Before you even place your order at a restaurant, the ingredients of your soon-to-be dinner are waiting in the fridge or the walk-in freezer. If that refrigerated food wasn't kept between 32 and 40 degrees Fahrenheit, you could be in for a rough time later on. That's why it's a good idea to invest in a refrigerator thermometer to ensure that your food stays in that safe temperature range until you're ready to cook it. Always throw your groceries in the fridge as soon as you get home, even if you're tired. Two hours is the longest time perishable food should be kept on the counter, and a one-hour window is long enough for illness-causing bacteria to breed in the summer. Consider bringing along an insulated bag to keep meats and frozen foods cold on especially long trips. And make sure your freezer is set at 0 degrees Fahrenheit or below to keep food at its freshest.