To inform consumers about pesticide residue levels in many fruit and vegetables, the US Environmental Working Group (EWG) has compiled a Dirty Dozen list. This list contains the top fruit and vegetables that the EWG strongly recommends people to buy as certified organic. These are the produce items that are heavily sprayed and contain the highest levels of pesticide residues.
According to the EWG, consuming 5 servings of fruits and vegetables from the 12 most contaminated would cause you to consume an average of 14 different pesticides a day!
You can view the Dirty Dozen list here. Bear in mind that this information is based on US research so it will be different in other parts of the world.
As a general rule though for wherever you are living, tree fruits, berries and leafy greens (including herbs) have the highest residues. Fruits and vegetables with thick skins have lower levels of pesticide residues.
So if you are concerned about eating clean food and want to limit chemical exposure, these are the three groups of fruit and vegetables that you should try to purchase organic: