When it comes to food for babies, the breast is best. Years of research have revealed the health benefits of breastfeeding for babies and for mothers, and public health officials, including those at the Georgia Department of Public Health (DPH), promote the practice.

But what happens when a mother can't give her baby as much milk as he needs or if she simply can't breastfeed at all? Parents who still want their babies to get the health benefits of breast milk may turn to a breast milk bank, where parents with a doctor's prescription can purchase breast milk donated by mothers with extra milk.

But according to a recent blog from the  New York Times, an increasing number of parents are turning to the Internet instead, joining an informal network of parents sharing breast milk.

However, this practice troubles many health experts and breastfeeding advocates who say milk from a stranger or even a close friend can harbor health dangers for newborns.

"You really don't know what you're getting on the Internet," said Marcia Hunter, state breastfeeding coordinator at DPH. "Mothers who are getting milk from a stranger have no idea of what's in the milk, and it could be damaging."

Breast milk offers enormous health benefits for babies. According to the American Academy of Pediatrics (AAP), breastfeeding provides a protective effect against ear infections, respiratory illnesses, gastrointestinal problems and allergies. The AAP recommends breastfeeding for at least the first six months of a baby's life. Milk from the baby's own mother is preferable, but if that's not possible, milk from another mother is beneficial.

But breast milk is also a bodily fluid that can transmit harmful bacteria and viruses like hepatitis and HIV. If a mother takes medication, smokes or drinks alcohol, those substances can be passed on to her baby through breast milk.

The Human Milk Banking Association of North America operates 11 breast milk banks in the U.S. and two in Canada, and all of them screen donor mothers for diseases and health behaviors. They also pasteurize donated milk to kill bacteria and viruses. The milk is then frozen and shipped to hospitals, where it is given to the smallest, sickest infants in neonatal intensive care units or to women with a doctor's prescription.

Many health experts warn that parents who get breast milk over the Internet or even from friends or family members are putting their babies at risk by not giving them milk that has gone through this screening process.

"If a woman, even a sister or a friend, has hepatitis and doesn't know it, that puts the baby at risk," Hunter said.

So why would parents seek breast milk from outside milk banks? One overwhelming reason is cost. Human breast milk is like liquid gold with a price tag to match. The New York Times reported that breast milk can cost up to $5.50 an ounce, and a 3-month-old can drink anywhere from 20 to 40 ounces each day. Many donors offering their milk to friends or strangers on the Internet don't ask for money -- they simply want to clear out space in their freezers or make sure their extra milk doesn't go to waste. Milk-sharing networks like Human Milk 4 Human Babies and Eats on Feets say they do not support the selling of milk in their networks.

Groups that operate these networks defend their systems, noting that milk banks are prohibitively expensive and parents can screen donors as efficiently as a milk bank. In a letter on its blog, Eats on Feets founder Shell Walker said community milk-sharing should be supported, not stymied.

Eats on Feets "does support a safe, free and truly altruistic form of milk sharing that can be as safe as the milk bank process, and has an even greater amount of regulation possible in order to meet the specific needs of individual donors and recipients," Walker wrote.

Both Eats on Feets and Human Milk 4 Human Babies encourage donors and recipients to have open discussions about the health risks of milk sharing, complete with the provision of medical records and blood screening test results by donor mothers. They also encourage a process called flash-heating, which is recommended by the World Health Organization as a method for HIV-positive mothers to reduce risk of transmission of the virus to their babies.

Hunter said choosing breast milk sources are a decision ultimately left to parents. But she added that she would never advise a mother to get breast milk from a milk-sharing network.

"But it's just up to the mothers to weigh the risks," she said.

-Story by Carrie Gann, DPH Communications