BEIJING — Former top-ranked badminton player Zhou Mi has submitted expert evidence in her latest attempt to overturn a two-year doping ban.

Zhou says she must have unknowingly ingested clenbuterol by eating pork tainted with the banned drug. Clenbuterol has been used in cattle and pig raising in China.

China’s official Xinhua News Agency says an independent assessment by a Hong Kong scientist showed the low concentration of clenbuterol found in Zhou’s system was inconsistent with what would have been found in an athlete using the drug to enhance performance.

The world badminton federation handed Zhou a two-year ban in September 2010 after a urine sample came back positive for clenbuterol.