INTRODUCTION Antimicrobial packaging material recently emer- ged as a potential means of assisting the preser- vation of perishable foods and of extending their shelf life. In typical antimicrobial packaging, the antimicrobial substances are incorporated in, or coated onto, food packaging material such as plastic or paper. 1,2 The proposed or tested an- timicrobial compounds for food packaging ap- plications include organic acids/anhydrides, fungicides, bacteriocins, enzymes, ceramic materi- als with Ag ions, plant extracts and inorganic gases. In particular, nisin, produced by Lactococcus lactis, has been proposed and tested as a natural antimicrobial agent that could be added during the fabrication of antimicrobial packaging films. 3–7 Nisin, being a hydrophobic protein, has GRAS (g enerally r ecognized a s s afe) status for use in cheese products in the USA and is effective against a wide range of Gram-positive bacteria that may cause spoilage and health hazards in foods. 8 Many recent studies have reported that packaging mate- PACKAGING TECHNOLOGY AND SCIENCE Packag. Technol. Sci. 2003; 16: 99–106 DOI:10.1002/pts.617 Wide-spectrum Antimicrobial Packaging Materials Incorporating Nisin and Chitosan in the Coating By Chan Ho Lee, a Duck Soon An, a Hyun Jin Park b and Dong Sun Lee a * a Division of Life Sciences, Kyungnam University, 449 Wolyoung-dong, Masan, 631-701, South Korea b School of Biotechnology, Korea University, 5-1 Anam-dong, Sungbuk-ku, Seoul 136-701, South Korea Nisin and/or chitosan were coated, in 3% concentrations, onto paper with a binder medium of vinyl acetate–ethylene co-polymer to provide antimicrobial activity for use in food packaging. The combined use of nisin and chitosan in the coating was an attempt to give a wide antimicrobial spectrum that could inhibit the growth of several food spoilage and poisonous microorganisms. The migration of the preservative from the coatings to water was evaluated at 10°C and related to the suppressed microbial growth in the water and microbial medium. After 8 days, 8.1–8.3% of nisin and 1.0–1.2% of chitosan had migrated, and the migration of each was not affected by the presence of the other. The paper coated with nisin was more effective than the chitosan-coated paper in inhibiting the Gram-positive bacterium, Listeria monocytogenes, whereas the latter was more effective against Escherichia coli O157:H7. Combined inclusion of nisin and chitosan in the coating gave antimicrobial activity against both bacterial strains, and could improve the microbial stability of milk and orange juice stored at 10°C. Copyright © 2003 John Wiley & Sons, Ltd. Received 1 November 2002; Accepted 6 June 2003 KEY WORDS: Listeria monocytogenes; Escherichia coli O157:H7; migration; acetic acid; binder * Correspondence to: Division of Life Sciences, Kyungnam University, 449 Wolyoung-dong, Masan, 631-701 Korea. Email: dongsun@kyungnam.ac.kr Copyright © 2003 John Wiley & Sons, Ltd.