What does "extra virgin" mean in olive oil?
Extra virgin is the highest quality olive oil, characterized by perfect flavor and odor, maximum acidity of 0,8% ( in oleic acid ).
The majority of olive oils ( 80% ) produced in Greece is extra virgin olive oil because the olives are cold pressed within 24 hours of harvesting.
What is P.D.O. Extra virgin olive oil  ?
A Protected Designation of Origin (PDO) is part of the Protected Geographical Status system in the European Union (EU). This framework is designed to protect the integrity of European food and drink by carefully legislating the labeling of certain European products. When something is given a Protected Designation of Origin, it means that only items produced in a specific area in a particular way may bear that label in the European market. For example, Kalamata Olive Oil has a PDO label, meaning that extra virgin olive oil produced in a specific style in the Greek region of Kalamata may be labeled as “PDO KALAMATA Extra Virgin Olive Oil”. 
Why is P.D.O. important?
P.D.O.  status was created by the European Union in 1992 as a way to ensure the quality and authenticity of the foods we consume, but also as a way to help promote those agricultural products and foods that have special value because of the way or place in which they are produced. 
What is cold extraction ?
Many olive oils are marketed as first cold pressed or cold extraction, this is a denomination describing the temperature at which the oil was obtained.
The olive oil producers in E.U. must prove that the temperature of malaxation and extraction was under 27°C (80°F). For olive oil bottled outside EU countries this regulation does not apply, and thus the consumer has no assurance that these statements are true.
The temperature of malaxation and extraction is crucial due to its effect on olive oil quality. When high temperatures are applied the more volatile aromas are lost and the rate of oil oxidation is increased, producing therefore lower quality oils. In addition, the chemical content in the polyphenols, antioxidants and vitamins present in the olive oil is reduced by higher temperatures. 
How long does olive oil last?

Olive oil naturally lasts for a very long time (about 18 months if properly stored). It keeps its natural properties due to the presence of natural antioxidants.
Is the olive oil still edible when it looks cloudy or white?

Yes, cloudiness is a natural effect due to exposure to low temperature, below 8°C / 46°F. However the olive oil will not lose any of its qualities even when exposed to low temperatures. During wintertime you can often notice this effect, even on the shelves of your supermarket. It gets clear again after some time at room temperature.

Does olive oil contain cholesterol?

Olive oil is cholesterol free, unlike animal fats. 
How can I know when my olive oil isn’t good to eat anymore?

Eating olive oil that hasn’t been perfectly stored is not dangerous. 
If you are unsure about your olive oil, check its smell and taste.
A mouldy or wine taste indicates that the olive oil has been wrongly stored, a metallic taste indicates that the oil has been in contact with metal for too long and oxidation during storage will cause the olive oil to become rancid.