EVALUATION OF ANTIBACTERIAL CHARACTERISTICS OF ZEIN EDIBLE FILM INCORPORATED WITH ZATARIA MULTIFLORA BOISS ESSENTIAL OIL AND MONOLAURIN AGAINST LISTERIA MONOCYTOGENES AND E. COLI O157: H7 IN VITRO

The aim of the study was to develop and investigate antibacterial characteristics of zein edible film assimilated with monolaurin (M) and Zataria multiflora Boiss essential oil (ZEO) alone and in combination with each others. Zein films containing M (1%) and ZEO (2 and 3%) were developed by casting method and subsequently, antibacterial characteristics were assessed based on disc covering and disc surface spreading methods against Listeria monocytogenes and E. coli O157: H7. Compared to the control films, significant enhancements were observed on antimicrobial activity when ZEO and M were added (P<0.05). This increase was influenced by the type of agents as well as type of bacteria, which L. monocytogenes was more susceptible than E. coli O157: H7. In both methods, all prepared films, with the exception of plain zein film, exhibited antibacterial activity against L. monocytogenes while only films containing ZEO showed antibacterial activity against E. coli O157: H7. Generally, films containing 3% ZEO showed an excellent antibacterial activity against both tested bacteria. However, bacterial growth under the films was negative for all applied films samples. It is concluded that in contrary to direct use of monolaurin and ZEO to control microbial pathogens, incorporating both agents into edible zein film strengthens antimicrobial characteristics of them.