Preparation and antimicrobial activity of polyethylene composite films with silver exchanged zeolite-Y

This study aimed at the preparation of antimicrobial films based on silver (Ag) exchanged zeolite Y. The zeolite was exchanged to a final concentration of 5% silver and was characterized by different methods. The inclusion of silver in the zeolite did not change its structure. The antimicrobial activity of the Ag-exchanged zeolite was assessed on Escherichia coli, by the minimum inhibitory concentration method (MIC). The zeolite with 5% Ag showed effective antimicrobial activity. The MIC was 0.5 mg zeolite/mL, which corresponds to 25 mu g Ag/mL. The leaching of Ag ions to the medium was assessed by AAS, which showed that 56% of the silver ions was leached from the zeolite to the medium. The polyethylene films with the Ag-zeolite were prepared by the methods of wet-casting and thermal pressing of polyethylene beads mixed with Ag-zeolite, varying the zeolite content from 1 to 10 wt%. The inclusion of the Ag-zeolite in the film did not change the film thermal degradation. The films that showed antimicrobial activity on E. coli were those prepared with 5% zeolite containing 5% silver, showing the potential application of such films in food preservation and safety. (C) 2012 Elsevier B.V. All rights reserved.