Some vegetables naturally contain harmful substances, and if they are not cooked through, the toxins may not be removed, and eating them can make you ill. A reminder: the following vegetables must be cooked through before eating!

1. Green beans

Harmful substance: saponin

Cause of illness: If green beans are not cooked through, the saponin in the beans strongly irritates the digestive tract, and the beans also contain phytohemagglutinin, which has a blood-clotting effect. In addition, green beans also contain nitrite and trypsin, which can irritate the human stomach and intestines, causing food poisoning and symptoms of gastroenteritis.

Detox method: To prevent green bean poisoning, the green beans must be cooked thoroughly and cooked through.

2. Wood ear mushroom

Harmful toxin: porphyrin-type photosensitizing substances

Cause of illness: Fresh wood ear mushroom contains porphyrin-type photosensitizing substances. After eating fresh wood ear mushroom raw, it can cause photodermatitis, and in severe cases, skin itching, edema and pain.

Detox method: Do not eat fresh wood ear mushroom; if you do eat it, it must be cooked through and thoroughly cooked.

3. Cassava

4. Wild rice stem

Harmful toxin: oxalic acid

Cause of illness: Vegetables that contain relatively high amounts of oxalic acid, such as spinach, bamboo shoots and wild rice stem, should first be blanched in boiling water even if they are to be served as a cold dish, to remove most of the oxalic acid they contain. In the intestines, oxalic acid combines with calcium to form hard-to-absorb calcium oxalate, interfering with the body's absorption of calcium and leading to calcium deficiency.

Detox method: It must be blanched in boiling water.

5. Spinach

6. Broad beans

Harmful toxin: vicine

Cause of illness: Broad bean seeds contain vicine. After people consume this substance, it can cause acute hemolytic anemia (favism). When eating fresh broad beans in spring and summer, improper cooking often causes poisoning. Onset generally occurs 4 to 24 hours after eating raw broad beans.

Detox method: To prevent broad bean poisoning, it is best not to eat fresh tender broad beans, and they must be cooked through before eating.

7. Fresh daylily buds

8. Purslane

Harmful cause: dust and small insects

Cause of illness: Wild vegetables such as purslane contain dust and small insects, which can cause allergies. In addition, before eating lettuce, water chestnut and similar foods raw, it is best to first peel and wash them and blanch them in boiling water, which is more hygienic and will not affect the taste or nutrient content.

Detox method: Before eating purslane, first blanch it in boiling water. Before eating lettuce, water chestnut and similar foods raw, it is also best to first peel and wash them and blanch them in boiling water.

9. Shepherd's purse

Harmful toxin: nitrite

Cause of illness: Certain substances contained in wild vegetables such as shepherd's purse and goosefoot may be converted into nitrite during cooking. If the human body takes in too much, poisoning is possible.

Detox method: Cook through before eating, and do not eat leftovers from the previous day.

These foods also cannot be eaten!

1. Sprouted potatoes

The young sprouts and the green parts of the skin of sprouted potatoes contain very high levels of solanine. It irritates the mucous membrane of the human stomach and intestines and also has a hemolytic effect and can paralyze the respiratory center. The levels are even higher in the bud eyes, bud roots and green parts of sprouted potatoes. After eating them, people may experience symptoms such as itchy throat, nausea, vomiting and abdominal pain, and in severe cases may die.

2. Rotten ginger

During the rotting process, ginger can produce a highly toxic organic compound called safrole, and safrole can cause degeneration of liver cells. If people eat this toxin, even in very small amounts, it can cause poisoning and degeneration of liver cells.

3. Green tomatoes

Unripe green tomatoes contain solanine, which is a toxic substance. Eating these unripe green tomatoes gives the mouth a bitter and astringent sensation, and after eating them symptoms of poisoning such as nausea and vomiting may appear. Eating them raw is even more dangerous, and if a pregnant woman eats them, it can also harm the fetus.

4. Sweet potatoes with spots

Spots on sweet potatoes are caused by contamination with black spot fungus, which makes dark brown patches appear on the surface, causing the sweet potato to become hard and bitter. This toxin cannot be destroyed even by boiling, steaming or roasting. Therefore, whether eaten raw or cooked, sweet potatoes with black spot disease may cause poisoning.

5. Old pumpkin stored for a long time

It has a high sugar content, and because it has been stored for too long, the flesh is prone to anaerobic alcoholic fermentation, and the quality of the pumpkin changes, making it unhealthy to eat.

6. Discolored nori

If nori after soaking in cold water appears blue-purple, it means the nori was contaminated by toxic substances before drying and packaging. This kind of nori is harmful to the human body and cannot be eaten.

7. Pickles not fully cured

If not enough salt is added when making pickles and the curing time is less than 8 days, it may cause nitrite poisoning.

8. Bean sprouts that are too fat and large

Bean sprouts grown with chemical fertilizer are all white and plump, clearly different from ordinary bean sprouts. A large amount of residual ammonia remains in them, and under the action of bacteria it produces nitrosamines. Eating a large amount can cause dizziness, nausea and vomiting.