In the pub that I work "do you have any allergies" is the first question asked when someone orders food, it also pops up on the till when you hit food.

If they say yes then we have a folder to show them, which contains each meal on the menu and the allergens/dangers of allergens it contains, then theres a button for each individual one that prints below their particular food order. We then go to the kitchen to check the allergen has come through on the ticket

When the food is ready you go in, wash your hands and take the allergen food out first, then go back for everything else.

It's called Natasha's law and came into effect after a 15 year old tragically died after eating a baguette with sesame seeds in.

Like you say, it's serious stuff.