Tuna Salad

Tuna salad keeps 3–4 days refrigerated and does not freeze — the texture collapses into mush.

Store it in a glass or plastic container, never in the open can. Once a can is opened it stops being a sterile container, and the exposed metal gives the tuna a distinctly metallic taste as it oxidizes.

The usual two-hour cumulative limit applies to time out of the fridge, and one hour above 90°F. Tuna salad sandwiches packed in a lunch bag should travel with an ice pack.

Drain the tuna well before mixing. Excess liquid dilutes the mayonnaise and gives you a wetter mixture that spoils faster and separates in the fridge.

Note that the clock starts when you open the can, not when you assemble the salad.

Tuna salad benefits from starting with an ingredient that has been thoroughly sterilized, and it is worth understanding what that does and does not cover.

Commercial canning heats the sealed can enough to destroy bacterial spores, which is why unopened canned tuna keeps for years at room temperature. Opening the can ends that protection completely and starts a 3–4 day refrigerated clock, no different from any other cooked protein.

One risk is already settled by the time you buy the can. Tuna is a scombroid fish, and if it was temperature-abused before canning it may contain histamine, which is heat-stable and survives canning. Nothing you do in your kitchen creates or removes it — this is a supply-chain matter, and it is why reputable canned tuna is a reasonable thing to trust.

What happens in your kitchen is ordinary contamination: Staphylococcus aureus from handling, introduced into a moist, neutral-pH, protein-rich mixture that will never be reheated.

The mayonnaise is again mildly protective rather than the villain — commercial mayonnaise is acidic and made with pasteurized egg.

Discard on a sharply sour or ammoniac smell, watery separation, sliminess, or any darkening. And discard at four days regardless.