MOSH/MOAH in edible oils & fats: routine analysis and EU regulation

Mineral oils, also called mineral oil hydrocarbons (MOH), play a major role in our engineered world. They are used as fuels and lubricants and as raw materials for the production of megatons of chemicals, paints, varnishes, plastics, etc. Due to their ubiquitous distribution, they can end up in food in various ways and are considered as food contaminants.

Mineral oils usually consist of saturated and aromatic hydrocarbons (MOSH and MOAH). Toxicological studies have shown that both fractions accumulate in humans. Although MOSH can cause inflammatory effects and the formation of microgranulomas in animals, there seems to be no major concern for human health regarding MOSH-uptake by foods. However, the MOAH fraction, in particular the three- to seven-ring systems, is suspected of being carcinogenic. Accordingly, EU authorities have issued recommendations for maximum MOAH levels in foods, where contents above 2 mg/kg in oils are classified as potentially being not safe for the consumer. A draft regulation is currently being discussed.

In view of the maximum levels, the need for analytical methods that allow reliable determination of MOAH at trace levels seems obvious. Unfortunately, the analysis of mineral oil fractions in food is challenging and the methods used in the past showed a lack of sensitivity and insufficient repeatability. These drawbacks can be compensated for by specific signal integration techniques, additional sample purification procedures and sophisticated analytical techniques such as LC-GC²-TOF MS//FID. However, as these measures can also have disadvantages in terms of analyte losses as well as time and cost aspects, some analytical experience is required to select the best solutions for specific types of oils and fats.

This presentation summarizes the status quo of current routine analysis and covers briefly EU regulative aspects.