In recent years, incidents of acute poisoning from consuming contaminated vegetables due to pesticide residues have occurred repeatedly. Therefore, eating vegetables also requires an environmental awareness. As consumers, one should learn to avoid contamination to prevent illness from entering through the mouth.
1. Do not eat vegetables with abnormal shapes or colors
Shape: Vegetables with normal shapes and 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, with chives, if the leaves are particularly wide and thick, twice as wide as regular broad-leaf chives, they may have been treated with hormones during cultivation. Untreated chive leaves are narrower and have a rich aroma when eaten. Some vegetables with abnormal colors should also be noted. For instance, if the leaves of alfalfa lose their usual green color and turn dark green, or if the green soybeans are abnormally vibrant, they may have been sprayed or soaked in methamidophos pesticides before harvesting and should not be purchased. However, if some vegetables with abnormal shapes or colors are confirmed to be new varieties, the rule does not apply.
2. Do not eat "pest-prone" or "high-pesticide" vegetables
Among the many vegetables, some are particularly favored by pests and can be called "pest-prone vegetables"; some pests are less fond of eating and can be called "pest-resistant vegetables." This is determined by the specific components and smells of the vegetables. Famous "pest-prone" vegetables include bok choy, Chinese cabbage, cabbage, and cauliflower. "Pest-resistant" vegetables include crown daisy, lettuce, celery, carrots, onions, garlic, chives, scallions, and cilantro.
Due to the high number of pests, "pest-prone" vegetables require frequent pesticide spraying, inevitably becoming heavily contaminated "high-pesticide" vegetables. One should generally choose "pest-resistant" vegetables as much as possible. However, during colder seasons, as pests hibernate for the winter, pesticide spraying stops, and it is then safe to eat small amounts of "pest-prone" vegetables.
3. Do not eat vegetables with heavy fertilization
Due to the large application of chemical fertilizers, especially an excessive amount of nitrogen fertilizers (such as urea, ammonium sulfate, etc.), nitrate contamination in vegetables can be quite severe. Nitrates themselves are not highly toxic, but after entering the gastrointestinal tract with vegetables, they are reduced into nitrites. Nitrites then combine with secondary amines in the gastrointestinal tract to form nitrosamines, which are carcinogenic.
Tests on market vegetables have shown that the nitrate levels vary among different vegetables, ranging from strong to weak in the following order: root vegetables, tuber and bulb vegetables, leafy vegetables, cabbage-family vegetables, onion and garlic vegetables, legumes, gourds, eggplant and fruit vegetables, and mushrooms. 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 far higher than that of the flowers, fruits, and seeds (i.e., the reproductive body), which may be a common protective reaction in the biological world. This pattern is very useful as it can guide our correct vegetable consumption. We should eat more gourds, fruits, and mushrooms, such as cucumbers, tomatoes, green soybeans, and shiitake mushrooms.
If you are very fond of leafy vegetables, you don't have to deprive yourself. Just be 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.