In mid-August 2011, the Formosan (Taiwanese) Department of Health turns away shipments of beef from the US after discovering residues of the drug ractopamine, a tissue-altering substance banned due to its harmful effects in 160 nations.

http://focustaiwan.tw/ShowNews/WebNews_Detail.aspx?Type=aALL&ID=201108110006
http://www.foodsafetynews.com/2011/08/taiwan-refuses-more-us-beef-for-drug-residues/
http://www.allaboutfeed.net/news/taiwan-and-us-at-stalemate-over-ractopamine-5348.html