What you see: Blackish spots or holes on your potatoes like those pictured above; they may go below the peel.
What it is: Likely pores that were damaged and then healed.
Eat or toss: Cut around them (they could have off flavors and textures), but don’t worry about eating the rest of the potato.
What’s that black spot on this potato?
The cells in all living things need to take in oxygen and expel carbon dioxide* to keep their systems running. Potatoes are no exception and, even after harvest, they continue to breathe through tiny openings, known as lenticels. Water also goes in and out of these little pores.
The potato can open or narrow its lenticels depending on its needs and the environment. But not everything that enters these specialized pores is invited.
“Sometimes just a little bit of bacteria go in,” explained Nora Olsen, a professor and extension potato specialist at the University of Idaho.
That bacteria might become widespread, as happened in this potato.
Or, the potato’s defenses might successfully hold it at bay, as appears to have happened in the potato we’re focusing on today.
“And then the potato just heals up,” Olsen said. “So they have that blemish sitting there, but it’s not doing anything more than just being a blemish. When we start to worry is when it continues and you can’t get ahold of it. Then it just starts to deteriorate the whole tuber.”
While the blackened areas pictured here appear to be dry and not hosting any active bacteria, the infection will probably lead them to have off flavors and an unpleasant texture.
Once potatoes are cooked and prepped, you probably won’t notice any differences in places with slight discoloration. However, more dramatic discoloration and a rough texture (like below) may impact your eating experience.
“I just cut them out of my potatoes,” Olsen said.
*This is respiration and it exists alongside photosynthesis, in which plants take in carbon dioxide and release oxygen.