Novel generation systems of gaseous chlorine dioxide for salmonella inactivation on fresh tomato

Authors: ZHOU, SIYUAN - Rutgers University; HU, CHANGYING - Rutgers University; ZHAO, GUOHUA - Rutgers University; Jin, Zhonglin; Sheen, Shiowshuh - Allen; Liu, Linshu; YAM, KIT - Rutgers University

Submitted to: Food Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/15/2018
Publication Date: 5/17/2018
Citation: Zhou, S., Hu, C., Zhao, G., Jin, Z.T., Sheen, S., Liu, L.S., Yam, K.L. 2018. Novel generation systems of gaseous chlorine dioxide for salmonella inactivation on fresh tomato. Food Control. 92:479-487. https://doi.org/10.1016/j.foodcont.2018.05.025.
DOI: https://doi.org/10.1016/j.foodcont.2018.05.025

Interpretive Summary: In a previous study, we placed the chemical salt, sodium chlorite crystals, and fresh tomatoes in a container, and found that gaseous chlorine dioxide (ClO2) was generated and protected the tomatoes from bacterial growth. To use this method on the commercial scale, we incorporated sodium chlorite crystals in films made from of acacia gum and in electrospun fibrous mats of polyethylene oxide. The films and the mats were tested as active packaging materials by packing with fresh tomatoes that were inoculated with Salmonella, bacteria that cause human illness. The number of Salmonella on the surfaces of the tomatoes were reduced to undetectable levels within 2 days using either the films or the mats. The color and firmness of the tomatoes were not impacted. This technology can be used for produce protection, and can benefit growers, processors, and consumers of fruits and vegetables.

Technical Abstract: Chlorine dioxide (ClO2) is an antimicrobial agent used in fresh produce sanitation to inactivate a broad range of pathogens. Compared to its aqueous form, gaseous ClO2 has a stronger penetrating ability and therefore a greater inactivation effect. A novel ClO2(g) generating method, utilizing the carbon dioxide and moisture naturally released from tomato during respiration to react with NaClO2 for ClO2(g) generation, has been proposed in our previous study. This study further developed two novel generation systems, with one based on electrospun fibrous mats and the other on releasing films of acacia gum, for the method under actual use conditions. The physical properties, viscosity, conductivity, pH and surface tension, of different poly(ethylene) oxide (PEO) polymer solutions (2%, 3%, and 4% PEO and 3% PEO with 0.15% or 0.3% NaClO2), the morphology and diameter distribution of the electrospun fibers produced as well as the loading efficiency of NaClO2 onto the fibrous mats or films were investigated. The successful generation of ClO2(g) from the two systems were observed. Approximately 4 log CFU Salmonella/tomato inoculated on the surface were reduced to an undetectable level (< 5 CFU/tomato) within 2 days under both systems. The surface color and firmness of the tomatoes were not impacted during the entire storage period (14 days at 10 degree C and 7 days at 22 degree C).