Planning your next summer cookout and potato salad is on your list? With every family having a unique twist on the recipe, potato salad has become a mainstay side dish at many gatherings. You can choose from a traditional recipe, a warm Bavarian salad, or you could go the exotic route and try a tempting Japanese version with Kewpie mayo. But with the weather warming up, a common question is: how long can potato salad safely stay out in the open? Here is all you need to know about serving your favourite spud recipe safely.

Perishable dishes like potato salad should not be in the so-called 'danger zone' for more than two hours, advises the U.S. Department of Agriculture (USDA). The danger zone referred to here is between 40°F and 140°F, where bacteria causing foodborne illnesses can quickly multiply, doubling their numbers as fast as every 20 minutes. Notably, if the temperature is above 90°F, food safety time reduces to just about an hour. This time frame shrinks even more for store-bought types of potato salad, keeping in mind the time it took for transportation from the store to your home and the time it was left outside while being made.

Regardless if your potato salad is homemade or store-bought, remember to refrigerate or serve it immediately. The trusty fridge can safely store your potato salad for approximately three to five days.

A common misconception is that mayonnaise is the primary cause of food spoilage. However, according to the FDA, most commercially-produced mayonnaise contains acids like lemon juice or vinegar that generally prevent bacterial growth. Actually, cooked potatoes are more susceptible to spoilage due to their high water and protein content as well as their neutral or slightly acidic pH. Additionally, potato salad often includes other perishable ingredients like cut vegetables that can spoil.

The two-hour rule (or one hour if temperature is above 90°F) applies to all types of potato salad, whether the salad recipe includes mayo, vinegar, yogurt, or mustard.

The best practice is to keep potato salad refrigerated until you're ready to serve. If your potato salad is likely to be outside for longer than two hours, place it on ice. You can make a homemade cooling tray by filling a large aluminum pan with about an inch of water and then freezing it. Once frozen, add smaller trays filled with potato salad. This hack works with bowls as well. Note that metal serving bowls or trays will keep your potato salad cooler for a longer period compared to plastic or glass plates or bowls.