Over the past years more and more doubts arise over the safety of mineral oils in foods. Foodwatch, the food watchdog, has proven that various products from different Dutch supermarkets contain detrimental remnants of mineral oils. It was also shown that the Dutch Food and Consumer Product Safety Authority hasn’t done research into contamination of foods with mineral oils for over ten years. But what exactly are mineral oils? And how can they harm our foods?
Mineral oils exist of a mixture of hydrocarbon molecules of various sizes. Hydrocarbons are organic compounds that consist of hydrogen and carbon. Distinction is made between saturated, unsaturated, aromatic and cyclic hydrocarbons. The simplest hydrocarbons consist of simple carbon bonds without rings and belong to the saturated hydrocarbons (alkanes). Unsaturated hydrocarbons (alkenes and alkynes) contain less hydrogens and are oil forming. Aromatic hydrocarbons are characterised by one or more benzene rings, think of furan and polycyclic aromatic hydrocarbons (PAHs). Finally, cyclic hydrocarbons have a carbon chain that form a ring. Mineral oils are obtained by liquefying coal, natural gas of biomass.
Mineral oils can be divided into two groups: ‘Mineral Oil Saturated Hydrocarbons’ (MOSH) and ‘Mineral Oil Aromatic Hydrocarbons’ (MOAH). MOSH are found in higher concentrations than MOAH and consist of saturated and cyclic hydrocarbons. MOSH can lead to bio-accumulation in organs such as the lymph nodes, spleen, and liver which can become damaged. MOAH mainly consist of alkaline polycyclic compounds and are mainly mutagens, carcinogenic and endocrine disrupting. Furthermore, these two groups have very volatile features and can evaporate slowly, both in the atmosphere and in food packaging.
Mineral oils can occur in materials that come in contact with foods. The main sources are recycled paper/cardboard and the printing ink on them. Furthermore, mineral oil is also used as glue in for example jute and sisal bags and as lubricant for the production of plastic for foods. Mineral oil can easily migrate into foods without inner pocket or with an inner pocket containing polyethylene or polypropylene.
Remnants of mineral oils can be found in nearly all foods. Mainly dry products with a large surface area can easily absorb this material. The migration of mineral oil can be prevented by using a functional barrier or an inner pocket consisting of aluminium, polyethylene terephthalate, metallised or coated polymeric foils of multi-layered foils that contain a polyamide or ethylene vinyl alcohol layer.
The general rules and regulations regarding the use of substances that come in contact with foods are determined in Regulation 1935/2004. However, no specific legislation has been determined for the use of mineral oils (MOAH and MOSH) in Europe to this day, with the exception of the provisions stipulated in Regulation 10/2011, with regard to the use of mineral oil as additive in plastic that comes in contact with foods. Herein the use of white mineral oil, paraffin and waxes derived from hydrocarbons is covered in the positive list for additives. Furthermore, Swiss legislation contains a chapter regarding the use of printing ink, in which MOAH-containing printing ink is specified as not yet evaluated substances and for which migration should be under 0,01 milligram per kilogram. In Germany, the BfR (Federal Institute for Risk Assessment) carried out a toxicological risk assessment of mineral oils. Based on this research they published guide values for the migration of mineral oil from papier in food. The European Food Safety Authority (EFSA) considers the migration of MOAH as critical considering the fact that this substance is mutagenic and carcinogenic.
It has been determined that mineral oils MOSH and MOAH can be detrimental to humans over time. They are found in foods more and more often, which can be a risk to the food safety. It is certain that there is a problem, the extent and the details of the problem are yet to be clarified. The developments of legislature regarding MOSH and MOAH are currently still in the early stages. We can expect to hear more on the subject in the coming years.