Project R-10069

Physico-chemical characterization and risk assessment of the fraction of nanoparticles in the food additive E174 (silver) in a legislative context. (Research)

Metallic silver is applied as food additive and referred to as E174. The recent EFSA opinion dealing with the re-evaluation of E174 indicated lack of data on toxicity studies on E174, unknown particle size distribution of E174 particles and evidence of the release of silver ions from elemental silver, which are specific concerns for risk assessment. In this perspective, an approach to characterize the fraction of nanoparticles in the food additive E174 based on EM-methodologies is developed, validated and applied. Conventional TEM methodologies are used to determine the size and shape distributions of nanoparticles in pristine E174 food additives and E174-containing products in a regulatory context. In addition, a semi-automated HAADF-STEM-EDX-based method is being developed for the physical characterization in combination with chemical identification of silver (nano)particles in food matrices. These TEM-based characterizations will provide relevant data for an exposure assessment of E174. In parallel, the hazard associated with E174 will be estimated by (pre)toxicological STEM-EDX-based testing on in vitro human intestinal models containing silver (nano)particles. By this means, a better understanding of processing-mediated artifacts and factors impacting the risk assessment will be obtained. Furthermore, a better estimation of the nanoscale-bound hazard of E174 in toxicity testing approaches may contribute to new safety measures. Existing knowledge gaps regarding the use of E174 will be closed and guidance documents will be refined.

01 October 2019 - 31 December 2020