This morning, I purchased a bag of “organic,” pre-chopped, pre-washed broccoli. Individual pieces comprised less than an inch of stalk with attached branches and florettes. I tossed the bag and transferred the broccoli to a Tupperware-like storage bowl as soon as I got home (about half an hour after removing the bag from the store’s open-air vegetable cooling section). The broccoli showed no external sign of spotting, yellowing or bruising.

A few hours later, I removed five pieces from the bowl, washed them and cut them up. The inside of the first four pieces looked as pristine as the outside; the fifth, however, showed a few black spots on the inside of the stem and lower part of the branches (see image).enter image description here The flesh around these spots was not unusually soft, discolored, or mottled. The flip side of this small stalk showed no black spots.

Another post to this forum (Are those black spots on the inside of kaki safe to eat?) asked about a similar situation with kaki (persimmon). Responses suggested that inner discoloration was not unusual for this fruit and did not render it unsafe. (Oxidation was suggested as a possible cause, which seemed a bit odd given the fruit’s moderate acidity.)

There are sufficient differences between broccoli and kaki that I won’t generalize from this response to my situation. In addition, the kaki discoloration shown in an image from the OP was diffuse—-not concentrated into distinct spots.

My best guess is that the spots on the inside of my broccoli reflect mold. But as this is the first time I’ve purchased pre-cut broccoli, I don’t know how likely that is nor whether such spots are commonplace for precut vegetables. I’m also curious about the mechanism by which mold could form on the inside of the plant but not on the outside.

I hope that someone with knowledge about broccoli can weigh in on the likely cause of these interior black spots. If the most likely cause is mold, then knowing whether there’s a strain of mold that’s particularly likely to be the culprit would be helpful. The Holy Grail answer, of course, would include information on the likely virulence and spread of the substance, since I munched on several unblemished pieces of the broccoli before I encountered the piece with spots. Thanks in advance for any input!

  • 3
    That could be mold, or it could be a tunnel left by an insect or slug pest. Can't tell from the picture.
    – FuzzyChef
    Aug 31, 2022 at 18:51
  • 2
    Chance of virulence is very low if it is a plant pathogen. I'd suspect a stem-rot of some sort or perhaps soft rot. You might get a better/quicker answer if you requested migration to the biology SE.
    – bob1
    Aug 31, 2022 at 20:02
  • 1
    I've seen what looks to be the same on the insides of stems of supermarket, non-organic, not-pre-cut broccoli, generally after it's been in the fridge for a while. That doesn't rule either oxidation or some kind of rotting out, but this isn't some unusual behaviour. I guess you just normally eat your broccoli fast enough that it doesn't develop.
    – dbmag9
    Aug 31, 2022 at 20:44
  • 090422 Thanks to everyone who has weighed in. I really wish that I could assign equal scores to all of your answers, as they’ve all been helpful.
    – Cyclone93
    Sep 4, 2022 at 14:53

1 Answer 1


That is more likely than not a hole left by a slug or insect.

Densely packed broccoli floral heads (as well as cauliflower) supply a protective environment for slugs and insects that want a little edible home base. As such, it's fairly common to find pest burrows in organic broccoli -- sometimes with pests included!

It's harmless but possibly bad-tasting, just cut out the discolored parts.

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