11/10/2021 3 min

A specific health risk assessment guide for nanomaterials in food

Nanomaterials are increasingly being used in our food, mainly to improve a product's appearance, packaging or nutritional content. However, their potential health impacts are raising many questions. This is especially true of titanium dioxide used as a food additive (E171), whose safety has been questioned by the European Food Safety Authority (EFSA) and which is in the process of being banned in the European Union with effect from 2022. To assess the risks posed by nanomaterials in food, a "nanospecific" assessment method is essential. This is the purpose of the scientific guide published by the Agency today.

Numerous nanomaterials found in food

In the food sector, engineered (manufactured) nanomaterials are mainly used:

  • as food additives, to improve a product's appearance and palatability by modifying its structure, colour or texture. For example, titanium dioxide (E171) and silicon dioxide (E551) are used respectively as a colouring and an anti-caking agent;
  • as technological additives in the formulation of food contact materials, to modify the properties of these materials (transparency, resistance, etc.), indicate the presence of any pathogens, or improve the organoleptic quality and shelf-life of food. This is the case, for example, of nanosilver used in plastic packaging for its antimicrobial function;
  • as ingredients with a nutritional function, for example, calcium carbonate used in infant formula to achieve an adequate calcium content.

A guide to specifically assess the health risks associated with nanomaterials

The presence of nanomaterials in our food has raised many questions about the health risks they may pose to consumers. To be able to assess them, a standard approach is not enough. "Nanomaterials require a 'nanospecific' risk assessment approach due to their complexity, properties and behaviour. For example, nanomaterials readily interact with other substances, which can change their stability and their fate in the body," explains Bruno Teste, scientific coordinator at ANSES.

Today, the Agency is publishing a guide on a risk assessment methodology for engineered nanomaterials used as food additives and ingredients with a nutritional function. This need for a specific method is not unique to ANSES: in 2018, EFSA published a guide to assessing dossiers on nanoscience and nanotechnologies in applications such as food additives, pesticides and food contact materials.

Although the two methodologies developed by EFSA and ANSES are based on similar concepts and risk assessment methodologies, ANSES's expert appraisal proposed specific adaptations related to regulatory definitions, particle size measurements, dissolution properties and hazard identification. This guide follows on from the work undertaken by the Agency over the last ten years, contributing to the scientific debate and the search for the best method of assessing the health risks of engineered nanomaterials.

A methodology to be tested on titanium dioxide

This methodology will initially be tested on the engineered nanomaterials previously identified in the first phase of the expert appraisal, depending on data availability. At this stage, titanium dioxide appears to be the nanomaterial with the best-documented exposure and hazard data. This would allow a full risk assessment to be conducted for a nanomaterial used in food. As a reminder, use of this additive in France has been suspended since January 2020, following the opinions published by the Agency in 2017 and 2019. In its opinion of May 2021, EFSA indicated that E171 could no longer be considered safe when used as a food additive. The decision-making process at European level has just reached a new stage, which should lead to this chemical being banned in the European Union from 2022. 

Further studies needed before assessing the risks

In the first phase of its expert appraisal, the Agency identified 30 substances suspected of being used as food additives or ingredients. It reiterated the need to conduct physico-chemical characterisation studies for these substances as soon as possible using electron microscopy approaches. This is because measuring size and particle size distribution is an essential preliminary step before assessing the risks of these nanomaterials.

In addition, the test conditions for physico-chemical characterisation, exposure calculations and toxicological studies need to be standardised, to facilitate the acquisition of appropriate and usable data for risk assessment.

Lastly, until their safety can be demonstrated, the Agency emphasises the need to limit exposure of workers, consumers and the environment to nanomaterials. To this end, it recommends promoting the use of safe products that do not contain these substances and are equivalent in terms of function, effectiveness and cost.