When specifying silicone elastomers for food contact applications, understanding the differences between European (BfR Recommendation XV) and U.S. (FDA 21 CFR 177.2600) standards is critical for compliance, material selection, and global market access.
While both standards aim to prevent harmful chemical migration into food, they differ significantly in jurisdiction, testing methodologies, extraction limits, and curing requirements.
Extraction Testing & Food Simulants
FDA 21 CFR 177.2600
The FDA standard measures the total extractable fraction of rubber or silicone articles intended for repeated use. The material is subjected to reflux extraction using two specific solvents:
Aqueous Foods: Refluxing in Distilled Water at specified time/temperature intervals.
Max extractables: 20 mg/sq. inch (first 7 hours), dropping to 1 mg/sq. inch (succeeding 2 hours).
Fatty Foods: Refluxing in n-Hexane at specified time/temperature intervals.
Max extractables: 175 mg/sq. inch (first 7 hours), dropping to 4 mg/sq. inch (succeeding 2 hours).
BfR Recommendation XV
BfR testing evaluates Overall Migration and specific substance limits using food simulants that reflect actual contact conditions (e.g., 10% Ethanol, 3% Acetic Acid, or Vegetable Oil/fat simulants).
Requires migration testing under representative temperature and time conditions.
Places additional purity requirements on heavy metals, organotin compounds, and aromatic amines.
Volatile Organic Matter (VOM) & Curing Systems
The most critical technical distinction between the two standards lies in Volatile Organic Matter (VOM):
BfR Recommendation XV Requirements:
Requires that cured silicone contains less than 0.5% volatile organic matter.
Peroxide-cured silicones frequently struggle to meet this threshold without extensive high-temperature post-curing to drive off byproduct siloxanes and organic residues.
As a result, platinum-cured (addition-cure) silicone is overwhelmingly preferred for BfR XV compliance because it yields no volatile byproducts during crosslinking.
FDA 21 CFR 177.2600 Requirements:
Focuses on the formulation composition (using listed ingredients) and the n-Hexane/water extraction limits.
Peroxide-cured silicones easily pass FDA testing if properly baked/post-cured to reduce extractables below the sq. inch threshold, even if their VOM exceeds 0.5%.
