For example
Sally and her friends went out one Saturday to the local branch of a chain restaurant for a meal. After the main course, she was choosing a dessert and asked the staff whether the strawberry gateau contained any nuts. She explained that she had a nut allergy and asked them to check.

The waiter came back and told her that he had checked the ingredients and the gateau contained no nuts. Sally took one bite of her portion and thought it tasted nutty. She asked staff to double-check the ingredients and somebody then realised that the waiter had read the box for the gateau usually ordered but that, on this occasion, a substitute had been sent by the supplier. Its ingredients list included nut crumb.

Sally's friends got her into a taxi and to the local hospital within a few minutes. Her symptoms were moderately severe and she was kept in overnight for stabilisation and observation. She was off work for another three days as her body recovered from the shock.