The perfectly seared ahi has a well-marked outside and inside that is not too well done. Known by the Hawaiian name for yellowfin or big-eyed tuna, ahi is a red tuna with a firm texture and light flavor. Ahi is perishable and you cannot keep it at room temperature for extended periods of time without bacteria on the fish multiplying to dangerous levels. Whether you serve ahi in slices or as a whole steak, any leftovers require immediate attention.
On the Plate
Once you complete the searing and the ahi tuna reaches the serving plate, the clock starts ticking. As the ahi cools, any bacteria remaining on the fish after cooking multiplies. After two hours at room temperature, enough bacteria may be present to make you seriously ill if you eat the ahi. If the air temperature reaches 90 degrees Fahrenheit or above, these bacteria multiply more rapidly, cutting the safe time down to one hour.
Keep it Cool
Refrigerate ahi tuna within the recommended two hour safe time or throw it away. Scoop the seared ahi leftovers into a shallow, airtight container with a label containing the type of leftovers inside along with the date of refrigeration. In a refrigerator set to 40 degrees Fahrenheit or lower, cooked ahi keeps for only two days. Once the two days pass, throw the fish away and wash the container with hot, soapy water.
Remove the seared yellowfin from the refrigerated container within the two-day refrigeration period and serve cold over a crispy bed of salad greens or reheat and serve over pasta. To reheat the seared ahi, crumble the fish into pieces and place in a skillet coated with nonstick spray. Saute over medium heat. The temperature of all reheated leftovers should reach 165 degrees Fahrenheit when you press a meat thermometer into the thickest part of the fish.
Freeze the seared ahi if you know that you will not eat it within two days. Temperatures of 0 degrees Fahrenheit and below halt bacterial growth, meaning that the seared ahi remains safe to eat indefinitely. Safety aside, stored in heavy-duty aluminum foil or freezer bags, the quality begins to deteriorate within just a few months. When you are ready to thaw, transfer the ahi from freezer to refrigerator 24 hours before reheating.