Avocado doesn’t start to ripen until picked from the tree, but the process happens relatively quickly afterward.
Once ripe, you have a narrow window of time — generally a few days — before the fruit spoils.
You may wonder how to determine when an avocado is rotten and no longer suitable to eat.
Here are 5 signs that avocado has gone bad.
1. Overly soft with dented skin
When checking for ripeness, use the palm of your hand to squeeze the avocado gently. Don’t press the fruit with your fingers, as this may bruise the flesh.
If the avocado is very firm and doesn’t give at all, it’s underripe. If it gives slightly, it’s likely ripe and ready to eat.
However, if squeezing leaves a small indentation, it may be too ripe for slicing and will work better mashed.
The fruit is overripe and probably spoiled if pressing leaves a significant dent and the fruit feels mushy.
Additionally, it’s likely past its prime if an avocado has a sunken area or looks deflated before you squeeze it.
Summary: If you gently squeeze an avocado in the palm of your hand and it retains a large indentation where you pressed, the fruit is overripe and likely spoiled.
2. Blackened skin
Some avocados undergo distinct skin color changes as they ripen — particularly the Hass variety, which accounts for about 80% of avocados eaten worldwide.
When not fully ripe, Hass avocados have bumpy, bright green skin. It progresses to dark green or brown when ripe. If the skin looks nearly black and the fruit feels mushy upon touch, it’s overripe and likely spoiled.
Other varieties, including the zutano and fuerte, retain their green skin color regardless of how ripe they are. Use other methods — such as feeling for firmness — to determine if they’ve gone bad.
Summary: Hass, the most common avocado variety, develops blackened skin when overripe and rotten. However, other varieties retain their green color when overripe.
3. Dark, stringy flesh
Once you cut an avocado, it’s easier to determine whether it has gone bad. Of course, this is only an option after you buy it.
An avocado that’s ready to eat has light green flesh. A rotten one has brown or black spots throughout the flesh.
Yet, an isolated brown spot may be due to bruising rather than widespread spoilage and can be cut away.
Another possible sign of rotting is dark streaks in the flesh.
Still, some avocados — particularly those harvested from young trees — may have dark streaks even though they’re not rotten. If the fruit looks good otherwise and doesn’t taste off, it’s fine to eat.
Similarly, the texture of avocado may be stringy when it has spoiled. Still, if there are no other signs of rot, it’s not necessarily bad. A fibrous texture can also be attributed to growing conditions.
Summary: The flesh of a rotten avocado has dark spots and a stringy texture that tastes bad. However, an isolated discolored area may be due to bruising.
4. Off-flavor or odor
Ripe avocados have a pleasant, slightly sweet aroma and somewhat nutty flavor. As the fruit spoils, it may develop an abnormal taste and odor.
If it has a sour taste or smell, it may have bacterial spoilage and should be discarded.
A chemical odor and taste may mean it’s rancid. This can happen when oxygen or microbes damage or break down the fruit’s unsaturated fat.
Rancidity can result in the formation of potentially toxic compounds. Don’t eat an avocado if you think it’s rancid.
The flavor of spoiled avocados can vary, but it’s usually easy to tell upon taste whether they’re past their prime.
Suggested read: How long do potatoes last? Raw, cooked, and more
You can determine whether an avocado has spoiled through smell, taste, touch, and visual inspection.
Summary: A sour taste or smell, as well as a rancid aroma and chemical flavor, mean that avocado is spoiled, and you should discard it.
Mold on avocados is generally white or gray and looks fuzzy. Don’t sniff it, as you may inhale mold spores and trigger breathing problems if you’re allergic to it.
Avoid buying avocados with mold on the exterior, as they can penetrate the flesh and cause decay.
If you cut open an avocado and see mold, discard the entire fruit. Though you may only see mold in one area, it can quickly spread through the soft flesh. Don’t attempt to salvage it.
Summary: Mold indicates that an avocado is spoiled. You should discard the entire fruit, as the mold can spread through the soft flesh but may not be entirely visible.
Safety of overripe avocados
Whether it’s safe to eat an overripe avocado depends on the type of decay and how far it has progressed.
Since ripening starts from the stem end and progresses downward, you might be able to use part of the overripe fruit if the flesh has just started to turn brown.
However, don’t eat discolored areas of avocado, as they won’t taste good. Additionally, don’t try to salvage any part of a rancid, sour-smelling, or moldy avocado, as it can make you sick.
Keep in mind that once you cut an avocado, the flesh starts to brown due to oxygen exposure. This is a natural process, similar to how apples turn brown when cut. If you find it unappetizing, skim off the discolored layer and eat the rest.
To minimize the browning of cut areas, brush lemon juice on the flesh and store it refrigerated in a sealed container.
You can reduce waste by keeping a close eye on avocados and refrigerating them to slow the ripening process.
Suggested read: Is it safe to eat moldy bread?
Overly soft but unspoiled avocados are safe to eat and can be used to make guacamole, smoothies, salad dressing, and baked goods.
Summary: If they taste fine, you can eat overripe avocados, but avoid spoiled ones. The more an avocado has deteriorated, the more likely it will be rancid or moldy — both of which could make you sick.
Avocados are rotten if they’re mushy when squeezed, brown or moldy inside, and have developed rancidity or a sour smell.
You may be able to salvage part of the fruit if it’s just starting to brown inside and the rest of the fruit looks, smells, and tastes fine.
Scrutinize avocados at the store and monitor them closely at home so you can avoid the need to discard them.