Better think twice before you purchase breast milk on Craigslist. You could end up with a mixture containing the ol' moo variety.
In findings published in the journal Pediatrics, researchers found that one in 10 samples of breast milk bought online contained some cow's milk, NBC News reports. This is bad news for babies, who tend to be very sensitive to cow milk, particularly preemies.
"The levels of cow's milk were high enough that we don't think it was just an accident," said Sarah Keim, the study's author and a principal investigator in the Center for Biobehavioral Health at the Research Institute at Nationwide Children's Hospital.
Many women sell breast milk online for those who cannot provide it for their own child. Some call it "liquid gold," as it can fetch about $1-2 an ounce or more. There is even a fad amongst bodybuilders who swear by its muscle-building benefits.
The Food and Drug Administration recommends against feeding babies breast milk acquired through the Internet because its purity cannot be known unless tested. For example, four of the 102 examined samples in the study contained cotinine, a chemical compound present in the breast milk of active smokers (two of those four sellers promised they were non-smokers). Also, the FDA notes that HIV, illegal drugs and dangerous germs may be present in milk purchased online.
"I think it's quite clear from this study that it's not safe to feed your baby milk that you've purchased on the Internet," Keim told NBC News.