Development of biodegradable antibacterial poly-lactic acid based packaging films with bioactive compounds

Biodegradability and antimicrobial activity food packaging materials are among the most important parameters of the modern food packaging industry. For development of poly-lactic acid films to antibacterial compositions, different concentrations of essential oil of Zataria Multiflora or propolis ethanolic extract were added to the polymer using the solvent casting method. The antimicrobial activity of the composites was evaluated using disc diffusion method against the four common foodborne pathogens. Our findings showed that the resulting films were effective against all the tested bacteria and the composites containing the essential oil had a good capacity to limit the growth of foodborne pathogenic bacteria. Moreover, the addition of propolis ethanolic extract to films containing the essential oil increased the anti-bacterial properties of the films less than expected, which hydrophilic and hydrophobic nature of films constituents were likely the probable reasons of the results. Based on the results of this study and other similar studies, the biodegradable poly-lactic acid polymer can be considered as a desirable base polymer for development of novel antimicrobial films, especially in combination with herbal antimicrobial agents.