In the past decade, the market for food inks has constantly grown as more and more packaging printers are using inks that are made especially for food packaging. This makes sense, as the number of regulations and customer demands are also increasing. Food packaging has to look appetizing; it needs to convey certain information about the content, the freshness, the caloric content and the origin of the food and is often used to protect the contents from environmental influences.

“While suitable solvent inks for gravure and flexo have been on the market for a long time, the hubergroup was the first printing ink manufacturer who offers low migration offset inks for printing food packaging,” says Josef Sutter, Product Manager for MGA (low-migration inks) and offset packaging inks at hubergroup, one of the leading ink manufacturer for packaging inks. In the meantime, most ink manufacturers have also developed inks for a wide range of common food packaging printing processes.

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While food packaging inks have to look good and work on several substrates and with different printing processes, one of the major concerns for ink manufacturers is migration. This term describes the unwanted transfer of components from ink, adhesive, varnish, substrate or the environment into the packaged goods, as Rick Hulme, ink specialist at Sun Chemical pointed out at a recent presentation at the Inkjet Conference.

Migration can occur at every stage of the process. Substances of low molecular weight from the ink and coating film can pass through the substrate and affect the food inside the packaging. This is especially relevant since 95 % of the food sold in Western Europe comes in a package. Another form of migration can happen when printed packaging sheets are stacked or rolled and the printed side is in contact with the non-printed side of the packaging material. This is commonly referred to as “set-off” or contact migration. Other forms of migration occur when the food is heated, cooked or baked in its packaging (gas-phase migration).

“In developing suitable inks, the challenge was to find substances that are evaluated for food contact by the European authorities and that fulfill the demands of the whole process,” says Sutter. As if this wasn’t difficult enough, the process is complicated by the fact that no unified European, let alone worldwide, legislation exists. The EU has passed various Regulations and Directives and while Regulations come into force in every EU country as soon as they are published, Directives have to be adopted, which can be a much slower process.

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In parallel, there are also different national legislations in different countries that have to be observed. “Until now, only Switzerland has introduced a specific legislation for printing inks”, says Sutter, referring to the Swiss Ordinance on Materials and Articles in Contact with Food SR 817.023.21. Meanwhile, German authorities are discussing a similar regulation. “A harmonized European legislation would reduce work of the ink manufacturers because we do not need to look after different national legislations,” says Sutter. “It would save time and money”. Clear testing procedures are also missing from the different legislations.

The hubergroup’s Ink Academy has published a paper titled “Printing Inks for Food Packaging” that covers technical and legislative requirements in much greater detail. Paying close attention to the requirements is certainly worth the effort: “In the worst case the packed food has to be called back from the shops or the market in case of non-compliance,” says Sutter.

A consequence every food manufacturer will want to avoid. “Compliance for food contact of a food packaging is not limited to printing inks. All components of the packaging like substrate, adhesives, coatings or other parts of the packaging or additives of the production process have to be evaluated in the same way”, emphasizes Sutter. It will definitely be an ongoing process as new and highly popular packages such as pouches, new substrates or new packaging processes could require further modifications of the printing inks.