Rotten ginger produces safrole when it spoils, which is highly toxic. Consumption can cause degeneration and damage to liver cells, leading to toxic hepatitis. Therefore, fresh ginger should not be stored in large quantities.
Moldy beans contain saponin and hemagglutinin. After consumption, they have a strong irritant effect on the digestive tract, causing symptoms of gastroenteritis such as nausea and vomiting, and they can also dissolve red blood cells. They must be thoroughly cooked until they are dark green and have no腥味 (raw smell) before being eaten.
Green tomatoes contain toxic solanine. When eaten, it breaks down into tomatidine in the stomach, which has a bitter taste. This can cause poisoning symptoms such as nausea, vomiting, dizziness, and excessive salivation.
Seaweed turns blue after being soaked. This is because it is contaminated with toxic cyclic peptides while growing in the ocean, and consumption can easily lead to poisoning.
Silver ear fungus can be contaminated with *Flavobacterium* during cultivation or processing, turning it dark yellow or blackish-yellow with a musty smell. Consumption can easily lead to poisoning.
Pumpkins that have been stored for a long time have a very high sugar content in their flesh. Through anaerobic fermentation, this sugar produces alcohol, causing the pumpkin to spoil. Eating it can cause poisoning. When preparing, remove all the flesh; if there is an alcoholic smell, it should not be eaten.
Some people experience fever, jaundice, and anemia after eating fresh fava beans, and in severe cases, it can lead to shock and renal failure. Fava beans contain vicine and isouramil toxins, so they should not be consumed in large quantities to avoid poisoning.
Fresh wood ear fungus contains photosensitive porphyrins. After consumption, exposure to sunlight can cause solar dermatitis. It should be dried in the sun before being eaten.
Fresh daylilies contain colchicine. After consumption, it is oxidized to produce the toxic colchicine, which can cause nausea, vomiting, abdominal pain, hematuria, and bloody stools. It should be dried in the sun before being eaten.
Moldy sweet potatoes Improperly stored sweet potatoes, especially at points where they are bruised, cracked, or have broken skin, are easily contaminated by *Ceratocystis fimbriata*, causing mold and spoilage. Consumption leads to poisoning, characterized by nausea, vomiting, diarrhea, muscle tremors, dilated pupils, and in severe cases, it can be life-threatening.
Vegetables stored for too long Cabbage, radishes, and lettuce contain nitrates. If stored for too long and they begin to rot, the nitrates are converted into nitrites. Consumption can cause poisoning symptoms such as abdominal pain, diarrhea, nausea, and vomiting.
Insufficiently pickled vegetables When pickling vegetables like *Suan cai* (sauerkraut) or pickled mustard greens, if not enough salt is used, bacteria will convert the nitrates in the vegetables into nitrites. The nitrite content peaks about a week after pickling, making it easy to cause poisoning if eaten. Pickled vegetables should be left to ferment for at least a month before the container is opened and consumed.
Canned foods When meats, seafood, or fruits are canned, or when making bean paste in a crock, if they are contaminated with *Clostridium botulinum*, the bacteria will multiply rapidly under anaerobic conditions and produce exotoxins, leading to food poisoning. Symptoms include paralysis of the eye muscles, difficulty with swallowing, speaking, and breathing. Therefore, if a can is bulging (a condition known as "swell can"), it must never be eaten, as it poses a great danger to health.