The antimicrobial efficiency of novel MtCu(2+)/LDPE nanocomposites against Escherichia coli 0157:H7 n/t was tested in the present work. Montmorillonite modified with copper (MtCu(2+)) was obtained using cation exchange in solution and nanocomposite films were prepared by melt mixing in an extruder at 200 degrees C with different compositions. Characterization of MtCu(2+) and MtCu(2+)/LDPE nanocomposites was carried out using XRD, AA, TGA, DSC, and microbiological analysis. The clay polymer nanocomposites (CPN) were more stable at higher temperatures, resulting from the incorporation of MtCu(2+) in the polymer. The results indicate that the antibacterial effect of the CPN increases with the proportion of MtCu(2+) added, obtaining a 94% reduction when 4% of MtCu(2+) was added to the polymer. (C) 2012 Elsevier B.V. All rights reserved.