Milking It: "Organic dairy means no use of antibiotics, synthetic growth hormones, genetically modified organisms, or conventional pesticides.... The health and natural behavior of cows are prioritized, with holistic and preventative care practices as a primary management strategy.".

• Author: McNeil, Maggie
• Position: EYE ON ECOLOGY

MILK is an important part of the human diet. It provides protein, fat, calcium, and vitamin D, and, for the youngest members of our population, it especially is critical as a main source of many nutrients--but not all milk is created equal.

For nearly 15 years, studies repeatedly have shown that organic milk has a healthier nutritional profile, as it contains more of the good omega 3 fatty acids, more antioxidants, and a higher nutrient mineral content than conventional milk. Dairy cows under organic management eat more grass than those under conventional management and that difference in their diet results in more nutrient-rich milk.

A study by researchers at Emory University, in collaboration with The Organic Center, and published in the peer-reviewed journal Public Health Nutrition found that a majority of samples of conventional retail milk tested positive for residues of antibiotics--two of which are banned from dairy production--and pesticides.

"This study is especially exciting because the researchers developed methods that are more sensitive than past analyses, including testing methods that have been used by the Food and Drug Administration," says Jessica Shade, director of Science Programs for The Organic Center.

"The study also measured levels of chemicals that were previously unreported. These new methods give us a true picture of the presence or absence of residues in milk, which is a great source of protein and important vitamins and minerals, and we want our children and our families to drink milk, but not all milk is created equal, as this study demonstrates."

Because the overuse of antibiotics can increase resistance and make these antibiotics less effective for both humans and animals, the FDA has set limits on detectable levels in food. In this study, antibiotics were detected in 60% of conventional milk samples--specifically, residues of amoxicillin, oxytetracycline, sulfamethazine, sulfadimethoxine, and sulfathiazole.

Residues of sulfamethazine were found in 37% of the conventional samples, and sulfathiazole in 26%. The use of both of these antibiotics for dairy cows long has been banned by the FDA due to concerns about the impact of sulfa drugs on human health. When cows are treated with sulfa drugs, residues of the drug show up in milk, and exposure to them can lead to health problems in humans. The biggest concern is a life-threatening allergic reaction (acute hypersensitivity). About two percent of the general...