We brought our Costco watermelon home and set it on the kitchen counter when it started foaming.

3. Internal Decay
Sometimes, watermelons develop internal decay caused by fungi or bacteria during storage or transport. These organisms release enzymes that interact with the melon’s juice, leading to foam formation.

Visual Clues : Look for leaks, discoloration, or strange textures near the stem end.

4. Temperature Shock
Bringing a warm watermelon straight into a cold environment (or vice versa) can cause condensation and pressure changes within the fruit. Though less likely to produce foam, this stress can lead to unexpected liquid release.

Solution : Allow produce to acclimate gradually instead of sudden temperature shifts.

What Should You Do Next?

Unfortunately, if your watermelon started foaming, it’s safest to avoid eating it. Here’s how to proceed:

Discard Immediately : Don’t risk foodborne illness—wrap the melon securely and dispose of it properly.
Clean the Area : Wipe down your counter and surrounding surfaces with mild soap or disinfectant to remove potential contaminants.
Inspect Other Produce : Ensure nearby items weren’t affected by leaking juice or bacteria.
How to Prevent Future Mishaps
To ensure your next Costco watermelon stays sweet and safe, follow these tips:

Check for Bruises or Cracks : Inspect the melon carefully before purchasing—blemishes can indicate spoilage risks.
Store Properly : Keep watermelons at room temperature until ready to eat, then refrigerate cut portions promptly.
Slice Wisely : Use clean tools and hands when preparing melons to avoid introducing bacteria.
Trust Your Instincts : If a melon smells off, feels overly soft, or shows signs of damage, skip it altogether.

Final Thoughts

While discovering a foaming watermelon is certainly alarming, it serves as a reminder to always inspect and handle fresh produce with care. Next time you grab a giant melon from Costco, give it a quick once-over and store it properly to savor every sweet bite.

And hey, maybe stick to smaller melons for now—you’ll appreciate fewer surprises and more delicious moments! Let us know if you’ve ever encountered something similar—or share your favorite watermelon recipes below. Here’s to staying safe and refreshed!