How Long Can You Leave Potato Salad at Room Temperature?

Potato salad is one of the most iconic cookout sides, and lends itself to so many preparations — you can opt for the classic version, make a warm Bavarian potato salad, or try an extra rich Japanese potato salad with Kewpie mayo. With summer cookouts (and temperatures) approaching, you might be wondering just how long this classic creamy side can actually sit out at a warm-weather gathering like a Juneteenth or Fourth of July party. Here’s everything you need to know about serving your spuds safely. 

How long does potato salad last at room temperature?

According to the U.S. Department of Agriculture (USDA), perishable foods like potato salad should be left in the “danger zone” (between 40°F and 140°F) for no longer than two hours. After that time frame, bacteria that causes foodborne illnesses can multiply rapidly, doubling in number in as little as 20 minutes. And if the temperature is above 90°F, that time decreases to about an hour. The window is even shorter for store-bought potato salad since you’ll want to account for the time it took to transport it home from the grocery store, and also for the time it sat out while being made.

Whether you’re making homemade potato salad or purchasing it from the store, be sure to refrigerate it or serve it as soon as possible. Potato salad will last in the fridge for about three to five days. 

What about potato salad made with vinegar or mustard?

You’d be forgiven for thinking creamy mayonnaise is the culprit here, but most commercially-produced mayo actually has acids like lemon juice or vinegar that generally help to prevent bacteria growth, according to the FDA. Cooked potatoes, on the other hand, are particularly prone to spoilage because of their high water and protein content, as well as their neutral or slightly acidic pH. Your potato salad may also contain other perishable items like cut vegetables.

So, the two-hour rule (one hour for temperatures above 90°F) applies to all potato salads, whether mayo, vinegar, yogurt, or mustard-based.  

How to keep potato salad cold

Keep potato salad refrigerated, whether in the fridge or in a cooler filled with ice, until you’re ready to serve it. If your potato salad will be left out for longer than two hours, make sure to serve it on ice — you can DIY your own cooling tray by filling a large aluminum pan with about an inch of water, freezing it, then popping smaller aluminum trays with your potato salad into it. (This trick works with bowls, too.) Also, metal serving bowls or trays will help your potato salad to stay cooler for a longer time than plastic or glass.