Temperature control: food safety tips. Use a fridge thermometer to check the temperature of your fridge regularly. The coldest part of the fridge should be between 0 degrees Celcius and 5 degrees Celcius (32 degrees Fahrenheit and 41 degrees Fahrenheit). aim to keep the coldest part of your fridge between 0 degrees Celcius and 5 degrees Celcius (32 degrees Fahrenheit and 41 degrees Fahrenheit). 2  keep a fridge thermometer in the coldest part and check the temperature regularly.