Washing or peeling fruit and vegetables can potentially reduce exposure to pesticides as some residues that appear on the surface will be eliminated, particularly traces of soil which may contain harmful bacteria. However, although washing or peeling will reduce the level of pesticides found on the outside of an item, they are unlikely to remove all pesticide residues. This is because many of the pesticides used are ‘systemic’, meaning that they are actually absorbed by a plant when applied to seeds, soil, or leaves and the residues are therefore contained within the body of the produce itself.
The government’s testing scheme tends to show citrus fruit as having the highest residues. This is often because of its peel – fruit such as oranges and grapefruits, will show higher residues than are actually being consumed. Having said that, people are increasingly using the zest of citrus fruits. In addition, handling of fruit covered in fungicides (which are used to prevent food rotting) can mean dermal absorption (i.e. through the skin) is a problem, particularly for children.