Reasons for Not Leaving Food Out Overnight

Bacteria

• Although there is some evidence that exposure to bacteria and germs might actually help improve immunity, eating food that has been left out overnight isn't the sort of exposure the experts had in mind. Improper refrigeration is a major cause of food-borne illness. The United States Department of Agriculture's Food Safety and Inspection Service recommends refrigerating food within two hours of preparation at a temperature of 40 degrees or below.

Vermin

• Bugs of another variety also love to snack on your leftovers. A covered dish won't stop them; roaches can slip though cracks the thickness of a dime. Many species of ants need even less space. Plastic wrap might keep out the creepy-crawlies, but mice can gnaw through solid wood. Household pests are a double threat; you might not know they've been nibbling, and many carry bacteria and parasites that can make you sick.

Taste

• Oxygen is another insidious enemy of food. Even those foods that aren't particularly susceptible to bacteria and that have been protected from bugs will suffer from exposure to air. Things that are left out overnight can go stale, loosing color, flavor and the appealing appearance they had when fresh out of the oven or package. So, rather than eating it out of the box you forgot under the couch, have that day-old slice of pizza cold from the fridge instead.

Other Dos and Don'ts

• Baked goods such as muffins, quick breads and cakes can be left at room temperature if you plan to eat them within three or four days. The same goes for fresh bread, which will actually go stale faster in the refrigerator. In hot, humid weather, however, all baked goods should be refrigerated to prevent mold growth. Fruits such as peaches, pears and melons should be ripened at room temperature before refrigerating them. Apples, grapes, plums and most berries will go soft faster at room temperature and are best stored in the refrigerator. Bananas should remain at room temperature since refrigeration will make them darken quickly.