The list of quality-compromised goods from China got longer Thursday as federal authorities slapped a highly unusual hold on shrimp and certain fish from that country after tests showed contamination from potentially harmful drugs.

The Food and Drug Administration said it would block all shipments from China of farm-raised shrimp, catfish, eel and two other kinds of fish until importers can produce independent test results showing the items to be free of drugs banned in U.S. fish farming.

Agency officials said there was no immediate threat to human health. An industry expert said he didn't expect shortages of shrimp because of the FDA action, because there was more than enough available on the world market.

Thursday's hold came just days after federal transportation officials ordered the recall of as many as 450,000 tires made in China after some lost their treads on the road. Toothpaste from China that was recalled because of contamination with an antifreeze chemical now turns out to have been distributed not just to a few discount stores but to prisons and mental hospitals in Georgia. This year, a pet food manufacturer recalled massive amounts of its products because of contamination from an ingredient imported from China.