Packaging not only protects food, it also serves as a carrier of information and as an advertising medium. Every package carries important labelling elements and often colourful images that should encourage consumers to buy the product. While the information is only printed on outside of the packaging material, particles of printing ink materials can be found in the food every so often.
The particles found are not ink, but specific components of colour formulas, which make it possible to use the colour in technological processes. We have to take a closer look at two substance groups in particular: on the one hand, there are the photoinitiators, required for UV curing ink (e.g. ITX and Benzophenons), and, on the other, mineral oils, which are also used as solvents for colours.
How do Ink Components Get into Food Products?
There are two import vectors. Migration occurs when substances are transferred from the packaging materials to the food product as a result of their solubility. Materials are “set off” when the printed side gets into contact with the inside of the material that touches the food product, either through rolling or stacking. Photoinitiators can contaminate food in both ways, while mineral oils are transferred primarily via migration.
How can Food Contamination with Photoinitiators be Prevented?
Complete UV curing fixes photoinitiators in such a way that a set off is not possible anymore. Migration can be avoided using an appropriate packaging design; adding a barrier to the packaging material is very effective, for instance. Correct process monitoring and in-house tests are an integral part of good corporate manufacturing practice, which is required by law.
How can Food Contamination with Mineral Oils be Prevented?
Only mineral-oil free ink should be used for food packaging materials in respect to good manufacturing practice. However, given the fact that recycled cardboard made of newspaper is a major source of contamination, the ink used for printing newspapers should be replaced with mineral-oil free ink. This is possible, but not common practice. As a result, food products must be protected from contamination by the appropriate measures (see paragraph: Mitigation Strategies by the CODE Commission), as paper recycling processes would be very difficult to optimise.
A further strategy for avoiding contamination is the exclusive use of mineral-oil free work and auxiliary substances (release agents, grease, machine oil, etc.) when producing food. Another source of mineral-oil contamination in food products are burlap sacks (for transporting coffee, cocoa etc.) that are treated with patching oils, for example, in addition to recycled cardboard.
Are There any Legal Regulations for Printing Inks?
Regulation (EC) No 2023/2006 lists detailed rules on good manufacturing practices, especially for printing inks. This Regulation defines that printing inks (used on the non-food contact side) or any of their substances must not be transferred through the substrate or by set-off in the stack or the reel in concentrations that lead to levels of the substance in the food which are not in line with the requirements stipulated in Article 3 of Regulation (EC) No 1935/2004. This applies to materials and items to which the ink is applied. The printed surfaces must not come into direct contact with food.
A European positive list, such as the Union List in Regulation (EU) No 10/2011 for plastics, is not available for printing ink components. However, some photoinitiators, such as Benzophenons, are listed with a specific migration limit in Regulation (EU) 10/2011 and, thus, evaluated toxicologically by the EFSA.
Printing inks used for print media are not subject to the provisions listed above. Contact with food is not intended in its original use and only occurs, if at all, following the paper recycling process. However, the food industry cannot function without resource-friendly recycled paper for environmental reasons.
Is There a Health Risk to Consumers?
Potential health risks are evaluated through a risk assessment. This assessment is based on knowledge of the type and quantity of the contaminate in the food product. Health risks to individual population groups (e.g. children, adults) can be evaluated using toxicological substance data, such as the TDI (tolerable daily intake) and consumption behaviour.
None of the tests conducted at AGES to date (also see “Activities in Austria”) have shown any contamination of food with photoinitiators that could pose a risk to our health.
The assessment of mineral oil contamination is more difficult, as they are a mixture of numerous, difficult to separate substances with varying levels of potential danger and their composition cannot be determined so accurately. The focus in the development of test methods and risk assessment is on identifying common cancerogenic, polycyclic aromatic hydrocarbons (or MOAH mineral oil aromatic hydrocarbons) and more short-chain, saturated hydrocarbons (or MOSH – mineral oil saturated hydrocarbons). The shorter the hydrocarbon chain, the higher the risk that they will be stored in the body. What makes a health assessment even more problematic is that there are no toxicologic studies available for these special mixtures.
Mineral oil is the main component in fuel and can be found as a solvent in many technological products (also in the food processing industry) and, as described above, also in printing ink and print media and, thus, in all newspapers, magazines and advertising brochures. These migration sources must also be taken into account during a risk assessment.
Mineral oils are undesired in food and their migration via packaging materials or printing ink has to be avoided.
The European Food Safety Authority (EFSA) has published a scientific expert study on the foodborne exposure of humans to mineral oil hydrocarbons (MOH). This study concludes that total exposure to MOH should be reduced. The occurrence of MOSH and MOAH in foods can also be attributed to the use of food packaging materials made from recycled paper, from which the substances can be transferred to the food product.
EFSA Press release: Gutachten zu Mineralöl-Kohlenwasserstoffen and Scientific Opinion on Mineral Oil Hydrocarbons in Food
BfR (German Federal Institute for Risk Assessment) on Mineralölbestandteilen in Schokolade aus Adventskalendern und anderen Lebensmitteln
Activities in Europe
A standardised, European-wide positive list for printer ink components, similar to the Union’s list for plastics, cannot be expected at present.
