Celery (Apium graveolens) belongs to the botanical family Apiaceae (or Umbelliferae). Other species of the same family are carrots, parsnip, aniseed, fennel, caraway, parsley and dill.
Proteins in different species of the same botanical family can be similar. Therefore, there is a certain risk for an allergic individual to react to several species of the same botanical family.
In Europe, celery is a common cause of pollen-related food allergy. In Central Europe (Germany, France and Switzerland) allergy to celery is often associated with birch pollen allergy. In Sothern Europe, on the other hand, celery is considered associated with mugwort pollen allergy.
Oral allergy syndrome is typical symptoms of allergic reactions to celery, i.e. itching of the mouth, urticaria, angioedema and breathing difficulties. Even severe symptoms like anaphylactic shock have been reported.
Three different proteins have been identified as the major celery allergens. One of these proteins is heat stable, the other ones are heat labile but to a different degree.
The root, sticks and the seeds of celery are consumed. Celery is not only consumed raw in salads but also cooked in vegetable dishes, in sauces and in soups. The seeds as well as the dried and milled celery root are used as a spice.
Labeling
The presence of celery and products thereof must always be declared, see further in LIVSFS 2004:27 Livsmedelsverkets föreskrifter om märkning och presentation av livsmedel [in Swedish] (see link to the right).
Examples of methods of analysis
At present there are no protein methods available for the identification or quantification of celery in food products. However, work is in progress for the establishment of methods.
Celery can be identified with DNA methods. A positive result in a DNA analysis indicates the presence of celery in a sample.
Allergic reactions / Doses
Few studies have been performed to determine the minimum tolerable dose in celery sensitized individuals.
Doses of celery between 0.7 and 2.7 g gave local itching of the mouth, and doses ranging from 7.5 g till 31 g gave systemic reactions. Similar results were also observed with cooked celery, while celery spice was able to induce systemic symptoms at very low doses ranging from 0.16 g to 5.85 g.