P3-85 Application of Cinnamon Oil Nanoemulsion to the Control of Foodborne Bacteria Such as Listeria spp. and Salmonella spp. on Honeydew Melon

Wednesday, July 12, 2017
Exhibit Hall (Tampa Convention Center)
Sumit Paudel , University of Central Oklahoma , Edmond , OK
Kanika Bhargava , University of Central Oklahoma , Edmond , OK
Hari Kotturi , University of Central Oklahoma , Edmond , OK
Introduction: Listeria and Salmonella related recalls and outbreaks are of major concern to melon industry. Cinnamon oil have shown their usefulness in food treatment due to strong antifungal, antiviral, and antibacterial activities. However, its applications are limited due to poor solubility of cinnamon oil in water. Utilization of cinnamon oil nanoemulsion may offer effective antimicrobial washing treatment to melon industry.

Purpose: The purpose of this study was to test the antimicrobial efficacy of cinnamon oil nanoemulsion on melons against major foodborne pathogens such as Listeria monocytogenes and Salmonella enterica.

Methods: Different formulations of cinnamon oil nanoemulsion was made by ultrasonication using Tween 80 as emulsifier. Nanoemulsion exhibiting the smallest oil droplets was applied. Oil droplets were characterized for particle size by dynamic light scattering. Microbroth dilution assay was performed on three strains each of L. monocytogenes and S. enterica to find out the antimicrobial efficacy of cinnamon oil nanoemulsion. Honeydew melons were artificially inoculated with the above mentioned strains followed by treatment in nanoemulsions (control, 0.1%, and 0.25%) for one minute. Samples were dried and enumerated after one hour of treatment on selective media (PALCAM and XLD agar).

Results: The average diameter of nanoemulsions was 19.6 nm. Minimum inhibitory concentration (MIC) of cinnamon oil nanoemulsion for both Listeria and Salmonella strains was 0.078% v/v and 0.039% v/v, respectively. The minimum bactericidal concentration was 0.078% v/v for both. Compared to the water control, melon showed one-log reduction in L. monocytogenes and two-log reduction in S. enterica, respectively. 0.5% v/v of nanoemulsions might yield better log reduction in future trials.

Significance: The data suggest that cinnamon oil nanoemulsion can be used as an effective natural microbial control agent for honeydew melons.