This Is How Long You Can Leave Potato Salad Out, According to a Food Scientist
Almost every summer BBQ or picnic features potato salad, but how long is it actually safe to leave out at room temperature? I went to a food scientist for answers.
When I go to a picnic or backyard barbecue, someone almost always brings potato salad. It’s such a summery dish, but when it’s hot and humid here in Atlanta, I wonder how safe it is to have potato salad on the menu.
How long you can leave potato salad out of the fridge depends primarily on outdoor temperature, says Kristen E. Gibson, scientific editor for the Institute of Food Technologists’ Journal of Food Science and director of the Center for Food Safety at the University of Arkansas.
“Potato salad is safe to leave out of the fridge for one to two hours as long as the ambient temperature is no greater than 70°F. This would be one hour or less if the temperature was 90°F,” she says. “The goal is to be sure that bacteria do not have an opportunity to grow, which can occur between 41°F and 135°F.”
Does Mayo Matter?
Everyone knows that mayonnaise and warm temperatures don’t go well together, but even if your potato salad doesn't contain mayo, you still have to keep an eye on the time.
“Mayo can certainly increase the potential for microbial growth when temperature is abused, but this does not mean that other mayo-free versions of potato salad are exempt from the rules,” Gibson says.
How to Safely Serve Potato Salad
You don’t have to avoid offering potato salad at your outdoor party. Just be smart about how you serve it.
Don’t let it sit outside for more than one hour, and to keep the risk down, keep it cool while it’s outdoors. You can freeze some water in a tray or bowl and then place your potato salad bowl on top of that. Place it on a cooling stone, which is a piece of marble or granite that can help absorb heat.
“But you would still need to adhere to no more than two hours outside of ‘real’ refrigeration,” says Gibson. “Keeping a digital thermometer handy would help provide some confidence in the actual temperature of the potato salad.”
Consider just putting out a little potato salad at a time and refilling the bowl from the fridge as people eat it.
It’s Not Obvious
Other than keeping track of the time that it has been unrefrigerated, potato salad doesn’t give any clues when its safety is questionable.
“There is no way to taste, smell, or see when a food is not safe to eat,” Gibson says. “When foods ‘go bad,’ this is an indication of declining quality, not safety.”
After your picnic or BBQ, your best bet is to toss any leftover potato salad if it’s been outdoors for an hour or more. Any leftovers that have been kept at refrigerated temperature can be stored for about three to four days.
If you make the potato salad yourself, be smart about kitchen cleanliness and storage. “Always ensure that the potato salad is being prepared in a way to prevent any sort of cross-contamination in the kitchen,” says Gibson, pointing out the importance of washing your hands and using separate surfaces for raw and prepared foods. “In addition, be sure to promptly refrigerate the prepared potato salad and separate into multiple containers if it is a particularly large batch to enable rapid cooling throughout.”
