Antimicrobial activity of alginate/clay nanocomposite films enriched with essential oils against three common foodborne pathogens

The overall objective of this study was to develop antimicrobial nanocomposite films to control the growth of foodborne pathogens. In the first step, the antibacterial effects of clove, coriander, caraway, marjoram, cinnamon, and cumin essential oils were studied against three important food pathogens, Escherichia coli, Staphylococcus aureus, and Listeria monocytogenes by application of agar diffusion assay. The intensity of antimicrobial efficacy was in the following order: marjoram > clove > cinnamon > coriander > caraway > cumin. In the next study, the three most potent essential oils were subsequently incorporated into alginate/clay nanocomposite films. The antibacterial effectiveness of the prepared films against E. coli, S. aureus, and L. monocytogenes was studied during 12 days. The antibacterial activity of the essential oils was maintained when incorporated into the nanocomposite film. The nature and amount of the essential oils play an important role in the film's antimicrobial activity. In all film matrices, marjoram showed the highest antimicrobial activity. Films with 1.5% marjoram decreased the numbers of L. monocytogenes, E. coli, and S. aureus populations with respect to the control up to 6.33, 4.52, and 5.80 log, respectively.