At Yili headquarters, reporters were shown a new station for melamine testing where workers wearing lab coats and gloves used testing equipment they said cost the company $15 million.

But while scientists say it's not dangerous to ingest small amounts, they cannot be definitive because there have been no tests on melamine's effects in humans.

The FDA said the low level of melamine was detected with the use of new technology that can detect minute traces of the chemical.