Sometimes I'll cut into a navel orange and notice something black inside which originates at the bottom of the orange, where the navel is. What is it?

I have seen it get pretty far into the fruit too. Like almost half way in... is it safe to eat an orange like this?

  • 4
    I don't recall ever having seen this
    – hobodave
    Aug 18, 2010 at 16:39
  • This stuff is more common on tomatoes.
    – papin
    Aug 22, 2010 at 12:32

4 Answers 4


I'm not as familiar with citrus, but tomatoes and peppers can develop something called blossom-end rot. This is caused by the plant not receiving enough nutrients (specifically calcium), whether b/c the plant isn't getting enough water and thus can't get the nutrients out of the soil or b/c the soil is deficient.

Regarding whether it's safe to eat, a tomato w/ blossom end rot is still safe to eat, once you remove the affected area.

I hope this is helpful!

Do you have a picture of the orange in question? That would help greatly with diagnosis.

  • 2
    I'll take a picture next time I see it
    – Senseful
    Aug 21, 2010 at 0:06

It's probably Alternaria alternata or Black Rot, a type of mold. The fungus penetrates the orange through cracks that develop after harvest or during growth if the tree suffered through drought, frost, or disease. Typically the orange will also have a pale color and after some time will develop black spots on the surface. Discard.


Like this?

inside of orange outside

I was surprised to have selected one that looked like this on the inside. You really couldn't tell before cutting into it.

The rest of the orange looked fine. My family ate it this morning and none of us suffered any ill effects, as of 16 hours later.

  • While the photo is certainly helpful and it would be nice to know if it is what the OP is talking about, this doesn't really answer the question about what it is. I'm glad that you suffered no ill effects, though.
    – Catija
    May 10, 2017 at 21:14
  • @Catija true, my answer is more supplementary, since the others already answered what it is; the OP did include the question "is it safe?" which seemed more opinion-based in other answers before mine.
    – Kev
    May 11, 2017 at 16:59

Depending on how long you have had these oranges, this could be mold. However if you just bought them and the fruit is firm, it is very unlikely. In terms of safety, if it isn't very soft but firm, I don't see a problem with it.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.