Mineral Oil Hydrocarbons in Food - An Analytical Challenge
In 2008, the Rapid Alert System for Food and Feed (RASFF) of the European Commission was notified that sunflower oil originating from Ukraine was found contaminated with high levels of mineral oil, but also earlier reports on the contamination of food from different food contact materials such as jute bags were published. A debate on residues of mineral oil hydrocarbons (MOH; divided into mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH)) in food started afterwards and is continuing till today, dealing with the still remaining knowledge gaps of analysis, exposure assessment, hazard characterisation and risk assessment.
In recent years there had been significant advancements in the field, although the analysis is still an analytical challenge. One of the biggest gaps is the lack of validated and standardized analytical methods for the whole sample preparation procedure to allow generation of reliable occurrence data. Since food is a complex highly variable matrix appropriate sample preparation steps for relevant food matrices have to be chosen. Those may include intensive clean-up and enrichment steps to achieve the sensitivity needed to analyse the residues in different food types. State-of-the-art analysis is done using the online-coupling of LC-GC-FID, but it is only one part of the deal, because analysis reveals unresolved humps with unknown origin. Therefore, confirmatory techniques using multi-dimensional chromatography, e.g. 2D-comprehensvie GC×GC with various detector types, such as flame ionisation detection (FID), Time-of-Flight (ToF) or quadrupole mass spectrometer (q-MS), are used to allow for an adequate substance class identification, recognition of false-positive values and therefore correct quantification of the humps generated in the LC-GC-FID analysis. Furthermore, toxicological studies on the identified individual substance classes are needed to fully understand and allow for the health risk assessment for consumers.