To prevent frost build-up, refrigerators should be kept at 37 to 40 degrees Fahrenheit. Frost build-up is typically caused by warm air entering the fridge due to the door being open and closed, or a problem with the door seal.
A refrigerator needs to be defrosted on a regular basis when ice builds up. A refrigerator must be emptied before defrosting, and all food should be moved to another fridge. The unit should be unplugged, all the drawers should be removed and the door must be propped open during defrosting.
Once the ice has been removed, the refrigerator should be cleaned and wiped dry before plugging in the unit, replacing the drawers and restocking food.