Although any food can be allergenic, the most common food allergies are to peanuts, nuts, fish or shellfish, milk or eggs. With the advent of speed scratch and prepared ingredients, however, even chefs might not know what's in a dish. Restaurants should maintain a list of ingredients in all foods or be prepared to show a patron the ingredients label from any box or bottle, say advocates for people with allergies. De Bruyn says that might include plain baked potatoes, canned corn or vegetables, salad with no dressing, frozen chicken breasts that could be microwaved without seasoning, and fresh fruit for dessert. Negative reactions Common allergic reactions to offending foods include itching, hives, swelling, difficulty in breathing, vomiting, diarrhea, cramping and a fall in blood pressure.
Reactions can occur in a few minutes, or hours after eating.
Far rarer is anaphylaxis, a sudden, violent reaction that can lead to death. Call 911 or the appropriate emergency number immediately, advises Grover. A restaurateur may spend an entire career without seeing such a case.