Websites selling human milk for infant consumption are gaining in popularity.
In the study, "Microbial Contamination of Human Milk Purchased via the Internet," published in the November 2013 issue of Pediatrics (published online Oct. 21), researchers purchased 102 cross-sectional samples of human milk through a popular U.S. milk-sharing website.
The milk samples were sent to a rented mail box in Ohio and later compared with samples of unpasteurized, donated milk obtained through a milk bank.
Seventy-four percent of the Internet milk samples were colonized with high bacterial counts overall, or had at least some Gram-negative bacteria; and 64 percent of the Internet samples tested positive for staphylococcous, compared to 25 percent of the milk bank samples.
Three of the Internet samples were contaminated with Salmonella.
The high overall bacterial growth and frequent contamination with disease-causing bacteria in the Internet milk reflected poor collection, storage or shipping practices, according to the study authors.
The study authors recommend lactation support for mothers who want to provide breast milk to their infants but who have difficulty making enough.
Women who have extra milk should consider donating to a milk bank.
One of the authors of the study, Sarah A. Keim, gives guidance for women considering buying breast milk on the Internet and offers information on alternatives if you can't breast feed.