Organic produce is often thought of as more expensive than conventionally grown produce, but Lu said an increased demand in recent years has led to lower prices.

"You may want to think about saving money just for buying organic apples and not buying organic other stuff," Lu said. "You switch your resources for the high risk produce and buy organic for those."

For the first time this year, the USDA also collected data on pesticide residue in baby food, finding many of the studied samples to be contaminated with organophosphate pesticides. In its report, the EWG stresses the importance of accelerating testing of baby foods and asks the Environmental Protection Agency to focus on reducing the organophosphate pesticide exposure allowed for Americans, especially infants.