In 2009, the German Federal Institute for Risk Assessment (BfR) – based on research findings of the Swiss Cantonal Laboratory Zurich – drew attention to the problem of the transfer of mineral oil components to food. 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.
MOH are not a chemically well-defined substance, but a highly complex composition of various hydrocarbons. This makes the determination, analysis and toxicological evaluation of the respective material very complicated.
As MOH of a certain carbon atoms range in food are considered to be of potential concern for human health, Siegwerk took immediate action and restricted the use of mineral oils in printing inks and varnishes.
Mineral oils in food packaging
The following ePaper about mineral oils in food packaging provides a quick overview of the most relevant topics regarding this issue. What are mineral oils? What are the risks for human health? How do mineral oils contaminate the food? And what are effective actions to avoid mineral oils in food packaging?
An analytical investigation carried out in 1989 by the Food Control Authority in Zurich, Switzerland first discovered that mineral oils can be found in foodstuff. The topic has gained more and more public and media attention alike.
The problem with mineral oils is their harmful effect on human health. Some Mineral Oil Saturated Hydrocarbons (MOSH) can accumulate in the organism and some Mineral Oil Aromatic Hydrocarbons (MOAH) are potential genotoxic carcinogens.
One of the main causes for MOH in food packaging is the usage of recycled paper or cardboard. Once used in packaging it either can contaminate the foodstuff via diffusion- and/or gas phase migration.
As of yet, there is no specific legislation that regulates mineral oils in foodstuff in Europe and Germany. However, the German Federal Ministry of Food and Agriculture (BMEL) has been working on a regulation for the past few years (the so called “Mineral Oil Ordinance“) and in Europe the “Framework Regulation” (EC) No. 1935/2004 broadly covers the topic.
Effective ways to prevent mineral oils from migrating out of the packaging into the food are for example the avoidance of recycled paper or the use of packaging inks that do not contain mineral oils. Additionally the usage of functional barriers can minimize or prevent the migration of mineral oils into the foodstuff.
Definition of Mineral Oils
MOH are not a chemically well-defined substance, but a highly complex composition of various hydrocarbons. They are mainly derived from crude oil but equivalent products can be synthesized from coal, natural gas or biomass. The EFSA considered in their “Scientific Opinion on MOH in Food” hydrocarbons containing 10 to about 50 carbon atoms.
The acronyms “MOSH” and “MOAH” have been introduced by Biedermann and Grob in 2009 to distinguish these substances amongst others from the hydrocarbons of plant origin (relating to MOSH) or the Polycyclic Aromatic Hydrocarbons (PAH), which consist of a limited number of largely nonalkylated ring systems.
- Mineral Oil Saturated Hydrocarbons (MOSH): comprise open-chain, often branched hydrocarbons (commonly: paraffins) and cyclic, saturated hydrocarbons, mostly alkyl-substituted (commonly: naphthenes)
- Mineral Oil Aromatic Hydrocarbons (MOAH): hydrocarbons mainly consisting of highly alkylated mono- and/or poly-aromatic rings
Furthermore, the following MOSH analogues have to be taken into consideration:
- Polymer Oligomeric Saturated Hydrocarbons (POSH): oligomers originating from plastics (PE, PP), heat sealable layers or adhesives, which due to their similarity to MOSH cannot be differentiated with standard analytics
- Polyalphaolefins (PAO): components in synthetic lubricants and hot melt adhesives
- Mineral Oil Refined Products (MORE): certain MOSH that may be introduced into food through the use of additives and processing aids that are approved refined mineral oil products, such as paraffin-like waxes or white oils
To clearly differentiate the MOSH from the MOSH analogues, the help of very specialized analytical experts and high sophisticated equipment is necessary.
The toxicology of MOH depends very much on its mixture and the substances involved.
The most critical fraction is represented by PAH with 3-7 rings and no or little alkylation. These substances are genotoxic carcinogens, whereas some highly alkylated MOAH can act as tumor promoters but are not carcinogens themselves. Nevertheless, MOAH can accumulate in the human body and therefore the German BfR recommends, that a migration of MOAH into food should not be detectable.
