Silica is safe as a food additive

Synthetic amorphous silica (SAS) is a well-proven and very common food ingredient which is used around the globe. In the European Union (EU), for example, it is approved as a safe food additive with the identification number E 551. SAS prevents lumping and caking, and it improves flowability of powdered food such as spices and seasonings, vegetable and fruit powders, milk powder, coffee creamer, egg powder, or instant beverages. Silica is also used for filtration of beer and wine to remove impurities.

By reducing the amount of food loss by caking, silica contributes to the sustainability of the entire food chain. Less food loss also means that the resources used in the run-up to production – for example animal feed, fertilizer, water, effort, and CO₂ consumption – were not wasted.
 

The effects of silica provide numerous advantages within the entire food value chain:

• Food manufacturers benefit from constant product quality and constant dosage of nutrients and flavors. And there is less waste of resources and cleaning downtime caused by caking of powders in production lines.
• Retailers profit from transport and storage stability.
• Consumers enjoy consistent quality and taste as well as convenient handling of free-flowing spices.

Synthetic amorphous silica acts as flow aids by coating the surface of powder particles, thereby reducing interparticle interactions interspersing and preventing interparticle interactions. By absorbing moisture, fats and oils, silica prevents bridging between particles and reduces stickiness

Anti-caking agents are substances that make powdered or granular foodstuffs free flowing, prevent lumps formation and sticking. They are used applications such as in table salt, spices or instant beverage. 

Silicon dioxide has been used as a food additive for decades and numerous studies have proven that it is safe to use it in this way. In the European Union (EU), synthetic amorphous silica (SAS) is approved as food additive with the identification number E 551. As with all “E numbers”, this approval is an official guarantee to all consumers that the additive is safe and can be used without any concerns. E 551 is also tested regularly by the European Food Safety Authority (EFSA).

Synthetic amorphous silica is one of the most intensively investigated substances and to date there have been no indications of adverse health effects in scientific tests, even with high doses that could not normally be absorbed via food.

None of the studies that were conducted according to the valid guidelines of the Organization for Economic Co-operation and Development (OECD), showed any indication of health-damaging effects of SAS on the liver or any other organ system, including the nerve and immune systems.

The most recent confirmation was given in EFSA’s current scientific opinion on E 551 in 2024: The re-evaluation of silicon dioxide (E 551) as a food additive in foods for infants below 16 weeks of age and follow-up of its re-evaluation as a food additive for uses in foods for all population groups lead to the conclusion that “E 551 does not raise a safety concern in all population groups at the reported uses and use levels.” The panel also concluded that “the use of E 551 in food for infants below 16 weeks of age does not raise a safety concern at the current exposure levels.” EFSA has carried out this safety assessment with an evaluation all particle sizes. The latest technical data provided by the manufacturers of silicon dioxide was sufficient to clarify open points since the completion of the re-evaluation of the food additive in 2018.

The safety of silica is proven by numerous studies. Synthetic amorphous silica (SAS) is an exceptionally well-known and probably the most extensively researched food ingredient in the market. The scientific data basis for SAS is very comprehensive. Regular critical reviews of existing literature based on a strong scientific data confirm the safety of SAS.
 

For scientific evaluation, Evonik provides all knowledge and decades of experience in the production and application of silica. As the production processes have essentially remained the same, the particle structure as well as the characteristics of Evonik SAS grades have not changed in decades.
 

In the European Union, SAS is approved as a food additive with the identification number E 551. E-numbers are only assigned to substances that have been tested, declared safe and technologically necessary. SAS is regularly re-evaluated by the European Food Safety Authority EFSA to ensure that all new data is considered. The EFSA confirms that the use of SAS in food is safe and according to the European law. 

Silicium dioxide, also known as silica, is the second most common compound in our environment. It is continuously absorbed via the air or in food. It has always been part of the human nutrition because it is a natural component of many plants and fruits. Amorphous silica is found, for example, in bananas and rice, i.e. in unprocessed vegetable foods.

Synthetic amorphous silica (SAS) created in an industrial process has an identical structure and is not distinguishable from naturally occurring amorphous silica in plants – but it offers a much higher purity and consistent product quality. Evonik’s synthetic amorphous silica is a nature-identical substance, it is safe and proven as food additive E 551 for decades. The body excretes natural and synthetic amorphous silica (SAS).

