The hazelnut (Corylus avellana) belongs to a group of foods, commonly referred to as “tree nuts”. This group of foods is a significant source of allergens, and hazelnuts are a frequent cause of food allergy. Consequently, there is a need for a sensitive and reliable test for the detection of specific tree nut allergens in foods. Any such test must be able to detect a heat stable protein component, otherwise false negative results could occur with samples that have been highly heat treated.A specific hazelnut protein was identified from high temperature treatments to be very heat stable and is used as the hazelnut protein indicator for the ELISA SYSTEMS ® Hazelnut Residue Kit.