A durability date is the date mark indicating how long a food keeps its quality — the umbrella term covering the best-before date and the use-by date. The best-before date marks quality: the food may lose flavour or texture afterwards but remains safe. The use-by date marks safety: perishable foods past this point should not be eaten. The durability date concept comes from European labelling law, which requires one of the two marks on most packaged foods, set by the manufacturer from shelf-life testing. Understanding which mark applies is the key to cutting food waste without risking illness — confusion between the two sends safe food to landfill and keeps risky food in the fridge. The durability date is the pack’s promise about time, and reading it correctly is basic food literacy.