Breast milk for sale online may contain cow’s milk

Breast milk isn’t always breast milk when it’s sold online.

That’s the finding of a new study published Monday on the safety of breast milk sold on the Internet. (Yes, people buy and sell breast milk online – an estimated 55,000 people are involved with online milk exchanges, according to the researchers.)

The study found that 10 percent of breast milk samples purchased online contained added cow’s milk or infant formula.

“We found samples of milk we purchased online had notable amounts of cow’s milk or infant formula added to it,” said Sarah A. Keim, of Nationwide Children’s Hospital and the lead author on the study, in the news release. “Drinking cow’s milk can be very harmful to a baby with an allergy or with intolerance to cow’s milk.”

The research team previously found that 21 percent of people buying human milk online did so for a child with a pre-existing medical condition and 16 percent specifically sought out the milk due to their baby’s intolerance to formula, according to a news release.

The researchers purchased and tested 102 samples of breast milk advertised on milk-sharing websites. They compared the samples with their own preparations of human milk diluted with cow’s milk to approximate the amount of contamination required in order to test positive for bovine DNA.

All purchased samples contained human milk, but 11 of them also contained bovine DNA – 10 of which had results consistent with more than minor, accidental contamination, according to the news release.

“The findings suggest that a notable number of sellers intentionally added cow’s milk or infant formula to the breast milk,” according to the researchers.

This wasn’t the first troubling finding by the researchers.

In 2013, the research team tested 102 samples of breast milk purchased online and found more than 75 percent had high levels of bacteria that could make a baby sick, according to the news release.

Marissa Harshman

Marissa Harshman

I'm the health reporter for The Columbian newspaper in Vancouver, Wash. I started at The Columbian -- my hometown newspaper -- in September 2009. Reach me at or 360-735-4546.

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