Inhibitory effect of plant essential oil nanoemulsions against Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Typhimurium on red mustard leaves

In this study, essential oil (EO) nanoemulsions as an alternative to chlorine-based sanitizers for red mustard leaves were prepared, and their inhibitory effects against pathogenic bacteria were examined. Red mustard leaves spot-inoculated with Listeria monocytogenes, Escherichia coli 0157:117, and Salmonella Typhimurium were treated with EOs alone, surfactants (SFs) (Tween 80 (T80), non-ionic; cetylpyridinium chloride (CPC), cationic) alone, and nanoemulsions formulated with EOs (0.02%) and SFs (0.002%). The results indicated that nanoemulsions containing CPC exhibited a higher inhibitory effect than those including T80. The reductions in all pathogens after treatment with nanoemulsions containing EOs and CPC were higher (0.1-0.6 log reductions) than those of 0.02% NaOCl. In addition, nanoemulsion treatment did not affect the sensory qualities of red mustard during storage. Therefore, nanoemulsions with EOs and CPC can become an effective substitute for chlorine-based sanitizers for fresh-cut produce if regulations allow the use of CPC. Industrial relevance: Foodborne-illness outbreaks related to fresh-cut produce have increased globally. The use of chlorine-based sanitizers in the fresh-cut produce industry has been decreasing due to health-related problems. Thus, an alternative washing treatment is needed to control pathogenic bacteria contaminating fresh-cut produce. Nanoemulsions with EOs and cationic SF developed in this study can be a suitable washing agent for inactivating foodborne pathogens on fresh-cut produce.