Producing food packaging as well as printing on food contact materials inevitably involves exposure to specific consumer safety concerns. These are triggered from various sides, such as from regulatory authorities all over the globe, which aim to protect consumers from potential risks originating from food packaging – from brand owners, who strive to protect their precious brand from all negative influences also resulting from packaging material alerts – and last but not least from NGO’s representing consumer concerns and not to forget, from critical consumers themselves.
Located at the centre of this packaging chain, the printer/converter has to deal with a multitude of aspects and parameters, whilst converting the various material streams (e.g. substrates, inks, adhesives) into the ready-made printed packaging, waiting to be filled with food or other content. It is due to this multitude of parameters, all of which having a pivotal influence on the compliance status/product safety profile of the final food packaging, that expert knowledge as well as open and transparent information are key in order to produce a high quality, fully compliant and fit for its purpose printed food packaging.
Among the different components of packaging material, packaging inks play a critical role, as they might hamper product and consumer safety. Each packaging ink is a mixture of different chemicals and some of these chemicals might be harmful, while holding the potential to migrate to the foodstuff when getting in contact. In terms of risk, the chemicals could be toxic, carcinogenic, mutagenic, repro-toxic and even endocrine disruptors.
Food safety and Migration
Migration can be described as a transfer of chemical contaminants from the food packaging material to the food, thereby making it unsafe. Migrants are substances which, due to their chemical characteristics and molecular size, move from a printed layer into the packed food.
There are different types of Migration
1) Diffusion Migration
Small and mobile molecules can easily penetrate into and diffuse across packaging material layers. This can occur even if the printed material has not yet been converted into a food package and filled with food, or later on, when the printed package is filled with food and the food starts to ‘extract’ the migrants from the packaging material.
2) Set-off Migration
Migrations can happen from one layer to another, such as a surface printed layer to the non-printed food-contact surface, which is later on brought into contact with food. If these are in direct or close contact, like in a reel or a stack after printing, set-off migration can easily occur due to the pressure existing in the reel or stack.
3) Gas-phase migration
Migration can also happen from a cardboard, (the ‘releasing reservoir’) via the gas phase within the pack to end up in food which acts as ‘recipient reservoir’ (gas phase migration). This can, for example, occur with migrants like mineral oils or some UV photo-initiators that might not be generally known as being volatile, such as organic solvents.
Consumer & Media Attention
Long before the public became aware, a number of scientific publications had already revealed the migration potential of substances present in prints. The transfer of low molecular plasticizers from flexible packaging printed with solvent-based inks into fatty snack foods was published in 1989 and into confectionery, chocolate bars, biscuits, potato crisps and similar in 1993. Beverage cartons printed with water-based inks were shown to transfer a low molecular surfactant in detectable quantities to mineral water (1998). Migration of the very low molecular photoinitiator “benzophenone” was measured in shelf-stable, refrigerated, frozen and microwaveable food packed in cardboard printed with UV inks (2000, 2003). In the US, the 1999-2000 National Health and Nutrition Survey detected phthalate metabolites in more than 75 percent of the US population.
A migration study with UV inks containing “benzophenone” and other low molecular photoinitiators was conducted in 2002. It became evident that packaging printed with the widely used so-called standard, UV inks – which were typically based on low molecular photoinitiators – could not be regarded suitable for food packaging.
All this knowledge about the migration of low molecular substances from printed layers did not spread. Instead, it remained largely unnoticed by the decision-makers in the packaging chain, until a series of incidents happened that began packaging safety into the limelight.
The first big migration scandal in 2005 that changed everything: Findings of isopropyl thioxanthone (ITX, a low molecular photoinitiator used in UV inks) in baby milk and other liquid foodstuffs (the “ITX case”) were reported all over Europe in the year 2005 and caused several product recalls. This food scandal alerted the packaging chain about the migration potential of substances from printing inks. The stakeholders within the packaging chain realized that substance transfer from printed and / or varnished layers, even if not intentionally brought into direct food contact can happen nevertheless. The transfer of ITX to food could be described by a set-off in the reel (due to reel-to-reel printing). As a consequence of the ITX case, the European Commission was prompted to take action and issued the so-called Regulation (EC) 2023/2006 on Good Manufacturing Practice, which addresses processes involving the application of printing inks. It was the first time that printing inks were explicitly regulated in the European food packaging legislation.
The Rapid Alert System for Food and Feed (RASFF) was put in place to provide food and feed control authorities with an effective tool to exchange information about measures taken responding to serious risks detected in relation to food or feed. The legal basis of the RASFF is Regulation (EC) 178/2002. Starting mainly with entries related to the food itself (e.g. salmonella and aflatoxins), packaging-related hazards also became increasingly reflected in the RASFF later on. In the year 2016, 2993 entries were made by the member states, of which 78 were migration issues.
In early 2009, new findings of the two UV curing photoinitiators “4-methylbenzophenone (4-MBP)” and “benzophenone” above the acceptable thresholds in breakfast cereals packed in polyethylene pouches included in cardboard boxes were entered into the RASFF. The issue gained huge media coverage, including evening TV news all over Europe. Food and packaging were recalled on a broad scale, bringing considerable financial losses to the affected companies and a negative image to the food production industry as a whole.
Another analytical investigation carried out by enforcement labs in Switzerland and Germany on cardboard packaging made of recycled fibres and / or printed with standard (non “low migration”) oleoresinous sheet-fed offset inks again, at the end of 2009 and in 2010, brought wide attention from prime-time TV broadcasts to the migration of mineral oils into foods. In particular, they were detected in dry, non-fatty foods like rice and flour, which so far had not been widely perceived to be able to accumulate migrants. The European Food Safety Authority (EFSA) issued in 2012, a call for data on the occurrence of Mineral Oil Hydrocarbons (MOH) in foods and in January 2017, the European Commission published recommendations for a monitoring of the presence of MOH in foodstuffs in all member states (Commission Recommendation (EU) 2017/84). Additionally, this has triggered the regulatory advancements in Germany and France.
Despite the Food grade concept introduced by Food Safety & Standards Authority of India and explicit ban on Toluene, Toluene based inks are still being used in Indian Market. Additionally, Mineral oil based inks are predominantly used for food packaging, which again contradicts the Food grade concept from Food Safety & Standards Authority of India, thereby ensuring the way to yet another Food Safety scandal.
The worldwide awareness of migration from food packaging is still increasing – and all companies in the supply chain will be affected sooner or later if they don’t comply to the food safety norms and compliant ink systems!!