Instructions

1. Freeze fresh tuna or use already fresh-frozen fish for ceviche. As the U.S. Food and Drug Administration notes, while freezing doesn't kill bacteria, it kills parasites, so this makes seafood that won't be heated safer. Seal it in an airtight freezer-grade bag and keep it in the freezer for at least 24 hours.

2. Thaw the tuna by putting it in the refrigerator the day before preparing ceviche. You also can defrost the tuna by immersing it in a bowl of cold water for an hour or two, changing the water every 30 minutes to keep it cold. Don't defrost the fish in the microwave, as you risk beginning to cook the exterior.

3. Dice the tuna into approximately 1/2-inch cubes with a sharp knife. While the exact size isn't essential, larger cubes need longer in the lemon juice, and you're likely to end up with some raw fish at the center. The extended marinating time also means the outside of the cubes may become too lemony and dried out.

4. Sprinkle the raw tuna with salt to taste, then place it in a glass or stainless-steel dish. Add enough fresh lemon juice to cover all the fish and allow the pieces to float freely. Cover the dish with its lid or plastic wrap.

5. Refrigerate the marinating tuna for 30 minutes to four hours. You only need the flesh to be opaque through to the center of each cube, but marinating time also is a matter of taste. The tuna may start becoming chalky after a few hours. Drain the tuna when you determine it's done.