Washing solutions containing nanoemulsified essential oils as a potential substitute of commercial washes for the decontamination of Escherichia coli O157:H7 on cherry tomatoes

Abstract

Fresh produce is still a food safety concern as it can be contaminated by bacterial pathogens. Most of these products cannot be pasteurized, making the application of a washing step essential for food safety. Commercial disinfectants can become a hazard for the consumer, which motivates this study to evaluate alternative washing solutions based on nanoemulsified oregano and rosemary essential oils (EOs) for the decontamination of E. coli O157:H7 on cherry tomatoes. Every washing solution was more effective than tap water, and the origin of the EOs (Romania or Spain) did not influence their antibacterial activity. The efficacy was depended on the concentration, with the highest oregano EO nanoemulsion concentration (10%) having a disinfectant effect equivalent to commercial chlorine solution (∼3.5 log CFU), while a 10% rosemary EO solution was less effective (∼2.5 log CFU). Using a QMRA model, it can be concluded that the consumer risk to E. coli O157:H7 would not increase by substituting the commercial chlorine-based solution with the 10% oregano EO-based nanoemulsion. In conclusion, although further research is still needed to fully assess its industrial implementation, the washing solutions based on EOs nanoemulsions developed in this study could be an alternative to the current chlorine commercial products for produce.