Processed fruits and vegetables often have lower levels of pesticide residues than fresh because they are peeled and because hey do not have to be cosmetically perfect. In addition, many canners have contracts with growers that specify what pesticides can be use. The EPA is required by the 1996 Food Quality Protection Act to re-examine the effects on children of widely used pesticides. The agency has already lowered estimates for safe daily limits for ingestion of 19 of about 40 organophosphate pesticide, including methyl parathion, but it has not yet lowered the residue limits of foods. Methyl parathion accounts for most of the total toxicity on the foods that were analyzed, particularly peaches, frozen and canned green beans, pears and apples.
Organophosphates are neurological poisons and work the same on humans as they do on insects.
Dieldrin, banned since 1974, continues as a significant risk because it remains in the soil. Unlike methyl parathion, dieldrin is absorbed into the pulp of root vegetables as well as squashes, melons and cucumbers. The only way to avoid it is to plant crops in uncontaminated soil. Aldicarb is the most acutely toxic of all pesticides currently in use. Like dieldrin, aldicarb cannot be washed or trimmed off.