Polyethylene Films Containing Plant Extracts in the Polymer Matrix as Antibacterial and Antiviral Materials

Abstract

Low density polyethylene (LDPE) films covered with active coatings containing mixtures of rosemary, raspberry, and pomegranate CO2 extracts were found to be active against selected bacterial strains that may extend the shelf life of food products. The coatings also offer antiviral activity, due to their influence on the activity of Φ6 bacteriophage, selected as a surrogate for SARS-CoV-2 particles. The mixture of these extracts could be incorporated into a polymer matrix to obtain a foil with antibacterial and antiviral properties. The initial goal of this work was to obtain active LDPE films containing a mixture of CO2 extracts of the aforementioned plants, incorporated into an LDPE matrix via an extrusion process. The second aim of this study was to demonstrate the antibacterial properties of the active films against Gram-positive and Gram-negative bacteria, and to determine the antiviral effect of the modified material on Φ6 bacteriophage. In addition, an analysis was made on the influence of the active mixture on the polymer physicochemical features, e.g., mechanical and thermal properties, as well as its color and transparency. The results of this research indicated that the LDPE film containing a mixture of raspberry, rosemary, and pomegranate CO2 extracts incorporated into an LDPE matrix inhibited the growth of Staphylococcus aureus. This film was also found to be active against Bacillus subtilis. This modified film did not inhibit the growth of Escherichia coli and Pseudomonas syringae cells; however, their number decreased significantly. The LDPE active film was also found to be active against Φ6 particles, meaning that the film had antiviral properties. The incorporation of the mixture of CO2 extracts into the polymer matrix affected its mechanical properties. It was observed that parameters describing mechanical properties decreased, although did not affect the transition of LDPE significantly. Additionally, the modified film exhibited barrier properties towards UV radiation. Modified PE/CO2 extracts films could be applied as a functional food packaging material with antibacterial and antiviral properties.

Zein-Based Films Containing Monolaurin/Eugenol or Essential Oils with Potential for Bioactive Packaging Application

“…This could be the reason for the lower inhibition activity against the Gram-negative bacteria E. coli and yeasts and molds, because of the hindered diffusion from the sample. On the contrary, no significant effect on the T g value was demonstrated in the study by Ordon et al [ 52 ], who modified polyethylene films with a mixture of plant extracts. On the other hand, good antimicrobial properties were observed during the agar diffusion test against Gram-positive S. aureus .…”

Overview of Food Antimicrobial Packaging

“…For instance, the demand for disposable polymers/biopolymers is expected to increase by 40% in packaging. Safety concerns related to shopping in supermarkets and small markets during the COVID-19 pandemic have led to the use of fresh-food products offered in polymer containers by suppliers and consumers, as well as the use of single-use food packaging materials and polymer bags to carry groceries [94,[96][97][98]. Multilayered active packaging systems are being developed to improve packaging properties, such as barrier properties, mechanical properties, antimicrobial effectiveness against bacteria, and yeast and molds responsible for food spoilage.…”

“…Multilayered packaging systems are being developed through coextrusion, lamination, or covering with coatings [95]. This safe packaging should have an internal coating or extruded film layer to protect food products and an external coating or extruded film layer with antiviral compounds to protect customers (Figure 2) [94][95][96][97][98]. Additionally, this packaging-coated material or material containing antiviral substance should be active during storage, meaning it should offer sufficient resistance against UV aging or be shielded against ultraviolet light through the shielding properties of additives [94,[96][97][98].…”

“…In order to prepare antiviral coatings or films, many compounds, which are effective against viruses, such as SARS-CoV-2, such as ZnO nanoparticles, Ag nanoparticles, essential oils, and plant extracts, may be used [94][95][96][97][98][99][100]. As an example, Mizielińska et al [94] developed an active coating based on nanoparticles of ZnO, geraniol, and carvacrol.…”

Frontiers in Antimicrobial Materials

“…Ordon et al investigated polyethylene films containing plant extracts in the polymer matrix as antibacterial and antiviral materials. They found that low-density polyethylene films covered with active coatings containing mixtures of rosemary, raspberry and pomegranate CO 2 extracts were active against selected Gram-positive and Gram-negative bacteria strains and also offered antiviral activity against a surrogate of SARS-CoV-2 [ 6 ]. The modified polyethylene CO 2 extracts showed good antimicrobial performance and the potential to be applied as a functional packaging material to extend the shelf life of food products.…”