Bacterial pollution is a great risk for human health. Nanotechnology offers a way to develop new inorganic antibacterial agents. Nano-inorganic metal oxide has a potential to reduce bacterial contamination. MgO is an important inorganic oxide and has been widely used in many fields. Many studies have shown that MgO nanoparticles have good antibacterial activity. Therefore, in this paper, the main synthesis methods, antibacterial activity and antibacterial mechanisms of MgO nanoparticles are reviewed

Bacterial contamination reduces the shelf-life of foods and presents serious risks to human health. Nanotechnology provides the opportunity for the development of new antibacterial agents. Nano-inorganic metal oxides have shown the potential to reduce bacterial contamination of foods. When the particle size of materials decreases from the micrometre to the nanometre range, nano-functional properties such as diffusivity, mechanical strength, chemical reactivity and biological properties are improved. Significantly, ZnO has been used in many applications with particular success. Many studies have shown that ZnO nanoparticles have enhanced antibacterial activity. This review discusses the main synthetic methods, antibacterial activity, antibacterial mechanisms and food applications of ZnO nanoparticles.

Encapsulation and immobilization technology is important for the food processing and bioengineering industries. Chitosan is a natural polysaccharide prepared by the N - deacetylation of chitin. It has been widely used in food and bioengineering industries, including the encapsulation of active food ingredients, in enzyme immobilization, and as a carrier for controlled drug delivery, due to its significant biological and chemical properties such as biodegradability, biocompatibility, bioactivity, and polycationicity. In this work, chitosan nanoparticles and nanofibers used to encapsulate bioactive substances and immobilize enzymes were reviewed. Preparation of chitosan nanoparticles and nanofibers, including the work achieved in our group on chitosan nanoparticles for enzyme immobilization, were also introduced. Some problems encountered with nano - structured chitosan carriers for bioactive substance encapsulation and enzyme immobilization were discussed, together with the future prospects of such systems