Olive oil can be defined as liquid fat at 20ºC directly obtained from the fruit of the olive tree. It shows a golden yellow colour and its appearance should be liquid, oily and translucent, with no sediments. Olive oil is considered the core of the Mediterranean diet having been cultivated and used since approximately 4000 b. C. According to the European regulation, the types of olive oil are the following:

-    Extra virgin olive oil is the one with the highest quality. It is obtained from the first pressing of the olive in its optimal state only by mechanical methods. It is mostly composed by oleic acid (78%), a monounsaturated acid. 
-    Virgin olive oil is also extracted by mechanical methods, but using olives at no so optimal condition, i.e., they may have some external damage.
-    Although not consumed by humans, lampante olive oil is made with olives that show external damages and are subject to physical and chemical processes. It is highly acid and need to be refined for consumption.
-    Once refined lampante olive il could be consumed but more often it is mixed with a percentage of virgin olive oil to obtain the category entitled ‘olive oil’, that is commercially presented under two labels, mild and intense olive oil.
-    Lastly, olive pomace oil is made with the residual olive after undergoing mechanical processes. It is extracted with solvents and also mixed with virgin olive oil, and mainly used for frying. 
Italy and Spain are the largest extra virgin olive oil consumers in the European Union. Also, European countries such as Greece, Spain, Italy and Portugal, are by far the countries where olive oil is mostly consumed, for cooking, seasoning, sauteing, frying, braising and even preserving food. 

Italy and Spain are the largest extra virgin olive oil consumers in the European Union. Also, European countries such as Greece, Spain, Italy and Portugal, are by far the countries where olive oil is mostly consumed, for cooking, seasoning, sauteing, frying, braising and even preserving food.