Potatoes contain sugars that create an environment where mold can grow. This means that you shouldn't eat raw potatoes even if they have been frozen (although you might get away with some exceptions).
It's safe to say that if your potatoes growing any amount of mold, they're no longer safe to eat. (And no, you can't just cut the mold off, because the tiny invisible spores could already be growing elsewhere in the tuber.)
If there's mold growing on it, or if the appearance of the dish has changed significantly, you should throw it away. Mold on food looks like dark spots or fuzz growing on the dish. It can be brown, red, white, black, or blue-gray in color.
It is okay to cut mold off of hard cheeses and hard fruits or vegetables like apples, potatoes, onions or cauliflower. Just be sure to cut away at least 1 inch as surface mold is more than what you see. It actually has hyphae or roots which can penetrate deeper into the food.
Black spots in potatoes are mostly attributed to internal bruises or the result of sugar concentrations brought on by any of several pre or post-harvest conditions and are generally harmless.
What causes black spots in a potato? Black spots are usually bruises which are caused by rough handling. One type of bruising happens when the skin is broken. The potato forms a thicker layer of skin to protect and heal the wound.
This process, which is called oxidation, happens because potatoes are a naturally starchy vegetable. And when exposed to oxygen, starches turn gray, brown, or even black. An oxidized potato is completely safe to eat. The process doesn't affect the flavor or texture of the vegetable.
Small, bumpy, irregular black lesions that look like dark soil on potato tuber skin are the classic sign of this fungal disease. Caused by the fungus rhizoctonia, black scurf generally occurs near the end of the growing season. Black scurf lesions do not wash off, but can be scraped off with a fingernail.
Black mold is a fungus that grows in warm, damp areas. Its spores may mistakenly trigger an allergic reaction in your immune system. An allergic reaction to black mold may cause various symptoms, including coughing, sneezing, congestion and irritated eyes. However, it rarely makes people very sick.
White mold of potatoes is caused by the fungus Sclerotinia sclerotiorum (Lib.) de Bary. (See life cycle chart). This fungus has a very wide host range. The fungus produces white and fluffy mycelium and also produces hard, black, irregularly shaped sclerotia.
Rotting potatoes give off a noxious solanine gas that can make a person unconscious if they've inhaled enough. There have even been cases of people dying in their root cellars due to unbeknownst rotting potatoes.
Raw potatoes will typically stay fresh for at room temperature for 1-2 weeks, or refrigerated for 2-3 months.
Dirt protects the potatoes from premature spoiling, and storing moist potatoes could lead to mold. Store potatoes in cool but not cold temperatures; between 45°F and 55°F is ideal. Store them too cold (i.e., your fridge) and the starches will turn to sugar, affecting taste and texture.
Potatoes are 80 percent water, so softness is usually just a sign of dehydration. But if they're extremely mushy or shriveled, do not pass go. Likewise, small sprouts can be removed with a vegetable peeler or knife. Long or large sprouts are a sign that the potato is probably past its prime and should be tossed.
Do You Have To Throw Out All Potatoes If One Is Moldy? No, you do not have to throw out all potatoes if one is moldy. If you spot mold [2] on one of your potatoes, you can cut off the affected area and the area around it, making sure to throw away the affected pieces.
Toxic mold can also have a grayish, soot-like texture, or a slimy, wet surface. In some cases, you may even notice furry orange or brown spots. If you find mold with any of these qualities in your home, don't get too close, and call a professional right away.
“However, some molds can cause allergic reactions and respiratory problems. Other molds can produce poisonous toxins and make you sick.” If you do eat moldy food and feel ill or short of breath, see a doctor immediately.
Symptoms of soft rot include soft, wet, rotted, tan or cream-colored tissues. Rot begins on the tuber surface and progresses inward. Infected tissues are sharply delineated from healthy tissue by dark brown or black margins. Shallow necrotic spots on the tubers result from infections through lenticels.
If potatoes turn black, it usually doesn't occur when they are in the freezer but more likely once they have been defrosted. The reason potatoes turn black is due to their exposure to oxygen.
raw potatoes can't be frozen. There is an enzyme reaction that has to take place to keep the potatoes from turning black.
However, If you do store raw potatoes in the freezer, they may last up to 10 to 12 months (more on storing potatoes later). To avoid a sweeter flavor and discoloration, blanch potatoes before refrigerating or freezing.
The spots look unsightly, but have no effect on the inside flesh of the tuber. The potato is edible and the spots can be easily peeled off before cooking.
Black scurf is a fungal disease producing hard, black growths on the surface of tubers that can be rubbed off. Although unsightly it is not destructive, but infected seed potatoes can lead to plants with stem cankers.