The European Food Safety Authority (EFSA) recently evaluated silver as a food additive (E 174) and concluded that it cannot confirm its safety. This uncertainty arises from significant gaps in scientific data, particularly regarding the physicochemical properties and potential toxicity of silver particles at the nanoscale. The EC will consider EFSA's opinion when shaping its policy on the use of E 174 as a food additive. 

Silver as a food additive – is it safe? 

In a recent follow-up evaluation of the food additive silver (E 174), EFSA concluded that it cannot confirm its safety due to critical gaps in scientific data. The assessment was intended to address questions surrounding the additive’s physicochemical characteristics and health effects that were raised in its previous evaluation in 2016.

Silver under review 

Silver is used as a decorative food colourant in confectionery and other speciality items. In its evaluation from 2016, EFSA concluded that there was insufficient data to determine whether the additive posed a health risk. In response, the European Commission invited stakeholders to submit additional data. 

A single company responded, submitting studies on the physicochemical properties of silver particles along with limited toxicological data. Despite the attempt to clarify safety questions, EFSA’s expert Panel on Food Additives and Flavourings (FAF) determined that the new evidence fell short. The submitted data lacked the necessary information and quality to support a conclusive risk assessment. 

Insufficient data on particle form and behaviour

The core issue revolves around the form in which silver is present in food products. EFSA noted that the silver particles used in E 174 are generally insoluble in water and may contain nano-sized particles. In its evaluation, EFSA highlighted that the characterisation of the particle size, shape, and surface behaviour was incomplete. Furthermore, the authority noted that the data did not demonstrate how much of the silver additive might dissolve into its ionic form within the human body—information deemed essential for understanding its potential toxicity.

Insufficient data on potential nano-specific toxicity

EFSA also raised concerns about the toxicology studies that were submitted. While two genotoxicity studies and one subchronic (90-day) study were provided, none offered sufficient detail or reliability to determine whether E 174 is (not) genotoxic or causes other longer-term effects. The Panel was particularly concerned that none of the studies addressed the specific behaviour of nanoparticles, an area that requires specific attention according to EFSA’s guidance for nanomaterials. EFSA therefore maintains that a nanoscale-specific risk assessment remains necessary before the additive can be judged safe for human consumption. 

Reflection by RIVM

It is unlikely that the EC will issue another call for more nano-specific safety data on silver. The EC’s next step will be to consider EFSA’s opinion when shaping their policy on the use of silver nanoparticles as a food additive. Meanwhile, other food additives containing nanoparticles will also be re-evaluated by EFSA. It remains to be seen whether industry players will respond with more comprehensive nano-specific data for these other additives.