How to Read the 9 Standards of the Food Contact Packaging GB 31604 Series: 3 Types of Testing Thresholds for Migration / Additives / General Rules — Printers Most Often Slip on Missing General Rules
💡 💡 At a Glance
The GB 31604 series is a collection of 9 sub-standards. Printers that only cite a single standard for testing will be judged as method missing. GB 31604.1 general rules are the methodological foundation and must be cited in conjunction with sub-standards to form an effective compliance report.
Last year, a Shandong customer making frozen dumplings used PE composite film packaging that passed GB 31604.7 (plastics) migration testing, but was judged non-compliant by regulators — the reason was incomplete standard reference. The regulator's words: «You only cited GB 31604.7, but GB 31604.1 general rules were not mentioned.» This customer is not an isolated case. The GB 31604 series has 9 sub-standards, and it is common for printers to only cite 1-2 of them for testing, and this is where regulators catch them.
What the GB 31604 Series Is — It's a Collection of 9 Standards, Not One
Many people mistakenly think GB 31604 is one standard, but it is actually a series of «General Safety Requirements for Food Contact Materials and Products» gradually issued by the National Health Commission and the State Administration for Market Regulation starting in 2016. The 9 sub-standards each govern a section:
GB 31604.1 General rules (general framework stipulating food simulants, testing conditions, judgment principles)
GB 31604.2 Label identification (mandatory content on food contact packaging)
GB 31604.3 Resins (specific migration limits for base resins)
GB 31604.4 Paper and paperboard
GB 31604.5 Metals
GB 31604.7 Plastics (most commonly cited sub-standard)
GB 31604.8 Coatings (can inner wall coatings fall under this)
GB 31604.9 Rubber
GB 31604.10 and subsequent related Additive use regulations (additives contained in inks, glues, coatings)
Each sub-standard is issued independently. Printers usually only care about the one related to their materials in actual work. But GB 31604.1 general rules are the «methodological foundation» for all test reports — without citing the general rules, citing only GB 31604.7 or GB 31604.8 alone will be judged as «incomplete method».
3 Types of Testing Thresholds — Printers Most Often Slip on «Missing General Rules»
Type 1: Migration testing. This is the core indicator specified by GB 31604.7 — after food simulant (food simulation liquid) contacts under specific temperature and time, the total amount of substances migrated from packaging material into food is tested. The threshold is total migration ≤ 10 mg/dm² (food contact area), specific migrants (such as formaldehyde, heavy metals, primary aromatic amines) are looked up according to the limit table in Appendix B of GB 31604.7. The most common mistake for printers is to test only samples without testing base materials — for example, only sending finished composite bags for composite bags, while regulators require migration test reports for each layer of base material.
Type 2: Additive testing. The GB 31604 series is implemented jointly with GB 9685 (Standards for the Use of Additives in Food Contact Materials and Products). Additives contained in inks, glues, and coatings must be compared against the limit list in Appendix A of GB 9685. The most commonly overlooked by printers is «additives in composite glue» — many food-grade packaging uses polyurethane glue containing free isocyanates, which is limited to ≤ 1 mg/kg per GB 9685, but printers assume «we are using food-grade glue» and don't test it separately.
Type 3: Methodological requirements of general rules. GB 31604.1 stipulates the selection of food simulants (acidic, alcoholic, oil-based, water-based 4 types), contact temperature (4 levels: room temperature / 70℃ / 100℃ / 121℃), contact time (10 minutes to 30 days). A common error when printers send for testing is choosing the wrong simulant — for example, dumpling packaging should use water-based simulant (frozen), but printers send oil-based (fried), resulting in migration data that is completely unusable, and the regulator will determine «test results do not apply to the product».
3 Things Printers Must Do Before Shipping
① Printers proactively provide customers with the GB 31604 testing list. The list should be combined as «general rules + sub-standards», for example, for PE composite bags: GB 31604.1 + GB 31604.7 + GB 31604.10 (additives) + GB 4806.7 (basic standard for food-grade plastic packaging). Customers often don't know they need to test the general rules, and printers that don't proactively inform leave a hidden danger.
