What design feature must racks in refrigerators or walk-in coolers have to ensure proper air circulation?

Racks in refrigerators or walk-in coolers must have slotted designs to ensure proper air circulation. The slotted feature allows cold air to flow freely around the stored items, enabling consistent temperatures throughout the unit. When air can circulate effectively, it helps maintain even cooling and prevents hotspots where food items may not get sufficiently chilled, which is critical for food safety and preservation.

Solid racks would impede airflow, leading to uneven cooling and potential spoilage of food products. Proper spacing between the racks is also essential, but it is the slotted design that primarily facilitates the movement of cold air. Therefore, incorporating slotted racks is crucial for the effective operation of refrigeration systems in maintaining food safety standards.