Ink suppliers say slimmer packs increase migration risk

Problems with photoinitiators in ultraviolet inks and the increased risks associated with packaging reduction have led to renewed calls for better supply chain communication.

According to the British Coatings Federation (BCF), migration of one ink constituent in particular 4-methylbenzophenone (4-MB) has triggered no fewer than nine full product recalls since the beginning of the year. This is a particular problem for the breakfast cereals industry, where ink may migrate from the carton through the liner bag and into the product.

Taint is recognised to be a problem with benzophenones generally. But Jo Watkins of the BCF's Printing Inks Council pointed out that the migration threshold on 4-MB is set especially low because there is so little toxicological data on the substance.

Watkins, who is also marketing manager for packaging at Sun Chemicals, said: "With the cereal cartons, manufacturers changed the inner liner bag from a metallic film laminate a functional barrier to straightforward polyolefin, which allowed migration."

The risk is that the same types of ink are used, even when thinner and probably cheaper packaging is specified.

In the 'blame game' that followed these product withdrawals, converters criticised the inks and coatings industry. Watkins explained: "Inks and coatings suppliers can advise converters on fitness for purpose, but we can't know about individual substrates or foods. Printers and converters are looking for an indemnified situation, when so much depends on how our products are used."

She added: "With so many links in the supply chain, the different parties need to work together to ensure fitness for purpose. Brand owners, in particular, need to take control of their supply chain."

But Nick Kernoghan, business manager for testing services at Pira International, questioned the implied assumption on the part of ink suppliers that migration levels would be limited by a given barrier.

"This sort of thing will only be avoided if the supply chain works in as open a fashion as possible," he said.

Over the first half of this year, the European Food Safety Authority (EFSA)'s food contact panel assessed the data on 4-MB, and said there was no risk from short-term exposure at the levels detected in cereals. But more research and specifically toxicity data was needed, said EFSA.