According to a study published in the journal Pediatrics, researchers found that one in every 10 samples of breast milk purchased online contained cow's milk. Researchers believe the breast milk was topped off with cow's milk to increase volume.
"Purchasing breast milk online is not a good idea and introduces too many risks for infants," lead author Sarah Keim, a principal investigator at the Center for Biobehavioral Health at Nationwide Children's Hospital in Cincinnati, told Live Science.
Researchers anonymously purchased 102 samples of breast milk on "milk-sharing" websites. Breast milk can cost anywhere from 50 cents to $3 per ounce, Keim told Live Science. Ten percent of the samples contained bovine DNA, and researchers estimated that 10 out of 11 samples were actually 10 percent cow's milk. (Researchers did note that their tests were unable to determine if the samples were adulterated with cow's milk or another product containing cow's milk, like a cow's milk-based infant formula).
Cow's milk isn't inherently dangerous, but pediatricians recommend that children under 12 months of age do not consume cow's milk to avoid intolerance or an allergy to milk proteins.
The study authors concluded: "Ten Internet samples had bovine DNA concentrations high enough to rule out minor contamination, suggesting a cow's milk product was added. Cow's milk can be problematic for infants with allergy or intolerance. Because buyers cannot verify the composition of milk they purchase, all should be aware that it might be adulterated with cow's milk. Pediatricians should be aware of the online market for human milk and the potential risks."
