Validation of Recipes for Double-Blind Placebo-Controlled Challenges With Milk, Egg White, and Hazelnut

Abstract

Background: The double-blind, placebo-controlled food challenge (DBPCFC) is considered the definitive diagnostic test for food allergy. Nevertheless, validated recipes for masking the foods are scarce, have not been standardized, and differ between centers. Sensory evaluation techniques such as the triangle test are necessary to validate the recipes used for DBPCFC. Methods: We developed 3 recipes for use in DBPCFC with milk, egg white, and hazelnut and used the triangle test to validate them in a 2-phase study in which 197 volunteers participated. In each phase, participants tried 3 samples (2 active-1 placebo or 2 placebo-1 active) and had to identify the odd one. In phase 1, the 3 samples were given simultaneously, whereas in phase 2, the 3 samples of foods that failed validation in phase 1 were given sequentially. A visual analog scale (VAS) ranging from 1 to 10 was used to evaluate how much participants liked the recipes. Results: In phase 1, the egg white recipe was validated (n=89 volunteers, 38.9% found the odd sample, P=.16). Milk and hazelnut recipes were validated in phase 2 (for both foods, n=30 participants, 36.7% found the odd sample, P=.36). Median VAS scores for the 3 recipes ranged from 6.6 to 9.7. Conclusions: We used sensory testing to validate milk, egg white, and hazelnut recipes for use in DBPCFC. The validated recipes are easy to prepare in a clinical setting, provide the equivalent of 1 serving dose, and were liked by most participants.

A Novel Double-Blind, Placebo-Controlled Food Challenge Matrix for Milk and Raw Egg

“…However, since allergens are also present in the egg yolk, this fraction of the egg also had to be included in this test. Nevertheless, most of the time only the egg white is used [12]. Since egg allergens are very prone to modification through processing, this work used raw freeze-dried egg powder to guarantee maximal allergenicity.…”

“…For example, in the study by González-Mancebo et al [12], soy was included in the milk matrices. Also in Protifar PLUS , which has been used in earlier DBPCFC studies as a milk ingredient [10, 11], soy lecithin is used as an emulsifier.…”

“…The objective is to discover whether a difference exists between two sam ples, no matter what is the attribution of difference [11]. This test is commonly applied during sensory tests of DBPCFC studies [11, 12, 17]. However, the detection of differences during this test will not directly indicate the detection of the allergenic ingredient in the food matrix [12].…”

“…Although several recipes have been developed in earlier studies for milk and egg [10-12], validated matrices are needed which are easy to prepare at home and available for consumption during longer periods (+/– 2 weeks or more) to monitor late-onset reactions. For milk, some studies report the use of hydrolyzed infant formulas [10, 11], which are convenient to prepare in a standardized way at home.…”

“…For egg, no validated matrices are reported yet containing the full egg (egg white and yolk) which are convenient to prepare at home. For instance, in the study of González-Mancebo et al [12], only egg white was used as the allergenic ingredient.…”