Scientific opinion on the re-evaluation of silver (E 174) as food additive

The present opinion deals with the re-evaluation of the safety of silver (E 174) when used as a food additive. Silver in food additive E 174 is present in its elemental form. The Panel noted that there are data gaps and concerns to be addressed to conduct a risk assessment with respect to the use of silver (E 174): lack of data on toxicity studies on elemental silver or the food additive (E 174); unknown particle size distribution of the food additive (E 174); evidence of the release of silver ions from elemental silver, which may be of concern. However, the extent of the release of the silver ions is unknown in the case of silver (E 174). The Panel concluded that the information available was insufficient to assess the safety of silver as food additive. The major issues included chemical identification an d characterisation of silver E 174 (e.g. quantity of nanoparticles and release of ionic silver) and similar information on the material used in the available toxicity studies. Therefore, the Panel concluded that the relevance of the available toxicological studies to the safety evaluation of silver as a food additive E 174 could not be established. The Panel recommended that the specifications for E 174 should include the mean particle size and particle size distribution (± SD), as well as the percentage (in number) of particles in the nanoscale (with at least one dimension below 100 nm), present in the powder form of silver (E 174) used as a food additive. The methodology applied should comply with the EFSA Guidance document, e.g. scanning electron microscopy (SEM) or transmission electron microscopy (TEM). The Panel recommended that additional data in line with the current Guidance document on evaluation of food additives would be required.