Full definition
Seals and gaskets manufactured from elastomer compounds that comply with FDA 21 CFR 177.2600 for repeated contact with food, and often additionally with EU (EC) 1935/2004, USP Class VI (biocompatibility for pharmaceutical), and 3-A Sanitary Standards (dairy industry). All compound ingredients must be FDA-listed, and the finished product must pass extraction tests in specified solvents. Approved materials: silicone VMQ (most widely specified — non-toxic, odorless, tasteless, -60 to +230°C, FDA/USP VI), white EPDM (water, steam, dairy, beverages — no carbon black), white NBR (edible oils, fats), white FKM (aggressive cleaning chemicals, high temperature), and PTFE (universal chemical resistance). Standard O-ring colors for identification: blue (detectable — contains metal detectable pigments for food safety), white, and translucent. Metal-detectable and X-ray visible elastomers are increasingly specified for automated contamination detection systems. Smooth surface finish (Ra <0.8 μm) per 3-A Standard 18-03 to prevent bacterial harboring. Applications: dairy, beverage, meat/poultry, bakery, brewery, pharmaceutical, and cosmetics processing equipment seals. Brands: Parker (compound E0540, E0893), Trelleborg (blue silicone), Freudenberg (70 EPDM 291).