Background: In a double-blind placebo-controlled food challenge (DBPCFC), it is necessary that recipes comprising the allergen cannot be distinguished from placebo.
Aims of the study: We investigated whether the method of paired comparisons, a sensory difference test, could be used to test the suitability of recipes for a DBPCFC.
Methods: We used two recipes, each with three concentrations of peanut or hazelnut flour. The recipe for peanut consisted of mashed potatoes with 2.7, 8.9, or 26.8 mg of peanut flour, and the recipe for hazelnut of oatmeal porridge with 74, 247, or 742 mg of hazelnut flour. Corresponding amounts of protein in the provided 15 g portions of each recipe were 0.7, 2.3, and 6.8 mg for peanut, and 11.6, 39, and 117 mg for hazelnut, respectively. Recipes were offered together with a placebo, and evaluated on sensory features by 81 healthy volunteers.
Results: The sensory test was easy to perform. Volunteers were not able to detect peanut flour in mashed potatoes, but they recognized hazelnut flour in oatmeal porridge on visual features.
Conclusions: Sensory testing by means of the method of paired comparisons is a useful method to evaluate masking of foods for DBPCFC.