The Antimicrobial Efficacy of Chitosan Nanoemulsion Coating Incorporating Ziziphora Clinopodioide Essential Oil and Nisin against Listeria Monocytogenes Inoculated in Vacuum-Packed Chicken Breast Fillet

Background: The present study aimed to determine the chemical composition and antibacterial activity of essential oil extracted from Ziziphora clinopodioide (ZCEO) in vitro. Furthermore, the study aimed to evaluate the effectiveness of chitosan nanoemulsion coating containing ZCEO and nisin in inhibiting the growth of Listeria monocytogenes inoculated on chicken breast fillets that were inoculated and vacuum-packaged, and stored at a temperature of ۴±۱ °C for ۱۶ days. Methods: The chemical composition and in vitro antibacterial activity of ZCEO were determined by gas chromatography-mass spectrometry (GC-MS) and microdilution method, respectively. The chicken breast fillet samples were divided into seven groups, namely, the control group (uncoated) without vacuum, control group with vacuum, chitosan nanoemulsion without vacuum, chitosan nanoemulsion with vacuum, chitosan nanoemulsion with ۰.۵% ZCEO and vacuum, chitosan nanoemulsion with nisin and vacuum, and chitosan nanoemulsion with ۰.۵% ZCEO, nisin, and vacuum. All the samples were stored in a refrigerator, and the population of L. monocytogenes was enumerated on days ۰, ۱, ۲, ۴, ۸, ۱۲, and ۱۶. Results: the chemical analysis of ZCEO revealed that carvacrol, thymol, and p-cymene were the three main compounds present in the oil. Application of chitosan nanoemulsion coatings, specifically chitosan nanoemulsion + ZCEO ۰.۵% + vacuum and chitosan nanoemulsion + nisin + vacuum, resulted in a significant reduction in the growth rate of L. monocytogenes in chicken breast fillet samples during storage. In addition, the chitosan nanoemulsion coating containing the combined ZCEO and nisin was found to be more effective in reducing the growth of L. monocytogenes during the storage period. Conclusion: Based on the results of this study, chitosan nanoemulsion + ZCEO ۰.۵% + nisin + vacuum coating can be used to reduce the risks that might be associated with L. monocytogenes in chicken breast fillets.

Keywords:

Chitosan nanoemulsion , Ziziphora clinopodioide , Nisin , Listeria monocytogenes , Chicken meat