Food-grade O-rings must be safe before they can be durable. These seals touch the product directly, so the compound must meet FDA 21 CFR 177.2600 and often 3-A or NSF standards. At the same time, it must survive hot CIP chemicals, steam, fats, and oils. This article explains how to choose O-ring materials approved for direct food contact. It also covers which compliance tier fits dry, aqueous, and fatty foods. For selection advice beyond food processing, visit our Complete Guide to Elastomer Seal Materials.
FDA Compliant Food-Grade O-Rings
Food-contact seals must be safe first and durable second. In the US, the governing rule is FDA 21 CFR 177.2600 for rubber articles intended for repeated use. Notably, FDA does not “approve” individual seals. Instead, the manufacturer certifies compliance, so always request a certificate of compliance.
The regulation has three tiers. Paragraphs A through D cover dry foods. In addition, paragraph E adds a water
extraction test for aqueous foods. Paragraph F adds an n-hexane extraction test for fatty foods. Therefore, match the compound tier to the food you process.
Marco supplies FDA-compliant O-rings in five main materials:
- FDA EPDM: best for hot water, steam, CIP chemicals, and beverages. However, avoid it with fats and oils.
- FDA Buna-N: a low-cost option for oils and fats at moderate temperatures. For example, Marco B1002 is FDA compliant per 21 CFR 177.2600.
- FDA silicone: handles baking and freezing temperatures and is odorless. However, it wears quickly in
dynamic seals. - FDA Viton® (FKM): resists fats, oils, and flavor oils at higher heat.
- Markez® FFKM: Z1416 is an FDA-compliant version of the flagship Z1028 compound for the harshest
conditions.
Beyond FDA, other standards often apply. For dairy lines, choose 3-A sanitary O-rings. For potable water, specify NSF-61 drinking water O-rings. Finally, metal-detectable O-rings and gaskets help inspection systems catch seal fragments before they reach packaging.
Elastomer Materials by Industry and Application
Visit our Complete Guide to Elastomer Seal Materials to consult our quick reference tables for typical temperature ranges and elastomer seal materials by application. Read on to find application-specific recommendations for other industries.
- Elastomer Seal Materials for Medical Device & Pharmaceutical Processing
- Plasma-Resistant Seals and Elastomer Seal Materials for Semiconductor Fabs
- Elastomer Seal Materials for Oil & Gas: Subsea, Sour Gas, and Refinery Service
- Chemical-Resistant Seals for Aggressive Solvents in Chemical Processing
- Aerospace & Defense: MIL-SPEC O-Ring Materials for Fuel, Hydraulics, and Cold
- Elastomer Seal Materials for Automotive & Industrial Equipment
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Related Reading
Standard O-Ring Size Charts
O-Ring Groove Design Guides
Custom Sealing Solutions – From Prototype to Production
Engineered Sealing Solutions: Your Questions About Custom O-Rings, Compounds & Assemblies, Answered