What Makes Stainless Steel “Food Grade”?
Not all stainless steel is suitable for food contact. “Food grade” must meet specific regulatory requirements for composition, surface finish, and migration limits. The term is governed by FDA 21 CFR (US) and EU Regulation 1935/2004 (Europe).
Common Food Grade Types
| Type | Key Properties | Applications |
|---|---|---|
| 304 (18/8) | Best general-purpose food grade | Tanks, pipes, kitchen equipment |
| 304L | Low carbon, better weldability | Welded tanks, piping |
| 316 (18/10) | Molybdenum for chloride resistance | Dairy, brewery, marine food |
| 316L | Low carbon 316 | Pharmaceutical, high-purity |
FDA Requirements (US)
Stainless steel is generally recognized as safe (GRAS) when it meets:
- Recognized food-grade alloy (304 or 316 most common)
- Surface roughness Ra ≤ 0.8 μm for food contact
- No lead, cadmium, or heavy metal contamination
- Passivated per ASTM A967 or ASTM A380
- Welds continuous, smooth, ground flush
EU Regulation 1935/2004
| Parameter | Requirement |
|---|---|
| Chromium minimum | ≥ 16% |
| Nickel migration | ≤ 0.5 mg/kg food |
| Surface finish | Ra ≤ 0.8 μm recommended |
| Passivation | Required before first use |
Surface Finish Requirements
| Finish | Ra (μm) | Food Contact? |
|---|---|---|
| No.2B | 0.1 – 0.5 | ✅ Yes |
| No.4 (Brushed) | 0.2 – 0.5 | ✅ Yes |
| No.8 (Mirror) | < 0.1 | ✅ Yes |
| BA | 0.05 – 0.2 | ✅ Yes |
| No.1 (Hot rolled) | 2.0 – 6.0 | ❌ No |
Hygienic Design Standards
- EHEDG – European Hygienic Engineering guidelines
- 3-A Sanitary Standards – US dairy/food industry
- Self-draining surfaces, no dead legs
- Ra ≤ 0.8 μm for product contact surfaces
Need Steel Products for Your Project?
CoreMetal Steel (Xi’an Coremetal Steel Co., Ltd.) is a professional steel and metal materials supplier based in Xi’an, China. We export to 60+ countries with ISO 9001 certification. Contact us today for competitive pricing and technical support.
Contact: Tracy | Email: tracy@coremetalsteel.com | Phone: +86 18291910632