Sulfur dioxide might not sound good enough to eat, but this food preservative does make its way into a number of edibles, including dried fruits such as raisins, dried apricots and prunes. Sulfur dioxide is one type of sulfite, a preservative whose name might be more familiar. Even a small amount of sulfite can wreak health havoc if you're sensitive to it. If you have asthma, sulfite sensitivity or sulfite allergy, eating dried fruits might cause serious health problems, including breathing problems, life-threatening allergy-like symptoms or, in rare cases, death.

Sulfites in Dried Fruits

Dried fruits are among the foods highest in sulfites, with raisins and prunes containing between 500 and 2,000 parts per million. By comparison, wine -- a food thought by many to be high in sulfites -- contains between 20 and 350 parts per million. The U.S. Food and Drug Administration mandates that foods containing more than 10 parts per million of sulfites must list this information on the food label. Countries have different standards for sulfites. The Australian government limits the amount of sulfites in foods to 3,000 ppm, while the British government limits sulfites in food to 2,000 ppm.

Asthma and Sulfite Sensitivity

If you have asthma, you have a much higher risk of developing a reaction to sulfur dioxide than a person without asthma. By contrast, if you don't have asthma, you have a very low risk of having sulfite sensitivity, a condition that causes asthma-like symptoms such as wheezing and difficulty breathing. While only around 1 percent of Americans overall have sulfite sensitivity, between 5 and 10 percent of asthmatics might react to sulfites. If you eat dried fruit, always have your inhaler and other asthma or allergy medications on hand. Seek immediate attention if you can't breathe, start wheezing, develop hives, facial swelling or collapse.

Sulfite Allergy

Sulfites are inorganic salts and don't contain the proteins that cause true allergic reactions to foods. Fruits themselves do contain a small amount of protein and can cause a true allergic reaction. If you develop asthma-like symptoms, hives, facial swelling or a rash after eating dried fruits, you could have allergy to fruit rather than sulfite sensitivity, although the symptoms might be very similar. A sulfite reaction can cause symptoms very similar to an allergic reaction, such as wheezing and difficulty breathing.

Sulfite-Related Deaths

Approximately 20 known deaths have occurred as a result of severe sulfite sensitivity. Death from sulfite sensitivity occurs from anaphylaxis, a severe sensitivity or allergic reaction that causes collapse of the circulatory system and throat swelling. If you have a severe sulfite sensitivity, ask your doctor to order injectable adrenaline and carry it with you at all times.

Avoiding Sulfite in Dried Fruit