1. Introduction
Concerning food quality, consumers requirements are on a high level: Food products ready-to-eat, preportioned, remaining fresh and retaining their attractive appearance for days are requested on the market and following retailers and distributors are demanding products that stay fresh and especially microbiologically safe for a long time. Therefore simple packaging with a passive barrier layer is often insufficient. Active packaging materials equipped with antimicrobials have been developed in order to increase the shelf-life of food products and reduce a potential microbial risk. Especially in the last ten years there has been done a lot of research to develop new films with antimicrobial properties. In 2009 a new EU regulation on active and intelligent packages has been established that facilitates the application of this new packaging technology in the European Union. At the Fraunhofer Institute for Process Engineering and Packaging IVV, Germany, a new antimicrobial packaging film has been developed. First trials have shown that this active film is very effective to protect food surfaces from the growth of various bacteria, yeasts and moulds. The active antimicrobial applied in this film is sorbic acid as a conventionally used preservative that represents no health or allergenic hazard. It is approved according to food law for many different kinds of foods. As there are still technological problems in the production of films with incorporated sorbic acid, the antimicrobial is embedded in a lacquer on top of the packaging film. The lacquer enables a successive release of low amounts of sorbic acid to the surface of the packaged food. In this way a protection from microbial contamination of the packaged food at the contact area could be provided. Thus longer shelflife and safer foods can be achieved. The objective of this study was to determine the antimicrobial activity of this active packaging film against various food contaminating microorganisms according to the Japanese Industrial Standard Method JIS Z 2801:2000 [7] and to study its antimicrobial efficacy on artificially contaminated foodstuffs like meat and cheese.