All frozen raw meats, poultry, and seafood should be thawed completely before cooking. Otherwise, the food may cook unevenly, leaving parts overdone and other parts underdone, or even still frozen.
The best conditions for thawing meats, poultry, and seafood are in the refrigerator. While this may take a while, it’s the safest method and best preserves the food’s texture and quality. Leave the food in its original wrapping and set it on a rimmed tray or plate to contain any juices.
The larger the item, the longer it will take to thaw. For instance, a 4-pound roast will take close to 24 hours, while an 8-ounce chicken breast will thaw in a few hours. A good guideline is 5 or 6 hours for every pound.
While you may be tempted to defrost something on the counter overnight, don’t. Left at room temperature, the outside of the food will warm up enough to be a possible breeding ground for harmful bacteria, while the inside remains frozen. (Food should be left out on the counter to thaw for no more than 2 hours.)
If you’re in a hurry, there are two options safer than the countertop. The first is to immerse the food, well wrapped (zip-top bags are best) in a large bowl or sink full of cold (around 50°F) water. Change the water occasionally to keep it fresh and cool. The food will defrost in a fraction of the time it would in the refrigerator. The second alternative is to use a microwave, following the manufacturer’s instructions for defrosting. But keep in mind that food defrosted in a microwave should be cooked immediately afterward, because the microwave heats food unevenly and may cause hot spots, where the food has actually begun to cook.
In general, once food is thawed, it should be cooked within 24 hours, since thawed foods spoil and deteriorate much more rapidly than fresh, unfrozen foods.