Food allergies represent an important health problem in developed countries. Undeclared allergens as contaminants in food products pose a major risk for sensitized people. In highly sensitized individuals, even the intake of minute amounts of allergens can provoke digestive disorders, respiratory symptoms, skin reactions, or life-threatening reactions like anaphylactic shock. Reliable detection methods for food allergens are necessary to ensure compliance with food labeling (Directive 2003/89/EC) and to improve consumer protection.