Antibacterial activity against E. coli O157:H7, physical properties, and storage stability of novel carvacrol-containing edible tomato films.

Edible films containing plant antimicrobials are gaining importance as potential treatment to extend product shelf life and reduce risk of pathogen growth on contaminated food surfaces. The main objective of the present study was to evaluate the antimicrobial activities, storage stabilities, and physical-chemical-mechanica1 properties of novel edible films made from tomatoes containing carvacrol, the main constituent of oregano oil. The antimicrobial activities against E. coli O157:H7 and the stability of carvacrol were evaluated during the preparation and storage of tomato-based films made by 2 different casting methods, continuous casting and batch casting. Antimicrobial assays of tomato films indicated that optimum antimicrobial effects occurred with carvacrol levels of approximately 0.75% added to tomato purees before film preparation. HPLC analysis of the films indicated that the carvacrol concentrations and bactericidal effect of the films remained unchanged over the storage period of up to 98 d at 5 and 25 degrees C. Carvacrol addition to the tomato puree used to prepare the films increased water vapor permeability of tomato films. The continuous method for casting of the films appears more suitable for large-scale use than the batch method. This 1st report on tomato-based edible antimicrobial tomato films suggests that these films have the potential to prevent adverse effects of contaminated food and promote human health associated with the consumption of tomatoes.