Cross-Contamination is what happens when a food touches a different surface that has food particles/residues remaining on it from a different food.
It is very important to avoid cross-contact/
~ Be sure to wash all surfaces in the kitchen before you prep any allergen-free foods.
~ Don't use any of the same utensils/equipment for preparing or mixing allergen-free foods that you have used for non allergen-free foods without washing them first.
~ Make sure everyone washes their hands before handling food or eating the foods.
~ Be weary of bulk foods if the person with allergies is especially sensitive. You never know who has stuck their hands inside the bins and what they have touched.
~ Ask for the table to be cleaned before you are seated or bring your own sanitizing wipes to wipe it down yourself.
~ Ask for a menu that might cater to your specific food restrictions. Or ask about certain menu items you are interested in. I know there are several restaurants that offer a gluten-free menu now.
~ Make sure the cook/chef knows that your order is to be prepared for an individual with allergies so they can change gloves/wash hands and clean their equipment.