Pesticides are a group of chemical compounds that can have different negative effects on health. The EFSA annually publishes the EU report (European Union report on pesticide residues in food) on pesticide residues and health risk assessment: https://www.efsa.europa.eu/en/press/news/170411

There are more than 1000 pesticides used around the world to protect plant products from harmful organisms. Each pesticide has different properties and toxicological effects. Some of them has systemic effect, some of them has contact effect to harmful organisms. Some of them may be broken down, or degraded by external factors such as sunlight, water or other chemicals, or microorganisms. This degradation process usually leads to the formation of less harmful breakdown products. But in some cases, they can produce more toxic products to environment and living organisms. Some of them can be very resistant to degradations and thus remain unchanged in the environment for a long time. The toxicity of a pesticide depends on its function and other factors. Therefore, there are recommended usage doses for all of them. If these doses are exceeded, that’s time they can have negative effects to environment and living organisms. These adverse effects are not amendable by washing. However, residues can only be reduced by washing or peeling for contact pesticides. In fact, there is another reality in agricultural foods. They should be sold according to complying with pesticide regulations, in particular with maximum residue limits. If it is so, there is no need to wash or peel.

As to disease like Parkinson's disease, it is highly-likely triggered by pesticides. However, there is no directly related study on it.

Respond to other your question; not only pesticide manufacturers and also other stakeholders such as regulation makers, authorities, even researchers and scientists are culpable for any long term side effects except farmers and retailers according to me.

Pesticide Residues in Fruits and Vegetables

January 2018

DOI: 10.1007/978-3-319-54528-8_76-1

In book: Bioactive Molecules in Food

Samira Mebdoua

Pesticides are a group of chemical compounds that can have different negative effects on health. The EFSA annually publishes the EU report (European Union report on pesticide residues in food) on pesticide residues and health risk assessment: https://www.efsa.europa.eu/en/press/news/170411

Thanks Nihada Ahmetovic

I wonder if our developing countries have the same sort of surveillance?

Dear dr Fazleh Mahomed

Every year, in Bosnia and Herzegovina, the Pesticide Residue Control Program is in and on food of plant origin, but without risk assessment for health.

See: http://www.fsa.gov.ba/fsa/bs/novosti/item/309-pracenje-rezidua-pesticida-u-i-na-hrani-biljnog-porijekla-u-bosni-i-hercegovini

Dear Fazleh Mahomed,

If we harvest fruit and vegetable prior to the Pre-Harvest Interval/period, there is high risk to contaminate fruit and vegetable by pesticides which are applied as spray on them. Washing is support to remove some pesticides from their surface. However, there should be a significant deference before and after washing for some pesticides.

Piyal Aravinna

I never ate fruit/vegetable without washing.

Dear Maham Muzamil,

Yes it is a good habit. However, some pesticides, especially some insecticides available on the surface/skin of fruit/vegetable is not removed by normal washing.

But, if you can wash it using light soap solution (like baby soap), it is very helpful to remove it. But I know that it is not practice always.

Piyal Aravinna

Adding to the above comments; residues on fruits and vegetables are surface residues. These residues are normally high when the pre-harvest interval is not adhere to (that's not practicing good agricultural practice). However, there are some pesticides which are carried into the fruits and vegetables. These are systemic pesticides, and they have the ability to enter into the fruits and the vegetables, aside the surface residues. Having said all these, if we are to follow the good agricultural practices in pesticides application, we will be sure of residues below the MRLs in our fruits and vegetables.

But sure, good washing of fruits and vegetables will get more of the surface residues off them but does none to the systemic residues. So our best bet is always to practice gap, and keep the research on pesticides residue and its associated risks going.

Thank you.

Dear Nirmala S. V.S.G

It is difficult to think that the effectiveness of application of cool water for removel of pesticde resudus from the surface of vegetable/ fruit than normal water. Generally solubility is decreased with low temperature. So, can you explain that the theory behind the removel of pesticde residues by cool water ?

Piyal Aravinna

Dear Samuel,

Yes, as you mentiond, " if we are to follow the good agricultural practices in pesticides application, we will be sure of residues below the MRLs in our fruits and vegetables" It is very good. I think that developed countries follow this.

Unfortunately, Most of the farmers in Sri Lanka handle mosaic of landuse with small farm lands （about 2 ha). Their profit from agriculture is low. They very much concern about the losses of yield than other's health. So that they don't consider much about Pre-Harvesting period . Further, It is difficult to control the sutution by rules and regulations. I think that this is a common issue for the developing countries with mosaic of land uses.

So, If we can remove pesticide residues avilable on the skin of fruit/ vegetable, It is very important.

Piyal Aravinna

all imported fruits and vegetables We don't know How and Type and time of pesticides that treated to fruits and vegetables. It's important information to detect the way to remove residuals.

I thank you for this debate, but to understand the degradation of pesticides, we need to understand the physiology of plant and metabolic processes occurring in the cell during the plant's physiological processes. The metabolism of the plant varied from plant to plant, therefore the time of degradation of the plant the same pesticide is different in different plants. The debate about how to clean the fruit is a simple debate. The systemic pesticids fall within the living plant cell and that pesticide does not degrade without respecting the time of degradation of each pesticide, the more active it is the activity the metabolic rate of the plant cell decreases pesticide degradation. On the other hand, the physiological activity of the vegetation increases the temperature and the length of the solar intensity. That is, the higher the temperature the fruits are in the branch, the faster the the process of degradation.

Therefore, the compliance of each pesticide with the dosage of use is the alpha and omega of the right understanding of the degradation process so that the fruit has a MRL within the allowed norms.

With respect: Prof. Dr. Mufail Salihaj

Dear Mufail Salihaj,

Yes, your idea is important for systemic pesticides. My country has very bad experience about application systemic pesticides, carbofuran. Within last two decades, carbofuran was main systematic pesticides applied for the fruit and vegetables of gourd family in Sri Lanka. At that time, farmers correctly applied carbofuarn to the soils (at the seedling stage) to control worms attaching the plant. Later on, frames of mosaic land uses had a trend to apply corbofuran at flowering/fruiting stage to control the worms who attack the directly to the fruit.

For such occasion, washing technique is not successful at all cost, as mentioned many repliers at the beginning of this discussion. So that government of Sri Lanka ban corbofutan.

Piyal Aravinna

The most important factor in pesticide residues in fruits and vegetables is the waiting (safety ) period .In case of contact pesticides ,they may removed by washing or other methods, but in case of systemic pesticides ,we must consider the waiting period. Salam and best wishes .