Washing: chlorine in tap water can remove some pesticide residues. Generally, vegetables are washed with clean water for at least 3 to 6 times, and then soaked in salt water before washing. For cabbage vegetables, you can cut them first, soak them in clean water 1 to 2 hours, and then rinse them with clean water to remove residual pesticides. Generally, after washing with clear water, the residual pesticides in vegetables can be removed by 40%, and tomatoes can be removed by more than 90%. However, water washing can only wash off ordinary water-soluble pesticides on the surface of vegetables, and at least two of them can't be washed off. One is acidic pesticide, which will react with vegetables and stick to the surface of vegetables tightly. There is also a certain permeability that can penetrate into the cells of vegetables. This kind of thing can't be washed off under any circumstances.
Alkali washing: first put a spoonful of alkali powder (anhydrous sodium carbonate) or ice alkali (crystalline sodium carbonate) into water and stir evenly, then add vegetables. Soak for 5-6 minutes, pour out alkaline water, and then rinse with clear water. If there is no alkali powder or ice alkali, baking soda can be used instead, but it usually takes about 15 minutes, and the soaking time is appropriately extended.
Cleaning with detergent: dilute with detergent 300 times, wash once, and then rinse with clean water 1-2 times to remove germs, eggs and residual pesticides on vegetables.
Boiling water: The best way to remove some residual pesticides is scalding, such as green pepper, cauliflower, beans and celery. It's best to scald it with boiling water before frying or burning it in a pot. After testing, it can remove more than 90% of residual pesticides. But if the detergent is not cleaned, it will be harmful
Sunlight exposure: Using the multi-spectral effect in sunlight, some residual pesticides in vegetables will be decomposed and destroyed. In this way, there is less pesticide residue in dried vegetables. According to the measurement, the residual loss of organochlorine and organomercury pesticides reached 60% when fresh vegetables and fruits were irradiated in the sun for 5 minutes. For vegetables that are convenient to store, it is best to leave them for a while. Oxygen in the air and chromozyme in vegetables have a certain decomposition effect on residual pesticides. After buying vegetables and leaving them at room temperature for about 24 hours, the average disappearance rate of residual chemical pesticides is 5%.
In addition, washing vegetables with rice washing water can remove some pesticides left on vegetables. At present, most organophosphorus pesticides used in China are methamidophos, phoxim, dichlorvos, dimethoate and so on. These pesticides will lose their toxicity when they encounter acidic substances. Soaking in rice washing water for about 10 minute and rinsing with clear water can reduce the residual pesticide components in vegetables.
In addition, the "fruit and vegetable cleaning ozone machine" launched in the market a few days ago can only remove pesticides on the surface of fruits and vegetables, and its cleaning power is no different from washing. Some fruits and vegetables contain nitrogen, which will react with ozone to produce nitrate or nitrite, which is toxic and carcinogenic.