The qualitative classification of the olive oil follows international standard that contribute to its final evaluation:
COLOUR:
The colour of the olive oil can vary from dark green to light green (golden), with many intermediate and other shades. This is due to substances that are predominant in the olives from which the oil is produced.
STOUTNESS:
The stoutness of the olive oil depends on the area produced, for example olive oil from Corfu has a low stoutness, unlike to the olive oil from the Peloponnese.
CLARITY:
The olive oil from mature fruits has a high clarity, unlike the olive oil deriving from early fruits.
ODOUR-FLAVOUR:
The odour and flavour of olive oil may show a lot about its quality. The pleasant odour and flavour are suggestive of special features and can be attributed to the area where the trees were grown and the way of their cultivation. The bitter taste indicates that the olives were gathered before maturing.
ACIDITY:
The degree of acidity of the olive oil indicates its content of oleic acid and depends on the health of the fruit, the stage of ripeness of the olives, how they were harvested and the time interval between harvest and olive oil production.
According to the instructions of the Ministry of Agricultural Development and Foodstuffs, to produce better quality olive oil, producers should pay particular attention to the following:
• The olives should be in optimum stage of maturity, i.e. have a purple-black colour;
• The olives gathered by beating, combing, etc. should be crushed to oil in a short time after collection;
• The olives gathered with nets, after a natural fall, should not be left in the nets for a long time;
• The transfer of the olive and its preservation before being crushed to oil should not be done under conditions of high temperature and poor ventilation,
• Its transfer must be made in plastic cases that will be then placed in a cool space until the fruit is driven to crushed to oil,
• The olive oil factory which will be used should have good standards of construction and operation,
• The preservation of the olive oil should be performed in appropriate stainless steel means and storage areas at low temperatures,
• Containers should be of suitable material, opaque and airtight-sealed.