Packaging aging migration testing quantifies the amount of substances that transfer from packaging materials into food, pharmaceuticals, or other contents after exposure to accelerated aging conditions that simulate long-term storage. This testing is essential for demonstrating regulatory compliance under frameworks such as EU Regulation (EU) No 10/2011, the GB 4806 national food safety standards, and the EN 1186 and EN 13130 method standards. This article explains the technical principles, sample types, testing items, analytical methods, and typical applications of migration determination on aged packaging materials.
Technical Overview
Migration is the mass transfer of substances from a packaging material into the packaged product or into a food simulant during contact. Substances that may migrate include residual monomers, oligomers, plasticizers, antioxidants, slip agents, adhesive components, printing ink ingredients, and degradation products formed during processing or storage. Because diffusion rates increase exponentially with temperature in accordance with Arrhenius behavior, laboratory aging at elevated temperatures allows months or years of intended shelf life to be simulated within days or weeks.
Packaging aging migration testing therefore combines two elements: a defined aging protocol (temperature, humidity, and duration) followed by a migration test performed on the aged sample. The results are expressed either as overall migration, meaning the total mass of all non-volatile substances transferred per unit contact area, or as specific migration, meaning the quantity of individually identified and quantified substances with toxicological reference limits.
The test is a core requirement for food-contact material compliance in most jurisdictions. EU Regulation (EU) No 10/2011 sets an overall migration limit of 10 mg/dm² and specific migration limits for listed substances; the GB 4806 series and GB 31604 method standards govern the same assessment in China; EN 1186 and EN 13130 provide the corresponding harmonized European test methods. Comparable frameworks exist in the United States under 21 CFR and in Japan under national food sanitation specifications. Accredited third-party laboratories routinely perform these determinations for manufacturers, brand owners, and regulatory submissions.
Testing Samples
Flexible Plastic Films and Laminates
Single-layer and multilayer films used for pouches, bags, wraps, and lidding, including polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyamide (PA), ethylene-vinyl alcohol copolymer (EVOH), and aluminum foil laminates. Laminated structures are of particular interest because adhesives and tie layers can contribute significantly to migration after aging.
Rigid Containers and Closures
PET and HDPE bottles, PP jars and tubs, thermoformed trays, closures, cap liners, and gaskets. For these samples, migration is typically tested in the finished container form to reflect the real contact geometry and surface-to-volume ratio.
Pharmaceutical Primary Packaging
Blister films, HDPE and PET bottles, cyclic olefin polymer vials and syringes, elastomeric stoppers, and infusion bags. In pharmaceutical applications, aged migration testing supports extractables and leachables programs and stability studies that accompany product registrations.
Paper, Board, and Coated Metal Packaging
Coated paperboard cartons, molded fiber trays, and internally lacquered metal cans and closures. Testing evaluates coating components, lacquer monomers, and set-off substances from printed surfaces.
Adhesives, Inks, and Coatings
Cured films or coated specimens of laminating adhesives, printing inks, varnishes, and barrier coatings, evaluated to characterize their contribution to total migration and to screen for photoinitiators, primary aromatic amines, and residual solvents.
Testing Items
Depending on the material, intended use, and applicable regulation, the testing program typically covers the following items:
- Overall migration into aqueous, acidic, alcoholic, and fatty food simulants, expressed in mg/dm² or mg/kg.
- Specific migration of listed monomers: bisphenol A (BPA), styrene, acrylonitrile, vinyl chloride, vinylidene chloride, 1,3-butadiene, caprolactam, and formaldehyde.
- Specific migration of plasticizers and additives: phthalates (DEHP, DBP, BBP, DINP, DIDP), adipates, citrates, hindered phenolic and phosphite antioxidants, erucamide and other slip agents.
- Epoxy derivatives: BADGE, BADGE hydrochloride and hydration products, and novolac glycidyl ethers (NOGE).
- Primary aromatic amines from polyurethane adhesives and azo pigment decomposition.
- Photoinitiators and ink components: benzophenone, 4-methylbenzophenone, ITX-type initiators, and mineral oil hydrocarbons (MOSH/MOAH) from paperboard.
- Elemental migration of barium, cobalt, copper, iron, lithium, manganese, zinc, antimony, and regulated heavy metals such as lead, cadmium, mercury, chromium, and arsenic.
- Residual solvents from printing inks and adhesives, measured by headspace gas chromatography.
- Non-intentionally added substances (NIAS), including oligomers, degradation products, and impurities, evaluated by targeted and screening approaches.
Testing Methods
Sample Preparation and Aging Protocol
Specimens are conditioned and aged in climatic chambers at defined temperature and humidity, for example 40 °C at 75% relative humidity or 60 °C for extended durations, selected to represent the intended shelf life of the packaged product. Accelerated conditions are derived using Arrhenius or Q10 kinetic modeling so that the thermal exposure corresponds to real-time storage. Aging may be applied to the empty material, the formed package, or the filled commercial product, and the migration test is performed immediately after aging.
