Mineral oils are hydrocarbons derived from petroleum, and their presence in green coffee can occur through environmental contamination, packaging, or processing. Studies have shown that mineral oils do not transfer in high levels from the coffee bean to the cup. However, the EU has issued guideline values. Although these are not legal limits, reporting the findings is mandatory and exceeding values may raise safety concerns, and in practice, can prevent the product from being able to be sold on the EU market.