In humans exposed to MOSH, microgranulomas have been observed in different organs for substances with a range between C16-C35, whereas no adverse effect was observed for MOSH between C10-C13. Even if these microgranulomas are considered of lower toxicological concern, the German BfR recommends in this case the minimization of the migration of MOSH into food according to the ALARA principle (As Low As Reasonable Achievable).
Sources of Mineral Oils
The contamination of food with MOHs can have two main reasons. Either the foodstuff is contaminated during the production process or the packaging could have caused the contamination.
There are a varied number of reasons for food contamination during production and processing e.g. lubricating oils from machines can contaminate the harvest or jute/sisal bags can be contaminated with mineral oils. Furthermore, the EFSA indicated contamination by the use of release agents in bakery products or pesticides.
The contamination of foodstuff by packaging is mostly caused by the usage of recycled paper or cardboard, which can have high amounts of MOHs, mainly originating from mineral-oil-based, non-food grade newspaper inks. The strongest contamination will take place if the primary food packaging itself is made of recycled paper. Other sources could be, for example, directly on the packaging printed MOH containing inks or the use of corresponding adhesives/Hot melts.
The transport box could also be made of recycled cardboard and the mineral oils contaminate the food by migrating through the primary packaging into the food. This corresponds to a combination of gas phase – and diffusion migration:
Primary packaging is defined in the Packaging and Packaging Waste Directive (94/62/EC and amendments) as packaging that constitutes a sales unit to the final user or consumer at the point of purchase whereas secondary packaging is defined as a packaging which is conceived to group a certain number of sales units and which can be removed from the product without affecting its characteristics.
Food Packaging Inks
The best option to prevent food contamination with mineral oils via inks is the use of packaging inks that simply do not contain any MOH’s. At Siegwerk mineral oils are not used in packaging inks as intentionally added substances in Europe. The declaration on the restricted use of mineral oils in printing inks and varnishes for packaging states how serious Siegwerk takes this matter. Additionally, the disclosure of even minute amounts of MOH’s (MOSH & MOAH, range C10-C35) from our raw material suppliers is requested. In regard to MOH’s – Siegwerk puts safety first and based on our high safety standards we can ensure that our inks are safe. Click here to read our full statement.
The integration of functional barriers is a solution to avoid the transfer of mineral oils via migration into the foodstuff.
Currently there are two major approaches for functional barriers:
- Usage of barrier coating: In this case the functional barrier is used on the primary packaging and prevents the migration of MOH’s e.g. from transport boxes or the environment. Siegwerk is also working on this important R&D project for packaging solutions. As the coating is applied on the outside of the packaging, it will be only effective if the used paper/cardboard and the inks are mineral oil free! This solution is called “barrier on box”:
- “Bag in box solution”: A bag in the box can also effectively minimize or even prevent migration. Whereas suitable films (e.g. coated PET) minimizes the migration of MOH’s into the foodstuff, the use of aluminum foil with a sufficient thickness (≥6 µm) stops any substance transfer and functions as absolute barrier.
Summary how to prevent contamination of food with mineral oils, originating from the packaging
To prevent foodstuff from being contaminated with MOH’s by gas phase- and/or diffusion migration from the packaging it needs a safety strategy.
The primary food packaging itself should always be made of virgin paper or cardboard. When it comes to the usage of inks: only use packaging inks that veritably do not contain mineral oils. It is always a sign of transparency if the ink supplier can provide a statement that clearly indicates the non-usage of mineral oils in their packaging inks and varnishes.
Another possible source for a contamination with MOH’s could be the transport box. Due to economic and ecologic reasons, recycled cardboard is here often used as substrate. In this case the application of a functional barrier helps to minimize the migration of mineral oils into the food. Other possibilities are the use of “bag in the box solutions” or the usage of absorbents (e.g. activated carbon). Moreover, short transport ways and lower transport or storage temperatures help, as the tendency for a migration of MOH’s from the transport box (or the secondary packaging resp.) through the primary packaging into the food increases with the time and the temperature.
Mineral oils, Overview
Mineral oil contaminated food analysis by on-line HPLC-GC
New analytical method for detecting the mineral oil contents in foodstuffs resulting from recycled cardboard
M. Biedermann, K. Fiselier, K. Grob; J. Agric. Food Chem. 2009, 57, 8711-8721