How should fruits and vegetables be washed to remove pesticide residues thoroughly?
Today's vegetables and fruits are all sprayed with pesticides, and pesticide residues are also very serious, so how should we wash them to minimize pesticide residues?
Excessive nitrogen fertilizer on fruits and vegetables - beware of cancer. Although eating fruits and vegetables is good for health, when nitrogen fertilizer is used excessively, the nitrate present in leafy vegetables can trigger diseases such as esophageal cancer, gastrointestinal cancer and liver cancer. Zheng Zhengyong, a professor in the Department of Horticulture at National Taiwan University, points out that without nitrogen fertilizer, crops would not grow, but any nitrogen-containing organic matter or chemical fertilizer in the soil will first be decomposed and oxidized into nitrate ions of smaller molecular weight, which ordinary people often call nitrate ions or nitrates. If animals eat plants containing too much nitrate, it may cause poisoning of varying severity; the most notable example is that infants, after ingesting large amounts of nitrate, develop "blue baby syndrome," which can cause breathing difficulties in babies and even suffocation.
Because countries around the world have gradually set regulations for the nitrate content of vegetables, but the standards set differ depending on the zone in which each country is located or the length of day and night; for example, European countries require only 1,500 to 2,000 ppm for most vegetables, but recently the regulations made by the mainland are more stringent, setting most vegetables at below 450 ppm, which is a very high standard. However, Taiwan, China, has so far still not paid attention to this problem. In winter, the nitrate content of some vegetables is even as high as 3,000 to 4,000 ppm.
Developed countries have successively regulated the concentration of nitrate in vegetables to protect consumers. For example, Germany stipulates that the nitrate content in spinach intended for infant consumption must not exceed 250 ppm. The safe dose published by the World Health Organization (WHO) is based on an intake of 3.65 milligrams per kilogram of body weight per day, that is, a person weighing 60 kilograms can consume about 220 milligrams of nitrate per day. Therefore, if calculated on the basis of eating half a jin (300 grams) of vegetables per day, the nitrate content in the vegetables must not exceed 670 ppm; if eating 400 grams, the content should be below 500 ppm.
Peng Wangjiakang, an academician of Academia Sinica and also director of the National Cancer Research Group, believes that in the past our country did not set regulations for nitrate in leafy vegetables, mainly because most farmers still used animal manure as fertilizer and rarely used chemical fertilizers. In recent years, the use of chemical nitrogen fertilizer has become more common; however, the cancer risk of nitrate may occur only after long-term accumulation, so she does not recommend that children eat vegetarian, because the risk for children eating vegetarian is relatively higher, and the nutrients needed for growth will also be insufficient as a result.
Principles for washing vegetables
