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How To Tell If A Sweet Potato Is Bad

How To Tell If A Sweet Potato Is Bad?

Determining whether a sweet potato has gone bad is an important step before eating it. Consuming spoiled sweet potatoes can cause serious food poisoning and stomach issues. There are several clear signs that indicate freshness and safety when selecting sweet potatoes. This article will outline the key ways to identify if a sweet potato is no longer good to eat.

How Long Do Sweet Potatoes Last?

Properly stored, fresh sweet potatoes can last 2-3 weeks in the pantry. The exact shelf life depends on the variety and storage conditions. Once cooked, sweet potatoes will keep 3-5 days refrigerated in an airtight container.

There are a few factors that affect how long sweet potatoes last:

  • Variety – Some types have a longer shelf life than others. Jewel and Garnet sweet potatoes keep longer than lighter-skinned varieties.
  • Storage Temperature – Ideal is 55-60°F. Colder fridge temperatures can negatively affect taste and texture.
  • Humidity Levels – Sweet potatoes last longest in a dry environment with low humidity. Moisture causes them to spoil faster.
  • Light Exposure – Sunlight and bright light causes sweet potatoes to sprout and spoil quicker. Store them in a dark place.

The best way to store raw sweet potatoes is loosely wrapped in plastic in the crisper drawer of the refrigerator. This prevents moisture buildup and extends shelf life.

Signs That Indicate A Sweet Potato Has Gone Bad

Here are the most common signs that a sweet potato is past its prime and no longer good to eat:

1. Foul Odor

A strong, unpleasant smell is a clear giveaway that a sweet potato has spoiled. It may have a sour, fermented scent or smell like ammonia. This happens as starches convert to sugars and alcohols during spoilage.

2. Discoloration

Fresh, good sweet potatoes have smooth, bright, uniform flesh. Avoid tubers with black, brown or gray spots or patches underneath the skin. This indicates mold and spoilage.

3. Soft, Mushy Texture

A firm, intact sweet potato is the sign of a fresh one. Discard any that feel too soft or mushy, which signals deterioration. Press gently – spoiled potatoes will cave in.

4. Mold Growth

The appearance of mold, fuzz or white mycelium on the surface signals full spoilage. Do not try to cut away mold – unsafe toxins may have spread.

5. Sprouting

Sprouts or shoots emerging from sweet potatoes means they are past peak freshness. The sprouted portions should not be eaten.

Why Eating Spoiled Sweet Potatoes Can Be Harmful

Consuming spoiled, rotten sweet potatoes can cause foodborne illness. The natural sugars have fermented into alcohols, while mold releases toxic particles.

Dangerous bacteria like Clostridium botulinum, Salmonella, and E. coli can grow along with fungal mycotoxins. Symptoms include nausea, vomiting, diarrhea, and intestinal upset.

Seek medical help immediately if you experience concerning symptoms after eating bad sweet potatoes. Food poisoning can become very serious for at-risk groups like children, pregnant women, seniors, and those with weak immune systems.

Choosing Fresh, Safe Sweet Potatoes

Selecting sweet potatoes while shopping can feel like a gamble – it’s hard to see what’s going on inside. Here are tips for getting the freshest, safest tubers:

  • Avoid potatoes with cuts, holes or splits in the skin which expose the flesh. Bacteria and mold can enter.
  • Pick firm, hardy sweet potatoes without soft spots or damp areas. Press gently to test.
  • Size matters – choose smaller potatoes, which cure better and have a longer shelf life.
  • Watch for sprouting, wrinkling skin or mildew growth, which signals age.
  • Verify sweet potatoes are separable – clustered ones were probably cured incorrectly.

Proper Storage Methods

The right storage is key to getting the longest shelf life out of sweet potatoes:

Raw Sweet Potato Storage

  • Cure fresh sweet potatoes at 55-60°F for 7-10 days soon after harvest.
  • Store cured sweet potatoes loose in a cool, dark, well-ventilated area around 55°F.
  • Place in perforated plastic bag in the refrigerator crisper drawer. Avoid moisture buildup.
  • Check frequently for sprouting and signs of mold or spoilage.

Cooked Sweet Potato Storage

  • Allow cooked sweet potatoes to cool 1-2 hours before refrigerating.
  • Store in an airtight container for 3-5 days. Moisture causes faster spoilage.
  • Cooked sweet potatoes also freeze well for longer storage.

Consequences of Eating Spoiled Sweet Potatoes

Eating a rotten, bad sweet potato poses some serious health risks:

  • Food Poisoning – Harmful bacteria like Salmonella, Listeria, E. coli and toxins cause vomiting, diarrhea, fever, cramps, nausea and weakness.
  • Allergic Reactions – Mold and fungi can trigger allergic reactions or sinus issues in sensitive individuals.
  • Digestive Troubles – Spoiled produce can irritate the intestinal tract and cause stomach cramps or constipation.

Seek medical treatment if concerning symptoms arise after consuming bad sweet potatoes. At-risk groups like pregnant women, small children, seniors and those with compromised immune systems are most vulnerable.

Frequently Asked Questions

Can you eat sprouted sweet potatoes?

It’s best to discard the entire potato once sprouting occurs. The sprouted portions contain higher amounts of alkaloids that can cause a bitter taste and be toxic.

How long do peeled, frozen raw sweet potatoes last?

Properly stored in airtight freezer bags, peeled, cut raw sweet potatoes can last 10-12 months frozen at 0°F. Allow to thaw in the refrigerator before cooking.

Is it OK to eat an old sweet potato that has no mold?

No, appearance alone does not determine safety. Older sweet potatoes can harbor unseen microbial growth and toxins that cause illness. It’s best to discard them if they are aged beyond their prime storage window.

Why do some sweet potatoes get soft spots while others grow mold?

Differences in variety, curing, storage conditions and length of storage can lead to spoilage as either softness or mold. Both indicate the sweet potato is past its prime.

How can you tell if an uncut sweet potato is still fresh?

Look for firm, taut skin without wrinkles, sprouting or bruises. Soft skin or indentations when gently squeezed means older internal spoilage. Freshest sweet potatoes feel hardy and heavy for their size.


Identifying whether a sweet potato is spoiled takes a combination of trusting your senses and knowing the signs of aging. If you see mold, soft spots, sprouting, foul odors or texture changes, err on the side of caution for food safety. Prevention is ideal – take steps like proper curing, storage conditions and frequent inspection to maximize freshness. Discard anything that seems questionable.

Final Tips For Determining Sweet Potato Freshness

  • Examine sweet potatoes closely before purchase and use. Look for bruises, cuts and mold.
  • Store raw sweet potatoes properly to prevent premature sprouting and spoiling.
  • Monitor refrigerated sweet potatoes and discard at first signs of spoilage.
  • Do not attempt to salvage spoiled or moldy sweet potatoes. When in doubt, throw it out.

By understanding how to identify bad sweet potatoes through sight, smell and touch, you can select the healthiest, safest tubers for consumption. Trust your senses, follow the recommended storage guidelines and enjoy fresh sweet potatoes.

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