Toxicologist Ivonne Rietjens wins prestigious Merit Award

The award of the EUROTOX Merit Award marks a significant milestone for Rietjens, who is set to retire in December 2025. She describes the prize as a wonderful acknowledgement by her European peers and is delighted to have received it while still in her active career. “It is an honour to receive this recognition; it’s a fitting conclusion to my career,” says the toxicologist.

Alternatives to animal testing

Throughout her career, Rietjens, along with her colleagues, developed alternatives to animal testing. One such method investigates how and when substances, such as pesticides and plant toxins, affect the development of an unborn child. For this, the researchers use stem cells in petri dishes that develop into beating heart cells, similar to what happens in a foetus. They then study at which concentrations these substances disrupt the natural process. “But in risk assessments, a concentration alone is not enough; you need to know the dose that would cause that effect in humans, through their food and drinks,” explains the professor. “So, we have developped computer programmes that translate concentrations into a dose.”

Rietjens emphasises that the award not only recognises her own work, but also that of the many research colleagues and the over 120 PhD students she has supervised over the years. This is important, as they are crucial for the future, she believes. “I am a strong advocate of animal-free testing methods. If the European Food Safety Authority takes steps to further implement these methods, we will need a generation of researchers familiar with them. These young researchers now possess the knowledge: they understand the opportunities and limitations.”

Assessing new substances

In addition to her academic work, Rietjens is actively involved in the approval of new substances for the market. Together with her colleagues, she assesses whether new substances are safe for release, based on reports and research. “When we look at the risks of substances in the food around us, they are not that significant,” Rietjens says. “That is because toxicologists do their job well.” The Wageningen professor worked for fifteen years with the European Food Safety Authority (EFSA) and currently serves on the panel that evaluates the approval of flavourings for the US market. She has no plans to abandon this passion anytime soon. “Even after my retirement, I will have a wonderful role there; I will definitely keep doing that,” said Rietjens.

The EUROTOX Merit Award

The EUROTOX Merit Award is an annual prize given to a European toxicologist with a long and distinguished career in toxicology. The award recognises exceptional contributions to the field of toxicology, whether in academia, government, or industry. The focus is particularly on individual achievements that have strengthened the science of toxicology.