How to Tell When a Potato Is Bad: Signs & Safety Guide

Discard potatoes showing significant green discoloration, soft mushy spots, extensive mold growth, or a foul odor. Potatoes with minor sprouting or small shriveled areas can often be salvaged by cutting away affected portions.

Spot Bad Potatoes Before They Make You Sick

Nothing ruins meal planning like discovering your potatoes have spoiled. Learning to identify bad potatoes protects your health and saves money by reducing food waste. This guide reveals exactly what to look for, when to toss potatoes, and how to store them properly.

Visual Inspection: What Bad Potatoes Look Like

Your eyes provide the first warning signs that potatoes have gone bad. Here's what to examine:

Color Changes That Signal Trouble

Healthy potatoes maintain their natural tan, red, or purple skin color. Watch for these dangerous color indicators:

• Green patches - Caused by light exposure producing toxic solanine
• Dark brown or black spots - Indicates advanced rot or bruising
• Mold growth - Appears as fuzzy white, green, or black patches

Condition	Safe to Eat?	Action Required
Minor sprouting (¼ inch)	Yes	Cut away sprouts and eyes
Small green spots	Yes	Peel deeply to remove all green
Extensive green discoloration	No	Discard entire potato
Soft, mushy texture	No	Discard immediately
Foul odor	No	Discard and clean storage area

Sprouting: When It's Still Safe

Sprouting alone doesn't mean your potatoes are dangerous. Small sprouts (under ¼ inch) can be removed safely. However, extensive sprouting with long shoots indicates significant nutrient loss and potential solanine buildup. The University of Minnesota Extension confirms that potatoes with minor sprouting remain safe after proper preparation.

Texture Tells the Truth About Potato Freshness

Your fingers provide crucial information that eyes might miss:

The Squeeze Test: What Different Textures Mean

• Firm throughout - Perfect condition, ready to use
• Slightly soft in spots - Early spoilage, cut away affected areas
• Mushy or slimy texture - Advanced decay, discard immediately
• Shriveled appearance - Dehydrated but potentially safe if firm

When checking texture, avoid pressing too hard which can create bruising. The USDA Food Safety and Inspection Service emphasizes that mushy potatoes often contain harmful bacteria even when no visible mold appears.

Smell Test: Your Final Safety Check

Fresh potatoes have an earthy, slightly sweet aroma. Trust your nose when you detect:

• Vinegar-like sourness
• Rotten egg smell (sulfur compounds)
• General mustiness

According to FDA food safety guidelines, any unpleasant odor indicates bacterial growth that could cause foodborne illness. When in doubt, throw it out - your sense of smell detects spoilage before your eyes can see it.

Understanding Solanine Poisoning Risks

Green potatoes contain solanine, a natural toxin that can cause:

• Nausea and vomiting
• Headaches and dizziness
• Neurological problems in severe cases

The National Institutes of Health reports that cooking doesn't destroy solanine. Potatoes with extensive green areas should be discarded completely rather than attempting to salvage portions.

Proper Potato Storage: Extend Freshness by Weeks

Follow these science-backed storage methods to maximize potato shelf life:

Ideal Storage Conditions

• Temperature: 45-50°F (7-10°C) - cooler than room temperature but above refrigerator levels
• Humidity: 90-95% - maintain moisture without creating damp conditions
• Light: Complete darkness - prevents greening and sprouting
• Ventilation: Breathable containers like paper bags or wicker baskets

Avoid storing potatoes near onions, which release gases that accelerate sprouting. The USDA recommends against refrigerating potatoes as cold temperatures convert starch to sugar, affecting both taste and cooking properties.

When Slightly Imperfect Potatoes Are Still Safe

Don't waste perfectly good food over minor issues:

• Small sprouts - Remove with a knife or vegetable peeler
• Minor green spots - Cut away generously (1/4 inch deep)
• Surface blemishes - Peel away affected areas

Only discard potatoes when spoilage affects more than 25% of the vegetable or when texture/smell indicates advanced decay. The Food and Agriculture Organization estimates that proper identification of salvageable produce could reduce household food waste by 15%.

Common Potato Storage Mistakes to Avoid

These everyday errors dramatically shorten potato shelf life:

• Storing in plastic bags (traps moisture causing rot)
• Keeping in warm kitchen cabinets (accelerates sprouting)
• Washing before storage (promotes mold growth)
• Storing near heat sources like ovens or refrigerators

For best results, transfer potatoes from grocery store packaging to breathable containers immediately after purchase. Check stored potatoes weekly and remove any showing early spoilage signs to prevent contamination of healthy ones.

Can you eat potatoes with small sprouts?

Yes, potatoes with small sprouts (under ¼ inch) are safe to eat after removing the sprouts and eyes. Cut deeply around each sprout to eliminate the growth points and any potential solanine concentration.

How long do potatoes last in the pantry?

Properly stored potatoes last 2-3 months in a cool, dark pantry. Ideal conditions are 45-50°F with 90-95% humidity. Check weekly for spoilage and remove any bad potatoes immediately to prevent contamination.

Why do potatoes turn green and is it dangerous?

Potatoes turn green when exposed to light, producing chlorophyll and the toxic compound solanine. Green areas contain higher solanine levels which can cause nausea, headaches, and neurological issues. Cut away all green portions deeply or discard heavily affected potatoes.

Can you refrigerate potatoes to make them last longer?

No, refrigeration converts potato starch to sugar, affecting taste and cooking properties. Cold temperatures cause potatoes to develop sweet flavors and darken when cooked. Store potatoes in a cool, dark place instead of the refrigerator for best quality and shelf life.

What's the white liquid that sometimes comes out of cut potatoes?

The white liquid is a mixture of starch and water, perfectly normal in fresh potatoes. It indicates the potato is still moist and fresh. This sap becomes more noticeable when cutting potatoes that have been stored in humid conditions.