There are four methods of thawing that are safe:
Safe Thawing: meaning they keep food temperatures in the safe zone until they are cooked.
Thawing in the refrigerator is the safest method, and it also preserves the taste and texture of foods the best. However, it can take 24-48 hours for a freezer meal to completely thaw in the refrigerator, so plan ahead.
Cold Water thaw
Meals that are completely sealed and watertight (such as in a freezer bag) can be submerged in COLD water for a quicker thaw. Check the water temperature every 30 minutes to make sure that it remains cold. If the water becomes to warm (40 degrees or above), replace it with fresh water.
As long as your meal is not stored in a foil pan or covered in aluminum foil, you can thaw it in the microwave. This is the quickest method for safely thawing food, but it can sometimes result in a change in food textures or food can thaw unevenly.
Some foods can be cooked or reheated directly from their frozen state. Generally you will need to add 50% of the original cooking time (so if a meal is to bake for 1 hour, you should bake it from frozen for 1.5 hours). This works well for meals such as soups and stews that have already been cooked or foods such as casseroles and lasagnas. DO NOT place frozen food, especially frozen meat, into a slow cooker as it will not be cooked fast enough to prevent the growth of bacteria.
Thaw at your own risk, but the powers that be DO NOT recommend thawing foods on the counter top (except for foods such as breads, muffins, pastries or produce) or in hot water as these methods can allow bacteria to multiply before the food is cooked.