It’s hard enough for many new mothers to breastfeed, let alone pump breast milk and freeze it.

But some women have an abundance of “liquid gold” in cold storage and don’t want it to go to waste. Enter the International Breast Milk Project, based in Boca Raton, which seeks milk for medically needy South African babies and for Prolacta Bioscience, a company that makes the only breast milk-based nutrition supplement sold to hospitals to feed sick infants.

Prolacta condenses the breast milk and adds nutrients designed to help premature babies grow. It gets 75 percent of the project’s breast milk for its product, and processes the remaining 25 percent, which is donated to South African hospitals and orphanages. The company also donates $1 to charity for every ounce used for its fortifier.

“Everyone knows you can donate blood, but not many people know you can donate breast milk,” said Amanda Nickerson, who runs the nonprofit project from her home in Boca Raton. Nickerson, 34, a mother of two with a third on the way, was a donor before she became executive director in 2010.

The project pays all a donor’s expenses, including sending a technician to her house to check her blood, reimbursing her for the pump and packaging and shipping her milk. Nickerson said the project usually works with about 200 donors at a time, although she would be thrilled to have many more. (Its website is breastmilkproject.org.)

There are 12 human milk banks in the United States, and an increasing number of hospitals are trying to feed breast milk to sick babies. Some nursing mothers have begun sharing milk informally through Facebook or Craigslist, decreasing the potential supply to the banks. Some say Prolacta, through aggressive marketing, is depleting the supply to the nonprofit milk banks.

Melissa Bixler, 28, whose son was born 10 months ago, researched her donation options and decided to work with the International Breast Milk Project. Bixler had an abundance of milk in her freezer and wanted to help needy babies.

“Some people on the Web tell you not to work with Prolacta,” said Bixler, who recently moved from Miramar to Jacksonville. “But [the International Breast Milk Project] made it so easy for me to donate. They send you all the kits. A lot of the milk banks make you do all the work on your own and deliver it yourself.”

Annette Leary, an Orlando pediatric nurse and spokeswoman for the International Lactation Consultant Association, said Prolacta needs mother’s milk to make its product, which is good for premature babies who can’t digest ordinary formulas.

“I’m glad we have a human milk fortifier rather than only having the option of cow’s milk-based formula,” she said.

Anne-Marie Sawicki, a Boca Raton lactation consultant, agreed.

“It’s not like it’s slave labor,” Sawicki said. “The bottom line is the milk is going to babies.”

Nickerson said the project is looking into expanding donation destinations to countries such as Haiti. She said she plans to start pumping for the project after she gives birth in November.

“The first time I did it, I didn’t know as much about how the project worked,” Nickerson said. “Now I can talk to the orphanage director and say, ‘My milk will be on the next shipment.’ ”