FDA 21 CFR Silicone Rubber

FDA 21 CFR 177.2600: Rubber Articles for Repeated Food Contact

FDA 21 CFR 177.2600 is the U.S. federal regulation under Title 21 of the Code of Federal Regulations that governs the use of rubber articles intended for repeated contact with food. Administered by the Food and Drug Administration (FDA) under the Federal Food, Drug, and Cosmetic Act, this regulation defines the types of rubber permitted in food-contact applications, the acceptable components (polymers, curing agents, fillers, antioxidants), and the extraction test methods and limits used to verify that the cured article does not transfer harmful substances to food.

For silicone rubber, 21 CFR 177.2600 is the primary compliance pathway for food-contact applications including baking molds, kitchen utensils, food processing seals, beverage equipment gaskets, and pharmaceutical process components.

What the Regulation Covers

21 CFR 177.2600 is organized around:

Permitted rubber articles: The regulation specifies rubber articles for "repeated use in contact with food" — meaning the same rubber component contacts food repeatedly over its service life, not just once.

Permitted components: The regulation lists acceptable base polymers (including polydimethylsiloxane for silicone rubber), crosslinking agents, antioxidants, processing aids, and pigments/colorants. Components not listed in 21 CFR 177.2600 may still be acceptable if they comply with other applicable FDA regulations (e.g., 21 CFR 178 additives, 21 CFR 73/74/81 colorants).

Extraction tests: The key compliance demonstration. Three extraction media are specified representing different food types:

• n-Heptane (represents fatty/oily food simulant)
• Distilled water (represents aqueous food simulant)
• 3% acetic acid (represents acidic food simulant)

Extraction limits: The regulation specifies maximum allowable extractable residues (mg/cm² of rubber article surface area) in each medium. Silicone rubber, when properly formulated and cured, typically yields extractables well below these limits, particularly for platinum-cured grades.

Why Platinum Cure Matters for FDA Compliance

Peroxide-cured silicone rubber produces decomposition products (benzoic acid from dicumyl peroxide; 2,4-dichlorobenzoic acid from 2,4-dichlorobenzoyl peroxide) that can appear in the heptane extraction. Post-cure treatment (200 °C, 4 hours) reduces these extractables but does not eliminate them completely.

Platinum-cured (addition-cure) silicone produces no organic decomposition products. The extractable profile is limited to residual PDMS oligomers (cyclic siloxanes D3–D10), which are present in both peroxide and platinum systems and are generally considered safe by FDA at the levels found in commercial silicone rubber.

For buyers who require the cleanest possible extractable profile — pharmaceutical process components, baby products, medical devices — platinum-cured silicone is strongly recommended over peroxide-cured grades.

How to Verify FDA 21 CFR Compliance from Your Supplier

Step 1 — Declaration of Conformity (DoC): Request a written Declaration of Conformity from the compound supplier stating that the silicone rubber compound complies with 21 CFR 177.2600. The DoC should identify the compound grade, the specific CFR citation, and the signatory's authority.

Step 2 — Extraction test report: Request the actual extraction test data for the compound in heptane, water, and acetic acid. Test reports from accredited analytical laboratories (ISO/IEC 17025) are the gold standard. In-house testing with method descriptions is acceptable if laboratory qualifications are documented.

Step 3 — Ingredient review: For novel formulations or compounds with pigments, request the full ingredient list and confirm each component against the 21 CFR positive lists. Non-listed components must be cleared under another CFR provision.

Step 4 — Pigment verification: Pigments in colored silicone rubber must comply with 21 CFR Part 73 (exempt from certification) or Part 74 (certified) or be permitted under other applicable provisions. Request pigment CAS numbers and their regulatory basis from the compound supplier.

Scope Boundary: What 21 CFR 177.2600 Does Not Cover

21 CFR 177.2600 covers rubber in contact with food. It does NOT automatically imply:

• Suitability for medical or pharmaceutical use (see USP Class VI)
• EU/LFGB compliance (different test methods and limits)
• Compliance for pharmaceutical drug-contact applications (see 21 CFR 211, cGMP requirements)

Contact us to verify certification documents and request FDA 21 CFR 177.2600 compliant silicone samples for your food-contact application.