Why heat works on bacteria but not on allergens
Cooking kills bacteria because heat destroys the organism itself — a living thing that can be killed. An allergen is not alive. It is a protein, and an allergic reaction happens when the immune system recognises the shape of that protein.
Heat does change proteins; that's what happens when an egg sets. But for most food allergens the fragments the immune system reacts to survive that change intact, and some are made more reactive by cooking rather than less. Roasted peanuts, for instance, are generally considered more allergenic than raw ones. Freezing, drying and fermenting don't remove them either.
This comes up on the test — and the training that covers it is free to read.
Start the Free TrainingWhat this means in the kitchen
It rules out every workaround people reach for. You can't fry an allergen out of a dish, you can't boil a shared utensil clean of it in the sense that matters, and you can't cook a mistake away. If a peanut has been in the pan, cooking the food for longer changes nothing for the customer who is allergic to peanuts.
The only control that works is separation: separate ingredients, separate equipment where practical, thorough cleaning between tasks, clean hands, and clean surfaces. That's why allergen management is taught as a cross-contact problem rather than a cooking problem.
- Wash hands and change gloves before preparing an allergen-free meal
- Use clean, dedicated equipment — boards, knives, tongs, containers
- Never use a shared fryer for an allergen-free order
- Clean surfaces properly first; sanitiser alone doesn't remove allergen residue
- Keep the meal covered and clearly identified all the way to the customer