The Swiss Utility Ordinance (Ordinance by the EDI on Utility Articles) also lists printing ink components and photoinitiators in Part B – non-evaluated substances. As these substances have not been subject to scientific tests to assess transfer, they may only be used if there is no transfer to food in line with the Swiss Ordinance (detection limit 10 μg/kg food).
Together with the Federal Institute for Risk Assessment (BfR), the German Federal Ministry of Food and Agriculture is working on a nation-wide, binding regulation for printing inks and mineral oils.
Furthermore, there is the Resolution ResAP(2005)3 by the European Council on packaging inks and the latest amendment of a directive for paper and cardboard, which also deals with the issue of recycling qualities in detail. (see Resolution ResAP (2005)2)
The European Printing Ink Association (EuPIA) has developed the EuPIA “Guideline on Printing Inks Applied to the Non-Food Contact Surface of Food Packaging Materials and Articles” and the document “Good Manufacturing Practices (GMP) : Printing Inks for Food Contact Materials Applied to the Non-Food Contact Surface of Food Packaging Materials and Articles”. The guideline includes a blacklist of printing inks and related products and is updated on a regular basis.
Activities in Austria
The BMG has initiated tighter checks on foods in respect to printing ink components and mineral oils primarily via focused measures. AGES has carried out tests specifically targeting the contamination of foods with printing ink components as part of these measures in recent years:
- Examining cardboard-packed foods with regards to the migration of 4 Methylbenzophenon, 4 Hydroxybenzophenon and Benzophenon into foods. A total of 31 cardboard-packed foods were tested on the migration of these substances into the actual food product. The samples were taken in Vienna and Lower Austria and included 10 breakfast cereal products (e.g. muesli, muesli bars), 11 frozen vegetable products and 10 chocolates/praline products. Measurements showed that the concentration levels in all samples were lower than the regulation limit of 0.05 mg/kg food and, thus, clearly below the specific migration limit of 0.6 mg/kg food (tests carried out in 2009).
- Examining cardboard-packaged foods with regards to the migration of 4-Methylbenzophenon, 4-Hydroxybenzophenon, 4-Phenylbenzophenon and Benzophenon into foods. This campaign included samples taken from all provinces and tested 53 colour-printed, cardboard-packed food products (breakfast cereals and frozen cakes) for the migration of photoinitiators. The measurements showed that the concentration levels in all samples were lower than the regulation limit 0.05 mg/kg food and, thus, below the specific migration limit of 0.6 mg/kg food (tests carried out 2010-2011).
- Additionally, a method was developed at AGES as part of a Master’s Thesis including 22 photoinitiators, 10 of which are Benzophenes. This method was used to examine 21 breakfast cereal and 24 fruit juice samples, as well as their packaging. All the packaging materials tested positive for at least one photoinitiator (2 to 13 different substances per sample), as was expected. While all food samples tested positive for at least one type of photoinitiator, Benzophenon was the most commonly found substance (in ca. 97 % of the samples). However, all the concentration levels found for Benzophenon were (much) lower that the specific migration limit of 0.6 mg/kg food and for other photoinitiatiors below 0.01 mg/kg food (tests carried out 2012).
- Furthermore, Umweltinstitut Vorarlberg ran the focus campaign “Migration of mineral oils from packaging materials” in 2011. Forty food samples and 9 cardboard-packaging material samples were taken in Austria and tested for MOSH and MOAH as part of the most recent screening. “Migration of mineral oils from packaging materials”
- A focus campaign carried out in 2015 tested 60 samples for barrier layers in recycled cardboard, differentiating between cardboard packaging material designed for long-term use (rice, pasta, muesli etc.) and that for short-term use (sandwiches, fast food, cakes, pizza etc.). Not all the products that were wrapped in recycled cardboard material and intended for longer storage (e.g. cocoa powder, rice, pasta etc.) met the requirements for effective barriers. More information: AGES Check – Mineral oils in recycled cardboard.
CODE Commission Mitigation Strategy
The Sub-Commission for Utility Articles of the Austrian Code Commission already issued a guideline on the use of recycled cardboard at GZ: BMG-75210/0018-II/B/13/2012 in 2012.
This guideline states that the migration of numerous substances – even substances not evaluated from a toxicologically perspective – must be expected when using recycled cardboard in food packaging materials. This is also because the raw materials for making recycled cardboard do not comply with the requirements for food packaging material use. Additionally, the use of printing inks may also contribute to the migration of undesired substances. The manufacturer cannot assume that the requirements are met should the food product be wrapped unprotected in recycled cardboard. This means that if foods are wrapped in recycled cardboard, appropriate precautions such as barriers or additional internal packaging, must be used to ensure that substance migration from the recycled cardboard will conform to Article 3 of Regulation (EC) No 1935/2004.