Process for cleaning pesticide residues on fruits and vegetables

fruits and vegetables

Introduction(Expert Homeopathy: Dr. Anutosh Chakraborty)
Modern agriculture has developed with the development of pesticides and fertilizers. As people pay more and more attention to health, pesticide residues on fruits and vegetables will cause people to worry more and more. In fact, "pesticide" is a very broad concept. Some people treat all agricultural substances except fertilizers as "pesticides", while some people only call "chemically synthesized" drugs used for insecticide and sterilization "pesticides." Regardless of the broad or narrow concepts, the types of pesticides in crop cultivation are extremely large. In the news media, there are often reports of "how many kinds of pesticides are detected on such fruits and vegetables".

Before discussing how to "remove" these pesticide residues, let us first explain two common sense points:
First, "detection of pesticide residues" is not the same as "hazardous to health". Any pesticide needs to arrive at a specific add-up to cause hurt. These "non-risky amounts" are managed by public norms. As a "toxic substance", the study of its toxicity is generally carried out on animals.

Feeding with different doses of pesticides (or contacting animals in other ways), find out the animals "do not show any abnormal maximum dose". Generally speaking, taking into account the differences between humans and animals and the "physical differences between people" ", use 1/100 of this dose as the "safe dose" for people. Then, according to the maximum amount of food people can eat every day, the "safe upper limit" in food is formulated. It can be said that based on the current science of the pesticide As long as it does not exceed this upper limit, it can be considered that there is no health risk. If there are new scientific data that show "may be harmful" at lower doses, then the safety standards will be revised.

Second, the “number of species of pesticides” and the “harmful doses” are two different things. Different pesticides are aimed at different pests or diseases, and their mechanism of action is generally different. Even if the effects of the same kind of pesticides are cumulative, it is still judged whether they are harmful according to their "how much residue" rather than "how many kinds". In other words, if the residual amount of each is lower than the national standard, then the hazard can be ignored; if the residual amount exceeds the standard, then even if there is only one, it is still a substandard product.

After all, pesticides are of no value to the human body, and the "safety data" are all speculated and formulated based on experimental data. Therefore, we still hope to "reduce their existence as much as possible." It is the fundamental way to develop lower-toxic pesticides and standardize their use in production. For consumers, for fruits and vegetables in their hands, what methods are there to remove "possible" pesticide residues? 

The scientific community has conducted a lot of research on this. Various pesticides have different characteristics, and any removal method is aimed at a certain characteristic. In other words, what is effective for some pesticides may not be effective for others. It is basically impossible to find a "universal" method that can remove all pesticides. In 2010, the "Food and Chemical Toxicity" magazine published a research review on the removal of pesticide residues in fruits and vegetables summarized by Belgian scholars. They found that blanching, peeling, frying, and washing (combined with other treatments) are the most effective ways.

Among them, frying can remove 90% on average, and blanching is close to 80%. However, considering that most vegetables and fruits are not suitable for frying, and frying itself brings high fat and high calories and destroys other nutrients, it is not a kind of Good choice. And blanching, that is, put it in boiling water and scald it, it is efficient and less damage to the nutrients, and it is more feasible for many vegetables. What is interesting is that if it is cooked for a long time, the removal efficiency of pesticides will be significantly reduced. The calculation result of this review is less than 20% on average. This may be that after a long period of heating, the vegetable cells are destroyed, and the pesticides in the water may enter the vegetables.

The effect of heating on pesticides may be more complicated than the digital display. For example, some pesticides decompose at high temperatures, and some of the decomposition products are non-toxic, while others may be more toxic. If it is not clear, it is undoubtedly a better solution to remove it through pre-cooking treatment.

Cleaning is the most studied method. A division of the Connecticut State Government in the United States once led a moderately enormous scope concentrate on cleaning and eliminating pesticide deposits. They selected 28 batches of lettuce, strawberries, and other fruits and vegetables to detect the changes in the content of several common pesticides before and after cleaning. They used tap water, detergent, and 4 kinds of special "fruit and vegetable cleaning agents". The results found that each method can significantly reduce pesticide residues, but the effect of these special fruit and vegetable cleaning agents is no different from that of water. They also found that whether these pesticides are easily washed off has little to do with their solubility, which is mainly removed by mechanical movements during cleaning. Therefore, their suggestion is: Rinse under running water for more than 30 seconds, accompanied by scrubbing.

Others like to soak fruits and vegetables in acid water, alkaline water, or saltwater. These methods are effective for certain fruits and vegetables and certain pesticides. For example, in one study, green peppers were soaked in 2% saltwater for 10 minutes and then washed, which can remove more than 80% of the pesticide residues. However, if some vegetable epidermal cells are destroyed by these soaking solutions, the pesticides washed into the water may enter the vegetables again, similar to the situation of blanching and boiling for a long time.

Cleaning can remove the pesticides on the surface, but it can't do anything about the infiltration of the skin. Generally speaking, the infiltrated part is mainly distributed in the epidermis, so peeling is a very effective method. For example, potatoes, peeling can remove more than 70% of the residual pesticides.

To sum up, the three tricks to remove pesticide residues in fruits and vegetables are: 
washing, peeling and cooking. If you are still worried, diversifying fruits and vegetables as much as possible will also help. Different fruits and vegetables use different pesticides, and diversified choices can reduce the intake of each pesticide. Because these different pesticides do not necessarily cause cumulative harm, it also helps to reduce the "risk in the case."

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