In this work, montmorillonite (Mt) was first ion-exchanged with silver ions (Ag + Mt) then organically modified with cetyltTimethylammonium bromide, CTAB (Ag + Mt). Active carrier Mt-layers were then compounded into low density polyethylene (LDPE) polymer using a high shear force co-rotating twin screw extruder. The order of Ag ion and CTAB adsorption on to Mt was revised in order not to form AgBr nano particles of which existence was reported in previous studies. Antibacterial activity of the Ag + OMt-LDPE nanocomposite films was then investigated against powerful gram negative Escherichia coli (E. coli) bacteria. It seems there is strong synergetic effect between silver ions and OMt nanoparticles as evidenced by the bacterial inhibition properties of thin blow molded Ag + OMt-LDPE nanocomposite film samples using liquid surface bacterial testing at a much lower active component concentration than similar studies appeared in the literature. (C) 2015 Elsevier B.V. All rights reserved.