Research in the safety of processed food has focused on performing antimicrobial edible films as a novel way to suppress pathogenic bacteria such as Listeria monocytogenes and Staphylococcus aureus. Previous studies have developed an antimicrobial polysaccharide edible film, incorporating the bacteriocin nisin, active against a large spectrum of Gram-positive bacteria. The film effectiveness is based on both nisin desorption from the film and its diffusion in food products. In the present work, nisin molecular transfer in agarose gel was investigated and apparent diffusion coefficients were calculated. Fick's second law well represented both nisin desorption from the film and its diffusion in agarose gel. The coefficient values for free nisin diffusion varied between 1.92 x 10(-11) and 8.14 x 10(-11) m(2) s(-1) for temperatures between 5 and 22degreesC. When nisin was added to the film, nisin transfer into agarose gel was slowed due to a desorption effect. This result indicated that nisin interacted with film components which induced partial retention of nisin in food surface. This is interesting because it would improve food safety by reducing aero-anaerobic pathogenic bacteria growth at food surfaces.