Scientists have developed a test to tell real virgin olive oil from cheaper products.
The recent popularity of Mediterraneran cooking has meant a big demand for high-quality extra virgin olive oil.
Importers of low-grade oils have cashed in by misleadingly packaging their products as high-grade oil.
Loughborough Univeristy academics have developed a technique called "optical fingerprinting", which can distinguish between real and fake virgin olive oil.
The real product, renowned for its taste and its nutritional benefits, has become a familiar item on supermarket shelves.
The low-quality oils have been flooding the market, duping customers and threatening the livelihood of producers of the top quality product.
The olive oil test was developed in the university's department of electronic and electrical engineering.
It uses the same device used in medicine to determine the concentration of oxygen in the blood.