardized process water (SPW), a watery suspension of iceberg lettuce, was used as model water system. In SPW (chemical oxygen demand (COD) 1130 mg O2 /L, 4 °C, pH 7) the chlorine demand was more than 10 times higher than the ClO2 demand. Dosing 5 mg/L ClO2 (0.40 mg/L residual after 2 min contact time) inactivated the total psychrotrophic plate count (TPC), including molds, to undetectable levels (>3 log reduction) after 2 min, and reduced Escherichia coli ( E. coli ) to undetectable levels (>5 log reduction) within 3 min. A dose of 70 mg/L chlorine (free chlorine residual of 1.7 mg/L after 2 min) was unsuccessful to inactivate molds to undetectable levels. About 77% of the consumed ClO2 was reduced to ClO2 − due to reaction with the SPW. Concerning disinfectant dose, ClO2 is more efficient than free chlorine for disinfecting fresh-cut lettuce wash water. However, data on the transfer of ClO2 − and chlorate (ClO3 − ) to the lettuce is needed before ClO2 can be recommended as wash water disinfectant. Highlights: ClO2 was compared with free chlorine as fresh-cut lettuce wash water disinfectant. The chlorine demand is more than 10 times higher than that of ClO2 . ClO2 is more efficient at inactivating molds than free chlorine. About 77% of the consumed ClO2 was reduced to ClO2 − . Possible transfer of ClO2 − to fresh produce needs investigation.