By Evert Delbanco, Flint Group Head of Global Regulatory PM & Group Toxicologist

Ensuring food packaging safety depends on the appropriate selection of materials and on well-controlled manufacturing processes. Inks and coatings must be designed to minimise the transfer of unwanted substances into food. As migration limits and substance traceability become core elements of regulatory compliance, all actors in the packaging value chain need to understand the mechanisms of migration and the requirements governing ink formulation, qualification and testing.

Food packaging serves several simultaneous functions. It provides a protective barrier against mechanical damage, light, oxygen, moisture and contaminants during storage and transport. It also carries mandatory consumer information, including ingredient lists, storage conditions and origin information. 

Packaging also fulfils a commercial function by communicating brand identity at the point of sale. Achieving consistent, high-quality print on food-contact materials (FCMs) while meeting food safety requirements places specific demands on ink formulation. The two objectives are not inherently in conflict, but they cannot be managed independently.

Migration is the transfer of chemical substances from packaging materials into packaged food. These substances may originate from intentionally added ingredients in the ink formulation or from non-intentionally added substances (NIAS). NIAS are substances that are not intentionally added but are present as a result of impurities in raw materials, reaction by-products, degradation products or process aids.

The rate and extent of migration depend on several variables, including the molecular weight of the substance, the barrier properties of the substrate, the nature of the food (particularly its fat or moisture content), the temperature at which the packaged product is stored or processed, and the duration of contact. Smaller, more mobile molecules at elevated temperatures pose the highest migration risk.

Migration can occur through three primary mechanisms: diffusion, set-off and gas-phase migration. Diffusion occurs when substances pass from the printed side of the packaging through the packaging material and into the product. Set-off occurs when ink components transfer from the printed surface to the reverse, food-contact side, for example, when printed materials are stacked or wound. Gas-phase migration occurs when volatile compounds evaporate from the ink, travel through the headspace, and recondence on the product or the food-contact surface.

Regulation (EC) No 1935/2004 is the overarching EU framework for food contact materials (FCMs). It requires that all food contact materials and articles be manufactured so that, under normal or foreseeable conditions of use, they do not endanger human health, cause unacceptable changes in food composition, or alter the food’s taste or odor. 

While Regulation (EC) No 1935/2004 sets out the overarching framework for food contact materials in the EU, it does not yet include harmonised, specific provisions for printing inks used on food packaging. In the absence of EU-wide legislation, national measures such as the German Ink Ordinance have emerged and may influence the regulatory landscape. Printers, converters, and ink formulators therefore share a duty to control the potential for migration by selecting appropriate raw materials, applying inks under validated conditions, and verifying the performance of the complete packaging construction.

For substances that have been toxicologically evaluated, specific migration limits (SMLs) set the maximum permitted amount of an individual substance that may migrate from food contact materials into food. SMLs are expressed in mg/kg of food and are derived from toxicological hazard assessment, typically based on a health-based guidance value such as a Tolerable Daily Intake (TDI). This value represents the amount of a substance that can be ingested daily over a lifetime without appreciable health risk. SMLs are set out in the relevant annexes of applicable regulations and ordinances.

Regarding printing inks, national frameworks complement EU law. For example, the German Printing Ink Ordinance requires a thorough selection of listed substances and/or non‑listed substances, which require a subsequent toxicological assessment for carcinogenic, mutagenic, or reprotoxic (CMR) properties.

Where substances are not included on the positive list, the German Printing Ink Ordinance permits their use only subject to strict conditions: the printing ink layer must not be in direct contact with food under normal or foreseeable conditions of use; the substance must not have CMR properties; and migration into food must not be detectable above 10 µg/kg (0.01 mg/kg). No corresponding permission exists for direct food-contact applications.

Developing inks suitable for food packaging begins with robust raw material management. Raw materials are selected in line with applicable positive lists, such as those defined in Swiss and German regulations. In parallel, manufacturers apply voluntary frameworks such as the EuPIA Charter on Raw Material Selection and Exclusion. Non-intentionally added substances (NIAS) are assessed as part of the overall risk assessment, and their presence is minimised through careful raw material selection, process control and analytical verification.

Migration behaviour depends on the overall packaging structure, including substrate type, film thickness, the presence of functional barriers, curing conditions. Even migration-optimized UV systems require sufficient curing energy to achieve stable performance. Product safety must therefore be considered at the design stage as a parameter of equal importance to print quality or throughput. Flint Group Packaging Solutions offers migration-optimized inks designed for regulatory compliance; however, responsibility for the final packaged product’s compliance rests with the manufacturer placing the product on the market, such as the food business operator or the pharmaceutical marketing authorisation holder.

Supply chain communication is central to FCM compliance. Because migration risk depends on the entire packaging system rather than any single component, the parties responsible for each element of the system must exchange sufficient information to ensure overall compliance.

A Statement of Composition (SoC) is the standard document through which ink manufacturers communicate the migration-relevant properties of their products to printers/converters. A SoC discloses the potentially migrating ingredients of a product in a way that supports regulatory compliance and helps the converter to calculate whether the quantities are within permissible limits.

The complexity of the technical and regulatory landscape means that many companies seeking compliance look for partners that invest in specialist FCM capabilities. These may include dedicated manufacturing of food-contact inks, structured training programmes, and access to laboratory services for analytical and migration testing. 

Migration from printing inks into food is a technically complex and regulated phenomenon. Managing it requires migration-optimized ink formulations, appropriate selection of substrates and packaging structures, correct processing conditions, and structured communication across the supply chain.

Managing migration is a continuous process that depends on informed material selection, controlled processing, effective collaboration across the value chain, and a clear understanding of regulatory expectations. Migration-optimized inks and coatings play an important role in enabling packaging that meets performance, compliance and safety requirements. Companies that invest in the right expertise, technologies, and partnerships will be best positioned to deliver packaging that meets both performance expectations and the highest safety standards.