Olive oil has an exalted status amongst edible oils because of the presence of high proportion of unsaturated fatty aids which are known to be have a protecting role for human health. Historically tree seed oils were manufactured using crushers of different design, the earliest being the pestle and mortar system. Since seed crushing, even if heavy duty hydraulic presses are used, does not remove oil completely, leaving a residual oil varying from 4% to 20% in the pressed cake. These pressed residues form the feedstock for the solvent extraction industry which recovers the remaining oil using mostly hexane. What is available in the market are refined oil freed from unsaponifiable matters, colors and free fatty acids. Many believe that cold pressing of oil seeds yield superior value products in terms of flavor and nutritive value, though presence of lipolytic and oxidative enzymes can pose problems for long term storage. When it comes to Olive oil the so called extra-virgin version which is basically cold pressed product fetches premium price in the market. This consumer sentiment is exploited by a section of the industry to palm of products which do not pass the test for genuineness. This market problem is being addressed by food standards agencies through stricter compliance action.
"The purity issue also remains a serious concern for some consumers. In the past, some state agencies have uncovered oils labeled 100% extra-virgin olive oil that were blended with cheaper canola or nut oils, which can be a serious health threat to people with allergies. (No such mixing was found in the UC Davis report.) Money is also at stake, because extra-virgin oil can be marketed as a premium retail product. A typical 750-milliliter bottle of olive oil can sell for $8 or less, while the same size bottle of high-end extra virgin oil can go for $12 or more. The report underscores problems in an industry that pulls in more than $700 million a year in U.S. retail sales. Industry officials generally agree that the "extra-virgin" designation is proper for oil that is cold-processed, has low acidity and has higher levels of healthful fats and antioxidants".
While marginal variations in the quality can be condoned to some extent considering that olive oil is sourced from different sources, deliberate tinkering with its natural composition is a serious economic fraud deserving severe punishment to the perpetrators of such heinous act. The issue whether extra-virgin olive oil is really more nutritious and healthy may be controversial but any product offered to meet consumer expectations, must be true to the label claims made by the manufacturer.