A health scare in Italy last year over traces of a UV photoinitiator in infant milk products has focused
Ink makers are having to move quickly to head off any attempts by the authorities in the European Union (EU) to impose legal restrictions on the use of inks in food packaging.
At the same time they are having to step up their efforts to convince major brand owners and supermarket chains that the chemicals in their inks will not migrate into the food in packaging in amounts which could potentially endanger human health.
“For makers of food packaging inks, the scene in Europe has completely changed,” said Chris Whitehead, Flint Group’s product innovation director for packaging inks in Europe.
“We are having to tackle the highly complex subject of how to evaluate the safety of inks in food packaging in relation to different substrates and their structures and also with respect to the nature of the food products,” he explained. “This challenge is going to pre-occupy ink makers in Europe for a significant period of time.”
The event which triggered the dramatic change was the discovery last year by a laboratory in Italy of traces of 2- isopropyl thioxanthone (ITX), a photoinitiator for UV curing of inks, in infant milk products made by the Swiss multinational Nestle.
The ITX had migrated through the packaging, comprising polyethylene-coated board printed by UV litho and manufactured by Tetra Pak, the Swedish-based international packaging business, due to set-off or the accidental transfer of the ink onto the adjacent sheet in the reel.
As a result of a court order obtained by the Italian health ministry, two million liters of Nestle’s Nidinia and Latte Mion brands were withdrawn from the Italian market.
ITX is not on the EU’s negative list of banned substances in food nor does the World Health Organization (WHO) categorize it as being detrimental to human health. After an investigation in the health risks of ITX following the incident, the European Food Safety Authority (EFSA) concluded that the levels of it found in foods, “while undesirable, does not give cause for health concern.” It also came to a similar conclusion about another photoinitiator, 2-ethylhexyl-4-dimethylaminobenzoate (EHDAB), which is used as a synergistic agent with ITX and was included in the inquiry.
The authority did point out, however, that although food packaging inks are not covered by specific European legislation, a framework regulation on food packaging introduced in 2004 specifies that food contact materials should be safe and should not cause “unacceptable changes in the composition or characteristics of foodstuffs.”
EFSA’s investigation also revealed a paucity of safety information on a chemical like ITX. Although there had been two animal studies on the substance, there was “a lack of other toxicity data” on it, according to the authority.
The migration levels of ITX were also found to be dependent on the composition of foods. Fat-containing food products and pulp-containing juices are more likely to attract the chemical. It was not detectable in clear fruit juices such as apple juice. Pack size was also a factor with concentrations being higher in smaller rather than larger cartons.
Need for Knowledge
Although the EFSA inquiry confirmed the safety of ITX, the deficiencies it found in the knowledge of the chemicals in inks has got the European food sector and its regulators worried. It has raised doubts among the processors, retail companies and legislators in Europe about the safety of not only UV inks in packaging but other inks as well. Brand owners and supermarket chains across Europe have told converters not to use ITX and some other UV photoinitators and also to apply inks on food packaging with specific low-migration properties.
The European Commission, the Brussels-based EU executive, has been finalizing proposals for a regulatory code of good manufacturing practice (GMP) for food-contact materials in the hope that this will help to prevent migration of chemicals through packaging. In the longer term it is considering bringing in regulations specifically applying to inks in food packaging.
The European Printing Ink Association (EuPIA), representing the vast majority of Europe’s ink producers, issued last year its own detailed GMP code on the production of packaging inks applied to the non-food surface of packaging materials.
EuPIA has also recently updated its own guidance on food packaging inks to help its members comply with the EU’s 2004 food packaging regulation, in particular the requirements on the avoidance of migration to safeguard human health and the composition and organoleptic properties of food.
A number of other organizations and companies along the packaging chain have been issuing their guidance documents. Sun Chemical has been distributing a best practice guide on low-migration packaging based on its own know-how and discussions with graphic arts experts.
“We have had a lot of enquiries from our customers and brand owners about the issue of low migration,” said John Adkin, European product director for sheetfed/UV inks at Sun Chemical. “We thought it best to produce a summary of information available on the subject. We’ve been doing our own research and development on low migration for some time.”
Sun Chemical has introduced on the open market a proprietary photoinitiator for UV inks in food and other packaging which is polymeric and as a result does not migrate. “It remains locked into the core matrix of the ink,” said Mr. Adkin.
Codes of good practice have become an important means of ensuring low migration levels in food packaging. They should help to achieve a consistency of approach throughout the packaging chain.
“We can produce inks to meet all the requirements for low migration but they have to be handled and processed properly,” explained Mr. Whitehead. “Even if the converter prints a low-migration ink correctly, the outcome can all go wrong if the printed packaging material is not stored properly. The whole chain has to work together to prevent migration.”
For ink makers and their customers, the major concern at the moment is the gathering of data on migration levels resulting from the use of different inks on different packaging substrates.
A key role in providing this information is being played by a task force of representatives from the ink and coatings producers, substrate manufacturers, food packers and converters. The Packaging Ink Joint Industry Task Force (PI-JITF) is being run under the auspices of the European Confederation of the Food and Drink Industry (CIAA).
Among the issues being tackled by the task force is the identity, potential levels and toxicological impact of contaminants in food from packaging inks and practical measures for minimizing the risk of contamination. Its immediate objective is to speed up the operation of evaluating substances used in packaging inks.
Throughout the European packaging sector, migration of non-evaluated substances are now only acceptable below a level of contamination of 10 parts per billion (ppb) except with potentially carcinogenic chemicals. At levels of 10-50 ppb, or the equivalent of 10-50 micrograms per kilogram, the substance must show absence of genotoxicity after three standard mutagenicity tests. Substances above 50 ppb should be rejected unless a full toxicological profile of them has been evaluated.
The limits on migration levels are not yet laid down in any EU legislation, but they have been included by the European Commission in proposed new regulations on food contact materials.
Ink producers and other players in the packaging sector have been aiming to obtain toxicological data on non-evaluated substances of migration levels of up to 50 ppb by December 2010 and of up to 10 ppb by December 2015,
“The regulatory authorities would now like some of the evaluations to be done more quickly,” said Martin Kanert, EuPIA’s executive manager. “We have agreed to prioritize the evaluations. We have been identifying the non-evaluated substances which have been causing the most concern in the packaging chain. We expect to have the first results on toxicological studies on them by the spring of next year.”
Information is needed not just on inks and their substances but also on how they behave in different substrates. Within the PI-JITF task force, a data collection working group has been divided into smaller groupings dealing with flexibles, metals, paper and board and plastics.
“We know there should not be any problems with a substrate like foil because it provides a very effective barrier, but some inks can have difficulties with a material like polyethylene which can be a poor barrier,” said Mr. Whitehead, who is involved in EuPIA evaluation work on migration levels.
“Also it is not just a matter of looking at substrates but also the different ways in which they can be structured in a package,” he added. “Polypropylene can, for example, can be constructed as a monoweb or as a polypropylene laminate or a laminate with another plastic like polyethylene or a laminate with a metal. We have to look at the ways inks behave in all of these.”
EuPIA is hoping that the work of the joint industry task force will be effective enough to persuade the European Commission that it does not have to press ahead with legislation dealing specifically with inks in food packaging. It also believes that the association’s guidance on the production of food packaging inks helps protect consumer health.
“We don’t expect the Commission to start work on proposals for legislation on packaging inks for at least two years,” said Mr. Kanert. “In the meantime we will be strongly advocating a voluntary rather than a legislative approach.”