How to Tell If a Lemon Is Bad (4 Signs)

Published Categorized as Food
Danko Natalya

The sour truth about bad lemons is that they sooner or later go bad. Here’s how to tell when that’s the case with the lemons in your kitchen.

Everybody loves lemons!

Although they’re a little pricey (and, with inflation, their price has gone up and up), they can be picked up at any grocery store, they keep very well, and they’re highly versatile in the kitchen.

Even if they keep very well, lemons eventually go bad. And when they go bad, they belong on the compost pile or in the trash, and they should never be cooked with or eaten. So that you know what to look for, we’re going to take a look at the telltale signs of lemon spoilage.

See below.

How to Tell If a Lemon Is Bad

A lemon is spoiled if the peel is brown and watery or white and moldy, if it smells musty and medicinal, and/or if its pulp has turned to mush and smells fermented.

If a lemon in your fruit bowl or refrigerator matches this description, throw it away and don’t eat it or drink its juice.

1. Look at the Peel

Quite often, the look of a lemon can give you the first indication that it might have gone bad.

A fresh lemon should be lively and plump, and have a smooth to waxy peel with a bright yellow color that’s pleasing to the eye.

Light green patches on the peel of the lemon—a sign that the lemon wasn’t handled very carefully during harvest—are okay. As long as, of course, you don’t mistake them for mold.

A spoiled lemon looks shriveled and deformed. It has brown, watery spots on the peel, and it may be covered with white to green mold (called Penicillium digitatum) or blue mold (called Penicillium italicum).

2. Squeeze the Lemon

Take the lemon in the palm of your hand and give it a gentle squeeze.

How firm is it?

A lemon that’s underripe is very firm and doesn’t give at all. A lemon that’s ripe enough to eat or use for juice gives slightly, but with plenty of resistance. A lemon that’s overripe or rotten is so soft and squishy that it can turn to mush if you squeeze it too hard.

3. Sniff the Lemon

Some lemons are so fragrant, just smelling them takes you on a vacation on Italy’s Amalfi Coast. Others have no smell at all, and that’s perfectly fine. Because, in this check, you’re not judging the lemons by how good they smell. Oh, no, what you’re looking for is off odors.

Hold the lemon to your nose, then exhale and sniff it. If the lemon smells musty and medicinal, it’s probably moldy. (Not everyone knows that the green mold that grows on citrus fruits is colorless in its early stages of growth.) If the lemon smells fermented, like cheap vinegar, it’s probably spoiled.

4. Cut It and Look at the Pulp

Cut the lemon in half, crosswise. If the lemon gives little to no resistance to the blade of your knife, or it turns to mush as you cut it, then there’s little doubt that it has gone bad and should be thrown away.

Last but not least, look closely at the pulp of the halved lemon and give it a good sniff. If it looks mushy and brown, or if it smells fermented or rotten, then the lemon is long past its prime and may have already spoiled.

How Long Do Lemons Last?

Kept in a fruit bowl on the kitchen countertop, whole lemons last up to 7 days. Refrigerated in the crisper drawer, whole lemons last for 3-4 weeks, depending on how fresh and ripe they were when you bought them.

Halved lemons and lemon slices shouldn’t be left to sit out for more than 1-2 hours. They are best kept in the refrigerator, in a ziplock bag or food storage container with the lid closed, where they will stay good for 3-4 days.

Discard bruised and spoiled lemons, as well as lemons that you have kept for longer than the above time periods; they may not be safe to eat.

Can You Get Sick From Eating a Spoiled Lemon?

Don’t eat a lemon if you suspect that it’s spoiled. Spoiled food by itself seldom makes us sick. However, spoilage is a sign that the food may also be overgrown with disease-causing germs, called pathogens, that can cause food poisoning.

These pathogens may live on the peel of the lemon. They may have gotten there through contact with the dirt, during the harvest, or during the processing, and then continue to feed on the nutrients in the peel and multiply. During prolonged storage, these bacteria can grow to potentially dangerous numbers and make their way to the pulp of the lemon through the rotted rind.

The tricky thing is that you have no way of ruling this out, because pathogenic bacteria are basically undetectable. They don’t alter the smell, taste, or texture of our food, so they can only be identified in a laboratory environment.

Once in your body, the living bacteria, which include Listeria monocytogenes and Salmonella, and the toxins that they’ve produced can cause food poisoning. In the U.S. alone, the Centers for Disease Control and Prevention (CDC) estimate that 48 million Americans contract food poisoning, 128,000 are hospitalized, and 3,000 die every year.

Can Lemon Juice Go Bad?

Just like the lemons it was squeezed from, lemon juice can go bad. When lemon juice spoils, its color fades and its taste changes from pleasantly sour to repulsively bitter, with a funky or musty undertone.

If you took a sip of lemon juice and it turned out spoiled, spit it out if you can and dispose of the rest right away. (You can pour it down the sink.)

In Conclusion

A shriveled and moldy lemon is a spoiled lemon, and a spoiled lemon has no place in your kitchen. Reduce food waste by buying your lemons fresh and firm, and always in quantities you can use within a couple of weeks.

Next up: What is a good substitute for lemon juice?

By Jim Stonos

When Jim isn't in the kitchen, he is usually spending time with family and friends, and working with the HCW editorial team to answer the questions he used to ask himself back when he was learning the ropes of cooking.

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