Q&A: Using light to detect food toxins


A VUB researcher has developed a non-destructive method of detecting harmful substances in common foods

Shine a light

From potatoes to processed meat, the food we consume every day may contain harmful carcinogens. Lien Smeesters, a PhD researcher at the Free University of Brussels (VUB), has developed a new and safe method of detecting them. She’s just received the European Innovation Award from Photonics21, an association of industries in the field of photonics, or light technology.

Do carcinogens pose a real threat to our health?

Unfortunately, yes. The presence of carcinogens in our food continues to be widely reported, and products are frequently recalled because they contain harmful substances. This goes to show that we need to develop accurate and safe ways to detect them.

You used optical spectroscopy to detect carcinogens. How does this work?

My team developed a real-time and non-invasive screening method for detecting acrylamides and mycotoxins, two types of carcinogens present in food. When a food product is illuminated with a light source, the light behaves in different ways – it can reflect or scatter on the surface, be absorbed or form entirely new fluorescent patterns.

And that tells you if there are carcinogens present?

Yes. Take frietjes. Potatoes that contain high levels of acrylamide-forming compounds release them at frying temperatures – that’s when they become toxic. We used technology that analyses the way light scatters inside a raw potato to identify these compounds.

When the potato is illuminated with a beam of light, some of the light reflects on the surface, while the rest interacts with the molecules inside the potato’s tissue. This light is then reflected in different places around the beam of light.

By studying both the reflected light and the light that scatters inside, we can monitor the composition of a raw potato and predict how much acrylamide it will release during frying.

And what does that mean for consumers?

Our technique can be used to scan each product – at a speed of several tonnes per hour – without affecting its quality. Once scanned, a product that contains toxins can be removed right away using a sorting machine, ensuring that no contaminated foods reach the market.