Watermelons are a nice and refreshing treat during the summer but some people have reported theirs have been foaming and ‘exploding’.
Emily Durbin, who lives in Florida, posted about one such case in the “Mommy Needs a Recipe!” Facebook group. In this post, she shared a picture of a large watermelon with foam oozing out from the side. She also wrote in the description that “the yellow juice was thick and that “the odor was absolutely foul.”
According to her post, she could feel the watermelon “rumbling on the inside” when she picked it up to throw it in the trash. However, she had no idea why as the fruit hadn’t been exposed to any direct heat.
Many people in the Facebook group commented that they’ve also experienced the same phenomenon with their watermelons.
One user wrote that they left their watermelon on the kitchen counter and that it had developed “an awful smell” by the next day.
Another person wrote that their watermelon “literally exploded” with a loud bang when they cut into it, though “it wasn’t leaking yet.”
Why Do Watermelons Foam and Explode?
According to Keith Schneider, who works at the University of Florida’s Food Science and Human Nutrition Department, foaming and ‘exploding’ watermelons aren’t as rare as people may think.
He explained that the fruit can begin fermenting, if slightly damaged, due to the heat. If the fermentation continues to occur, it will produce a large amount of gas, which will lead to internal pressure inside the fruit, and over time, that can cause the watermelon to crack or ‘explode’.
He also said that the “excessive summer heat” is responsible for the quality of the fruits – and that it’s one of the many consequences of climate change.
During the fermentation process, microbes can also be introduced into the fruit and if that happens, they will convert the sugars in the melon into alcohol. He explained that it’s the same process that occurs in wine and beer making.
Dr. Steve Reiners, a professor at the School of Integrative Plant Science at Cornell University, also added that even if the fruits aren’t fermenting, fungal/mold disease or bacteria may have been introduced to the melon – that while the inside of the fruit is normally protected by the rind, there are a few microorganisms that can find their way inside.
However, he emphasized that the fruit will not ‘explode’ in these situations unless the entry hole is ‘completely plugged up’ .
Can You Eat Foaming Watermelons?
Foaming watermelons may be interesting to look at but they’re definitely not the best to eat. For one thing, the foaming means they’re undergoing decay. For that reason, it’s best to bring it back to the store for a replacement or just throw it in the trash.
Having said that, you don’t have to worry too much if you’ve accidentally eaten foaming fruit as plant diseases typically don’t make humans sick. You may feel a bit uncomfortable for a bit but that’s it.
Some fruits, however, may be contaminated with human pathogens such as salmonella or E.coli. For example, this can happen if the fruit has a small hole, especially if heavy rainfall has moved water from areas where wildlife is present.
In 2011, a crop of Del Monte watermelons was recalled after they were found to be contaminated with salmonella.
What’s the Best Way to Store Watermelons?
Ideally, you want to leave your watermelon in a cool, dark place, out of direct sunlight – that will help extend its shelf life. Any leftovers should also be put in the fridge.