Bright Dairy, a major Chinese producer of milk products, said it has recalled a batch of milk tainted by an alkaline cleaning product.

"All the 300 cartons of that faulty batch have been taken off the shelves and recalled immediately after the problem was detected by some consumers and the quality watchdog," Shanghai-based Bright Dairy and Food Co said in a statement on its website dated June 26.

It is not believed the products posed a health risk.

Zhang Xiazi, a manager of public affairs with the company, declined to tell China Daily on June 28 why the problem was not found in the first place because every batch undergoes a spot check before leaving the factory.

The products involved were 950-milliliter cartons of UBest, the company's high quality fresh milk, produced in a Shanghai plant on June 25. It was caused by some alkaline water used for cleaning that seeped into the milk on the production line, according to the company.

Fan Zhihong, an associate professor with China Agricultural University’s college of food science and nutrition engineering, said alkaline water may not pose dangers to safety as it is often used in food processing.

"But the vitamins in the milk may be destroyed, and the mouth feel may be affected," she said.

The company said it has tested the stability of the production equipment and is sure there are no problems.