Agroindustry: ENEA developed the first photoacoustic laser for food fraud detection

“SafeFood”, the first photoacoustic laser system for detecting adulterated foods, developed by ENEA, is available to food industries and large distribution chains. The prototype can detect in real time contaminants on untreated samples of small amounts of product. “This laser system, designed to be installed in production lines,  can be easily carried and the  measurement conducted in just a few minutes ”, Luca Fiorani, researcher at the ENEA Diagnostics and Metrology Laboratory of the Frascati Research Center.

The photoacoustic laser technique, in addition to its speed, stands out for its accuracy and reliability in identifying some significant food frauds, like those occuring in fish, rice, fruit juices, oil, milk and spices, in particular oregano and saffron.

ENEA researchers are already working on a second prototype to be used directly in points of sale, from store shelves to market stalls. “The system we have developed, in fact, does not require the sample to be pre-treated with chemical reagents, so it can be easily used by non-specialized personnel after a brief training on how to use it”, Fiorani pointed out.

The prototype testing was conducted on adulterated saffron. Since real saffron -derived  from the three dried stigmas of a flower- is very expensive, there’s a risk it can be mixed with tartrazine, a synthetic food colorant, or yellow spices like turmeric.

Starting from pure saffron, various contaminated samples were prepared, to reach concentrations of tartrazine and turmeric of 2%, to test the system’s ability to detect extremely low amounts. The outcomes of the study were published in an article in the international journal Sensors.

‘SafeFood’ is based on photoacoustic laser spectroscopy, a technique already used in medical diagnostics, explosives detection systems and pollution monitoring. After the pioneering work with CO2 lasers, today it makes use of the performances and size of quantum cascade lasers. The system uses light and sound to work: most of the light generated by the laser beam is modulated at an acoustic frequency and sent into the photoacoustic cell, where it interacts with the sample, generating a sound wave that is picked up by a microphone, whose signal is then amplified.

“The greater the absorption of the sample, the stronger  the sound wave: that’s how the infrared absorption spectrum of the sample is measured, with the advantage, compared to other spectroscopic techniques, of being able to irradiate it with a much more powerful source.  The spectra of a food and therefore of a contaminant, are not always clearly distinguishable. Fortunately, sophisticated techniques can be applied to the spectra, such as the analysis of the main component , which allows to differentiate the components,” Fiorani explained.

This laser system has already made the big ‘leap’ from laboratory to industry. “We have an agreement with a beekeeping company to track the honey supply chain, starting with the detection of pesticides in pollen and bees. In addition, we have entered into an agreement with the company Chelab of the multinational Mérieux NutriSciences Corporation, present in 24 countries, with 100 laboratories and 7000 employees, which aims at protecting the health of consumers worldwide and offers a wide range of analytical and consultancy services regarding food, environmental, agrochemical, consumer, cosmetic and pharmaceutical products ” Fiorani said.

The ENEA researchers are also collaborating with two other companies in the fight against food fraud: Orsell, a distribution company of zootechnical products, and Tecnoalimenti, a consortium working in the technical-scientific research for innovation in the agri-food industry, comprising 31 companies, which accounts for approximately 12% of sales in the sector in Italy, with the participation of the MIUR Applied Research Fund.

For more information please contact:

Luca Fiorani, Diagnostics and Metrology Laboratory – [email protected]

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