The general manager, Mao Lijun, is being held in the coastal province of Jiangsu about 320 miles northwest of Shanghai, the New York Times reports.
Mao heads Xuzhou Anying Biologic Technology Development Company, a company identified by American regulators as one of two Chinese firms that produced the contaminated ingredients found in pet foods that have sickened or killed thousands of dogs and cats in the United States. Investigations revealed that the pet food contained melamine, a mildly toxic industrial chemical.
Chinese officials have not said why they are holding Mao or indicated if he is facing any charges.
Mao denied any wrongdoing during a telephone interview with the Times a few weeks ago.
Scientists remain uncertain about why the contaminated food sickened or killed so many animals. Melamine is mildly toxic but is not considered dangerous at low levels.
