EFSA raises red flag for silicon dioxide safety over nanoparticles

By Niamh Michail

- Last updated on GMT

© GettyImages/Jag_cz
© GettyImages/Jag_cz
The European Food Safety Authority (EFSA) cannot give food additive silicon dioxide the safety all clear because it may contain nano-sized particles, and has urged the Commission to change the specifications.

Silicon dioxide, also known as synthetic amorphous silica (SAS), is used by food manufacturers as an anti-caking agent in spices or creamers, to ensure fine flowing powders or to absorb water.

It is made up of aggregated nano-sized primary particles which are usually greater than 100 nm.

However, in an opinion published yesterday,​ EFSA scientists warned that, depending on the starting material and the process used to manufacture the additive, “it cannot totally be excluded​” that some aggregates may be smaller than the nano threshold of 100 nm.

Since no long-term study with nano silicon dioxide has been conducted, EFSA could not give the additive the safety all-clear.

“The Panel concluded that the EU specifications are insufficient to adequately characterise the food additive E 551. Clear characterisation of particle size distribution is required​.”

It urged the Commission to change current specifications to include particle size distribution.

An adequate specification would use appropriate statistical descriptors, such as range, median and quartiles, as well as the percentage – both in number and by mass – of particles in the nanoscale, it said.


While the EFSA scientists said there is no indication that E 551 is toxic at the reported use and levels, limitations in the available data mean the current acceptable daily intake (ADI) is ‘not specified’.

A chronic toxicity study using “an adequately characterised material representative of SAS used as a food additive E 551​” would provide better toxicological data that would allow EFSA scientists to derive an ADI, they said.

The ANS Panel did not receive a newly submitted dossier but received data from interested parties, such as The European Chemical Industry Council (CEFIC). It also used Mintel’s global product database to determine the prevalence of the additive in food.

Silicon dioxide can be made using a thermal or wet process and can also take the form of fumed (pyrogenic) silica and hydrated silica (precipitated silica, silica gel and hydrous silica).

Nano risks

The opinion was published in the same week that the French government agency for competition, consumption and fraud (DGCCF) presented its findings on titanium dioxide nanoparticles to the minister of the economy and finance, Bruno Le Maire.

“[The DGCCRF] provides for a labelling requirement for the presence of manufactured nanomaterials, especially in food and cosmetics. Analyses conducted by the DGCCRF show that this obligation is insufficiently respected,” ​a statement issued by Le Maire’s ministry said.

Of the 40 cosmetic products analysed, 87% contained nanoparticles while 39% of the 74 food products contained nano-sized materials.

Despite this prevalence, only one product mentioned on its labelling the presence of nanomaterials.

The tested food samples included confectionery, bakery decorations and spices.

The DGCCRF is due to present its findings to the European Commission in order to organise EU-wide controls “in a coordinated manner​”.

Le Maire asked the DGCCRF to be particularly vigilant to this emerging risk. “[…] Protection of consumers comes from both product safety but also transparency of information”, it said.

The meeting also focused on the Lactalis scandal where infant formula manufactured at the French company’s site in Craon was contaminated with salmonella, leading to 39 cases of sickness so far. 

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1 comment

Misleading headline

Posted by Bernd Haber,

A red flag would mean to have severe concerns on the safety of a product. In the case of the re-evaluation of silicon dioxide EFSA on the contrary has clearly stated that there is no safety risk from the current use of the additive. Your headline is strongly misleading even though EFSA recommends that some further work on the specification is recommended. This is a quite common procedure in the re-evaluation of an additive and have been seen in many cases so far. So, not a big story in my opinion. The big story would be to tell that EFSA does confirm that there is no safety concern. Think about!

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