Titanium dioxide (TiO2) particles are used as a food additive that can prevent a broad spectrum of ultraviolet light from penetrating containers, which decreases the spoiling time and increases the shelf life of food. Titanium dioxide is also used as an additive to make food/paint/consumer goods appear white and more attractive to the consumer.
When Titanium Dioxide is exposed to UV light, it becomes a photocatalyst and absorbs the UV light, disposing it as heat. This property allows the titanium dioxide to be used as a sterilization/anti-fouling/deodorizing/self-cleaning agent. Since titanium dioxide is not irritating to the skin, and does not discolor when exposed to UV light, it is often used in sunscreen and other products where discoloration/irritation would be a detractor to the value of the product, such as in food.
Titanium dioxide nanoparticles can make materials appear whiter. Titanium dioxide is naturally occuring and does not need extensive processing to synthesize the raw material into nanoparticles. As a food additive, titanium dioxide prevents premature spoilage in foods that react with UV light. As a photocatalyst, titanium dioxide nanoparticles sterilize and deodorize products.
Titanium dioxide nanoparticles have been shown to be a possible carcinogen in lab mice. Oral ingestion of titanium dioxide by lab mice has shown these particles bioacumulate and lead to health concerns about bio-distribution and acute toxicity. This raises concerns over the fate and transport of titanium dioxide nanoparticles in ecological systems.