Learn How to Avoid Contaminated Vegetables
I. Avoid vegetables with abnormal shapes or colors:
Shape: Vegetables with normal colors are generally conventionally cultivated and have not been treated with hormones or other chemicals, so they can be eaten with confidence. "Abnormal" vegetables may have been treated with hormones. For example, when chives have leaves that are particularly wide and thick, twice as wide as regular broad-leaf chives, they may have been treated with hormones during cultivation. Chives that have not been treated with hormones have narrower leaves and a richer aroma when eaten. Some vegetables with abnormal colors should also be noted. For instance, when the leaves of clover lose their usual green color and turn dark green, or when green soybeans are abnormally bright green, they may have been sprayed or soaked in methamidophos pesticides before harvest and should not be purchased. Some vegetables with abnormal shapes or colors, if confirmed to be new varieties, are an exception.
II. Do not eat "pest-prone" or "pesticide-heavy" vegetables:
Among the many vegetables, some are particularly favored by pests and can be called "pest-prone vegetables"; some are not very palatable to pests and can be called "pest-resistant vegetables." This is determined by the specific components and smells of the vegetables. Among pest-prone vegetables, the "famous" ones include Chinese cabbage, cabbage, head lettuce, and cauliflower. Pest-resistant vegetables include crown daisy, lettuce, celery, carrots, onions, garlic, chives, scallions, and cilantro.
Because pest-prone vegetables have many pests, they have to be frequently sprayed with pesticides for control, inevitably becoming heavily contaminated "pesticide-heavy vegetables." In daily life, you should choose pest-resistant vegetables as much as possible. However, during colder seasons, as pests hibernate for the winter, pesticide spraying stops, and it is harmless to eat small amounts of pest-prone vegetables.
III. Do not eat vegetables with heavy fertilization:
Due to the large application of chemical fertilizers, especially excessive application of nitrogen fertilizers (such as urea, ammonium sulfate, etc.), nitrate contamination in vegetables can be quite severe. Nitrates themselves are not very toxic to humans, but after entering the gastrointestinal tract with vegetables, they are reduced to nitrites. Nitrites then combine with secondary amines in the gastrointestinal tract to form nitrosamines, which are carcinogenic.
After testing market vegetables, it was found that the nitrate accumulation capacity varies among different vegetables, from strong to weak in the following order: root vegetables, tubers and corms, leafy vegetables, cabbage-type vegetables, onion and garlic-type vegetables, legumes, gourds, eggplant and fruit-type vegetables, and edible fungi. The difference in nitrate content can be as much as several dozen times. The pattern is that the contamination level of the roots, stems, and leaves (i.e., the vegetative body) of vegetables is much higher than that of the flowers, fruits, and seeds (i.e., the reproductive body), which may be a protective reaction common in the biological world. This pattern is very useful as it can guide our correct vegetable consumption, encouraging us to eat more gourds, fruits, and edible fungi, such as cucumbers, tomatoes, green soybeans, and shiitake mushrooms.
If you really like leafy vegetables, don't be too hard on yourself. Just make sure to supplement with some vitamins. Because vitamin C can block the formation of nitrosamines, it can reduce the potential danger of eating leafy vegetables.