Evaluating cinnamaldehyde as an antibacterial agent in a produce wash for leafy greens

Escherichia coli is a common foodborne pathogen in produce, especially leafy greens, which are often consumed raw. Post-harvest sanitizing is an essential step in mitigating the risk of foodborne illness associated with uncooked produce. We explore the potential antibacterial effects of cinnamaldehyde against E. coli when used as a produce wash for leafy greens. We hypothesized that treating leafy greens with cinnamaldehyde, a promising antibacterial agent, would yield an observable decrease in E. coli growth contamination, measured in colony-forming units (CFUs). In this study, we treated lettuce samples with various concentrations of cinnamaldehyde solution and compared the E. coli growth to water and bleach treatment controls. By analyzing either the leaf surface or the wash solution, we were able to detect the presence of E. coli. Lettuce treated with cinnamaldehyde in any concentration displayed significantly lower CFUs when compared to lettuce treated with chlorine bleach (p<0.00001). 0.5% and 1.0% cinnamaldehyde solutions were also more effective at inhibiting E. coli growth than 0.2% cinnamaldehyde (p=0.00387). Cinnamaldehyde had an effect on the survival rate of E. coli on lettuce that was equal to or greater than that of bleach. The concentration of cinnamaldehyde in the solution had a significant effect on the bacterial counts after washing; thus, we anticipate that cinnamaldehyde treatment may lead to a possible leafy green post-harvest wash solution.