how do you know when a potato is bad

Sprouting is a natural part of a potato’s life cycle, and it is common to see in your pantry. However, this still leaves the question of whether they are safe to consume. So, can you eat sprouted potatoes? You can eat sprouted potatoes if you remove the sprouts and any green skin or flesh. The sprouts and green parts of a potato contain solanine, which is a toxic glycoalkaloid that can make you sick if you eat too much of it. You should also avoid potatoes that are soft, wrinkled, moldy, or black. Of course, there is another option for a sprouted potato. You can plant it and try to grow a new plant to produce more tubers! In this article, we’ll talk about sprouted potatoes and when they are safe to eat. We’ll also look at some other potential food safety hazards when it comes to potatoes. Let’s get going. Can You Eat Sprouted Potatoes? You can eat sprouted potatoes, but first you need to get rid of the hazardous parts, such as: Sprouts (sprouted eyes that grow out of the tuber) Green Skin Green Flesh You can eat a sprouted potato, but you need to get rid of the toxic parts first, including the sprouts & any green skin or flesh. Use a clean knife to cut out the sprouts until you can see the potato flesh underneath. It might not be enough to just cut away the outside part of the sprout, so dig in to the flesh deep enough to be sure that you have removed the entire sprout. The North Carolina State University also suggests removing any soft spots that may have formed in the skin and flesh at the base of the sprout. If you see any green skin, cut that part away, and go deep enough to remove any green flesh as well. If it goes too deep, you may want to dispose of the potato instead (you can still put it in your compost pile so it doesn’t go completely to waste). Green skin or flesh on a potato indicates that it may contain chlorophyll and the toxic substance solanine.Image courtesy of user:Anicius Olybriusvia:Wikimedia Commons: https://commons.wikimedia.org/wiki/File:Evil_green_potato.jpg Potato tubers turn green when exposed to sunlight due to the production of chlorophyll. However, this is not what makes them dangerous! Potatoes that are exposed to sunlight can also produce the toxic substance solanine in large amounts. Solanine is a glycoalkaloid found in potatoes that can poison you in large amounts (since it is a neurotoxin). Solanine is found in higher concentrations in the sprouts and green skin or flesh of a potato. According to Mother Earth News, green potatoes contain 20 times as much solanine as potatoes that are not green. Of course, solanine is found in the leaves and stalks (stems) of a potato plant. These parts are also toxic to us and should never be eaten. (There are other toxic parts of a potato plant besides the stem and leaves - you can learn more here). The stems and leaves of a potato plant are also toxic, since they contain solanine. According to the Texas A&M University Extension, sun exposure often happens after a rainfall washes away the soil covering potato tubers. This can happen even if you used hilling for your potatoes during the season. According to the Iowa State University Extension, a potato that contains solanine will have a bitter taste. In that case, you should throw it away, even if you cut away all of the green parts and cooked it thoroughly. The reason is that chlorophyll and solanine can occur together or separately. So, you can get potatoes that are green but not toxic, and you get potatoes that look fine but taste bitter and are toxic. However, the two are often produced together. The table below summarizes what to do with various types of potatoes (sprouted, green, and soft or wrinkled). PotatoAppearanceAction To TakeFirm with no green skin or flesh & no sprouts.Should be OKto cook & eat, but check for bitterness.Firm with no green skin or flesh, but sprouted.Cut out the sprouts. Then cook as usual.Soft flesh.Throw away or compost.Skin or flesh is green.Cut out green skin & flesh, cut out sprouts, cook as usual.This table summarizes what to do with various types of potatoes. What Happens If You Eat Sprouted Potatoes? If you eat enough sprouted potatoes (or too much green skin or flesh), you will suffer from solanine poisoning. Depending on the amount ingested, solanine poisoning can cause the following symptoms: Vomiting Diarrhea Headaches Paralysis Coma Death Potatoes that contain large amounts of solanine will taste bitter, and they may burn your throat. This is true even after cooking them. Eating sprouted or green potatoes can make you sick due to the high solanine content. Cut out the bad parts, throw them away, or compost them, but don't give them to animals. If your potatoes taste bitter after cooking, throw them away (don’t give them to animals, since they may also suffer the same solanine poisoning!) Can You Cook Potatoes With Eyes? You can cook potatoes with eyes if they have not started sprouting. The eyes, or buds, are the spots on the potato where sprouts will emerge after that potato goes through a period of dormancy. You can usually tell where a potato eye is by a small indent in the skin. You can cook potatoes with eyes, since they don't contain as much solanine as sprouts or green flesh. These eyes may contain some toxic substances (such as solanine). However, they won’t contain much compared to the sprouts and green skin or