Surprise: That 'Human Breast Milk' You Bought Online Contains Cow Milk

Researchers tested samples of online-purchased breast milk for a study that was published in Pediatrics this week. The results: 10% of the samples contained cow’s milk.

Not surprisingly, the study says the cow’s milk was probably added on purpose to thicken the milk. According to Mashable:

The analysis found that 10% of the breast-milk samples tested contained bovine DNA, meaning it was not 100% human milk but rather was tainted with cow’s milk products.

The researchers noted that their analysis was not able to determine whether the adulterated breast milk contained cow’s milk itself or another product, such as cow’s-milk-based infant formula.

The researchers estimated that 10 of 11 adulterated breast-milk samples contained at least 10% cow’s milk.

All of this is kind of a no-brainer. A previous study discovered bacteria in breast milk purchased online. Also, the sites that sell breast milk don’t have strict testing policies:

Although these websites post suggested guidelines for women about safely collecting, storing and shipping breast milk, they don’t test the breast milk itself or screen the participants. Unlike breast milk sold online, human breast milk banks, which supply breast milk for sick babies, have stringent criteria for donors and even pasteurize human milk.

The study’s lead author Sarah Keim adds this warning, “Purchasing breast milk online is not a good idea and introduces too many risks for infants.”