One recognized food allergy is a reaction to sulfites. These are preservatives added to foods, usually during manufacturing but sometimes at the point of sale, as with some restaurant salad bars. Sulfites are harmless to most people but can cause reactions that are severe and sometimes fatal to those sensitive to them, especially to persons with asthma. FDA requires that products containing sulfites be labeled so that consumers who wish to can avoid them. Less than 1 percent of the population is thought to be sensitive to sulfites.
Nuts are another allergen that can be threatening.
The officials are also encouraging patrons to ask about the ingredients in a restaurant's food. A migrane-like reaction to certain foods can also indicate a food allergy. The test confirmed that migraine in these particular cases was an immune response to an allergen. In fact, she said, it has the potential to become the major consumer food issue of the next decade. Twenty-two percent said they actually avoided certain foods on the chance that they might contain an allergen.