Antimicrobial effect of zinc oxide nanoparticles on Campylobacter jejuni and Salmonella enterica serovar Enteritidis

Authors: He, Yiping; Capobianco, Joseph; IRWIN, PETER - Former ARS Employee; Reed, Sue; Lee, Joseph - Joe

Submitted to: Journal of Food Safety
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/21/2022
Publication Date: 4/3/2022
Citation: He, Y., Capobianco Jr, J.A., Irwin, P., Reed, S.A., Lee, J. 2022. Antimicrobial effect of zinc oxide nanoparticles on Campylobacter jejuni and Salmonella enterica serovar Enteritidis. Journal of Food Safety. https://doi/10.1111/jfs.12979.
DOI: https://doi.org/10.1111/jfs.12979

Interpretive Summary: Antimicrobial resistance is considered one of the most serious health threats to both animals and humans. Resistance of bacteria to antibiotics is a pressing concern, which has generated an unmet need for new treatment strategies to bacterial infections. Rather than focus on the development of new antibiotics, which can ultimately lead to resistance, this multidisciplinary project concentrated on an alternative strategy using inorganic materials generally recognized as safe (GRAS) by the U.S. Food and Drug Administration. Multiple grades of low-cost zinc oxide powders (ZnO) demonstrated the ability to significantly reduce the microbial load of Salmonella and Campylobacter, two leading common causes of foodborne illnesses. The impact of size, shape and distribution of the particles on their antimicrobial effect was assessed for two common foodborne pathogens, Salmonella and Campylobacter. The research indicates that Campylobacter is more sensitive to treatment with ZnO, and that lower concentrations and exposure times are required to observe antimicrobial activity than for Salmonella. However, it was demonstrated that both pathogens could be completely inactivated by ZnO in less than six hours. In addition to demonstrating the antimicrobial properties of ZnO on two common foodborne pathogens, the research investigates the role of the particle size, size distribution and shape on the efficacy of the treatment. The results indicate that large micron-sized agglomerations of the nanoparticles are effective, and that deagglomerating to their primary nanoparticle size may not be necessary. This observation is valuable because it highlights that the particles may not need to be nanosized to be effective, which can facilitate their adoption as there are concerns from US and European regulators about the use of nanomaterials as food additives and/or on food contact surfaces.

Technical Abstract: Antimicrobial resistance is considered one of the most serious health threats to both animals and humans. Resistance of bacteria to antibiotics is a pressing concern, which has generated an unmet need for new treatment strategies to bacterial infections. Rather than focus on the development of new antibiotics, which can ultimately lead to resistance, this multidisciplinary project concentrated on an alternative strategy using inorganic materials generally recognized as safe (GRAS) by the U.S. Food and Drug Administration. Multiple grades of low-cost zinc oxide powders (ZnO) demonstrated the ability to significantly reduce the microbial load of Salmonella and Campylobacter, two leading common causes of foodborne illnesses. The impact of size, shape and distribution of the particles on their antimicrobial effect was assessed for two common foodborne pathogens, Salmonella and Campylobacter. The research indicates that Campylobacter is more sensitive to treatment with ZnO, and that lower concentrations and exposure times are required to observe antimicrobial activity than for Salmonella. However, it was demonstrated that both pathogens could be completely inactivated by ZnO in less than six hours. In addition to demonstrating the antimicrobial properties of ZnO on two common foodborne pathogens, the research investigates the role of the particle size, size distribution and shape on the efficacy of the treatment. The results indicate that large micron-sized agglomerations of the nanoparticles are effective, and that deagglomerating to their primary nanoparticle size may not be necessary. This observation is valuable because it highlights that the particles may not need to be nanosized to be effective, which can facilitate their adoption as there are concerns from US and European regulators about the use of nanomaterials as food additives and/or on food contact surfaces.