The Chinese investigation into the swimmers failed to determine how the athletes ingested the banned substance, but concluded that they must have ingested it when they ate hamburgers in Beijing.
China's anti-doping organization informed the International Anti-Doping Organization Wada that a banned substance had been found, but that it was a case of contamination. Wada was not convinced by the explanation, but could not find any evidence to the contrary and did not pursue the case further.
According to the American newspaper, it was at least the third time in recent years that China had blamed positive doping tests on contaminated food.
In April, The New York Times, together with ARD and Daily Telegraph, revealed that 23 Chinese swimmers had tested positive for doping in January 2021 – six months before the Olympic Games in Tokyo.
The test results contained traces of the heart medication trimetazidin (TMZ), the same substance for which Russian figure skater Kamila Valieva was caught at the 2022 Olympic Games.
However, the amounts were so small that the Chinese anti-doping agency dismissed the doping allegations, claiming that the athletes had ingested the substance through contaminated food.