How safe is your packaging ink?

Throughout the last few decades, the awareness of potential health risks associated with the use of chemicals has risen in industrialised societies around the world. Simultaneously, there has been a growing agreement that the risks should be understood equally in all nations so that products can be traded unimpeded by varying risk assessments.

Consequently, the safety of food packaging has become more regulated, though there is still a lack of harmonised legislation which governs printing inks specifically.

Who’s responsible for compliance?

The ink manufacturer’s responsibility is to supply products that are fit for the intended purpose as defined by the other members of the food packaging chain. The final responsibility for the compliance of food packaging lies with the seller of the packed food.

Ink manufacturers are not liable for any aspects of the production of food packaging once the packaging inks have left the manufacturing site as these are outside ink manufacturers’ control. They are not able to issue certificates or declarations of compliance which cover all the legal responsibilities of the entire packaging chain.

The manufacturer of the packaging and the filler are responsible for the properties of the food packaging and its compliance with legal requirements. They also have an obligation under the Good Manufacturing Practice (GMP) Regulation to monitor and record all materials in their manufacturing and to execute appropriate control for printing, storage and delivery processes to ensure consistent product quality and full traceability throughout the whole supply chain.

For plastic containers and film substrates, there is a lack of clarity in the packaging industry on their permeability. An infinite number of combinations of food type, packaging materials, and printing inks and varnishes are possible. Therefore, a certain packaging layer might show different barrier functionality.

To ensure a functional barrier, which prevents migration through the packaging material into the packed food, migration tests with the final package construction are strongly recommended.

Why is migration a concern for food packaging?

Migration can lead to contamination of food with hazardous chemical substances. Hence, regulations and industry guidelines have been implemented to protect consumers.

The regulations focus on components with a molecular weight of less than 1000 Daltons. Larger molecules are generally regarded as not being able to permeate cell membranes during transit through the body, and are therefore of no concern.

Possible sources of migratable materials include: inks, coating and adhesives, the environment (climate, transportation, storage), substrate (paper and board, films, storage) and presses (contamination, hygiene, detergent).

Migration is measured as migration per surface area and is noted as mg/dm². To calculate the concentration of migrating substances in a packed food noted as mg/kg from the mg/dm² value, the size of the surface of the packaging and the weight of the food in the package need to be known.

If the actual packaging design is unknown, EuPIA advises that the concentration of migrating substances in the packed food is made under the assumption that 1 kg food is packed with a total surface area of 6 dm².

Potentially carcinogenic and genotoxic substances must not migrate at all. For substances which have not been toxicologically evaluated, migration must be below 10ppb (parts per billion). For substances which have been investigated toxicologically to some extent, specific migration levels can be defined as acceptable, depending on the results, between 10–50 ppb when the absence of mutagenicity has been proven.

Migration levels above 50 ppb are allowed when a substance has been fully evaluated and approved. The European Food Safety Authority (EFSA) or a national authority sets the values for the specific migration limit and tolerable intake based on a toxicological dossier submitted by the raw material supplier.

What affects the level of migration?

Varnishing and laminates may seal in the ink and make it more resistant to solvents, but neither will automatically eliminate migration. They may slow down or reduce migration; however, neither coatings nor laminates are absolute barriers.

The substrate is an important factor for migration. It can affect the migration of the ink components significantly. Migration out of virgin pulp board is minor. However, it can be considerable when recycled material is used.

Apart from ink composition and substrate, other print parameters that might affect the migration risk are film weight, completeness of cure, the size of the printed area relative to the possible food contact area, the use of press side additives, rewind tension and the storage conditions of the printed reel.

Some other aspects related to the food package that should be considered when assessing the migration include: the kind of food (eg, dry, fatty, acidic), storage time and temperature, as well as processing of the packed food (eg, freezing, heating, sterilisation).

Food packaging compliant ink

Food packaging compliant ink is a UV printing ink which has been formulated so that any potential migration from the print is below the accepted limits, provided the ink is applied on a suitable packaging structure under GMP for food packaging, which means that the manufacturing is being conducted according to defined rules.

Food packaging compliant ink must be used if a transfer of substances from the printing ink onto or into the packed food cannot be excluded because the packing material does not constitute an absolute barrier against migration. Only glass and metal composites provide absolute barrier properties.

The printer should conduct representative practical investigations, such as migration testing or worst-case scenario calculations, for each packaging application category and structure.

Conclusion

EuPIA recognises that fulfilling the requirements for food packaging compliance is challenging. Companies involved in the whole packaging supply chain should adopt a ‘Continuous Improvement Strategy’ to control potential migrants from packaging inks.

It is also recognised that the period of time for companies to comply with all the regulations and guidance (including migration testing, deep cleaning, training etc) will be significant. Where required limits are not achieved immediately, it is expected that an action plan is generated to set out a program to ensure compliance within an agreed and manageable timescale.

Jet Technologies’ partner Pulse Roll Label Products strongly recommends that only food packaging compliant ink, varnishes and substrates, proven by the testing of the final package, are used in the manufacture of food packaging and labelling under GMP conditions.

Further detailed information is available at https://www.jet-ap.com/product/print-and-finish/inks/.

Image credit: ©stock.adobe.com/au/ra2 studio