First, let’s define old. A whole, uncut watermelon can last for two to three weeks at room temperature. But once you slice into it, the clock starts ticking much faster. A cut watermelon is a paradise for bacteria, which is why it begins to spoil after just a few days in the fridge.
The smell is your number one clue. If it smells sour, like fermented fruit or even a whiff of vinegar, do not eat it. Next, check the texture: a good watermelon is crisp; an old one has a mushy, almost grainy interior. If the flesh is slimy or there’s a film of liquid pooling at the bottom, it’s time to say goodbye.
Finally, look for dark, wet spots or any fuzzy growth. That fuzzy mold is a celebrity of the spoilage world, and its presence means the fruit is officially off limits. Think of it as the watermelon’s version of a red flag at the beach.
