So-called phytotoxins can be dangerous for humans. In order to assess the potential danger of phytotoxins in Switzerland, researchers at Agroscope, the Swiss government's centre of excellence for agricultural research, are investigating which plant-based toxins are present in our waterways.

Many substances are toxic: classic examples are pyrrolizidine alkaloids in tea and honey, solanine in the green parts of tomatoes or potatoes, phasin in raw beans, prussic acid in apricot kernels or coumarin in cinnamon. Other interesting substances include sambunigrin in elderberry, anthraquinone and oxalic acid in raw rhubarb, and nicotine in the green parts of aubergines. Some herbal teas are contaminated with carcinogenic pyrrolizidine alkaloids.

While residues of synthetic pesticides in water and food are subject to strict legal limits and are regularly monitored, there are hardly any regulations for many plant-based toxins. Public perception of this issue is paradoxical. A famous example of this distorted perception is the study by US biochemist Bruce Adams, which showed as early as the 1990s that 99.99% of the pesticides found in our food are of natural origin.

A well-informed debate on food safety and water quality should therefore be based on scientific findings and give equal consideration to all potential risks. And it is precisely this intention that is the focus of Agroscope's research into natural toxins in our food.