In order for USADA to have accepted the excuse from Wilson there MUST be some such data somewhere. If anybody has it, a link would be great.
According to the USADA, there are no such data.
Because they got so many questions after Wilson's case, USADA set up a web page called "What Athletes Need to Know about Zeranol." The message is simple: Nobody needs to worry about testing positive for zeranol because they ate "contaminated" beef. Nobody needs to worry because: 1) Only one American athlete has ever tested positive for zeranol; world-wide, only six athletes have ever tested positive; and, 2) USADA, which looks for zeranol in animals, rarely finds it; the most recent case was in 2014, and that was in a pig, not a cow.
Given the facts of Wilson's case -- the amounts were miniscule, and Wilson had recently tested clean -- USADA concluded "the beef did it." Given the facts of the world -- only she has tested positive, and almost no meat has zeranol -- Deadspin nailed it when they called this "the curious case of Ajee Wilson."