"I would like to make it very clear, in the strongest terms possible that I have never knowingly or deliberately ingested clenbuterol," the Saxo-Tinkoff rider, who failed the test at the Japan Cup on Oct 20, said in a statement.
"I can advise that during the period 8th-17th of October, before arriving in Japan, I was present in China for the World Tour race, Tour of Beijing.
"I understand that it has been acknowledged by the World Anti-Doping Agency (WADA) as well as other anti-doping bodies, that food contaminated with clenbuterol is a serious problem in China." [Source]
Reuters adds that Rogers' team mate "was handed a two-year ban following a positive test for clenbuterol on the 2010 Tour de France despite arguing he was victim of food contamination." The banned drug, Clenbuterol, thought to increase muscle mass and cut down on fat in pigs, caused a widespread scandal when traces of the additive appeared in Chinese pork in 2011.