Antimicrobial and antioxidant effects of chitosan film containing nanoemulsion of Melissa officinalis L. extract and Bunium persicum essential oil on Listeria monocytogenes inoculated into camel meat

The aim of this study was to investigate the antimicrobial and antioxidant effects of chitosan edible film containing nanoemulsion of Melissa officinalis L. extract and Bunium persicum essential oil on Listeria monocytogenes inoculated into camel meat. The studied films were prepared using 2% chitosan and 2.5% and 5% of nanoemulsion of Bunium persicum essential oil and 4% of Melissa officinalis L. extract. The antimicrobial and antioxidant effects of coated camel meat during 16 days of storage at 4 °C with a 4-day interval (0, 4, 8, 12, 16) were evaluated. The coated portions were chemically evaluated. Most of the essential oil compounds include: cuminaldehyde (24.37%), γ-Terpinene (19.99%), and P-cymene (9.71%). The MIC of Melissa officinalis L. extract and Bunium persicum essential oil against L. monocytogenes were 1% and 0.25%, respectively. The antioxidant effects of films by DPPH method showed that the addition of essential oils and extracts increases the antioxidant properties of films. The antimicrobial effect of films by disk diffusion method, the largest diameter of growth inhibition zone (17.15 ± 0.16) was related to chitosan film containing 5% Bunium persicum essential oil and 4% Melissa officinalis L. extract. The average count of L. monocytogenes in the control treatment was higher than the other treatments. The results of TBARS showed that the antioxidant properties of films containing Bunium persicum essential oil and Melissa officinalis L. extract was higher than the control sample. The pH level in the samples coated with chitosan film containing 5% Bunium persicum essential oil and 4% Melissa officinalis L. extract was lower than the other treatments. In general, the prepared films have good antimicrobial and antioxidant properties against L. monocytogenes, which increase with the addition of plant compounds.