If you're shopping around for some fresh eggplant, these simple rules of thumb will help you avoid the ones that have gone bad. Sheela Prakash at The Kitchn suggests you look at two things when choosing an eggplant.
Photo by Mike Mozart.
First, make sure the skin is smooth and shiny. Dull or wrinkled skin is a sign that the eggplant was harvested a long time ago and may have gone bad. And any bruising or discoloration could mean the flesh underneath the skin has been damaged and that's not ideal either.
Second, make sure the stem is green. If the stem is brown, dried out, or starting to decay and mould, it's past its prime. The perfect eggplant should also feel a little heavier than it looks. Grab an eggplant that looks fresh and one that looks old and you'll notice the difference.