Charge-governed ionic essential oil-loaded liposomes for enhanced penetration and removal of Listeria monocytogenes biofilms.

The high incidence and spread of Listeria monocytogenes biofilms present significant challenges to conventional sterilization means, posing a serious threat to food safety. In the context of food microbial safety, this study employs Litsea cubeba essential oil (LC-EO) as a phytogenic antimicrobial and investigates the penetration and eradication mechanisms of ionic LC-EO-loaded liposomes against L. monocytogenes biofilms. Using rhamnolipids and chitosan for surface modification, two types of ionic essential oil-loaded liposomes with opposite charges yet comparable charge density and particle size were successfully prepared. The resultant surface-modified liposomes exhibited significantly improved stability in various aqueous environments compared to conventional liposomes, along with remarkable efficacy in biofilm removal. Biofilm retention assays revealed that anionic liposomes possess stronger biofilm penetration capacity, while cationic liposomes show enhanced adsorption rates on biofilm surfaces. When applied on different food-contact surfaces, ionic liposome solution effectively removed L. monocytogenes biofilms, reduced secondary contamination, thus improving food safety.