Display cases are built to sell. They use glass on the front, top or sides so the product is visible, lighting that shows colour without heating the food, and shelving or decks arranged at viewing height. Serve-over versions are loaded and served by staff from the back; self-service versions let customers take items through front doors.
Display creates a conflict: glass and lighting let in heat, and open fronts or frequently opened doors let in warm air, while the food on show is often delicate and ready to eat. Good cases control airflow so cold air washes over the product without drying it out, and many use gentle, humidified or static cooling for items like cakes and sushi that dry quickly in strong airflow.
A café in Chandigarh might use a straight-glass display case for sandwiches, salads and cut cakes at the counter. The case keeps food at around +4 to +8 °C during opening hours, and staff move unsold items to a back refrigerator overnight.