PhD Defence by Sim Ray Yue

Principal supervisor:

• Professor Katrine Lindholm Bøgh

Co-supervisors:

• Assistant Professor Kitty C.M. Verhoeckx
• Professor Geert F. Houben
• Senior Toxicologist Mélina Galano
• Senior Adviser Tue Christensen
• Professor Erwin Marten Schoof

Examiners:

• Senior Researcher Morten Poulsen, DTU Food
• Professor Lotte Bach Larsen, Aarhus University
• Adjunct Assistant Professor / Managing Director Benjamin C. Remington, University of Nebraska / Remington Consulting Group B.V

Moderator at defence:

• Researcher Abid Hussain, DTU Food

Resume
Food allergies are caused by immune reactions to certain proteins in food and can have a major impact on daily life. People with food allergies must constantly monitor what they eat, where they eat, and how food is prepared, which may significantly affect their quality of life and well-being. At the same time, our food system is rapidly changing, with new foods, including new protein sources, plant-based alternative foods, and novel foods, being introduced to the market to support sustainability, nutrition, and innovation. This raises an important question: could exposure to newly introduced food proteins lead to the development of new food allergies?

This PhD project explores a new, exposure-based way of thinking about food allergy risk assessment. Instead of asking only whether a protein is allergenic, the thesis investigates whether there may be a threshold of allergenic sensitisation (TAS), which is a level of exposure below which a protein is unlikely to trigger the first step of developing a food allergy (sensitisation). The key idea is that if exposure to a protein is very low, it may be unlikely to cause sensitisation, even if the protein itself has allergenic properties. Thus, proteins below this threshold do not require testing.

To investigate this concept, this thesis combines food consumption survey data with advanced protein analysis (proteomics). Well-known allergenic foods (peanut, hazelnut, black tiger shrimp, and Atlantic cod) were used as reference foods, allowing individual allergens and proteins to be quantified and linked to how much protein of these foods people typically consume. This approach made it possible to estimate how much protein a person might be exposed to under different eating scenarios. The lowest observed allergen exposure levels across different eating scenarios were then used to test candidate thresholds for evaluation.

The results show that when exposure was taken into account, a large proportion of food proteins fall below a potential TAS, suggesting that many proteins below this threshold level may not require extensive allergenicity testing. The concept was tested on other legumes, including soybean, green pea, and fava bean, demonstrating how the approach could be applied to other foods.

Overall, this work represents a first, exploratory investigation into the feasibility of establishing a TAS as a proof-of-concept. Importantly, the TAS is not intended to determine whether a novel food protein is allergenic, but rather as a framework to support decisions on how many and which proteins should be prioritised for allergenicity assessment. Further investigation across a wider range of foods, populations, and processing conditions is required to evaluate the robustness, generalisability, and limitations of the TAS concept.

A copy of the PhD thesis is available for reading at the department.