Organic foods are foods that are produced using methods that do not involve modern artificial inputs such as synthetic pesticides and chemical fertilizers, do not contain genetically modified organisms, and are not processed using irradiation, industrial solvents, or chemical food additives. With regard to genetic modification, I have explained this misunderstanding previously (see Labeling of Genetically Modified Foods—Fact versus Fiction).
All that certainly sounds lofty enough, but two recent scientific reviews  have disclosed the fact that no scientific evidence supports any benefit whatsoever from such culinary habits. The weight of the available scientific evidence encountered by these researchers has not shown any real difference between organic and more conventionally grown food in terms of safety, nutritional value, or taste. Given that the controversy about organic food dates back to the 1950s, it is surprising research has been somewhat sparse since then.
Despite such evidence to the contrary, there is currently a mystique surrounding the proposed health benefits of “organic foods”.
The issue of pesticides, hormones, and antibiotics is tangential to the subject of organic foods. There are indeed lower levels of these synthetic agents in organic produce than in conventionally grown equivalents, but does that render them safer to consume? In the review cited above, the authors found no evidence of greater safety of organic food.
One additional caveat about pesticides is that organic farming may employ “organic”, but not synthetic, pesticides, such as a rotenone-pyrethrin mixture, which has not been as well studied as synthetic pesticides. This combination often requires multiple applications and may persist in soil longer than synthetics. Thus, the use of natural pesticides is probably nothing more than an appeal to the naturalistic fantasy. Notwithstanding the need for more intensive research, there is currently no credible evidence, attesting to the superior safety of organic products.
Human exposure to pesticides should always be minimized. This is easily accomplished by washing all produce thoroughly prior to consumption. Although direct comparisons of the presence of pesticide residue in organic produce vs. thoroughly washed conventional produce are lacking, residue levels are generally below safety limits, and can be lowered further by washing. This subject, however, requires continued monitoring and further research.
In conclusion, I would suggest avoiding the organic label, since these products lack clear benefits and are generally more expensive.
 Smith-Spangler, et al. Are organic foods safer or healthier than conventional alternatives. Annals of Internal Medicine, 2012:157:348-366.