73D-7 |
Nisin coating on polymeric packaging films |
P. P. LEUNG1, M. Khadre, T. H. Shellhammer, and A. E. Yousef. (1) Department of Food Science and Technology, The Ohio State University, Parker Food Science and Technology Building, 2015 Fyffe Court, Columbus, OH 43210-1007 Nisin, a commercially valuable bacteriocin, is effective against some Gram-positive bacteria, including foodborne pathogens. The use of nisin as a surface coating on packaging films can inhibit bacterial growth and extend shelf life of foods. The efficacy of nisin-coated antimicrobial packaging film is dependent on the binding affinity of nisin to the synthetic polymer. The proper combination of treatment conditions, such as contact time, nisin concentration and solution pH, are required to maximize the attachment of nisin to a flexible packaging film. The purpose of this study was to identify treatment conditions that maximize the binding of nisin to the surface of a flexible packaging film. Ethylene acrylic acid copolymer film was cut into circular disks (5 mm diameter) and sterilized with ethanol. Film samples were immersed in nisin solutions of concentrations 10 - 250 IU/ml, at pH 2 – 12, for 30 seconds to 2 hours. Nisin-coated films were immobilized on a microtiter plate and the amount of nisin on the film was quantified by a modified ELISA technique. Nisin activity was also evaluated using agar diffusion assay. Contact time and temperature as well as solution pH had a significant effect on the quantity of bacteriocin attached to the packaging film. The amount of nisin on the film, as measured by the ELISA technique, showed a significant dependence on contact time. Bacteriocin surface coverage measurements using the ELISA technique had a significant linear correlation with the log of coating solution concentration. ELISA measurements also correlated well with agar diffusion assays. Optimization of bacteriocin attachment to surfaces of a polymeric packaging material has the potential to enhance the safety of foods packaged in such material.
Session 73D, Food Packaging
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