Clear water, salt water, rice water and detergent, which kind of washing liquid is better for washing pesticides to remove pesticide residues? Recently, a post of “Brine Washed Vegetables Best†was circulated on the Internet, which said that the vegetables were soaked in salt water. In 5 minutes, the pesticide residue can be minimized. Subsequently, some media have pointed out through experiments that the ability to remove pesticide residues from detergents and rice water is ranked first and second respectively. Then, who is more effective? Recently, the reporter conducted a comparison experiment on the effects of the above four kinds of washing liquids in the National Key Laboratory of Agricultural Product Safety Testing of the Technical Center of Guangxi Inspection and Quarantine Bureau. Purpose of the experiment: Wash dishes with 4 kinds of washing liquids to see which method is the best to remove pesticide residues. Experimental materials: Randomly purchase 1000 kg of common spinach and cucumber in the market, 1 bottle of detergent, 1 package of refined salt, a bottle of chlorpyrifos EC of 48% concentration, and a bucket of rice in the canteen. Experimental method: According to the instructions, firstly dilute the purchased chlorpyrifos EC pesticide, dilute it and pour it into a small sprayer to simulate the vegetable farmers to spray the pesticides on the two vegetable samples. After 1 hour, the reserved part is not washed. The vegetables are then immersed in the water bowls of the four washing liquids by dividing the remaining two vegetable samples into equal parts. After 10 minutes, the vegetables were rinsed in the environment where the vegetables were washed under the tap, and then the vegetables washed by the four washings were sampled, placed in test tubes, and the unwashed vegetables were also sampled. Into the test tube, all samples were placed in the gas phase chromatograph to detect the pesticide residue, and the experimental data is shown in the table to the right. Experimental analysis: From the data point of view, the pesticide was sprayed without any cleaning, the residual pesticide content of the water spinach was 36 mg/kg, and the pesticide residue of the cucumber was 3.26 mg/kg. After washing with four kinds of washing liquids, it was found again that in the spinach samples, the most obvious effect of removing pesticide residues was detergent and water; in cucumber samples, the best effect of removing pesticide residues was detergent and salt water. Dr. Wu Yujie, National Key Laboratory of Agricultural Product Safety Testing, Guangxi Inspection and Quarantine Bureau said that from the overall data, these washing liquids have the effect of removing pesticide residues. However, it is unscientific to rank their effects of removing pesticide residues by one or two experiments. Dr. Wu said that this experiment only carried out simulation tests on two kinds of vegetables and one kind of pesticide. There are many kinds of vegetables on the market. Each vegetable has different characteristics and different ability to inhibit and adsorb pesticides. In addition, the varieties of pesticides actually used by farmers are also diverse. The data obtained by experimenting with other pesticides will be different. Therefore, ranking the washing liquid by one or two experiments will mislead the public. From the experimental data analysis, it shows that the degreasing effect of detergent is the most obvious. So, does this mean that we should use detergent in the future? Dr. Wu said that detergent itself is weakly acidic, pesticide In a weakly acidic or weakly alkaline environment, it will exhibit instability and may degrade to produce harmful substances. From the experimental data, the pesticide content of vegetables washed with detergent has been reduced, but it will degrade what kind of substance is produced, or a very complicated process, it is difficult to say clearly without special inspection; Moreover, detergent It is also a petrochemical raw material. It is also used to wash vegetables. It also produces residual substances. It is not recommended to use it for washing vegetables. Dr. Wu finally suggested that no matter which kind of lotion is used by the public when washing vegetables, they should wash it with flowing tap water several times after fully soaking. This is reassuring. Extended reading>> According to the authoritative data of the agricultural sector, combined with the different characteristics of different vegetables at the time of planting, the following vegetables are most likely to have pesticide residues. The first is to grab the fruits and vegetables that are rushing for seeding: due to the weather, it is easy to ignore the safe harvesting period of pesticide use, and the pesticide residue is likely to exceed the standard. The second is anti-season fruits and vegetables: anti-season fruits and vegetables will have more pests and diseases, and it is not easy to grow. Therefore, many pesticides and ripening agents must be used to deal with pests and diseases, so that the results are huge. Strawberries and cherries appearing in spring, and beans and bitter melons that appear in the off-season are more likely to be sprayed with pesticides. The third is large leaf vegetables: including cabbage, celery, cabbage, rape, cabbage, mustard and so on. According to experts, these vegetables have large leaf surfaces and large areas of pesticide exposure, so pesticide residues are relatively high. It is recommended that you choose to eat relatively safe vegetable varieties such as onions, garlic, carrots, lotus roots, pumpkin, winter melon, yam, winter bamboo shoots, bamboo shoots, etc. Reporter Wei Wanchun
Which kind of washing liquid is best for removing pesticide residues from vegetables?