Nanoparticle food applications and their toxicity:  current trends and needs in risk assessment strategies.

Nanotechnology has developed as one of the most ground-breaking scientific fields in the last few decades since it exploits the enhanced reactivity of materials at the atomic scale . The current classification of nanoparticles (NPs) used in foods is outlined in relation to their production and physicochemical characteristics.  This review aims at presenting concisely the  most popular and widely used inorganic and organic NPs in food industries.   Considering that  the toxicity of NPs is often associated with their chemical reactivity, a series of  in vitro  toxicity studies are also summarised, integrating information on the type of NP studies and reported specifications, type of cells used, exposure conditions and assessed endpoints. The important role of the digestive system in the absorption and distribution of nano-formulated foods within the body is affecting the resultant cytotoxicity. Examples of how nano particles and their accumulation within different organs are presented in relation to the consumption of specific foods. Finally, the role of developing human health risk assessments in order to characterise both the potential impact of the hazard and the likelihood or level of human exposure is outlined. Uncertainties exist around risk assessment and exposure assessment of NPs due to limited information on several aspects, including toxicity, behaviour and bioaccumulation. Overall, this review presents current trends and needs for future assessments in toxicity evaluation to ensure the safe application of nanoparticles in the food industry.