Liquid engineering throws light on fakes in extra virgin territory

Researchers are looking for companies to commercialise a system which is claimed to be able to detect fake extra virgin olive oils.

The spectrometer-based system, developed by light engineers at Loughborough University and in Italy, could also be used for determining the origins of many other liquid foods and drinks, including water, milk and wine, said Peter Smith, professor of photonics at Loughborough.

By a 3-D plotting of spectra of light scattered from more than 100 oil samples researchers had identified clusters of spectra which pinpointed the sources of the oils.

"This allows reliable, low-cost analysis that can easily distinguish the frauds from the genuine extra-virgin articles," said Smith.

Olive oil is popular because of its acidity, which depends on the suspensions in the liquid. The testing method was developed from work with on-line sensors to monitor the quality of water and port wine, using spectrometers to collect light of different wavelengths scattered from material suspensions. A hand-held spectrometer costs less than £2,000 and a commercial food tester could probably be developed within a year, said Smith.

His research was carried out with colleagues at the CNR Institute for Applied Physics in Florence and the CNR Trees and Timber Institute in Sesto Fiorentino, as part of a European Union project called Optimo.

Smith said that whereas other researchers had measured the colours of light passing through liquids, the perception of colour was based on scattered light.

"It's much more about the perceived colour than the actual colour," he said.

Smith added that the Portuguese government was already introducing food regulations requiring measurement of the turbidity of wine rather than the colour.