How recycled food packaging can manage chemical migration

As packaging manufacturers increase recycled content in food-contact applications, controlling chemical migration becomes an important part of ensuring that the resulting packaging is suitable for its intended use.

Recycled content can reduce demand for virgin materials and support more circular supply chains. But recovered material can also carry substances from previous applications that need to be controlled.

The issue is particularly relevant to recycled paper and board. Recovered fibre can come from newspapers, magazines, commercial print and packaging that was never designed for food contact.

Chemicals associated with printing inks, coatings, adhesives and other applications can therefore enter the recycling stream.

This does not mean recycled food packaging is inherently unsafe. Chemical migration is not unique to recycled materials, and virgin packaging can also contain substances capable of migrating into food.

The particular challenge with recycled material is greater variability in its chemical composition, with some substances originating from previous uses rather than from the formulation of the new package.

Managing that uncertainty requires controls throughout the packaging chain: controlling recovered material and the recycling process, assessing what remains, designing the pack to restrict migration and testing the finished structure for its intended use.

Control what enters the recycling stream

The first opportunity to manage chemical migration comes before a food package is manufactured.

Paper and board entering recycling systems have had many previous uses. Chemicals associated with printing inks, coatings, adhesives and other applications can enter recovered fibre alongside the cellulose that manufacturers want to reuse.

Mineral oil hydrocarbons are one example. They have been associated with printing inks and can enter recycled paper and board through printed products such as newspapers.

Other substances of interest include photoinitiators and certain plasticisers. Research has demonstrated that several of these substance groups can migrate from recycled paperboard into dry foods.

The quality and source of recovered fibre therefore matter.

Sorting and material controls can help limit unwanted substances entering the recycling process. Subsequent operations such as pulping, cleaning and deinking can remove many contaminants, but manufacturers cannot assume that every substance will be eliminated.

Research commissioned by the UK’s Food Standards Agency (FSA) has examined chemical markers that can indicate how effectively paper and board recycling processes remove contaminants.

Testing recycled material for every conceivable pollutant would be impractical. Process controls and suitable indicators are therefore important when recovered fibre is intended for food-contact applications.

For packaging producers, recycled content cannot be treated simply as a percentage on a material specification.

The source of the recovered material, how it has been processed and whether it is suitable for the intended food-contact application all need to be considered.

Understand what remains in the material

Feedstock and recycling-process controls can reduce uncertainty. Chemical assessment remains important because not everything present in recycled packaging will necessarily be known in advance.

This is where non-intentionally added substances (NIAS) become relevant.

NIAS are substances present in a food-contact material that have not been deliberately added for a technical purpose. They can include impurities and contaminants, as well as substances formed through chemical reactions or degradation.

In recycled materials, some substances may have originated in products made during an earlier use of the material. Their presence may therefore have little to do with the formulation of the new food package.

Chemical analysis can help identify known contaminants and unexpected substances that require further assessment.

Detection alone, however, does not establish that a substance will migrate into food or present a health concern.

The amount that transfers, the resulting consumer exposure and the toxicological properties of the substance also need to be considered.

This makes chemical characterisation one part of a wider assessment rather than an end in itself.

Design the pack to restrict migration

Packaging design provides another important control.

Research into recycled paperboard has detected mineral oil saturated hydrocarbons (MOSH), mineral oil aromatic hydrocarbons (MOAH), printing-related substances such as photoinitiators and certain plasticisers.

Studies have also demonstrated migration of some of these substances into packaged dry foods.

Migration does not always require direct contact between the recycled material and the food.

Research involving foods such as muesli and egg pasta has found that mineral oil hydrocarbons can migrate from recycled paperboard primarily through the gas phase. Migration was affected by factors including storage time, temperature and packaging structure.

Volatile and semi-volatile substances can, in some circumstances, move through the internal atmosphere of a pack and reach the food even when it is not in direct contact with the recycled board.

One way to reduce migration is to introduce a functional barrier between the recycled material and the food.

Depending on the application, the barrier could be an inner bag, coating, film or another layer designed to restrict the movement of particular substances.

