How to obtain a report for the inner liner of a metal thermos flask in accordanc
Date：2026-07-10 13:56:52 Classification
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Guidelines for Obtaining Reports on Metal Insulated Mug Liners under China GB4806
I. Standard Explanation
The inner liner of an insulated mug is typically made of stainless steel (mostly 304 or 316), and the corresponding mandatory standard is GB 4806.9-2016, "National Food Safety Standard - Metal Materials and Articles for Food Contact." The core testing focus is on heavy metal migration and compliance with alloy composition regulations.
II. Application Process (5 Steps)
1. Consultation and Solution Confirmation → Submit product images, material grade (e.g., SUS304), specifications, and intended use (for food packaging). The testing agency will issue a testing plan.
2. Application Form Completion → Provide client information, product information, and specify testing items (generally including sensory evaluation, lead, cadmium, arsenic, chromium, nickel migration, etc.).
3. Sample Submission → Prepare 2-3 complete inner liners (or processed flat metal sheets). It is recommended to retain the original packaging.
4. Laboratory Testing → Simulate food contact conditions according to GB 4806.9 and GB 31604.1, and test migration levels after immersion. The cycle is generally 5-7 working days.
5. Report Issuance → Issue a testing report with CMA + CNAS accreditation. Chinese/English versions are available.
III. Core Testing Items
| Testing Item | Standard Limit | Remarks
| Sensory Evaluation (Appearance, Color, Immersion Solution) | Smooth surface, no odor | Basic Items
| Lead (Pb) Migration | ≤ 0.05 mg/kg | Simulated Immersion
| Cadmium (Cd) Migration | ≤ 0.02 mg/kg | Simulated Immersion
| Arsenic (As) Migration | ≤ 0.04 mg/kg | Simulated Immersion
| Chromium (Cr) Migration | ≤ 0.4 mg/kg | Specific to Stainless Steel
| Nickel (Ni) Migration | ≤ 0.1 mg/kg | Key Focus, Required Testing for 304/316
| Alloy Composition Analysis | 304: Cr≥18%, Ni≥8%; 316: Cr≥16%, Ni≥10%, Mo≥2% | Verify Material Authenticity
Important Reminder: Nickel migration is the most likely item to exceed the standard for the inner liner. Some companies use 201 stainless steel to impersonate 304, which does not meet food-grade requirements.
IV. Key Required Documents
**Testing Application Form (Provided by the Institution)**
**Product Manual/Specification**
**Material Certificate (Providing a steel mill material report can expedite the review process)**
**Client's Business License**
**Sample (A complete inner liner is recommended for simulating actual use)**
V. Important Notes for Processing
1. **Qualification Selection:** A third-party testing institution with CMA accreditation must be selected for the report to be legally valid (Dezewei Testing CMA No.: 201919124330)**
2. **Sample Condition:** The submitted inner liner should be clean and free of oil stains to avoid contamination and abnormal results.
3. **Simulation Solution Selection:** Choose according to the intended use (e.g., 4% acetic acid for acidic foods, special simulation solution for infant formula).
4. **Report Validity:** Usually 3-5 years, but retesting is required if the material, process, or supplier changes.
5. **Expanded Testing Scope:** If the thermos contains plastic/rubber sealing rings, straws, coatings, etc., it is recommended to simultaneously test GB 4806.7 or GB 4806.7. 4806.11
6. Cost Reference: Single-material inner liner: approximately 1000-2500 RMB;
Compliance Recommendation: When processing the report, it is recommended to request the laboratory to clearly indicate "for food contact use" in the report to facilitate compliance review by e-commerce platforms, supermarkets, and export customs. For exports to the EU market, LFGB or EU 1935/2004 testing is also required.
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