Hypersensitivity to apple and carrot can be reliably detected with fresh material.

Hypersensitivity to birch pollen was linked with allergy to apple and carrot, apple seeds and carrot seeds and also with their fractions. Skin reactions among other atopics were rare, and non-atopic patients showed no reactions to fresh fruits and vegetables. Apple and carrot as well as apple seeds and carrot seeds were fractionated using column chromatography. Two major fractions were obtained, one with sugar and proteins, and one with proteins, the latter giving skin reactions more often than the former. The correlation between clinical symptoms and skin test results with the fractionated material was somewhat lower than that obtained with the non-fractionated fresh material. The allergens of fruits and vegetables might be proteins (enzymes).