I didn't have the faintest idea.

Food spoilage is primarily caused by the growth of bacteria, yeast, and molds. These microorganisms thrive in environments where moisture and nutrients are present, such as in tuna salad. Temperature plays a critical role in the rate of spoilage; bacteria multiply rapidly between 40°F and 140°F, known as the 'danger zone.' Refrigeration slows down bacterial growth, but it does not stop it entirely. Over time, even refrigerated foods can become unsafe to eat as bacteria continue to multiply, albeit at a slower pace.

To maximize the shelf life of tuna salad, it should be stored in an airtight container in the refrigerator at a temperature below 40°F. It is advisable to consume tuna salad within 3 to 5 days of preparation to ensure safety and quality. When serving, only take out the portion you plan to eat immediately, and return the rest to the fridge promptly. Avoid leaving tuna salad at room temperature for extended periods, as this can accelerate spoilage.

There are several indicators that tuna salad may no longer be safe to eat. A sour or off smell is a strong sign of spoilage. Changes in texture, such as a slimy or mushy consistency, can also indicate bacterial growth. Discoloration, particularly if the salad takes on a grayish hue, is another warning sign. If any of these signs are present, it is best to err on the side of caution and discard the salad.