Can fruits and vegetables soaked in vinegar remove Pesticide residues

Recently, a method of washing fruit with vinegar has been circulated on the Internet, which makes people "shine in front of their eyes". The method said: "the Chemical Engineering Department of Kaohsiung Gaogong (Kaohsiung Advanced Industrial Vocational School) found that three drops of common white vinegar into the water and two minutes of pickled cauliflower could remove the pesticides. This method is also suitable for fruits such as strawberries. " Is this method really effective?

For acid pesticides, the effect is not good.

Our reporter found that the news spread not only on Wechat and Weibo, but also in Taiwan through instant messaging tools.

According to local media reports in Taiwan, many people have verified the authenticity of Kaohsiung Advanced Industrial Vocational School through various channels. The school responded: "washing vegetables with vinegar does not remove all pesticides." Only pesticides with amino and base structures can be removed by vinegar. " It can be seen that vinegar can dissolve some pesticides, but not all pesticides. Therefore, vinegar is by no means an omnipotent fruit and vegetable cleaner.

In principle, the method of washing fruit with vinegar uses the principle of acid-base neutralization. Some pesticides are acidic, some pesticides are alkaline, in which alkaline pesticides can interact with acid to achieve the role of cleaning pesticides. But for acidic pesticides, the effect of vinegar is not good.

Organophosphorus pesticides and organochlorine pesticides are commonly used in China. The former is mostly water-soluble, clear water can be washed off directly; the latter is fat-soluble, not easy to dissolve in water, even if soaked in white vinegar, it is also difficult to remove. "for common pesticide residues, it may be better to soak with baking soda." Said Zhu Yi, an associate professor at the School of Food Science and Nutrition Engineering at China Agricultural University.

Secondary chemical residues, which have not been completely resolved

In addition to vinegar and baking soda, cleaning methods such as salt water and rice washing water are also circulating on the Internet. Experts said that these methods have their own advantages and disadvantages, "one trick fresh" can not "eat all over the sky", should be based on the types of fruits and vegetables to choose specific cleaning methods.

In fact, there is another perspective to judge the effect of removing pesticide residues. Pesticide residues in fruits and vegetables are usually divided into two categories: one is adhesion, pesticide residues are only attached to the surface of fruits and vegetables, and the other is internal absorption, pesticide residues infiltrate into fruits and vegetables. By rinsing water or detergent for tens of seconds, accompanied by rubbing action, most of the adhesive residues can be removed. The latter can only be partially removed by peeling, heating and so on.

It should also be noted that there is a secondary chemical residue problem that has not been completely solved by using special fruit and vegetable cleaning agents. On September 22 this year, China's "Food Safety National Standard detergents" will be implemented. This more stringent new standard classifies detergents into category a, which is directly used to clean food, and category b, which is used to clean tableware and contact with food, tools, equipment, containers, etc. Therefore, consumers should pay more attention to the choice of cleaning agents in the future. (song Hui)