|ZHOU, SIYUAN - Southwest University|
|ZHAO, GUOHUA - Southwest University|
|YAM, KIT - Rutgers University|
Submitted to: Food Research International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/2/2020
Publication Date: 2/7/2020
Citation: Zhou, S., Jin, Z.T., Sheen, S., Zhao, G., Liu, L.S., Juneja, V.K., Yam, K. 2020. Development of sodium chlorite and glucono delta-lactone incorporated PLA film for microbial inactivaton on fresh tomato. Food Research International. 132:1-7. https://doi.org/10.1016/j.foodres.2020.109067.
Interpretive Summary: Foodborne pathogens can contaminate the surfaces of fresh fruits and vegetables, causing food safety concerns. In this study, a novel antimicrobial film was developed to reduce Salmonella and E. coli O157:H7 on fresh tomatoes. The film incorporated glucono delta-lactone and sodium chlorite and released gaseous chlorine dioxide into package headspace after triggered by moisture generated by fresh tomato in the package. The results revealed that the gaseous chlorine dioxide treatment achieved over 99.999% reductions of both pathogens, and no bacterial growth was observed throughout the 14-day storage period at both 10 and 22ºC.
Technical Abstract: Chlorine dioxide (ClO2) is an effective disinfectant used in the sanitation of fresh produce. Compared to the aqueous form, gaseous ClO2 has an enhanced microbial inactivation capability. This research focused on the development of a novel ClO2(g)- releasing film which incorporated Glucono Delta-Lactone (GDL) and NaClO2 for ClO2(g) generation, utilizing moisture naturally released from tomato as the reaction trigger. The surface morphology of films produced from different formulations was investigated. The impacts of polylactic acid (PLA) amount, reactants/substrate ratio, NaClO2/GDL ratio, temperature and relative humidity on the release profiles of ClO2(g) were elucidated. The microbial inactivation results revealed that the generated ClO2(g) reduced populations of surface-inoculated Salmonella and E. coli O157:H7 from ca. 5 log CFU/g to an undetectable level (< 1 log CFU/g) within 2 and 4 hours respectively and the complete elimination in populations of both bacterial species was maintained throughout the 14-day storage period at both 10 and 22ºC. The sensory qualities (including texture, surface color and characteristic odor) of tomatoes under treatments were evaluated and exhibited no significant difference (p > 0.05) compared with controls. The results from the film storage study indicated that film efficacy could be maintained throughout storage for 4 weeks under ambient conditions. The developed film can be used to protect the microbial safety of fresh tomato during the storage, transportation and retail stages. It can also be used for the safety enhancement of many other fresh produce items and for the potential inactivation of many other pathogens.