Enhancing antimicrobial activity of chitosan films by incorporating garlic oil, potassium sorbate and nisin

Antimicrobial effect of chitosan edible film incorporating garlic oil (GO) was compared with conventional food preservative potassium sorbate (PS) and bacteriocin nisin (N) at various concentrations. This activity was tested against food pathogenic bacteria namely Escherichia coli, Staphylococcus aureus, Salmonella typhimurium, Listeria monocytogenes and Bacillus cereus. Mechanical and physical properties were characterized and Fourier Transform Infrared (FTIR) was also performed to determine functional groups interactions between the matrix and added agent. Incorporation of GO up to levels at least 100 μl/g, PS at 100 mg/g or N at 51,000 IU/g of chitosan were found to have antimicrobial activity against S. aureus, L. monocytogenes, and B. cereus. At these levels, the films were physically acceptable in term of appearance, mechanical and physical properties. GO components did not affect the physical and mechanical properties of chitosan films as it did not have any interaction with the functional groups of chitosan as measured by FTIR.