JEFFERSON CITY, Mo. -

Doctors are constantly saying that breastfeeding is good for both mother and child. However, it turns out you can't just use just any breast milk.

A study from the Nationwide Children's Hospital found that 75 percent of breast milk purchased online was tainted with a wide range of dangerous bacteria.

The hospital bought milk anonymously on the Internet and analyzed it in the lab.

Three-quarters of the milk studied was full of disease-causing bacteria, like the kind found in human waste.

However, experts say not all milk banks are dangerous. They say you just have to do a little research first.

"Women can talk to their healthcare providers, lactation consultants, call their hospital and get that information," said Melinda Ridenhour of the Cole County Health Department. "There are milk banks set up across the United States that pasteurize and processes the milk accordingly."

The Human Milk Banking Association of North America guidelines say to make sure the milk bank you use properly pasteurizes the breast milk, as well as screens the donors.