The European Food Safety Authority (EFSA) has released new guidance on evaluating nanoparticles in food that dissolve in lipids before consumption. The guidance uses the 1-octanol-water partition coefficient (KOW) method to waive nanospecific considerations for particles that dissolve in lipids. The KOW method is a ratio that describes how a substance distributes between two solvents, and for nanoparticles, it can be used to estimate solubility in fatty media. If the log KOW value is above 3, solubility in fats is likely.
However, EFSA also outlines scenarios where the KOW method is not applicable, such as materials with coatings, surface modifications, or heterogeneous mixtures. The guidance aims to avoid unnecessary work for industry and regulators by providing a method to identify situations where nanospecific considerations are not needed for safety assessments. While the KOW method has limitations, it can help identify situations where read-across to non-nanoforms is possible and when nanospecific considerations may not be needed. The new guidance is an Annex to EFSA’s 2021 guidance on evaluating nanoparticles in food and feed.