Breast milk that is purchased from the Internet makes babies more vulnerable to the risk of infectious diseases, as most are adulterated by cow's milk.

Researchers believe that because money is exchanged in these transactions, there might be an incentive to boost milk volumes in order to make more money.
"Cow’s milk and infant formula resemble human milk and could potentially be added to boost volumes without the recipient knowing," Keim said. "Mothers who consider purchasing breast milk over the internet should beware -- when you obtain milk from an unfamiliar source, you cannot know for sure that what you are getting is safe for your baby," Keim said.
For the study, the researchers purchased and tested 102 samples of breast milk advertised on milk-sharing websites. All purchased samples did contain human milk, but 11 also contained bovine DNA, 10 of which had results consistent with more than minor, accidental contamination with cow’s milk.
Purchased breast milk also makes babies more vulnerable to the risk of infectious disease from bacterial and viral contamination of such milk, which was identified in a prior study by the same research team.
Source-IANS