Thinking about purchasing breast milk online? It might be wise to think again. A new study released today has found that most of the breast milk found on popular Internet sites is contaminated with bacteria.

OK, let's back up a bit for those who are wondering why on earth one would ever consider purchasing something like breast milk in the first place, let alone purchasing it from a stranger via the Web. Women have been donating and even selling breast milk to new parents in need for generations. Time and time again we hear the mantra that "breast is best" for babies. So for mothers whose breast milk doesn't come in, or those who face time, work, or family pressures that make it difficult to breastfeed, purchasing breast milk may seem like a good option.

When my eldest daughter was born, I had plenty of breast milk to go around, so I donated hundreds of ounces to a milk bank at Duke University that primarily gave the milk to premature or sick babies in need. There are many such milk banks in operation that work in conjunction with pediatric hospitals to supply sick babies with breast milk. Some milk banks also offer breast milk for sale, but at prices as high as $5 per ounce (or $40 a bottle!)

So in recent years, a cottage industry has sprung up bypassing milk banks and bringing together mothers in need of breast milk with those who have a surplus. Actress Alicia Silverstone launched a vegan breast milk co-op just a few months ago. Thousands of new moms with breast milk to spare place ads on these sites offering breast milk to other moms in needs, often at prices closer to $1 or $2 per ounce. But health experts have been wary of this unregulated system for years, and now it looks as though they may have the data to back up their fears.

In a new study published today in the journal Pediatrics, researchers tested 101 milk samples they bought on milk-sharing websites and found that almost 75 percent were tainted with bacteria such as E. coli, Streptococci, or even salmonella. The amounts detected in some of the samples were sufficient to make a baby — particularly a preemie — very sick. This is in contrast to the breast milk found at regulated milk banks where the milk is consistently tested to ensure that it is clean and safe for babies.

At present, the Food and Drug Administration does not regulate the buying or selling of breast milk, but the agency does discourage the practice of purchasing and sharing breast milk.

Related posts on MNN:

Breast milk purchased online may be tainted
New study finds most of the breast milk sold on the Internet is contaminated with bacteria.