flesh of a potato tuber. If you want to be extra careful, you can use a knife to remove any small sprouts you see by digging into the potato flesh. You can also just peel away the skin and remove the eyes at the same time. Is Solanine Destroyed By Cooking? Solanine is not destroyed by cooking. According to Cornell University, solanine and other glycoalkaloids are not removed or broken down when potatoes are cooked or dried at high temperatures. http://poisonousplants.ansci.cornell.edu/toxicagents/steroid.html So, don’t try to cook green potatoes (or potatoes with sprouts) to make them safe to eat. As mentioned earlier, remove the sprouts and any green skin or flesh before cooking your potatoes. How Do You Know When A Potato Is Bad? According to Healthline, you will know that a potato is bad when you see the following: Black Spots Soft, Mushy Flesh Wrinkled Skin Moldy Appearance or Odor If left to sprout for too long, potatoes will eventually get wrinkled due to the loss of water and energy. They also suggest eating any cooked potatoes within 4 days (and refrigerating them right after cooking). You can learn more about why potatoes turn black in my article here. Are Soft Wrinkled Potatoes Still Good? Soft wrinkled potatoes may contain elevated levels of the toxin solanine, especially if they have begun sprouting. As a potato sprout forms and grows, it draws energy (carbohydrates) and water from the flesh of the tuber. This causes the potato to become soft and wrinkled over time. Even if it doesn’t contain solanine, a soft and wrinkled potato will not have a great texture for eating, even after you cook it. So, avoid eating soft and wrinkled potatoes – just throw them away or compost them and avoid the doubt. How To Prevent Potatoes From Sprouting If you want to prevent potatoes from sprouting, store them at cool temperatures. The University of Maine suggests storing seed potatoes at 38 degrees Fahrenheit (3 degrees Celsius) to prevent sprouting. Avoid freezing potatoes, since this will damage them and reduce the quality. It will also prevent them from sprouting if you want to plant them to produce a new crop. Remember that potatoes will dry out and wither or wrinkle when stored in a place with low humidity. In fact, the University of Maryland Extension suggests storing potatoes at 90% relative humidity. Remember that store-bought potatoes are often treated with a sprout inhibitor (clorproham). However, if you buy organic potatoes from a farmer’s market, they may not be treated, which can cause them to sprout faster. Store bought potatoes are often treated with the sprout inhibitor clorproham. Untreated potatoes will sprout faster. You can learn more about why potatoes sprout (and how to prevent it) in my article here. What To Do With Potatoes That Have Sprouted Maybe you don’t want to cut away the sprouts and green parts of the tuber to eat the good parts, or maybe you just don’t want to risk it. Either way, you still have other options for your sprouted potatoes. Can You Compost Sprouted Potatoes? You can compost sprouted potatoes and they will break down eventually. Give it enough time and nature will turn them into nutrients for next year’s garden. You can put sprouted potatoes in a hot compost pile, but they may start to grow in a cool pile. However, there are some things to remember. First, be sure to put the sprouted in hot compost. If you bury sprouted potatoes in cool compost, they just might take root and start to grow. Eventually, they will break ground and start using up the nutrients in the pile! This might be good for the potato plants, but it’s not so good for your other plants that were hoping to get some nutrients from the compost! The other caution is related to the spread of disease in your garden. If you suspect that your potatoes have any kind of disease (such as late blight), avoid putting them in the compost pile. Not only can a disease like late blight spread to other potato plants, but it can also spread to relatives in the nightshade family, including tomatoes. You can learn about blight (and how to prevent it) in my article here. Can You Plant Sprouted Potatoes? You can plant sprouted potatoes in the garden or in a container to get new plants. These plants will eventually produce their own potato tubers that you can dig up, store, and eat or replant the following year. You can plant sprouted potatoes in a container or in the ground to grow new plants and tubers. If you want to encourage potatoes to sprout for planting, put them at room temperature (around 70 degrees Fahrenheit or 21 degrees Celsius) for 2 weeks before planting. You should plant sprouted potatoes no earlier than 3 weeks before the last spring frost date. You can find the last spring frost date for your area with this tool from the Old Farmer’s Almanac. You can learn more about how to plant sprouted potatoes in my article here. Conclusion Now you know what to do with sprouted potatoes before you eat them (or if you decide to plant them instead). You also know what other potential problems to look for in deciding whether a potato is safe to eat. I hope you found this article helpful. If so, please share it with someone who can use the information. You can learn about which potatoes are best for long term storage here. If you want to read some of my most popular posts, check out the “Best of GreenUpSide” page here. Enjoy! ~Jonathon