Development of LDPE-based antimicrobial films for food packaging

The integration of antimicrobial (AM) agents into packaging materials is aimed at killing or inhibiting the spoilage and pathogenic microorganisms that may contaminate packaged food products. Over the years there has been an increased emphasis on naturally derived AM agents and polymer films containing AM agents derived from basil, for example, exhibit an AM effect against a wide spectrum of microorganisms. Due to the relatively high temperatures involved in manufacturing such films, however, there is a considerable evaporation loss of AM agent during the film blowing process. The present study aims at developing effective AM films and subsequently reducing the loss of active AM agents. The effect of polyethylene glycol (PEG) and ethylene vinyl acetate (EVA) in minimising the loss of active AM agent during the manufacturing of low-density polyethylene (LDPE) film is explored by measuring the release of AM agent into food simulants. The release of AM agents from the film is satisfactorily and consistently described by short-term and long-term migration equations and by first order kinetics. Furthermore, the polymer additives PEG and EVA play a role in controlling the release of the AM agents. The incorporation of AM agent does not adversely affect the mechanical or optical properties of the extruded LDPE/EVA film and the films retain ca. 75% of AM agents after extrusion