These are temperatures where bacteria multiply rapidly. Thaw food in the refrigerator at 40°F or less, in cold running water less than 70°F, or in the microwave if you'll be cooking or serving it immediately. Thawing in the refrigerator takes the longest time and advance planning. A large frozen item like a turkey requires at least a day (24 hours) for every 5 pounds of weight. Even small amounts of frozen food –- such as a pound of ground meat or boneless chicken breasts –- require a full day to thaw.