How to Tell If Potatoes Are Bad: Simple Signs to Check Before Cooking

If you have ever wondered how to tell if potatoes are bad, you are not alone. Potatoes are one of the most versatile and commonly used foods in kitchens worldwide, but because they are a starchy vegetable, they can go bad faster than you might expect if stored incorrectly or left too long. Eating spoiled potatoes is not only unpleasant but can also be dangerous, as harmful toxins can form in potatoes that are past their prime. Knowing the signs of spoilage will help you avoid health risks, reduce food waste, and make sure the potatoes you use in your recipes are safe and delicious.

Signs Raw Potatoes Have Gone Bad

When it comes to raw potatoes, the most obvious indicators of spoilage are visible changes in appearance, texture, and smell. Fresh potatoes should be firm, smooth, and free from any major blemishes. They should smell earthy and mild, with no offensive odors. If your potatoes look or feel different, it may be time to toss them.

Sprouts and “Eyes”

One of the first signs you will notice as potatoes age is sprouting. These little growths, often called “eyes,” begin to appear on the surface of the potato. A few small sprouts do not necessarily mean the potato is unsafe, but they are an indicator that the potato is aging. You can safely cut away small sprouts and use the rest of the potato if it is otherwise firm and fresh. However, if the potato is heavily covered in sprouts, with long, thick growths, it has lost much of its nutritional value and may no longer be safe to eat. Sprouted potatoes often become softer and may taste bitter, making them less appealing.

Green Spots

Another key sign of spoilage is the appearance of green patches on the skin. These green areas are caused by chlorophyll, which forms when potatoes are exposed to light. While chlorophyll itself is harmless, the green coloration is a warning sign that the potato may contain solanine, a natural toxin. In small amounts, solanine might not make you sick, but in larger quantities it can cause nausea, headaches, and other symptoms of food poisoning. If the potato has only a few small green spots, you can peel or cut them away, but if it is covered in green patches, it is best to throw it out.

Texture Changes

Fresh potatoes should feel solid and firm when you hold them. If your potatoes feel soft, mushy, or shriveled, they are no longer fresh. Softness usually indicates that the potato has lost moisture, which affects both flavor and safety. A wrinkled or shriveled potato may not be dangerous in the earliest stages but it will not taste good and should be avoided if the texture is noticeably degraded. If the potato feels squishy, that is a clear sign that it has gone bad and should not be eaten.

Smell

The smell of a potato is one of the most reliable indicators of whether it has gone bad. Fresh potatoes have a mild, earthy aroma. If you notice a sour, musty, or moldy smell, the potato is spoiled. A foul odor often means bacteria or mold are present inside the potato, even if it looks okay on the outside. Because the smell of a rotten potato can be very strong and unpleasant, it is usually easy to identify this sign. If your potato smells bad, do not take chances—throw it out immediately.

Mold

Visible mold is an unmistakable sign that your potato has gone bad. Mold may appear as fuzzy spots in colors such as white, blue, green, or black. Sometimes mold grows on the skin, and sometimes it forms in cracks or bruised areas. Moldy potatoes are unsafe to eat, and cutting away the moldy section is not enough, as the mold can penetrate deeper into the potato than what you can see. If there is any sign of mold, the entire potato should be discarded.

Signs Cooked Potatoes Have Gone Bad

Cooked potatoes have a shorter shelf life than raw ones and can spoil quickly if not stored correctly. If you are reheating leftover potatoes or checking cooked potatoes in the fridge, you need to pay attention to smell, texture, appearance, and storage time.

Odor

Like raw potatoes, cooked potatoes should not have a bad smell. Freshly cooked potatoes smell appetizing, often enhanced by the seasonings or cooking methods you used, such as butter, garlic, or herbs. If your cooked potatoes develop a sour, rancid, or unpleasant odor, they are spoiled. This change usually happens because of bacterial growth after sitting too long in the fridge or being stored at the wrong temperature.

Texture

Cooked potatoes should maintain their intended texture—whether mashed, roasted, or boiled. Spoiled potatoes often develop a slimy or mushy texture. They may also feel unusually dry, grainy, or crumbly if they have been sitting in the fridge for too long. Sliminess is a particularly strong sign of bacterial contamination and is a clear indicator that the potatoes should not be eaten.

Appearance

Visual changes can also alert you that cooked potatoes have gone bad. If you see mold on the surface, whether in fuzzy patches or discolored spots, the potatoes are no longer safe to eat. Discoloration, such as dark spots, streaks, or a film on the surface, can also signal spoilage. Potatoes that look significantly different from when you first cooked them should be discarded.

Storage Time

Even if your cooked potatoes look and smell fine, storage time is a crucial factor. Cooked potatoes stored in the refrigerator should be eaten within three to five days. Beyond that window, the risk of bacterial growth increases significantly, even if spoilage is not immediately visible. If you cannot remember when you cooked them, it is safest to assume they are no longer good.

How to Store Potatoes to Keep Them Fresh Longer

Proper storage can extend the shelf life of your potatoes and help you avoid spoilage in the first place. Whether raw or cooked, handling potatoes correctly will keep them fresher and safer for longer periods.

Storing Raw Potatoes

Raw potatoes should be kept in a cool, dark, and well-ventilated place. The best temperature for storing raw potatoes is between 45°F and 55°F (7°C to 13°C). A pantry, cellar, or cupboard away from direct light and heat sources is ideal. Exposure to light can cause potatoes to turn green and produce solanine, while warm temperatures speed up sprouting and spoilage.

It is important not to refrigerate raw potatoes. Storing them in the fridge can cause the starches in the potatoes to convert into sugars, which changes their flavor and makes them too sweet. It can also affect how they cook, especially when frying, leading to undesirable browning. Instead, focus on keeping them in a breathable container, such as a paper bag or basket, to allow airflow. Avoid plastic bags, which trap moisture and encourage mold growth.

Check your stored potatoes regularly and remove any that show early signs of sprouting or softening to prevent them from affecting the rest. Potatoes stored properly can last several weeks, and in some cases even up to two months.

Storing Cooked Potatoes

Cooked potatoes need to be stored differently. Always place cooked potatoes in airtight containers before refrigerating. This prevents bacteria from spreading and helps retain moisture and flavor. Store them at 40°F (4°C) or lower, and eat them within three to five days.

If you want to keep cooked potatoes for longer, freezing is an option. While whole cooked potatoes may not freeze well because they can become watery and grainy when thawed, mashed or partially cooked potatoes freeze much better. Place them in airtight containers or freezer bags, label them with the date, and store for up to two or three months. When reheating, ensure they are thoroughly warmed to kill any potential bacteria.

Extra Tips for Storage

Keep potatoes away from onions when storing. Onions release gases that can cause potatoes to spoil faster. Also, handle potatoes gently to avoid bruising, as damaged potatoes spoil more quickly. If you buy potatoes in bulk, rotate them so that older potatoes are used first.