Recent reports have indicated that pesticide residues in leafy vegetables are higher than in other root and fruit vegetables, making pesticide residues in produce a topic of concern for consumers again. So, is it unsafe to eat leafy vegetables? How can we eat them more safely? Pesticide residues are higher in leafy vegetables.
The nutritional value of leafy vegetables cannot be replaced by that of root and other vegetables, but do leafy vegetables have more pesticide residues than other vegetables?
"Generally, that's the case," said Professor Sun Zhiqiang, director of the Horticulture Department at Henan Agricultural University, confirming this statement. This is mainly due to several factors: first, pesticides are generally applied to leaves to prevent pests and diseases, and it takes time for them to transfer to the fruit; second, leafy vegetables in summer are more prone to attracting pests, requiring more pesticide use; and finally, leafy vegetables grow fast, usually reaching the market in over 20 days, so the interval after pesticide application is short, and there isn't enough time for much pesticide to decompose.
Professor Feng Shuangqing from the College of Food Science at China Agricultural University pointed out that the "specific surface area" (the area of an object of the same weight) of leafy vegetables is much larger than that of fruit vegetables. Therefore, relatively speaking, there will be more pesticide residues. For fruit vegetables, the skin can be peeled off, and root vegetables are more durable in storage, allowing more pesticides to decompose. These are all factors that cause relatively higher residues in leafy vegetables. However, she also noted that this is not an absolute rule, because pesticide residues are related not only to the contact area but also to the plant structure and pesticide type. Contact pesticides have a greater impact on leafy vegetables, but systemic and mixed pesticides have an equal impact on fruit vegetables.
Sun Zhiqiang said that because systemic pesticides are more harmful to the human body and are not easily removed, they are rarely used in our province now. The most commonly used are contact pesticides. Vegetables with special odors have fewer pests
Some vegetables with special odors have fewer pests and diseases, requiring less pesticide use. Sun Zhiqiang gave examples, such as common coriander, celery, fennel, and water spinach, which have fewer pests and diseases. However, cruciferous vegetables have more pests and diseases, such as common bok choy and Shanghai Qing, which belong to this category. In addition, among fruit vegetables, beans have more pests and diseases. Vegetables like potatoes, lotus roots, and taro generally have few pests.
So, should we be afraid to eat green vegetables? "Currently, market monitoring requires vegetables to be sold 7 days after pesticide application. Coupled with the use of efficient, low-toxicity, low-residue pesticides, the qualification rate for pesticide residues in vegetables is now quite high. The so-called 'more residues' is only relative," Sun Zhiqiang believes there is no need to worry too much. Soaking in rice washing water can remove pesticides
However, besides market monitoring, consumers have no way of knowing if the vegetables they bought have gone through a sufficient interval period. So, how can we make the vegetables on our table safer?
Feng Shuangqing told consumers two methods.
The first method is to rinse with running water, washing it several times.
The second method is to soak in rice washing water for a period of time, because most pesticides are acidic, while rice washing water is alkaline and can remove pesticides. However, the entire vegetable must be washed; do not cut it before washing.
Sun Zhiqiang also gave his own advice: rinse with clean water. He introduced, "Currently, most pesticides are water-soluble. We have specially conducted experiments on this. Rinsing with clean water two or three times can remove more than 80% of the surface pesticide residues. Soaking for 10 to 20 minutes makes little difference, and the effect is similar to that of washing." There is an art to buying vegetables □ Chen Jinping
Pest-prone vegetables: Vegetables that are easily "favored" by pests are called pest-prone vegetables, such as green vegetables, cabbage, cabbage, and cauliflower.
Less-pest vegetables: Some vegetables that pests are not very fond of are called less-pest vegetables, such as crown daisy, lettuce, celery, carrots, onions, garlic, chives, green onions, and coriander. This is determined by the specificity of different components and odors of vegetables.
Due to the large application amount of chemical fertilizers, especially excessive application of nitrogen fertilizers (such as urea, ammonium sulfate, etc.), it can cause nitrate pollution in vegetables.
The ranking of nitrate content from strong to weak is: root vegetables, tuber and root vegetables, leafy vegetables, cabbage vegetables, onion and garlic vegetables, legume vegetables, gourd vegetables, eggplant and fruit vegetables, and edible fungi. The difference in nitrate content among them can be up to 10 times. The pattern is that the pollution level of the roots, stems, and leaves of vegetables is much higher than that of the flowers, fruits, and seeds.