Answer: It’s important to keep the temperature of your refrigerator at or below 40° F. Any warmer than that, says the U.S. Food and Drug Administration, and the types of bacteria that can cause both food spoilage and foodborne illness will multiply too quickly. Of course, you don’t want to go to the other extreme and be confronted with frozen milk every morning. To prevent your food from getting icy, keep the fridge temperature no lower than 35º F. And you can reap energy savings by keeping it at about 37º F. How can you tell if your refrigerator is in that ideal temperature range? Unless your fridge has a built-in digital thermostat, it's difficult. Your best bet to buy a refrigerator thermometer; you can find inexpensive models at most grocery and hardware stores.