"Switching to organic is tough for many families who don’t want to pay higher prices or give up their favorite foods. But by choosing organic versions of just a few foods that you eat often, you can increase the percentage of organic food in your diet without big changes to your shopping cart or your spending.
The key is to be strategic in your organic purchases. Opting for organic produce, for instance, doesn’t necessarily have a big impact, depending on what you eat. According to the Environmental Working Group, commercially-farmed fruits and vegetables vary in their levels of pesticide residue. Some vegetables, like broccoli, asparagus and onions, as well as foods with peels, such as avocados, bananas and oranges, have relatively low levels compared to other fruits and vegetables." (Thanks Ayman)
The worst products according to the study: Milk, potatoes, peanut butter, ketchup, apples. For those interested: Healthy Basket has daily supplies (almost daily) of organic, certified apples, potatoes, and home-made ketchup. Alas no milk.