Cooling is the lowering of temperature, usually after cooking — and in food safety, one of the most consequential steps there is. Cooked food must race through the danger zone between 60°C and 5°C, because the spore-formers that survive cooking germinate and multiply in lukewarm food. Blast chillers, ice baths, shallow pans, and portioning all accelerate the drop; deep pots left on counters invite disaster. Validated cooling curves, logged and checked, separate professional kitchens from food-poisoning statistics. Cool it fast, or do not cook it at all.