Nanoemulsified orange essential oil for decontamination of some foodborne pathogens on cherry tomatoes during simulated domestic washing

Abstract

Surface decontamination is key for ensuring the food safety of ready-to-eat (RTE) produce. However, current chlorine-based washes raise health concerns, highlighting the need for alternative decontamination strategies, in response to increasing regulatory restrictions across several European countries. Thus, the aim of this study was to assess the potential of an alternative solution based on nanoemulsified orange essential oil (OEO) for the disinfection of relevant foodborne pathogens like Escherichia coli O157:H7 (E. coli), Salmonella enterica subsp. enterica ser. Enteritidis (S. Enteritidis) and Listeria monocytogenes (L. monocytogenes). The antimicrobial effect of different OEO concentrations (0.33, 1.66, 5, and 10%) and exposure times (2, 5, 10, and 15 min) were evaluated, using water washing as baseline (no antimicrobial effect) and washing with a commercial chlorine solution as a reference. Both OEO concentration and the contact time increased the antimicrobial effect, reaching a plateau at high value. The highest concentration (10%), applied for 5 min, achieved reductions of up to 2 log CFU/g for E. coli and S. Enteritidis, comparable to the commercial chlorine-based wash, but only ∼1 log CFU/g against L. monocytogenes. Extending the washing time to 15 min further increased reductions to 2.5 and 3.5 log CFU/g for E. coli and S. Enteritidis, respectively, demonstrating the effectiveness of OEO under simulated domestic washing conditions. Based on a quantitative microbial risk assessment (QMRA), the use of the alternative solution was estimated to maintain consumer protection against salmonellosis and shiga-toxin producing E. coli, highlighting its potential as a chlorine-free washing treatment for fresh produce.