The Food Allergen Detector (F.A.D.) is a hand-held device that uses Raman Spectroscopy, a method that requires focusing a UV laser beam on a food sample and detecting the scattered light. A small percentage of the scattered light is shifted in frequency. The frequency shift of the Raman scattered light (Raman Spectrum) is unique to the substance and therefore can be used as a "fingerprint." To identify the allergens, the F.A.D. uses each one's Raman Spectrum.
This is a diagram of the Food Allergen Detector (F.A.D.). Each allergen is shown on the screen, with a "Yes" or "No", which determines whether or not that allergen is present in the food sample.