You create a dish in the Dashboard and add its ingredients. Each ingredient maps to an allergen profile maintained by food safety specialists. The engine reads the full list, resolves compound ingredients to their components, and returns the complete allergen profile for that dish.
Sub-recipes resolve automatically. If your Massaman curry uses a house curry paste, and that paste contains peanuts, the curry gets flagged for peanuts. If the paste is used in three other dishes, all four get the same flag. A supplier product that lists "may contain traces of nuts" carries that warning through to every dish that uses it. You do not need to track any of this manually.
The engine catches what people miss. Worcestershire sauce contains fish. Some stock cubes contain celery. Certain mustard brands contain gluten. These are the allergens that hide inside compound ingredients and get overlooked on a spreadsheet at 10pm on a Friday. The engine reads every ingredient in every recipe every time, and it does not get tired.