PHNOM PENH, Cambodia — Cambodia has permanently banned the export of human breast milk by a company headed by a former Mormon missionary that pioneered the business two years ago.

A letter issued Tuesday by the Cabinet to the Health Ministry said Prime Minister Hun Sen has ordered a halt to U.S.-based Ambrosia Labs Ltd. buying and exporting the milk. The product is marketed as food for babies and as an supplement for adults with special needss, and sells for as much as $4 an ounce.

The letter indicated national pride was at stake. “Even though we are still poor, we are not so poor that we have to sell human breast milk,” said the statement by Secretary of State Ngor Hongly.

The milk’s export was recently suspended while the Health Ministry investigated the health effects on babies of nursing mothers selling their milk and whether the business violated a law on trafficking in human organs.