Edible and water solvable corn zein coating impregnated with nisin for Listeria monocytogenes reduction on nectarine and apple

Authors: MENDES-OLIVEIRA, GABRIELLA - Oak Ridge Institute For Science And Education (ORISE); Gu, Ganyu; Luo, Yaguang - Sunny; ZOGRAFOS, ANTHONY - Collaborator; Nou, Xiangwu

Submitted to: Postharvest Biology and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/8/2021
Publication Date: 12/16/2021
Citation: Mendes-Oliveira, G., Gu, G., Luo, Y., Zografos, A., Nou, X. 2021. Edible and water solvable corn zein coating impregnated with nisin for Listeria monocytogenes reduction on nectarine and apple. Postharvest Biology and Technology. 185:111811. https://doi.org/10.1016/j.postharvbio.2021.111811.
DOI: https://doi.org/10.1016/j.postharvbio.2021.111811

Interpretive Summary: Contamination by pathogenic bacteria on fresh produce is a major source of foodborne illness outbreaks. In collaboration with Akorn Technology, who have previously developed an edible corn zein formulation for coating fruits for slowing fruit decay, ARS scientist tested the effectiveness of the natural antimicrobial nisin incorporated into the edible coating against contamination by foodborne pathogen Listeria monocytogenes on nectarine and apple. Findings in this study indicated that nisin incorporated in the edible coating formulation effectively reduced Li. monocytogenes contamination. The findings are useful for further developing this technology as control tools in controlling pathogen contamination on fresh produce, especially on tree fruits.

Technical Abstract: A corn zein based water soluble coating formulation impregnated with nisin at 1mg/ml (CoZWN), or without nisin (CoZW), was evaluated for performance against Listeria monocytogenes as edible coating on nectarine and apple. In comparison to uncoated (NC) control and coating with petroleum-based wax (Wax), CoZWN coated nectarine showed significantly higher reduction of L. monocytogenes population after storage for 2 days at 2.2°C in simulation of refrigerated transportations, followed by additional 2 day at 22°C in simulation of retail display. L. monocytogenes populations were reduced by 1.3 or 1.1 log in comparison to uncoated controls when coating was applied before or after L. monocytogenes inoculation, respectively. The performance of this nisin impregnated corn zein formulation was further validated as a post-contamination coating using gala apples stored at room temperature (22°C) for up to 10 days in simulation of retail display. Gala apples coated with CoZWN significantly accelerated the decline of L. monocytogenes populations during the early stage of the simulated storage, and significantly outperformed Wax through the entire period against L. monocytogenes. CoZWN did not significantly impact the survival and growth of molds and yeasts on nectarine but performed comparably to Wax against molds and yeasts on Gala apple. Data presented in this study indicated that nisin impregnated corn zein coating is a promising strategy for mitigating L. monocytogenes contamination on fresh produce. It also demonstrated that this water soluble coating could be impregnated with other natural antimicrobials to target a wide range of foodborne pathogens.