– Store leftover tuna pasta salad in the refrigerator in an airtight container. Consume the leftovers within 2-3 days of preparing the salad. As with any dish, exercise your best judgment regarding leftover consumption. – If making ahead of time, this recipe can be prepared up to 24 hours before your gathering. Keep in mind that the pasta absorbs some of the dressing over time. To preserve the freshness, you might opt to assemble the salad the day before and add the dressing just before serving.