Recent evaluation of the safety of Synthetic Amorphous Silica (SAS) as food additive (E551) by the European Food Safety Authority (EFSA)

Subject of investigation

Re-evaluation of silicon dioxide (E 551) as a food additive of synthetic amorphous silica, approved in the EU for use as a food additive (E 551).

Core statement

No new indication for toxicity of E 551 as a food additive.

The substance

E 551 is artificially produced amorphous silicon dioxide, also known as synthetic amorphous silica (SAS). Over the decades, two production methods (wet chemical and pyrogenic) have become established, for which the resulting E 551 products are chemically identical. The food additive is available for downstream processing as a powder or a granulate. It is important to note here that E 551 is not what is known as colloidal silica, which is a liquid with extremely finely divided nanoparticles.

Results in detail

  • On the basis of the available data, there is no indication of any toxic effects of E 551 for authorized types and intensities of utilization. Nor was there any indication of genotoxic or reprotoxic effects.
  • Estimates of actual silica exposure in organisms suggest a maximum value of 50 mg per kg body weight per day. This is at least one order of magnitude lower than the doses actually administered in toxicological studies, where they were proven to be unproblematic.
  • Over the last few decades, various public authorities and expert groups of the EU and individual member states as well as the WHO and the UN have investigated whether oral intake of silica or silicon impacts organisms negatively. There are no indications that it does.
  • As the state of knowledge continues to improve further, the expert committee proposes that in the future the particle size distribution for the amorphous silicon dioxide used in the investigations be more accurately determined. This would allow a better understanding of the effects of individual particles in the agglomerates as well as better categorization of the findings.

Type of study

A metastudy: The authors have reassessed the safety of E 551 in accordance with the regulatory requirements of the EU and on the basis of the current scientific literature and the opinions of the industry. Such reassessments are prescribed for food additives that were approved within the European Union before 2009, or if there are new scientific findings.

About the authors

The Scientific Panel on Food Additives and Flavourings assesses the safety of chemical substances added to foods and the exposure of consumers to these substances. The Panel’s work concerns mainly those substances assessed by the European Food Safety Authority (EFSA) before their use in the EU can be permitted. The members of the Panel are scientists from Europe with specific expertise in the relevant areas.

Original publication:

EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS), EFSA Journal (2018), DOI 10.2903/j.efsa.2018.5088