How are food allergies handled in dining service?

Parent of current HS junior interested in W&M for Chemistry. D has severe food allergies - milk proteins, sesame, shellfish, peanuts, and most tree nuts. Does anyone have first hand knowledge of how well dining service handles special diets and food allergies? We have been told that what is written in school publications doest not always reflect the day to day experience of the severely allergic individual. We were advised to talk directly to students with food allergies to get a real idea of how accommodating a school is. Any input would be most welcome!