Bacteria that cause food spoilage are Listeria monocytogenes, Staphylococcus aureus, Salmonella typhimurium, and Campylobacter jejuni. Pathogens developing in poorly stored products may cause food poisoning or even debilitating infective diseases such as meningitis. Food contamination, whose source can be, e.g., packaging processes, poses a severe threat to human health (foodborne infection). Films made from chitosan composites could be an excellent alternative to traditional packaging. Moreover, advances in the search for new materials capable of extending the shelf life of food products may significantly reduce the current worldwide food waste problem, which is a cause of inefficiency of the global food system and contributes to environmental pollution. In addition to the protective function against environmental factors, the ideal package should also influence the quality and safety of the product. They are often enriched with toxic compounds (polyethylene, polypropylene, and other petroleum compounds) that harm human health. Commonly used metal and plastic packaging are serious environmental problems. Currently, people are more willing to accept natural compounds as preservatives due to their safety. Increasing consumer demands for safe, unprocessed foods and prolonged storage time has mobilized the food industry to introduce antimicrobial food packaging. One line of research is the use of chitosan as a component of food packaging. The presence of amino groups in the polymer chain gives some valuable characteristics, e.g., the ability to chelate metals and exhibit catalytic and antimicrobial activities. Total biodegradability and biocompatibility are common features of a broad group of biopolymers, whereas the versatile use of chitosan is mainly due to the presence of amino groups in the polymer backbone.
Chitosan is also synthesized by fungi, such as Aspergillus niger or Penicillium notatum. This polymer is commonly obtained from chitin, which composes the exoskeleton of crustaceans (crabs, shrimps, crayfish).
It is the second most widespread polysaccharide on Earth, after cellulose. Due to the presence of functional groups, it can be subjected to various modifications in order to obtain good biological activity.Ĭhitosan, a linear β-1,4-D-glucosamine, is a natural polysaccharide obtained from the deacetylation of chitin. Chitosan is a promising feedstock for the production of functional biomaterials. These materials should be readily available with low production costs. Currently, the synthesis of polymers is a widely studied process, but special attention is sacred to biodegradable, nontoxic materials. Chitosan films with graphene (GO, GOP, GOP-HMDS, rGO, GO-HMDS, rGOP), titanium dioxide (CS-TiO 2 20:1a, CS-TiO 2 20:1b, CS-TiO 2 2:1, CS-TiO 2 1:1a, CS-TiO 2 1:1b) and zinc oxide (CS-ZnO 20:1a, CS-ZnO 20:1b) may be considered as a safe, non-cytotoxic packaging materials in the future.Īs a result of technological development, the demand for natural materials with unique physico-chemical properties is increasing. Moreover, graphene-based chitosan films caused high inhibition of both tested strains. The CS-ZnO films had excellent antibacterial activity towards L. monocytogenes 19115) properties compared to native chitosan films. All chitosan-metal oxide films and chitosan-modified graphene (oxide) films displayed improved antibacterial ( C. Finally, this research helps elucidate the interactions of these materials with eukaryotic cells. Moreover, we wanted to check whether the incorporation of antimicrobial constituents such as TiO 2, ZnO, Fe 2O 3, Ag, and graphene oxide (GO) into the polymer matrices can improve the antibacterial properties of these nanocomposite films. The purposes of this study were to evaluate the antibacterial activity of a set of chitosan-metal oxide films and different chitosan-modified graphene (oxide) films against two foodborne pathogens: Campylobacter jejuni ATCC 33560 and Listeria monocytogenes 19115. From a biological point of view, chitosan is very attractive for food packaging. Synthetic materials commonly used in the packaging industry generate a considerable amount of waste each year.