How to Eliminate Pesticide Residues in Vegetables and Fruits

Modern agriculture developed with the development of pesticides and fertilizers. As people pay more and more attention to their health, pesticide residues on fruits and vegetables have become more and more worrying. In fact, "pesticide" is a very broad concept. Some people regard all agricultural substances other than fertilizers as "pesticides", while others only call "chemically synthesized" drugs used for insecticide and sterilization as "pesticides".
  
Pesticide residues in vegetables are an important issue in food safety. Especially in summer, it is not only the peak period of vegetable consumption, but also the active period of pests. In order to catch up with business opportunities, producers either use excessive concentrations of pesticides to kill insects, or use pesticides to harvest them in advance, resulting in a large number of vegetable pesticide residues that seriously exceed the standard. According to statistics, under normal circumstances, the qualified rate of pesticide residues in summer vegetables is more than 20% lower than that in winter.

 

 

Regardless of the broad or narrow concept, the types of pesticides in crop cultivation are extremely large. In the news media, there are often reports of "how many pesticides have been detected on certain fruits and vegetables". Before discussing how to "remove" these pesticide residues, let's make two common sense:
  
First, "detecting pesticide residues" is not the same thing as "harming health". Any pesticide needs to reach a certain amount to be harmful. This "no hazard amount" is regulated by national standards. As a "toxic substance", studies on its toxicity are generally carried out in animals. Feed (or otherwise expose animals) different doses of pesticides and find the "maximum dose at which the animals do not show any abnormality." In general, taking into account the differences between humans and animals and the "physique differences" between people, 1/100 of this dose is used as a "safe dose" for humans. A "safe upper limit" in food is then established based on the maximum amount of food people can eat each day. It can be said that based on the current scientific understanding of the pesticide, as long as this upper limit is not exceeded, it can be considered that there is no health risk. If new scientific data emerges that "may also be harmful" at lower doses, then the safety standards will be revised.
  
Second, "how many pesticides there are" and "harmful doses" are two different things. Different pesticides are aimed at different pests or diseases, and the mechanism of action is generally different. Even if the effects of similar pesticides are cumulative, it is still based on "how much residues", not "how many species" are there to judge whether it is harmful. That is to say, if the residual amount of each kind is lower than the national standard, the harm can be ignored; if the residual amount exceeds the standard, even if there is only one kind of product, it is still a substandard product.
  
After all, pesticides are of no value to the human body, and "safety data" are also speculated and formulated based on experimental data. So, we still want to "reduce their presence as much as possible". The fundamental way is to develop pesticides with lower toxicity and regulate their use in production. For consumers, what are the ways to remove the "possible" pesticide residues in the fruits and vegetables in their hands?
  
After all, pesticides are of no value to the human body, and "safety data" are also speculated and formulated based on experimental data. So, we still want to "reduce their presence as much as possible". The fundamental way is to develop pesticides with lower toxicity and regulate their use in production. For consumers, what are the ways to remove the "possible" pesticide residues in the fruits and vegetables in their hands?
  
Since pesticides are mainly attached to the surface of fruits and vegetables during the spraying process, as long as effective washing and processing methods are adopted, the residual amount of pesticides can be reduced and the edible safety of vegetables can be ensured.

 

 

The scientific community has done a lot of research on this. Various pesticides have different properties, and any removal method is specific to one property. That is, what works for some pesticides may not work for others. Finding a "one size fits all" way to remove all pesticides is basically impossible.
  
In 2010, in the journal "Food and Chemical Toxicity", a research review on the removal of pesticide residues in fruits and vegetables summarized by Belgian scholars was published. They found that blanching, peeling, frying, washing (and combining with other treatments) were the most effective approaches.
  
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 good choice. And blanching, that is, putting it in boiling water for a while and then taking it out, is efficient and less damaging to nutrients, which is more feasible for many vegetables. Interestingly, if boiled for a long time, the removal efficiency of pesticides will drop significantly. The review calculated that it averaged less than 20%. It is possible that after a long time of heating, the vegetable cells are destroyed, and the pesticides in the water may enter the vegetables.
  
The effects of heating on pesticides may be more complex than the numbers suggest. For example, some pesticides decompose at high temperatures, and some of the decomposed products are non-toxic, while others may be more toxic. Under the premise that it is unclear, it is undoubtedly a better solution to remove it by pre-cooking.
  
Cleaning is the most studied method. A department of the Connecticut state government once conducted a relatively large-scale study on cleaning and removing pesticide residues. They selected 28 batches of lettuce, strawberries and other fruits and vegetables, and detected changes in the content of several common pesticides before and after cleaning. They used tap water, detergent, and 4 special "fruit and vegetable washes". It was found that each method significantly reduced pesticide residues, but these specialized fruit and vegetable cleaners were indistinguishable from water. They also found that the ease with which these pesticides were washed had little to do with their solubility, and was largely removed by mechanical movement during washing. So, their advice: Rinse under running water for 30+ seconds, followed by scrubbing.
  
Others like to soak fruits and vegetables in acid water, alkaline water or salt water. These methods are effective for certain fruits and vegetables and certain pesticides. For example, in a study, green peppers were soaked in 2% salt water for 10 minutes and then washed, which could remove more than 80% of pesticide residues. However, if some vegetable epidermis cells are damaged by these soaking solutions, the pesticides washed into the water may enter the vegetables, similar to the situation of blanching and long cooking.
  
Washing can remove pesticides on the surface, but nothing can be done to penetrate into the skin. Generally speaking, the infiltrated part is mainly distributed in the epidermis, so peeling is a very effective means. For example, peeling potatoes can remove more than 70% of the residual pesticides.
  
To sum up, the three axes for removing pesticide residues in fruits and vegetables are: cleaning, peeling, and cooking. If you're still concerned, trying to diversify your fruits and vegetables as much as possible can also help. Different fruits and vegetables use different pesticides, and a variety of choices can reduce the intake of each pesticide. Because these different pesticides don't necessarily add up to harm, this also helps reduce the "what ifs".