the fruit is toxic or contaminated with chemicals.
Clean internal cavities can simply be caused by hollow heart, uneven growth, or other natural growing conditions.
What matters more is the condition of the flesh.
If the watermelon is firm, juicy, fresh-smelling, and normal in color, internal cracking alone is usually less concerning.
But if you see foam, bubbling liquid, slime, mushiness, leaking, or a sour fermented smell, do not eat it. Those are much stronger signs that the watermelon has spoiled
