Watermelon is the quintessential summer fruit: sweet, juicy, and brightly colored enough to instantly elevate any picnic, barbecue, or cocktail party. But to protect you, your family, and your guests from bringing home a not-so-fun remembrance of your outdoor event—a nasty case of food poisoning—you’ll want to make sure you’re taking a crucial step before carving in.
“Washing melons before slicing is critical,” Darin Detwiler, PhD, a food safety expert and associate teaching professor at Northeastern University’s College of Professional Studies, tells SELF. While the idea might never have crossed your mind before—after all, you don’t eat the rind— this advice actually makes sense when you think about it.
Unlike berries, watermelons grow on the ground, exposing them to all sorts of contaminants—dust, soil, dirty water, animal waste, improperly composted manure, and more. Once harvested, they can pick up even more during storage, handling, and transport as they make their way from field to retailer, and then from retailer to kitchen counter. By the time you purchase your melon, it’s probably been touched by dozens of different people, some of whom may have petted animals, picked their noses, used the bathroom, or otherwise made contact with germs beforehand without washing their hands first. “You don’t know where their hands have been,” Dr. Detwiler says.
Then, when you take a knife to your melon, the blade can transfer all that nasty stuff directly from the exterior to the interior, “dragging bacteria straight into your food,” Dr. Detwiler says. From salmonella to Listeria to E. coli, these bugs have the potential to make you seriously sick. (In fact, contaminated watermelon has been implicated in a bunch of salmonella outbreaks in the US over the last decade or so.) If you do become ill, you can most likely expect classic food poisoning symptoms like nausea, vomiting, and diarrhea, which typically pop up within a few hours to several days and last around the same amount of time. Spending a beautiful summer day camped out by the toilet is an experience sure to make you wish you’d never taken a bite in the first place.
How watermelon is usually prepared also puts it at a sanitary disadvantage, according to Dr. Detwiler. Unlike, say, corn on the cob, watermelon is typically eaten raw, so potential pathogens aren’t killed off by cooking. For that reason, “the only effective measure” that you could take to reduce the food poisoning risk is washing your melon before cutting into it, Dr. Detwiler says. This removes potential exterior contaminants before they have a chance to reach the interior.
Not only is washing effective, it also doesn’t have to be complicated. First, rinse your melon in cool, running water (holding it under the kitchen tap, say). Next, scrub it all over with a clean brush. Then, pat it dry with a paper towel to reduce surface moisture, since bacteria like wet surfaces. “Don’t use soap or bleach, just water and friction,” Dr. Detwiler says. Finally, make sure that your knife and cutting surface are clean as well; otherwise, you run into the additional risk of transferring bacteria from the knife or board to the watermelon flesh.
