Foods and beverages contain a lot of aromatic compounds, some naturally present in the raw materials and some forming during processing. GC-MS is extensively used for the analysis of these compounds which include esters, fatty acids, alcohols, aldehydes, terpenes, etc. It is also used to detect and measure contaminants from spoilage or adulteration which may be harmful. The contaminants are often controlled by governmental agencies, for example pesticides.