Normally a domestic freezer is best set to −18 °C (0 °F) or colder, as that's what the expiration dates for many food items are based on. It's also a requirement for freezers in restaurants, supermarkets & other places that sell food (at least here in Europe) to maintain a temperature of at most -18 °C.n order to keep food out of the Danger Zone, your fridge must be set between 32-40°F (0-4°C). Your freezer must be below 32°F (0°C). I keep mine as cold as it will go. Keep your freezer efficient by half-filling it with bottles of water.