More of the old back and forth.
Only a piddling amount of money is involved -- as yet -- if any. It appears to be a simple statement without any details of the offending shipments. Did it really occur, i.e., is it an agressive tactic or only a mouthful of threat?
But that's not the most important question. Instead: who'll cave when the stakes are truly high? Will the Americans even last that long?
UPDATE (June 28, 2007)
From the New York Times:
The Food and Drug Administration today issued an alert challenging imports of five major types of farm-raised seafood from China, including shrimp and catfish, because testing found recurrent contamination from carcinogens and antibiotics.
The alert means that the fish will be allowed for sale in the United States only if testing proves that it is free of certain antibiotics and carcinogens
UPDATE (June 29, 2007):
American consumer reaction to Chinese food imports has been overwhelmingly negative. See for example this page.