Assessment of the Impact of Rosemary Chitosan Microemulsion Effect on Escherichia coli and Listeria monocytogenes Dipping in Chicken Meat Stored at 4˚C

This article studies the potential use of the Rosemarry (REO) microemulsion with/without chitosan to assess the growth inhibition of Gram-positive and Gram-negative pathogenic bacteria represented by Listeria monocytogenes and Escherichia coli. The chicken samples were divided into four groups after inoculation of E. coli and L. monocytogenes separately: control group (without treatment), 1% chitosan nanoparticle treatment group, 0.5% REO microemulsion treatment group, and 0.5% REO + 1% chitosan microemulsion treatment group. Chicken samples were dipped into the treatments for 15 days of refrigerated storage at 4°C. All groups were kept refrigerated, and bacterial counts were taken on days 0, 1, 3, 6, 9, 12 and 15. Chitosan nanoparticle and REO microemulsion with/without chitosan were spherical shape and showed a narrow size distribution of 23.98 ± 0.83, 34.24 ± 2.2 and 28.01 ± 1.36 nm with a polydispersity index (PDI) of 0.86, 0.33 and 0.54, respectively indicating that greater homogeneity was achieved. REO chitosan microemulsion has 12 components detected by GC-Mass as follows: pinene (22.21%), borneol (21.32%), 1-(4-methoxyphenyl) ethanoneoxime (3.48%), oxocamphor (0.49%), camphor (2.99%), limonene (0.29%), cis-linalool oxide (0.87), 2-(5-chloro-methoxyphenyl) pyrrole (2.19%), homofarnesol (0.27%), levoverbenone (0.45%), peruviol (0.73%) and campesterol (1.22%). The results showed a substantial reduction in L. monocytogenes and E. coli count in all treatment groups when compared to the control group, with the greatest inhibitory efficacy in the 0.5% REO chitosan microemulsion group. A favorable effect of chitosan treatment on chicken acceptability during refrigerated storage was reported, with an improvement in the sensory qualities of the products. Thus, REO chitosan microemulsion is advised to be used in chicken to enhance resistance to harmful microorganisms. © 2022 Friends Science Publishers