Breast Milk Sold Online Isn't Always Purely Human

Women who purchase breast milk online likely have their baby's health in mind, which makes the findings of a study published today in Pediatrics so concerning. Researchers led by Nationwide Children's Hospital bought 102 samples of milk via milk-sharing websites and discovered that 10 of them "had a level of bovine DNA consistent with human milk mixed with at least 10% fluid cow's milk," they write in the study. That's a concentration high enough to indicate the cow milk was intentionally added, either straight from the carton or by way of baby formula. "This poses a risk to infants with an allergy or intolerance to cow's milk," says researcher Sarah Keim, in a press release. One milk bank director tells USA Today infants could experience bloody diarrhea or eczema as a result of ingesting it.

The newspaper reports that one of the sites the researchers purchased the milk from is Only The Breast, which bills itself as a "community for moms to buy, sell, and donate natural breast milk" at prices that USA Today noted were typically $1 to $6 per ounce. The site referenced its terms of use in an emailed statement, pointing out that members were barred from adulterating the milk. Why might someone do so? Profit. "Because money is exchanged in these transactions, there might be an incentive to boost milk volumes in order to make more money," says Keim, who advises pediatricians to caution mothers against sourcing any needed breast milk this way. USA Today notes these particular samples were used in a 2013 study by the team, which found that 72% of those samples contained bacteria; the types of bacteria they identified were pretty off-putting. (More breast milk stories.)