Occurrence, determination, and assessment of mineral oils in oilseeds and vegetable oils

Mineral oil hydrocarbon contaminations can often be found in oilseeds, oils, and fats as these matrices are good keepers to accumulate them from all kind of sources along the production chain. In addition, seeds and vegetable oils contain naturally occurring hydrocarbons in various compositions. These naturally hydrocarbons can serve for a proof of authentication and they have to be taken into account for the analysis of mineral oil hydrocarbons as contaminants. In this review, the many sources of contamination like environmental effects, production machinery, and packaging materials are referred to and reported data for contaminated vegetable oils like sunflower, olive, and palm oil and in addition raw materials and feed are focused on. This is of special importance for the food survey and for the production as it is a challenging task to survey the many routes of contamination along the production chain and during storage in order to improve the food quality. There is still discussion where to fix a reasonable limit for such contaminants in oils and fats, where levels are often very high compared to levels found for migration from packaging materials into low fat products. For the later ones draft limits have been discussed, but it will be a challenge to reduce mineral oil hydrocarbon contamination in oils and fats to a similar extend. In addition, the determination of low levels of hydrocarbon contamination is demanding and validation of sophisticated coupled LC-GC methods in collaborative trials is still in development.