Essential Oil Vapors Assisted Plasma for Rapid, Enhanced Sanitization of Food-Associated Pathogenic Bacteria

Antimicrobial treatment procedures are often applied during produce post-harvest processing and storage as a complementary measure to reduce the potential risk of foodborne illness. Herein, we investigate the feasibility and efficacy of utilizing essential oil vapor–assisted plasma treatments to sanitize lettuce, spinach, and tomatoes. These fresh produce items are often associated with foodborne illnesses. Additionally, potatoes were chosen to introduce topography diversity into the study. It was observed that the exposure times of bacteria-inoculated tomatoes, to essential oil vapor–assisted plasma, strongly affected bacterial inactivation of Salmonella enterica subsp. Enterica serovar typhimurium lilleengen type (LT) 2 ( Salmonella typhimurium LT2), a gram-negative bacterium. Combining essential oil vapors with atmospheric plasma for 100 s resulted in a significant increase in logarithmic scale reductions compared to atmospheric plasma alone. For Salmonella , the logarithmic scale reduction in viable bacteria increased from 0.9 ± 0.38 to 1.7 ± 0.27 log 10 CFU/cm 2 when the treatment atmosphere was changed from atmospheric plasma to essential oil vapor–assisted plasma. In Listeria innocua , a surrogate for L. monocytogenes , gram-positive bacteria, logarithmic scale reduction increased from 1.5 ± 0.22 to 2.5 ± 0.20 log 10 CFU/cm 2 . When an optimal treatment time of 100 s was used to treat the other vegetable substrates using essential oil vapor–assisted atmospheric plasma, there was no discernible effect of variations in the produce surface roughness and hydrophilicity on the bactericidal efficacy against Salmonella and Listeria. Overall, we conclude that the use of essential oil vapor–assisted plasma is a viable and rapid means of controlling contamination outbreaks.