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Overview of antimicrobials in edible films |
J. M. KROCHTA and L. R. Franssen. Dept. of Food Science & Technology, Univ. of California, Davis, 1 Shields Ave., Davis, CA 95616 Edible films and coatings have been used for many important functions, such as prevention of physical damage, protection from oxidation or moisture change, and enhancement of product appearance. By incorporating antimicrobials, the functionality of edible films and coatings can be extended to protect food products from microbial spoilage and extend product shelf-life. With the many different edible films and types of antimicrobials available, edible antimicrobial films can be engineered for almost any food product. Because food products are so complex, several factors influence the type of film and coating material to be used, such as intrinsic food properties (pH, water activity, and composition) and extrinsic factors (temperature and relative humidity in processing and storage conditions). Film and coating materials that are currently used include lipids (oil, waxes, emulsions), resins (shellac, rosin), carbohydrates (celluloses, pectins, chitin, starches, gums) and proteins (milk, soy, collagen/gelatin, wheat, corn, peanut). Additionally, plasticizers, emulsifiers or surfactants may be added to enhance the film or coating. In choosing an antimicrobial, the effectiveness against the target microorganism is the primary consideration. Antimicrobial interactions with the film material, food, and environment must also be considered. Current antimicrobials include: organic acids (acetic, benzoic, lactic, proprionic, sorbic), fatty acids, parabens, bacteriocins (nisin), sulfites, sucrose esters, and other natural antimicrobials (natamycin, lysozyme). Because of these many factors, current antimicrobial edible film research ranges from broad theoretical experiments to product-specific applications. Requirements for a practical and effective antimicrobial film or coating include: antimicrobial effectiveness, controlled migration of the antimicrobial, good adhesion and interaction with the food product, and reasonable application procedure. Evaluation of these requirements is key to success and many experimental methods are in use. With greater understanding of film and coating properties, edible antimicrobial films and coatings could be effectively engineered for any food product.
Session 24, Packaging tackles food safety: A look at antimicrobials
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