Harmonization of the EU nanomaterial definitions:

Harmonization of the EU nanomaterial definitions:

a much-needed initiative

Christian Micheletti


In European Union legislation, the regulatory status of nanomaterials in sectoral regulations is established by their definition, indicating what is considered a nanomaterial, and thus subject to the application of specific nano provisions in each product category. Therefore, there is more than one regulatory definition of nanomaterial. The first definitions were those of cosmetics [1] followed by the food labelling regulation [2]. The European Commission then released a Recommendation for nanomaterial definition [3]. It must be kept in mind that a Recommendation is not binding unless included in a Regulation. The Recommendation is based on particle number size distribution as the primary parameter and specific surface area as the secondary parameter. In addition, it was stated that >50% particles by number must be in the size range 1–100 nm for a substance to be considered a nanomaterial, which made the parameters measurable and thus the EC Recommendation applicable. The recommendation was taken up by more recent legislation, such as the Biocide Product Regulation [4] and the Medical Device Regulation (approved on 5 May 2017). Since 2011, the use of the EC Recommendation has resulted in issues and the need for clarification, which in turn led to the ongoing revision that should be released soon by the Environment Directorate-General. The expected revision will not include major modifications but will only add some text clarifications. Also, guidelines for implementation of the Recommendation will be issued, setting out the best testing strategy to date to identify a substance as a nanomaterial. After the revision is published, it is expected the Commission will harmonize the definition of nanomaterial across sectoral regulations.

Regulatory definition(s) of nanomaterial

The definitions of nanomaterials used in cosmetics and food are more a statement of principle than regulatory enforceable definitions. In cosmetics, nanomaterials are defined as intentionally produced substances which have particle size between 1 and 100 nm and are biopersistent and insoluble, but there is no particle number benchmark. Therefore, in principle, even one nanoparticle (if detectable) in the substance is sufficient to make it a nanomaterial, with the consequent burden of safety dossier notification. However, other nanomaterials such as nanosomes are not considered nanomaterials under the cosmetic regulation since they are not biopersistent. The result is that even if the technical function of the nanomaterial is necessary to the product, and while the safety of the ingredient has to be demonstrated, it is not necessary to provide a notification with the full nano safety dossier 6 months before placing the product on the market. The definition of nanomaterials used for food is even less clear, since it includes intentionally produced (and not ‘intentionally in the nano-range’) materials, and does not establish a particle number benchmark. In addition, it specifies that nanostructured or aggregated materials with nano-properties have to be considered nanomaterials. Therefore, in principle even a natural ingredient intentionally produced to be used in food, with one particle in the nanosize range, would be considered a nanomaterial and thus be labelled as such. Consequently, the entering into force of the Novel Food Regulation [5] which refers to the same nanomaterial definition, would make almost all substances with detectable nanoparticles novel foods. It is also not clear if nanosomes or other soft nanomaterials will be considered nanomaterials or not. This uncertainty results in the non-applicability of nano specific requirements in food. For example, there are foods using additives that are known to contain detectable fractions of nanoparticles, such as E551 (silica dioxide). However, the labels of such marketed products do not mentioned them as being nano, even though they should. This example shows the current non-application of the nano definition in food.

There are other examples suggesting that even if not official, the tendency is to consider the EC Recommendation as the de facto working definition in food. The best example is the recent EFSA opinion on TiO2 (E171) re-evaluation, which found E171 to be safe for use. The EFSA Scientific Opinion on E171 [6] reported that, based on information collected from stakeholders and other sources, E171 is not a nanomaterial because the number of particles is below 50% (i.e., ranging between <1% and 36%). Therefore, literature data on nano-TiOwas considered not relevant (and therefore not used) in the safety assessment of E171.Nano-related data were only used in the comparative assessment of the behaviour after ingestion of nano and bulk forms (essentially, absorption, distribution, metabolism and excretion (ADME)). To complete the safety assessment, EFSA launched a call for data on reproductive toxicity and on particle size distribution because of the need to indicate nano fraction in E171specifications‘ due to its potential importance for toxicokinetics and toxicity’[7].


The EFSA Opinion on E171 shows there are different ways of defining nanomaterials in food. According to the food definition of nanomaterial, E171 must be classified as a nanomaterial. Therefore, for consumer information [2], (nano) should be placed beside E171 on the label’s ingredient list. However, this has not been done for products on the market. On the other hand, when determining which safety data to use, the EFSA Panel decided to follow the EC Recommendation instead (which is not mandatory for food, as it is only a Recommendation), thus deciding that E171 is not a nanomaterial. Which view is the correct one?

It is thus clear that the Commission’s intention to make the revised EC Recommendation enforceable in all regulations is necessary to eliminate the unjustified difference in the safety assessment of nanomaterials for companies in different industry sectors. The fact that the same substance can be considered a nanomaterial in one regulation and not in another with different safety requirements is not acceptable.


1. Regulation EC 1223/2009. OJ L 342, 22.12.2009, p. 59–209

2. Regulation EU 1169/2011. OJ L 304, 22.11.2011, p. 18–63

3. Commission Recommendation of 18 October 2011 on the definition of nanomaterial. OJ L 275, 20.10.2011, p. 38–40

4. Regulation EU 528/2012. OJ L 167, 27.6.2012, p. 1–123


6. EFSA ANS Panel (EFSA Panel on Food Additives and Nutrient Sources added to Food) (2016) Scientific Opinion on the re-evaluation of titanium dioxide (E 171) as a food additive. EFSA Journal 2016;14(9):4545, 83 pp. doi:10.2903/j.efsa.2016.4545

7. EFSA (2017) Call for scientific and technical data on the permitted food additive titanium dioxide (E 171). https://ec.europa.eu/food/sites/food/files/safety/docs/fs-improv-additive-20170130-call_sci-tech-data-e171.pdf

by Cec Editore