Antiadhesion effect of the chitosan-based film incorporated with essential oils against foodborne bacteria

In the food sector, bacterial adhesion on surfaces followed by biofilm development is responsible for food contamination and spoilage, and foodborne illness, leading to considerable economic losses. Therefore, this present study aimed to elaborate a biodegradable material that inhibits bacterial adhesion and thus biofilm formation. For this purpose, chitosan-based films (CH-films) containing four different essential oils (EOs) were elaborated. The impact of these EOs on the physicochemical properties as well as the antiadhesion activity of the CH-films was evaluated. The contact angle results showed that the addition of EOs has modified significantly the physicochemical properties of the CH-film. The electron donor (γ-) and Lifshitz-Van der Waals component (γLW) values increased, whereas the qualitative hydrophobicity (θw) and electron acceptor (γ+) values decreased. The analysis of bacterial adhesion using environmental scanning electron microscopy (ESEM) revealed that the CH-film containing C. zeylanicum EO exhibits the strongest antiadhesion activity against E. coli, E. hirae, and S. aureus compared to the other CH-films, with coverage rate values equal to 5.16 ± 1.13%, 2.8 ± 0.38%, and 1.52 ± 0.53%, respectively. Moreover, ESEM analysis showed that the antiadhesion effect of C. zeylanicum EO on P. aeruginosa strain was accompanied by a rupture of bacterial cells. From these findings, the CH-films incorporated with EOs could potentially be applied in the food industry to prevent microbial adhesion to surfaces and eventual biofilm formation.