Final answer:
During the cooling step, it is not recommended to keep foods uncovered as it can lead to freezer burn.
Step-by-step explanation:
During the cooling step, it is not recommended to keep foods uncovered. When food is exposed to air during cooling, moisture from the food evaporates, leading to the process called sublimation. Sublimation causes water to turn from solid to gas without passing through the liquid state, resulting in the loss of moisture from the food and the formation of freezer burn. Freezer burn can affect the texture and taste of the food, making it less appetizing.