Xuzhou Anying Biologic Technology Development Company Ltd. was named in a notice issued by the U.S. Food and Drug Administration as the source of wheat gluten containing a chemical found in plastics and pesticides.

Geng Xiujuan, Xuzhou Anying's sales manager, said the company was aware of the notice and was looking into the accusation that large concentrations of melamine had been found in its wheat gluten, a protein source used as an ingredient in the pet food.

However, Geng said the company based in the eastern province of Jiangsu had not manufactured the gluten but had instead bought it from companies in neighboring provinces. She said Xuzhou Anying sold it onward to another Jiangsu company, Suzhou Textile Import and Export Co.

"There are many other exporters and I don't see why they would just blame us," Geng said. However, "We are doing the self inspection now," she said, adding it was too early to announce any results.

The U.S. investigation has traced the melamine to wheat gluten that Menu Foods, Nestle Purina PetCare Co. and Hill's Pet Nutrition bought from an unnamed U.S. supplier.

The latter two companies have recalled a limited number of products since Friday.