What is the food additive number for silicon dioxide?

December 14, 2025 •

3 min read

According to the European Food Safety Authority, silicon dioxide is authorized as a food additive under its specific identifier. The food additive number for silicon dioxide is E551, a code used by the European Union to signify its purpose as an anti-caking agent in various food products. This article will delve into what this number means, its function, and its presence in the global food supply.

Quick Summary

The food additive number for silicon dioxide is E551 in the European Union and INS 551 internationally, where it functions primarily as an anti-caking agent. It is a synthetic amorphous silica that helps prevent powdered ingredients from clumping together, ensuring consistency in texture and stability.

Key Points

European Food Additive Number: The European E-number for silicon dioxide is E551, used to denote its presence as a food additive.
International Food Additive Number: Under the International Numbering System, silicon dioxide is identified as INS 551.
Role as Anti-Caking Agent: Silicon dioxide's primary function in food is to absorb moisture, preventing powdered and granulated ingredients from clumping together.
Broad Range of Applications: E551 can be found in many dry food products, including spices, powdered milks, instant beverages, and dietary supplements.
Safety Profile: Global food safety authorities have evaluated silicon dioxide and consider it safe for consumption at approved levels in food.
Synthetic Amorphous Silica: The form used in food production is synthetic amorphous silica (SAS), which is distinct from potentially hazardous crystalline silica.
Labeling Information: The E551 or INS 551 code provides a universal identifier on ingredient lists, promoting consumer transparency.

What is E551: The Food Additive Number for Silicon Dioxide?

The food additive number for silicon dioxide is E551, which is part of the 'E-number' system used within the European Union for food additives. This system identifies additives on ingredient lists, regardless of language. Globally, the International Numbering System (INS) designates silicon dioxide as 551. These numbers indicate the additive has been evaluated and approved for specific food uses, mainly as an anti-caking agent.

Silicon dioxide is a synthetic amorphous silica (SAS) produced through thermal or wet processes. The resulting white powder or granules effectively absorb moisture, preventing powdered and granulated foods from clumping and maintaining their free-flowing consistency.

Where is E551 (Silicon Dioxide) Used?

As an anti-caking agent, E551 is added to a variety of dry and powdered food products to absorb moisture and prevent clumping, which helps maintain quality and shelf life. Without it, many items would solidify.

Common products containing E551 include:

Spices and Seasonings: Prevents clumping.
Powdered Milk and Creamers: Ensures a smooth texture when mixed.
Infant Formulas: Helps prevent sticking during processing and storage.
Instant Coffee and Cocoa Mixes: Prevents caking and allows for easy dissolution.
Chewing Gum: Used for surface treatment to prevent sticking.
Table-top Sweeteners: Guarantees a free-flowing texture.
Dietary Supplements: Keeps powdered supplements from clumping.

Safety and Regulation of Silicon Dioxide

Food safety authorities worldwide, including the European Food Safety Authority (EFSA) and the Joint FAO/WHO Expert Committee on Food Additives (JECFA), have evaluated silicon dioxide and consider it safe at typical usage levels. JECFA has assigned an "acceptable daily intake 'not limited'" for silicon dioxide.

It is important to distinguish food-grade synthetic amorphous silica (SAS) from crystalline silica, which is a potential health hazard when inhaled but is not used as a food additive. Research shows minimal absorption of food-grade SAS by the body, with excess excreted by the kidneys. While EFSA monitors potential nano-particle risks, the consensus is that E551 is safe at current levels.

E-Number vs. INS Number: Global Identification

E-numbers are standard in the European Union, while the INS is an international standard used by many countries. Both systems use numerical codes to identify food additives.


Feature	E-Number System	INS Numbering System
Governing Body	European Union (EU)	Codex Alimentarius Commission (FAO/WHO)
Designation for Silicon Dioxide	E551	551
Purpose	Regulates and identifies food additives within the EU for consumer information.	International standard for identifying food additives globally.
Benefit	Provides clear, standardized labeling across EU member states.	Facilitates international trade and uniform ingredient labeling worldwide.
Example on Label	Ingredients: ... anticaking agent (E551) ...	Ingredients: ... anticaking agent (INS 551) ...

Understanding Food Additive Numbers

Standardized numbers like E551 and INS 551 are vital for regulators and consumers. They provide transparency on ingredient lists, indicating the additive is approved silicon dioxide and complies with safety standards, enabling informed food choices.

Conclusion

In conclusion, the food additive number for silicon dioxide is E551 in the EU and INS 551 internationally. As an anti-caking agent, it is crucial for preventing dry, powdered foods from solidifying, preserving their quality and texture. Regulatory bodies like EFSA and JECFA have affirmed its safety for use at approved levels. The numbers E551 or INS 551 on labels offer a standardized way to identify this common and functional ingredient.

What is the food additive number for silicon dioxide? Key Takeaways

E-Number: E551 is the European food additive code for silicon dioxide.
INS Number: INS 551 is the International Numbering System code for silicon dioxide.
Primary Function: It acts as an effective anti-caking agent, preventing powdered foods from clumping.
Common Applications: Found in spices, milk powder, instant coffee mixes, and other dry goods.
Safety Status: Regulatory bodies worldwide, including EFSA and JECFA, have deemed it safe for use at approved levels.
Form: It is a synthetic amorphous silica, different from crystalline silica.

Frequently Asked Questions

Yes, regulatory bodies around the world, such as the European Food Safety Authority (EFSA) and the Joint FAO/WHO Expert Committee on Food Additives (JECFA), have evaluated E551 and concluded it is safe for consumption at the levels typically used in food.

The main difference lies in the regulatory system. E551 is the specific code used within the European Union, while INS 551 is the internationally recognized number assigned by the Codex Alimentarius Commission. Both refer to silicon dioxide used as a food additive.

Silicon dioxide is added to food primarily as an anti-caking agent. It absorbs excess moisture, which prevents dry, powdered ingredients from sticking together and forming lumps.

E551 can be found in a variety of dry goods, including powdered spices and seasonings, instant coffee and cocoa mixes, powdered milk, and certain infant formulas.

No, studies indicate that food-grade silicon dioxide is poorly absorbed by the body. Any silicon that is absorbed is effectively eliminated by the kidneys and does not accumulate in tissues.

On food packaging in the EU, it will be listed as 'silicon dioxide' or by its code 'E551'. In other regions, it might be labeled as 'silicon dioxide', 'INS 551', or simply 'anti-caking agent'.

No, food-grade silicon dioxide is a highly purified, synthetic amorphous silica, which is different from the crystalline silica that makes up sand. Its form and manufacturing process are strictly controlled for safety in food applications.