You cannot eat potatoes if their skin turns blue. Because during storage, if potatoes are exposed to light for a long time, chlorophyll will be produced on the surface and they will sprout. Then the chlorophyll part will produce a large amount of solanine. Green potatoes obviously have more chlorophyll and solanine.

For humans, solanine is corrosive and has an irritating effect on the human gastrointestinal mucosa. If poisoned, symptoms such as nausea, vomiting, abdominal pain, and diarrhea will occur. In addition, solanine has a strong inhibitory effect on the cholinesterase activity of the central nervous system. If it is severely poisoned, convulsions, shock, coma and difficulty breathing will occur.

Of course, fresh potatoes are edible. In 2007, the "Risk Assessment Study - Natural Toxins in Edible Plants" released by the Hong Kong Center for Food Safety conducted a survey on fresh potatoes and found that different amounts of dragon were detected in samples of different varieties of fresh potatoes on the market. The content of solanine in potato meat ranges from 26 to 88 mg per kilogram (average 56 mg per kilogram). The content of solanine in potato meat is less than 10 mg per kilogram, while the content in potato skins ranges from 90 to 400 mg per kilogram. Even if eaten every day There will be no problem.

: Solanine is a toxic substance in potatoes, also called potato toxin (also found in eggplants and unripe tomatoes). It is a toxic glycoalkaloid. It is soluble in water, corrosive and hemolytic, but can be decomposed and destroyed when heated with acetic acid. Generally, every 100 grams of potatoes contains only about 10 mg of solanine, which does not cause poisoning. The content of solanine in immature potatoes or potatoes that have turned green and sprouted due to exposure to sunlight during storage can be as high as 500 mg per 100 grams. If such potatoes are eaten in large quantities, it may cause acute poisoning.