Selection of Food Simulants
Simulants are assigned according to the food type in contact, following EU Regulation (EU) No 10/2011 and GB 31604.1: 10% ethanol for aqueous foods, 3% acetic acid for acidic foods, 20% and 50% ethanol for alcoholic foods, 95% ethanol or isooctane as fatty-food simulants, and modified polyphenylene oxide (Tenax) for dry foods. For pharmaceutical and cosmetic applications, suitable extraction media are selected to simulate the actual formulation.
Migration Test Conditions
The time-temperature combination mirrors the worst foreseeable use conditions. Common overall migration conditions include 10 days at 40 °C for long-term room-temperature storage, 2 hours at 70 °C for hot-fill, 2 hours at 100 °C or reflux for boiling applications, and 2 hours at 175 °C for high-temperature oven use. Test geometries include total immersion, single-side contact cells, pouch tests, and filled-container tests, per EN 1186 (overall migration), EN 13130 (specific migration), and the GB 31604 method series.
Analytical Techniques
Overall migration is determined gravimetrically after evaporation of the simulant and constant weighing of the residue. Specific migration of organic substances employs gas chromatography-mass spectrometry (GC-MS), headspace GC-MS for volatile compounds, high-performance liquid chromatography (HPLC) with UV or fluorescence detection, and liquid chromatography-tandem mass spectrometry (LC-MS/MS) for trace-level targets. Elemental migration is quantified by inductively coupled plasma optical emission spectrometry (ICP-OES) or ICP mass spectrometry (ICP-MS). NIAS screening is performed using high-resolution mass spectrometry followed by tentative identification against spectral libraries.
Expression and Evaluation of Results
Results are reported in mg/dm² of contact area or converted to mg/kg food using the conventional ratio of 6 dm² of packaging per kilogram of food, with appropriate fat reduction factors applied where permitted. Each value is compared with the applicable overall migration limit, specific migration limits, or specification limits, and the method validation data, including limits of quantification and measurement uncertainty, accompany the test report issued by the laboratory.
Applications
Packaging aging migration testing supports a wide range of commercial and regulatory objectives:
- Regulatory compliance demonstrations for food-contact materials intended for markets governed by the GB 4806 series, EU Regulation (EU) No 10/2011, and national food-contact frameworks.
- Generation of data supporting declarations of compliance and safety assessments across multilayer supply chains.
- Pharmaceutical packaging qualification, extractables and leachables studies, and stability programs accompanying product registrations.
- Shelf-life substantiation for packaging systems, confirming that migration remains within limits throughout the claimed storage period.
- Supplier qualification, material comparison, and change control when resins, adhesives, inks, or structures are modified.
- Safety evaluation of recycled content, such as recycled PET, and of novel bio-based and biodegradable packaging materials.
- Research and development of functional and active packaging, where additive release behavior must be characterized.
FAQ
What is the difference between overall migration and specific migration?
Overall migration measures the total mass of all non-volatile substances that transfer into the simulant, reported against a single limit of 10 mg/dm² in the EU system. Specific migration quantifies individual named substances, such as BPA or a particular phthalate, against substance-specific migration limits derived from toxicological assessments.
Why is aging performed before migration testing?
Aging simulates the cumulative effect of long-term storage. Because migration is diffusion-controlled, higher temperatures accelerate the release of substances, so an aged specimen reveals whether migrants that remain immobilized in fresh material will exceed limits by the end of the product shelf life.
How are accelerated aging conditions selected?
Conditions are selected using Arrhenius kinetics or the Q10 rule so that the thermal exposure at the accelerated temperature is thermally equivalent to the intended real-time storage period. The chosen temperature must remain below levels that would induce degradation mechanisms not representative of actual distribution conditions.
Which food simulant should be used for my product?
Simulant selection follows the classification of the food: aqueous foods are represented by 10% ethanol, acidic foods by 3% acetic acid, alcoholic foods by ethanol-water mixtures, fatty foods by 95% ethanol or isooctane, and dry foods by Tenax. Accredited third-party laboratories can confirm the appropriate assignment based on the intended use declaration.
What are NIAS and why are they evaluated?
Non-intentionally added substances are impurities, reaction intermediates, oligomers, and degradation breakdown products that are not deliberately added to the material but can still migrate. Regulatory frameworks require that they be assessed using risk-based principles, typically through screening analysis of aged migration samples.
How long does the testing take?
Turnaround depends on the aging duration and the analytical scope. A standard overall migration test with 10 days of contact requires roughly two to three weeks, while programs combining extended aging with specific migration and NIAS screening of numerous target substances may require four to eight weeks or longer.