When you don't buy organic foods be sure to wash all of your produce just before serving by running it under a lot of running water and scrubbing the skin gently to remove dirt or residue. Use a vegetable brush if needed.
Be sure to also wash melons, oranges and bananas – though you won’t eat the skin, it is easy to transfer germs from the outside to the inside during preparation and eating. For waxy foods like cucumber, scrub very thoroughly as pesticide gets trapped under the food grade wax coating. It also tastes bitter so a thorough scrub will make it taste better.
If you wish you can use a drop of all natural dishwashing liquid to help clean produce.