A barrier, however, is not a universal solution.

Its effectiveness depends on the barrier material, the substances being controlled, the construction of the package and the conditions of use.

Experimental work on recycled paperboard has demonstrated substantial differences between barrier structures. Some polymer-based structures have substantially reduced mineral-oil migration under the conditions tested, while other films have provided less protection.

Barrier selection therefore needs to be matched to the migration problem.

A structure that performs well against one group of substances will not necessarily provide equivalent protection against another.

Recycled feedstock is also not the only potential source of migrants.

Printing inks, adhesives and coatings applied during conversion can introduce additional substances that need to be considered alongside those already present in the substrate.

Printing can create another migration pathway through set-off.

This can occur when printed surfaces come into contact with food-contact surfaces while packaging sheets are stacked or reels are wound during production.

Components from an externally printed surface can consequently transfer to a surface that later faces the food.

The FSA has investigated both visible and non-visible set-off and the potential for printing ink components to migrate into food.

For converters and packaging suppliers, food-contact safety therefore needs to be assessed across the complete packaging structure.

That includes the substrate, barriers, inks, adhesives and coatings, as well as what happens to them during manufacture, filling, storage and use.

Test the package for its intended use

Even detailed knowledge of packaging composition cannot establish migration risk without considering how the finished package will be used.

Migration is influenced by the properties of the substance and packaging material, but also by the food, temperature and duration of contact.

A carton containing a dry product for an extended shelf life can present a different migration scenario from packaging used for a product with a short shelf life.

Higher temperatures can also increase the rate at which some substances move through packaging.

Migration testing is therefore an important tool for establishing whether a packaging structure is suitable for its intended food-contact application.

Testing can use foods or appropriate food simulants under defined conditions designed to represent, or conservatively cover, foreseeable use.

Where substances migrate, the results can contribute to an assessment of consumer exposure and potential toxicological risk.

This approach separates three questions that can easily become conflated:

Is a substance present in the packaging? Can it migrate into the food? And, if it does, does the resulting exposure present a safety concern?

The answers will not necessarily be the same.

For converters, packaging suppliers and food businesses, food-contact suitability therefore needs to be assessed for the finished packaging system and its intended application.

It should not be inferred from the recycled-content specification or the presence of a barrier alone.

This also requires information to move through the packaging supply chain.

Recovered-fibre suppliers, paper and board manufacturers, converters and food businesses may control different parts of the finished structure. Material specifications, information on intended use, supporting test data and supplier qualification can therefore all contribute to the overall assessment.

Build chemical safety into circularity

Regulation provides the baseline for these controls.

Under the EU’s general framework for food-contact materials, packaging must not transfer constituents to food in quantities that could endanger human health or cause unacceptable changes to the food.

These principles apply regardless of whether the packaging contains virgin or recycled material.

Chemical management is also becoming more prominent in wider packaging legislation.

The EU’s Packaging and Packaging Waste Regulation (PPWR) provides that, from 12 August 2026, food-contact packaging containing PFAS at or above specified concentration limits cannot be placed on the EU market, subject to the regulation’s conditions.

The requirements apply regardless of whether packaging contains recycled material.

The wider principle for the packaging industry is clear: circularity does not override chemical safety.

Recycling systems are designed to retain useful materials in the economy, but unwanted substances can potentially travel through those material cycles as well.

Chemical management therefore needs to form part of circular packaging design rather than being treated as an obstacle to it.

Better sorting can improve the quality of recovered feedstock. Cleaning and deinking can reduce contaminants entering the next material cycle.

Chemical analysis can identify substances requiring further assessment. Carefully selected inks, adhesives and coatings can limit new sources of migration.

Functional barriers can restrict the movement of residual substances, while migration testing can determine whether the finished structure performs appropriately under its intended conditions of use.

Effective control comes from combining these measures rather than relying on any one of them.

As demand for recycled content grows, a circular food-packaging system ultimately has to achieve two objectives at once: keeping valuable materials in use while preventing unwanted substances from accompanying them into their next application.