Synergistic antimicrobial action and effect of active chitosan-gelatin biopolymeric films containing Thymus vulgaris, Ocimum basilicum and Origanum majorana essential oils against Escherichia coli and Staphylococcus aureus

Abstract

To replace synthetic preservatives and expand green consumption, several essential oils have been tested in foods and food packaging due to their antimicrobial properties. This study aimed to analyze the synergistic antimicrobial action of a chitosan-gelatin based active biopolymers with the addition of essential oils (EOs). The antimicrobial agents were tested against foodborne microorganisms Staphylococcus aureus and Escherichia coli strains. The antibacterial activity of Thymus vulgaris, Ocimum basilicum, Origanum majorana, and the synergistic interactions among them were assessed according to the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using the microdilution method. Chitosan-gelatin based active biopolymers were developed, and 23% (w/w) of each essential oil and combined oils were added. The antimicrobial effect of active films was measured using the disk diffusion method. Active films with the addition of essential oils have potential applications as active packaging agents, especially those that demonstrated inhibition zones. Combined EOs can be used to enhance the antimicrobial activity, ensuring reduced doses used in active packaging and decreasing the association with adverse sensory characteristics.

Polysaccharide-Based Edible Films Incorporated with Essential Oil Nanoemulsions: Physico-Chemical, Mechanical Properties and Its Application in Food Preservation—A Review

“…Moreover, different EOs having a synergistic antimicrobial activity can be combined and added to chitosan-based films to limit the organoleptic defects often reported following the addition of single EOs at concentrations needed to effectively inhibit microbial food spoilage. This strategy was successfully used for inhibiting E. coli and S. aureus growth [ 26 ]. These authors also reported that Origanum majorana and Ocimum basilicum EOs mixture had an additive effect against both E. coli and S. aureus and that adding a mixture of Origanum majorana and Thymus vulgaris EOs in chitosan-gelatin films was the only combination of EOs active against these two bacterial species.…”

Improvement of the Antimicrobial Activity of Oregano Oil by Encapsulation in Chitosan—Alginate Nanoparticles

“…For the purposes of the food industry, OrO is often not added to the product itself, but is incorporated into biocomposite packaging films or other types of edible coatings. Edible coatings based on polysaccharides are environmentally friendly alternatives and can reduce the use of chemical preservatives [39][40][41][42][43][44]. The application of such packages is investigated for numerous types of raw or processed foods such as pork, ham, chicken wingettes, fish fillets, seafood, vegetables, fruits, juices, etc.…”

Conjugation of Ctx(Ile21)-Ha Antimicrobial Peptides to Chitosan Ultrathin Films by N-Acetylcysteine Improves Peptide Physicochemical Properties and Enhances Biological Activity

“…This would indicate that a formulation using MIC values would be sufficient for dermatological application in order to avoid hemolysis and prevent the entry of pathogens into open wounds . Likewise, this formulation can be a promising protective film for foods since other films previously reported in the literature presented values above those reported in this study. − …”