② Don't let customers substitute the brand owner's test report. Many brand owners (especially large customers) will give the printer a report stating «our products have passed GB 31604.7 testing», requiring the printer's packaging to directly reference it. This report can only cover the brand owner's own product formula, and cannot cover the packaging actually produced by the printer — because the printer's ink, glue, and composite processes may be inconsistent with the original report's reference samples. The printer must conduct a «packaging factory full-process testing» covering its own process chain.
③ Test reports must be kept for 5 years. According to GB 31604.1 general rules and Article 52 of the «Food Safety Law», production records and test reports for food contact materials must be kept for no less than 5 years. A common error in actual printer work is «only giving the customer a copy, not keeping their own file» — once regulators need historical reports for traceability, if the printer cannot produce them, it constitutes a violation.
Relationship Between GB 31604 and GB 4806
Many printers confuse these two standards. GB 4806 is the basic standard for food contact materials (GB 4806.1 general rules + GB 4806.7 plastics + GB 4806.8 metals + GB 4806.9 metals + GB 4806.10 coatings + GB 4806.11 rubber, etc.), stipulating «what is food grade». GB 31604 is the supporting testing method standard for GB 4806, stipulating «how to test whether food grade is qualified». The relationship is: GB 4806 is the product standard, GB 31604 is the testing method standard. A complete food contact packaging compliance report must simultaneously cite GB 4806 (indicating the product is food grade) + GB 31604 (indicating the testing method is compliant).
Further Reading
GB 4806.1 to 4806.11 Clearly: 5 Core Standards for Food Contact Packaging
FAQ
What is the relationship between GB 31604 and GB 4806?
GB 4806 is the product standard (specifying what is food grade), GB 31604 is the testing method standard (specifying how to test whether food grade is qualified). A complete food contact packaging compliance report must cite both standards simultaneously.
Does the printer have to test GB 31604 itself? Can the brand owner's report be used?
The brand owner's report can only cover the brand owner's own product formula, and cannot directly cover the printer's process chain (inks, glues, composite processes may be inconsistent with the original report's reference samples). The printer must conduct a 'packaging factory full-process testing' covering its own process.
What does GB 31604.1 general rules specifically govern?
The general rules specify the selection of food simulants (acidic, alcoholic, oil-based, water-based 4 types), contact temperature (4 levels), contact time, and judgment principles. Testing under all sub-standards (31604.7 / 31604.8, etc.) must be performed according to the methods of the general rules, otherwise it will be judged as method missing.
How many standards should be tested for composite bags?
PE/PP composite bags need to test at least 3 standards: GB 31604.1 (general rules) + GB 31604.7 (plastics) + GB 31604.10 (additives) + GB 4806.7 (basic standard for food-grade plastic packaging). The actual testing list increases or decreases based on customer and regulatory requirements.
How to choose simulants for migration testing?
Choose based on the actual type of food contacted: water-based (dumplings, frozen food, water-containing food), acidic (juice, yogurt, acidic condiments), alcoholic (alcohol-containing food), oil-based (fried food, meat, nuts). Sending the wrong simulant will result in test results that do not apply to the product.
How long do GB 31604 reports need to be kept?
According to Article 52 of the 'Food Safety Law' and GB 31604.1 general rules, production records and test reports for food contact materials must be kept for no less than 5 years. The printer must keep its own files, not only give them to the customer.
The awkward question bosses ask purchasing: the customer only gave a GB 31604.7 report, should the printer accept the order?
It is not recommended to accept. GB 31604.7 is the plastics sub-standard and must be cited in conjunction with GB 31604.1 general rules, otherwise it will be judged as method missing when sampled. The customer must be required to supplement the general rules report before accepting the order, otherwise the printer bears the risk of regulatory penalties.
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