For safe food storage, the bottom area of the refrigerator must be kept at 40 degrees Fahrenheit. It can be set lower if needed. This keeps food at a temperature that either prevents or slows the development of bacteria such as E.coli and salmonella.
The longer ready-to-eat foods are in the refrigerator, the greater the chance they are growing a bacteria called listeria. Even with the refrigerator at the proper temperature, ready-to-eat foods are best when consumed within a few days. The freezer area temperature is ideal at 0 degrees Fahrenheit. Perishable foods should be refrigerated immediately and should never be left out more than two hours.