When classifying particles, which can mainly occur as contaminants in food, a distinction is made between micro- and nanomaterials. Nanoparticles are chemically different particles in the size range 1–100 nm (= 10−9 m) that can occur in food. According to Recommendation 2011/696/EU (EU, 2011) of the European Commission, nanomaterial is a natural, process-derived or manufactured material that contains particles in an unbound state as an aggregate or agglomerate and in which at least 50% of the particles in the number size distribution have one or more external dimensions in the range from 1 nm to 100 nm. Known nanoparticles include titanium dioxide (TiO2), which is often used as a coating to improve the appearance of confectionery or to brighten salad dressings as an approved food additive E171, or silicon dioxide (SiO2), also known as silicic acid, which is used to improve the fow properties of ketchup, e.g., and as a fow aid for powdered foods. In addition to inorganic nanoparticles, there are also a large number of natural nanoparticles (e.g.fat micelles), which can be found in milk, hen’s eggs, fats and fat by-products or are used as carriers for functional nutrients such as poorly soluble bioactive substances. These so-called organic nanoparticles are completely degraded in the human metabolism. For some inorganic nanoparticles, such as TiO2, strict restrictions have recently been imposed in the food sector, such as the withdrawal of approval for E171 in Europe, as there are indications of possible genotoxicity (EU, 2022/63).