Question: What should I look for in labels and menus to detect foods processed or made with allergens?
Answer: So the best way to look for foods that might be hidden in the foods you're eating is to read labels. And what's key is knowing what to look for in labels. Sometimes, if you're allergic to peanuts for example, it's obvious, it says 'peanuts.' Or if it says, if you're allergic to milk, it says 'milk.' And sometimes it's not so obvious -- it might be milk component like casein or whey. So what can be helpful is having good list of the things that the foods are called to which you're allergic.
You can get a good list from allergists, and also from The Food Allergy & Anaphylaxis Network or foodallergy.org. They have these lists in English and in Spanish that show you lists of the foods that what they're called on labels.
If you're going to a restaurant, there you are dependent on talking with the people at the restaurant -- the workers at the restaurant and the chefs -- to make sure that they're using equipment that has not been contaminated with the food to which you're allergic, and that there's no hidden allergenic foods in what they're preparing for you.