Packaging · 4 min read
Food-grade packaging: board, inks and migration
Food packaging has a requirement no other category shares: nothing in the pack may end up in the product. That sounds obvious and is quietly difficult, because paper is porous, ink is chemistry, and the two spend weeks pressed against each other before anyone opens the box.
Migration is the risk you cannot see
Migration is the movement of substances out of packaging and into the food it contains. It does not require contact with a liquid or any visible defect. Some compounds simply evaporate off the printed surface and are absorbed by the product across the air gap inside the pack.
This is why food packaging cannot be specified the way a cosmetics carton is. The question is not only whether the board is clean, but what the ink is made of, how completely it cured, and how long the pack and the product will sit together.
Virgin fibre versus recycled board
Recycled board is the environmentally attractive choice and the riskier one for food. Recovered paper streams include newsprint and printed matter, and those carry mineral oil residues from inks that were never intended to touch food. Those residues survive the recycling process.
The practical rule: for direct food contact, use virgin fibre board, or use recycled board with a functional barrier between it and the food. Choosing recycled board for a food pack without a barrier is the single most common food packaging mistake, and it is usually made for the right reasons.
Low-migration inks, and why cure matters
Low-migration inks are formulated so the components that could migrate are either absent or bound into the film once cured. They exist for exactly this application and they cost more than standard inks. On a food job that difference is not where to economise.
Cure is just as important as formulation. A partially cured ink film still contains unreacted material that can migrate, so a low-migration ink run badly offers less protection than the specification implies. Ask how cure is verified, not only which ink is used.
Direct contact and indirect contact are different jobs
If the food sits inside a sealed inner bag or a wrapper, the carton is secondary packaging and the requirements ease considerably, because the barrier is already there. If the product touches the board, the carton is primary packaging and everything above applies in full.
Be explicit about which case you are in when you brief the printer. Many food cartons are quoted as though they were secondary packaging simply because nobody said the biscuit would be resting on the board.
Grease, moisture and the barrier trade-off
Fatty and moist products need a barrier or the board stains, softens and loses strength. A polyethylene coating solves it completely and is the traditional answer. Water-based dispersion coatings do a similar job with less material, and are worth asking about.
The trade-off is recyclability. A PE-coated carton is difficult to recover in Pakistan's recycling stream, so it effectively becomes waste. A dispersion-coated board usually recycles with ordinary paper. If sustainability claims matter to your brand, that choice is where they are won or lost.
What to ask your printer
Five questions cover most of it. What board grade is being quoted, and is it virgin fibre? Which ink system, and is it a low-migration formulation? Is the pack direct or indirect contact in this design? Can you provide a declaration of compliance for the materials used? And are food and non-food jobs run on the same press without a documented wash-up between them?
A supplier that can answer those without checking is a supplier that has done food work before. We print food and beverage cartons alongside the pharmaceutical work in Lahore, and the controls that regulated pharma packaging demands, line clearance, batch segregation and documented material specification, are the same controls a food carton needs.
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