Submitted to: International Journal of Food Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 3, 2008
Publication Date: January 3, 2009
Citation: Jin, Z.T., Liu, L.S., Zhang, H.Q., Hicks, K.B. 2009. Antimicrobial activity of nisin incorporated in pectin and polylactic acid composite films against Listeria monocytogenes. International Journal of Food Science and Technology. 44:322-329. Interpretive Summary: Films with pectin plus polylactic acid were developed using extrusion. The films were coated with nisin and used for inhibiting pathogenic Listeria monocytogenes in a growth medium, liquid egg, and orange juice. The developed films with nisin significantly inhibit the growth of L. monocytogenes in all the tested media over 48 hour incubation at 24 degree C. The results of this study indicate that nisin incorporated into Pectin/Polylactic acid films can be an effective approach to control L. monocytogenes in a typical growth medium as well in foods.
Technical Abstract: Extruded composite films from 20% pectin and 80% polylactic acids (PLA) were developed and nisin was loaded into films by a diffusion post extrusion. Inhibitory activities of the films against Listeria monocytogenes were evaluated in brain heart infusion (BHI) broth, liquid egg white and orange juice. The mechanical properties and surface structure of films were also examined. Pectin/PLA films with nisin significantly inhibited growth of L. monocytogenes in BHI broth. L. monocytogenes in liquid egg white with Pectin/PLA film containing nisin was reduced from 6.8 logs to 2 logs while control maintained at 6.5 logs over 48 h incubation at 24 degree C. A 6-log reduction of L. monocytogenes in orange juice with Pectin/PLA film containing nisin was observed after 48 h. Pectin in Pectin/PLA films played an important roll in embedding nisin into the films. Pectin/PLA films had similar stiffness but lower tensile strength, elongation, and fracture energy than pure PLA films. The results of this study indicate that nisin incorporated into Pectin/PLA films can be an effective approach to control L. monocytogenes in a typical growth medium (e.g. BHI broth) as well in foods (e.g. orange juice and liquid egg).