Atlanta, GA--Antibiotics, pesticides, growth hormones...researchers at Emory University, working in collaboration with The Organic Center, collected and tested milk from stores across the United States and found traces of such chemicals in conventionally produced milk, according to arelease from the University.The experts at Emory note that though most samples did not exceed FDA and EPA safety limits, some did. Several samples of conventional milk, they note, exceeded FDA limits for a few of the antibiotics tested.

The study authors, reporting inPublic Health Nutrition, add that "sufficient exposure to pesticides may lower birth weight, contribute to delayed motor and neurological development, and increase cancer risk." They also point to the hypothesis that antibiotics in dairy and meat products could lead to antibiotic resistance and hypersensitivity.

In a release outlining the research,The Organic Center reported that some samples of conventionalmilktested positive for residues of antibiotics that are banned from dairy production, as well as for controversial pesticides. Organicmilkshowed no such contaminants, and residues of growth hormones in conventionalmilkwere 20 times higher than in organic.

“Milk is a valuable source of important nutrients that are often underconsumed by U.S. children and adults,” said lead author Jean Welsh, Ph.D., MPH, associate professor of Pediatrics at Emory University School of Medicine. “While more research is needed to understand the health impact, if any, of exposure to the antibiotics, pesticides and growth hormones used by some milk producers, our results suggest that consuming organically produced milk, when possible, will help to minimize any possible impact."

Though the study was small (researchers collected samples from  69 half-gallon milk cartons, 34 organic and 35 conventional, including multiple brands collected from across the U.S.) Dr. Jessica Shade, Director of Science Programs for The Organic Center, noted, "The statistical significance was so clear and decisive that it gives us confidence that what we found in the study would also be the results of a larger sampling."

"Milk is a great source of protein and important vitamins and minerals, and we want our children and our families to drink milk," Dr. Shade added. "But not allmilk is created equal, as this study demonstrates. This study finds that the presence of antibiotics and pesticides in conventional milkis much more prevalent and pervasive than previously thought–and that organicmilkdoesn't contain any of these contaminants. We hope this study will let people know that the choice is out there for good clean organic."

Related: Organic Milk Found to be More Nutritious Than Conventional

More information on the study can be found in The Organic Center's full report,The Benefits of Organic Dairy.