Udisha
Warm spot
The heat extracted by the refrigerator from the interior makes the top of the fridge warmer than the rest of the appliance. Hence, storing bread on the top of the fridge will expose it to a warmer environment than desired.
Makes the bread dry
Exposure to heat also causes the crumb of the bread to dry. The moisture moves to the crust, rendering the bread tough and dry.
Mold
Bread is extremely susceptible to mould. If a packet of bread is kept on top of the fridge which is already warm, moisture will easily get trapped inside the plastic, causing spots and mold.
Poor air circulation
The air circulation on the top of the refrigerator is relatively poor. Due to lack of proper ventilation and changing external temperature, the heat gets further trapped leading to fluctuations in temperature. This instability is poor for the bread.