A smooth transition from freezer temperature to 40 degrees Fahrenheit means the difference between freshly thawed tuna steaks that stay fresh up to 48 hours and potentially unsafe tuna with a mushy, waterlogged texture. Bacteria thrive and multiply between 40 and 140 F, or the "food danger zone," making slow, uniform thawing of tuna as much a safety precaution as it is a way to preserve taste and texture. You get the best quality from tuna when you thaw it in the refrigerator, but if you're pressed for time, you can speed up the process with cold water.
Transfer the tuna steaks from the freezer to a shallow dish lined with paper towels. Leave the freezer bag or package intact.
Thaw the tuna steaks on the bottom shelf of the refrigerator for 12 hours per pound. Drain the dish and change the paper towels if you see water pooling.
Discard the original packaging after the tuna thaws. Pat the tuna dry with a paper towel before cooking.
If you're not cooking the tuna steaks immediately after thawing, wrap them in plastic wrap and store them in the refrigerator up to 48 hours.
Transfer the tuna steaks from the freezer packaging to a sealable food-storage bag if not already. Place the sealed bag of frozen tuna steaks in bowl.
Add cold water to the bowl until the tuna steaks submerge. Set the bowl aside.
Change the water every 30 minutes until the tuna fully thaws; it takes about 30 minutes to thaw 1 pound of tuna. If you're not cooking the tuna steaks immediately after thawing, wrap them in plastic wrap and store them in the refrigerator up to 48 hours.