Since last year, the FDA has been restricting entry of shrimp, catfish, dace, eel and basa from China unless those shipments come with an independent lab report certifying the seafood is free of such additives. Melamine isn't included on that list of additives.
The Chinese government, facing increasing pressure from the public, has begun to crack down on melamine suppliers and has widened inspections to include feed. And many Chinese exporters of farmed fish say government inspectors are coming around more often and examining samples.
Last month, 26 containers of shrimp, crawfish, tilapia and other fish from China were refused entry in Long Beach and other U.S. seaports. Inspectors cited a variety of reasons: salmonella, unsafe additives, unapproved drugs and labeling problems, according to FDA records on its website.
U.S. consumer advocates say the FDA has its own resource issues.
"They're so understaffed at the borders that despite whatever orders they have, we can't be sure that products aren't just coming through anyway," said Jean Halloran, food policy initiatives director for Consumers Union, the publisher of Consumer Reports. "We need much better testing," she said, including of melamine in fish.
FDA officials last month opened three offices in China, part of a strategy to deploy agency staff in countries where many U.S. foods now originate and where they can work with local inspectors and the industry.
"We cannot inspect our way to import safety; we have to roll our borders back and work with producers and have [their products] certified by people we trust," said Michael Leavitt, secretary of the U.S. Health and Human Services Department, under which the FDA operates, during a visit to China last month.
A food-source issue
Karunasagar, the U.N.'s fishery expert, said governments in China and elsewhere needed to tackle the problem at the source. "More than the fish, we should monitor melamine in the feed."
But that's easier said than done. In the U.S., commercial fish farms have to use feed from a handful of approved suppliers, but in China, there may be hundreds of thousands of sources for feed, said Steve Dickinson, an American attorney in China's coastal city of Qingdao who ran a salmon-farming business in Washington state.
Melamine has "infected the whole system in China," he said.
More than 15 feed suppliers in various parts of China were contacted for this story. Most of them declined to comment or said they didn't add melamine. But some of them said the practice of spiking feed with it had been going on for at least the last six years, with inspectors checking some types of feed products more tightly than others.
"It is not so regulated, for example, in the fish powder industry," said Zhuge Fulai, manager of Lianfeng Protein Feed Plant in Shandong province.
Fang, the feed research manager in Shanghai, said adulterating feed was particularly rampant in 2003 and 2004. He doubts that many feed suppliers today are adding melamine, given the awareness and the government's publicized crackdown, but neither he nor anyone else thinks the problem has been eradicated.
"We still need more government supervision," Fang said. "We need to have more random checks and to fully execute regulations and standards."