White substance (often resembling cotton wool, mold, or sand) inside a peach—especially around or near the pit—is a fairly common phenomenon.

In most cases, it’s not dangerous mold, but a natural reaction of the tree. Here’s what it is and whether you can safely eat the peach.

What is it?

This white substance appears in peaches with split pits. When the pit cracks during fruit growth, a cavity forms inside, allowing air and moisture to enter. The peach reacts to this in two ways:

Callus tissue (the most common cause): This consists of clusters of newly formed, undifferentiated plant cells. The tree uses them to “heal” the wound caused by the cracking of the pit. This network looks like white sand or fine white pellets and is completely harmless to humans.

Harmless mycelium: Sometimes, due to moisture, a fine layer of mold forms inside a cracked peach pit. As long as it remains confined to the pit and doesn’t spread into the flesh, it poses no danger to the rest of the fruit.

Why does a peach pit crack?
Peach pits most often crack in spring and summer for the following reasons:

Rapid weather changes: For example, heavy rainfall after a long dry spell, when the fruit grows too quickly and the pit can’t keep up with the flesh.

Cold weather during the early stages of fruit development.

Variety characteristics: Some early peach varieties are more prone to pit cracking.

Can you eat such a peach without worry?

Yes, the peach flesh is safe.

Simply follow this rule:

Remove the pit along with the white mass and dispose of it.

If the flesh around the pit is firm, healthy, and smells good, and has no unusual taste, you can eat the peach without hesitation. If the flesh around the pit is visibly rotten, brown, or smells bad, cut out that part or discard the fruit.

Note: It’s best not to eat the pit (the part inside the peach) because it contains amygdalin, which is converted into hydrocyanic acid in the body (this applies to all peaches, not just those with a cracked pit).