Tuna salad may be simple to prepare, but it is still a perishable food that requires proper storage. Whether it contains mayonnaise, celery, onion, or relish, homemade tuna salad should generally be eaten within 3 to 5 days when kept refrigerated at 40°F (4°C) or below. Knowing this simple time limit can help prevent an unpleasant foodborne illness.

Once tuna is combined with mayonnaise and other ingredients, it should be treated as a prepared perishable food. Refrigeration slows the growth of harmful bacteria, but it does not stop it completely. Tuna salad should not be left at room temperature for more than 2 hours, or more than 1 hour when the temperature is above 90°F (32°C).

For better storage, place tuna salad in a clean, covered or airtight container and refrigerate it promptly. Keeping it toward the back of the refrigerator can help because temperatures in the door tend to fluctuate more. Use clean utensils when serving and return the container to the refrigerator as soon as possible.

You cannot always determine whether tuna salad is safe simply by smelling or looking at it. Harmful bacteria may be present without producing an obvious odor, discoloration, or other visible warning signs. If the salad has been left out too long, stored beyond the recommended period, or you are unsure how it was handled, it is safer to throw it away rather than taste it to test its freshness.

So, if you have a container of tuna salad sitting in the refrigerator, think about when it was prepared before taking another bite. Three to five days is the general refrigerator guideline, and proper storage matters just as much as the ingredients. When in doubt about how long it has been stored, the safest choice is to discard it.