Food, especially food of plant origin, can contain high levels of natural silica (corresponding to a daily silica intake of up to 400 mg and more, but only a small part of this is reabsorbed). Beer also contains a large amount of natural silica, which can exceed 100 mg per liter. (Casey et al. J. Sci. Food Agric. (2010) 90, 784–788.) Since silica in beer is in a colloidal dissolved form, resorption may be higher than with solid food. 

In the European Union there are currently different nanomaterial definitions for different areas of law. The relevant definition of "engineered nanomaterials" for food can be found in the Regulation on Novel Foods (EU) 2015/2283, which came into force on January 1, 2018.

It is important to know that synthetic amorphous silica (SAS) used in food is not an "engineered nanomaterial". It is regarded as a nano-structured material – but it does not contain isolated nanoparticles (primary particles). These would be far too small to fulfill the desired function of silica as an anti-caking agent. Moreover: Moreover: Silica is approved as a food additive (E 551) and has been produced and used with the same production processes and product specifications for many decades. It is a well-known and safe additive – not a new substance to achieve novel nano properties in food.

E 551 is not produced to show novel nano properties in food. Rather, silica acts as a spacer between the particles of the powdered food and is therefore approved as an anti-caking agent in Regulation (EC) 1333/2008. Unbound silica primary particles would be too small to act as an anti-caking agent. It is aggregates that fulfill this function. Aggregates normally have dimensions in the micrometer range. No individual primary particles of E 551 have been found in commercially available silica products. Therefore, according to the Food Information to Consumers Regulation (EU) 1169/2011, E 551 does not have to be labeled with the affix “(nano).”

According to current regulations and definitions, silica as a food additive does not have to be labeled as “nano” on the ingredient list of food products.

The European Union is striving to standardize the definition of nanomaterials for all member states. This includes an amendment of the current Novel Food Regulation (EU) 2015/2283. According to proposed definition, all manufactured materials consisting of solid particles where 50% or more of these particles have external dimensions the size range of 1 nm to 100 nm are considered "engineered nanomaterials". In consequence, all food additives that meet these criteria, may have to be labeled with the affix (nano) on ingredient lists in accordance with the EU Food Information Regulation. This would then also apply to silica and silicates.

What does not change is the fact that silica from Evonik is a safe food additive, because the term "nano" is only an indicator of size and not a risk indicator.

Food manufacturers can therefore continue to use silica as a safe and effective anti-caking agent – only the labeling on the packaging needs to be adapted. However, there is no declaration obligation if silica is only used as a processing aid.

In the food industry, adding silica in powdered foods helps to prevent disruptions in the manufacturing process due to clogging of pipes. This saves time, cleaning efforts (e.g. downtime when handling powders), materials, and energy. 
 

SAS supports efficient spray drying, which is the preferred method of producing a dry powder in food manufacturing. 80% of all food products have components produced in a dry state at some point of their processing path. SAS reduces caking in the dryer, resulting in less waste of food and water, less energy consumption as well as less CO₂ emissions.

SAS contributes to enhanced product stability and better storability due to prevention of clumping of many food products such as food powders, reducing food waste, and inefficient use of resources. SAS in food ensures for example longer usability by consumers. Clumps in consumer’s food often lead to the unnecessary early disposal of otherwise still good food.
 

SAS for example helps to avoid cream powder clogging in coffee dispensing machines or spice powders caking in the shaker. It hence prevents that ingredients need to be thrown away as they cannot be used anymore.
 

Free-flowing ingredients are easier to use whether it is to season a meal or to make an instant beverage. Flowable spice powders are easy and precise to dose, even after several months. More efficient dosing means more sustainable use.

At European level, the European Food Safety Authority (EFSA), supported by national institutes, evaluates every additive. EFSA members are renowned scientists from all over Europe who advise the European Commission on all aspects of safety. EFSA works independently and prepares its assessments based on scientific work and health considerations.

“E” originally meant “Europe” and is an international code that indicates that a certain additive has passed the strict evaluation by the EFSA and can be used within the European Union with approved safety. has been found to be safe.
 

Additives are listed on the labels with a class name indicating the reason for use, followed by their chemical name or E number. As the chemical names are sometimes very long, the E numbers are used as a kind of shorthand. E Numbers are only assigned to substances that have been tested and are declared safe. There is no health risk from these additives in foods.