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2026
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National Food Safety Standard: Food Additive - Silicon Dioxide (GB 25576-2020)
Issued by the National Health Commission of the People's Republic of China and the State Administration for Market Regulation on September 11, 2020, this standard officially came into force on March 11, 2021. It replaces the previous version GB 25576-2010, with several key updates to better regulate the production and quality control of food-grade silicon dioxide.
Scope of Application
This standard applies to three types of food additive silicon dioxide produced via distinct processes:
- Fumed silica, manufactured through the hydrolysis of chlorosilane in an oxyhydrogen flame
- Silica gel and hydrated silica gel, produced by reacting sodium silicate solution with acids
- Precipitated silica, made by reacting silicic acid solution with acids
Key Updates from the 2010 Version
- The loss on drying limit for Class I fumed silica has been revised to a maximum of 7.0%.
- Adjusted the drying duration in the loss on drying test method and the ignition time in the loss on ignition test method.
- Updated the referenced methods for determining lead (Pb) and arsenic (As) contents, enhancing the accuracy of contaminant detection.
Technical Requirements
Sensory Requirements
All three classes of products must meet the following sensory criteria, which are inspected by placing an appropriate amount of the sample in a 50mL beaker and observing under natural light:
Item | Class I (Fumed Silica) | Class II (Hydrated Silica Gel) | Class III (Precipitated Silica, Silica Gel) |
Color | White | White | White |
State | Uniform powder | Amorphous particles | Uniform powder or particles |
Physicochemical Requirements
Stringent physicochemical limits are set to ensure product safety and quality, with specific test methods specified for each index:
Index | Class I Limit | Class II Limit | Class III Limit | Test Method |
Silicon dioxide (SiO₂) content, w/% | ≥ 99.3 | ≥ 99.0 | ≥ 96.0 | AA.4 |
Loss on drying, w/% | ≤ 2.5 | ≤ 70.0 | ≤ 7.0 | AA.5 |
Loss on ignition, w/% | ≤ 2.0 | ≤ 8.5 | ≤ 8.5 | AA.6 |
Lead (Pb) content, mg/kg | ≤ 5 | ≤ 5 | ≤ 5 | AA.7 |
Heavy metals (as Pb), mg/kg | ≤ 30 | ≤ 30 | ≤ 30 | AA.8 |
Arsenic (As) content, mg/kg | ≤ 3 | ≤ 3 | ≤ 3 | AA.9 |
Soluble dissociated salts (as Na₂SO₄), w/% | ≤ 1 | ≤ 4 | ≤ 4 | AA.10 |
Inspection Methods
The standard details comprehensive testing procedures for all indices, including identification tests, content determination, and contaminant detection. Key notes for testing are as follows:
- Some reagents used in the tests are toxic and corrosive. Operators must handle them with care. In case of skin contact, rinse immediately with water and seek medical attention if necessary.
- Reagents and water should comply with analytical grade standards and the Grade 3 water specifications in GB/T 6682, unless otherwise specified.
- For the determination of silicon dioxide content, samples are ignited at 950°C ± 50°C, then decomposed with hydrofluoric acid. The content is calculated based on the mass loss after ignition.
Significance of the Standard
As a widely used anti-caking and thickening agent in food production—applied in milk powder, condiments, solid beverages, etc.—food-grade silicon dioxide’s quality directly impacts food safety. The implementation of GB 25576-2020 helps standardize production practices, eliminate outdated production capacity, and guide the industry toward refined and regulated development. It also provides clear technical guidelines for enterprises’ self-inspection and regulatory authorities’ supervision and sampling, ensuring the safety of end products in the food market.
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