Antimicrobial Properties of the Films. Bacterial strain Escherichia coli CECT 434 (ATCC 25922) was obtained from the Spanish Type Culture Collection (Valencia, Spain). This strain was chosen as a Gramnegative model because of its relevance in Food Industry. It was stored in liquid medium Tryptone Soy Broth (TSB) supplied from Scharlab (Barcelona, Spain) with 20% glycerol at -80 °C until needed. The stock cultures were maintained by periodic subculture on agar Tryptone Soy Agar (TSA) from Scharlab (Barcelona, Spain) slants at 4 °C and transferred monthly. To test antimicrobial effect of active films, the microatmosphere method, in which the volatile active compound released from the film to the headspace of the Petri dish interacts with the microorganisms, was carried out. In this method, 100 μL of a bacteria suspension containing approximately 10 7 colony forming units (CFU)/mL were spread over the 15 mL of TSA surface, and a disk of the antimicrobial films (80 mm in diameter) was adhered to the lid of the Petri dish, without direct contact with the microorganism, sealed with Parafilm and incubated at 37 °C for 24h.