Answer: 41°F (5°C) or lower
If you're preparing a tuna salad with canned tuna it needs to be cooled to within 4 hours, it must be set at 41°F (5°C).
Tuna salad is considered potentially hazardous foods because it contains high protein foods like tuna. Other foods that are hazardous when not stored properly are meat, eggs, dairy and cooked vegetables. Bacteria multiply rapidly if food is held in the temperature danger zone (41° to 140°F).