Why Foaming Watermelon Is a Red Flag
Watermelon is naturally high in sugar, which makes it especially vulnerable to bacteria and yeast. When these microorganisms infiltrate the fruit, they feed on the sugars and begin a fermentation process. As this happens, gases like carbon dioxide build up inside the melon.
Eventually, that pressure needs to escape. When it does, the gas mixes with liquid inside the fruit and pushes out as foam or bubbling liquid through cracks in the flesh or rind. Essentially, the watermelon has turned into a small fermentation chamber.
