If we go to a grocery shop we usually find a wide range of Olive Oil and few labelled as Extra Virgin. The latter is rightly considered premium Olive Oil, top of quality and the most expensive.
A true Extra Virgin Olive oil is immune from defects and it has a “fruity” taste of fresh olives. In fact, it should be the result of cold-pressing or mechanical pressing of fresh and integer olives.
From a chemical point of view there are specific parameters that qualify an Olive Oil as “Extra Virgin”. These are the most important:
Oleic Acidity is certainly the most popular parameter among consumers. It is a qualitative indicator. The higher it is the lower is the quality of the oil. The degree of Acidity is directly correlated with fatty acids which are consequence of hydrolysis. Acidity provides an indicator of how olives are treated from harvesting to milling. Good quality requires olives to be harvested at the right degree of ripeness, properly stored and pressed as soon as possible: ideally within 24-48 hours from harvesting.
Peroxide, K 270, K 232 and Delta K indexes are parameters that help detecting the oxidation of the oil and also help detecting possible blends or adulterations with other refined oils.
In practice, producing an Olive Oil that meets all the above parameters is not difficult: it requires correct harvesting and mechanical pressing within 24-48 hours. Unfortunately, there is a quicker and much cheaper alternative: adulteration and blending of refined oils. Of course in this case quality is low to the point that the product could be bad for consumer health.
How can consumers be sure of buying a genuine Extra Virgin Olive Oil? Unfortunately just reading labels is not always a guarantee of quality. The ideal solution is buying from olive farmers or as close as possible to a milling plant. The majority of consumers cannot buy from a farmer or an oil mill, in this case check the price. Bringing on the shelves an Extra Virgin Olive Oil at a price below Euro 6 per litre it is a very hard challenge.