A worker labels a menu item as 'nut-free' but it was fried in oil also used for breaded items containing tree nuts. Why is this dangerous?

Explanation

Shared fryer oil carries allergen protein from one food to another, so an item fried in that oil is not nut-free even at high heat. Labeling it nut-free gives an allergic guest false assurance and can cause a severe reaction. Allergen-free items require dedicated, clean equipment and oil.