Bright Dairy & Food Co Ltd published a letter on Friday's edition of the People's Daily apologizing to consumers for a series of food safety issues.

The letter said that the company established a quality and food safety department to prevent similar cases.

The Shanghai-based company recalled a batch of its Ubest-brand milk products in June after an investigation revealed that the products might have been contaminated with lye, according to the city's quality and technical supervision bureau.

The contamination was caused by a mechanical malfunction during regular maintenance procedures.

Earlier this month, the company was ordered to remove a cheese product from shelves after it was found to contain an additive banned in food for babies. