**1.6 UV-aging of antimicrobial packaging materials**

In general, an active coated packaging material or packaging material containing antimicrobial agents incorporated into the polymer matrix should function during storage to inhibit microorganism growth to extend the shelf-life of the food product and maintain its quality. This means that the coatings and active films should offer sufficient resistance against ultraviolet (UV) radiation or be shielded against UV [90–92]. UV radiation is a part of the nonionizing region of the electromagnetic spectrum that comprises approximately 8–9% of total solar radiation. It can lead to a degradation/deterioration in the optical, physicomechanical, and antimicrobial properties of packaging materials. Introducing an active, antimicrobial agent sensitive to UV in a coating carrier or into a polymer matrix can lead to an inactivation of the coating or active film after UV-aging. Introducing an active compound that is resistant to UV in a coating carrier/polymer matrix, or adding a substance with shielding properties, can prevent the inactivation of the coating/active film after UV-aging [90, 92]. As a result of nanotechnology development, ZnO nanoparticles have been incorporated into the matrix of many polymers or many coating carriers to obtain active layers to enhance the properties of such films/coatings without significant influence on their transparency. Additionally, these nanoparticles have attracted great interest and the development of coating/film applications as agents to improve
