Growing fruit trees and shrubs can be problematic due to pests and pathogenic fungi. For this reason, farmers commonly use protection measures at various stages of plant development. The goal is to prevent crop reduction. Pesticide residues can pose a threat to human health, which is why EU regulations specify the highest permissible level of pesticide residues (MRL - ​​Maximum Residue Level) in food.

'In Europe, we have an advanced system for assessing pesticide levels, which means that we as consumers can feel safe. If farmers or gardeners perform pesticide applications correctly, and protect products after harvesting, the level of pesticides is safe for humans in light of current toxicological assessments', says Henryk Ratajkiewicz, PhD, from the Department of Entomology and Environmental Protection at the Poznań University of Life Sciences.

He explains that plant protection products used by farmers cannot disappear to zero levels after the so-called grace period. 'The grace period is the time from the application to the harvest of fruit and vegetables. We should also expect some pesticide residues after this time. However, this threshold of plant protection product residues is maintained significantly below the so-called permissible daily intake for humans', the researcher points out.

The expert admits, however, that there may be situations in which a farmer makes a slight mistake or a certain part of a bush or tree is treated with a larger amount of a plant protection product than another. 'These situations are calculated into the risk, but generally, even in these cases, the values ​​of the permissible level of plant protection products on fruit are very rarely exceeded', he says.

MRL limits are updated based on data on the assessment of toxicological safety and the conditions of use of such products. Over the last decade, some pesticides have been completely banned.

As consumers, we should remember to wash fruit and vegetables, preferably in lukewarm water. 'However, this will only wash off what is actually on the surface of the fruit and not permanently bonded to the surface of the skin. Using detergents for this purpose is not a recommended solution, because we might not rinse them off well, and they may also be harmful to health', Henryk Ratajkiewicz describes.

However, residues of some pesticides cannot be washed off with water. In many cases, pesticides penetrate deep into the fruit, or they reach it 'from the inside' through a system of conductive bundles.

Research conducted in 2022 at the University of Life Sciences in Lublin showed that conventional water washing (approx. 1.5 litres per fruit) had no effect on the level of pesticide residues in the analysed fruits. Peeling apples reduced this level by 24% to 100%, depending on the type of pesticide detected.

'It must be said that a lot of plant protection products are used in the case of apple trees. Therefore, you can expect to find a large number of different substances on apples. However, they are almost always at a very low level anyway', the researcher emphasises.

What's more, as Paweł Struciński, PhD, from NIZP PZH-PIB said in an interview with PAP, properly protected crops can be characterized by better health quality.

'For example, proper use of appropriate fungicides will not only make apples prettier, but they will also not support the development of certain species of fungi that produce genotoxic, carcinogenic patulin, and cereals will not contain spores of the red ergot fungus containing alkaloids toxic to humans', he pointed out.

In 2022, scientists from the University of Life Sciences in Lublin examined whether - and how much - pesticides we consume with fruit. It turned out that between 2012 and 2020 there was a significant reduction in the level of pesticides identified in edible parts of fruit. Importantly, no cases of use of banned plant protection products were found in the newer samples. Detailed analyses conducted in the laboratories of the University of Life Sciences in Lublin identified 26 pesticides (fungicides, insecticides, plant growth regulators, insecticides) in apple samples from 2012, while in fruit from the 2020 harvest - 'only' seven.

'It is worth emphasizing that our European farmers supply products that are at a higher level of safety than those originating from outside the EU. In food originating from the EU, the highest permissible pesticide residues are exceeded less frequently than in products originating from other regions of the world. It is worth bearing this in mind when choosing products in stores', Henryk Ratajkiewicz concludes.

Ewelina Krajczyńska-Wujec (PAP)

PAP - Science in Poland

ekr/ zan/ amac/