A portable ice chest comes in handy as a substitute refrigerator to keep food and beverages cool and will reduce opening the refrigerator. Even though it may seem wasteful, never eat any perishable foods such as meat, poultry, fish, milk and cheese that have been without refrigeration for more than several hours. It may seem fine but could contain bacteria that can cause food poisoning. Meats least likely to spoil are large, solid, unboned cuts like leg of lamb or rump roast. Cream cheese, open containers of cheese spread and cottage cheese spoil quickly.
Fresh milk spoils quickly without refrigeration.
Foods such as custard or creamed foods spoil very quickly and should be discarded. Fruits and vegetables such as bananas, apples, and citrus keep at room temperature for several days. Also, if one fills the empty space in a freezer with water filled milk jugs, the freezing capacity is increased and the water is available when thawed. When in doubt throw it out. In addition, I would like to add that cooking thawed foods extends their life for next several meals.