Sulfites are chemicals that are used as preservatives in some foods, either naturally or as additives. They have been used since Roman times to preserve food flavor and color, inhibit bacterial growth, reduce food spoilage, and help preserve medications. Sulfites release sulfur dioxide gas, which is the active component that helps preserve drinks, foods, and medications. Sulfites can cause allergic-like symptoms in some individuals, and their reaction can range from mild to life-threatening. Sulfites are not allowed on fresh vegetables and fruits (except sliced potatoes and raw grapes) and are also not allowed on pre-packaged meat, poultry, and fish (other than tuna and crustaceans) . In Canada, sulfites must be listed on the package label, and Canadian guidelines require that sulfite-containing products are clearly labeled. Examples of foods that may contain sulfites include baked goods, soup mixes, jams, canned vegetables, pickled foods, gravies, dried fruit, potato chips, trail mix, beer and wine, vegetable juices, sparkling grape juice, apple cider, bottled lemon juice and lime juice, tea, many condiments, molasses, fresh or frozen shrimp, guacamole, maraschino cherries, dehydrated, pre-cut, or peeled potatoes. Some medications also contain sulfites. If you have a sulfite allergy, it’s important to check food labels for sulfites so you can avoid a reaction.