Impact of starch-based emulsions on the antibacterial efficacies of nisin and thymol in cantaloupe juice

• Stable starch-OS based emulsions containing nisin, thymol, or both were prepared.
• Starch-OS emulsions retained nisin and thymol over extended storage at 4 °C.
• Emulsions showed longer effects to reduce Listeria and Salmonella than non-emulsions.
• Emulsions with both nisin and thymol had greatest inhibition against both pathogens.

The use of antimicrobial compounds to prevent foodborne pathogens from contaminating fresh-cut produce has received broad attentions; however, the applications of these compounds are hindered by their rapid depletion in foods. To prolong their efficacies, the use of delivery systems is essential. In this study, oil-in-water emulsions formed using starch octenyl succinate (starch-OS) were used to stabilize nisin and thymol in cantaloupe juice-containing fluid. Listeria monocytogenes V7 and Salmonella enterica serovar Typhimurium were used as model pathogens to evaluate the antimicrobial activities of nisin and thymol formulations in cantaloupe juice. The results showed that the emulsions had much greater capability to retain nisin and thymol over the storage and displayed much greater effect to inhibit Listeria and Salmonella than non-emulsion, aqueous formulations. Starch-OS based emulsions not only retained nisin and thymol activities separately, but also exhibited their cooperative antibacterial effects.