You’re about to make a nice hot cup of tea, you cut your lemon… and then, the shock. A dark spot, almost star-shaped, appears in the flesh of the fruit. No suspicious smell, no visible abnormality on the outside, and yet… this lemon hides a little secret that you’d do well to know before you drink a drop.
Why do some lemons turn black inside without warning?
It’s a more common phenomenon than you might think. On the market stalls, lemons look fresh, firm, and perfectly yellow. Yet, some can be damaged… on the inside. And no, that’s not necessarily a sign of poor quality.
What you may have noticed are traces of a fungus called Alternaria , responsible for what is known as black rot of lemons ( or Alternaria rot ). Not very appetizing, it’s true… but above all, completely invisible from the outside!
The cause: stress that lemon cannot digest
Yes indeed, even lemons have their little bouts of fatigue! Alternaria rot develops when the fruit has suffered stress: a small injury on the skin, storage for too long, excessive humidity or even thermal shock during transport.
The result? Inside, the pulp begins to turn black, often taking on a recognizable star or circle shape, with dark areas of varying sizes. If you don’t cut your lemon all the way through, it’s difficult to notice in time.
