Abstract: Chitosan can be used as an active antibacterial agent or film-forming substrate in foods, and has become a powerful substitute for synthetic plastic polymers because of its good biodegradability, film-forming capacity and antibacterial activity. However, chitosan films have several limitations such as poor water solubility and weak mechanical properties, which limit its application in antibacterial food packaging materials to a certain degree. The safety of applying the antibacterial activity of chitosan in foods has attracted much attention in recent years. In order to provide new ideas for further development and utilization of chitosan-based antibacterial composite materials, this paper expounds the antibacterial mechanism of chitosan and the methods to improve its antibacterial performance, and summarizes the current status of the application of chitosan-polysaccharide, protein or lipid composite films in food preservation.

Key words: chitosan, antibacterial, composite materials, application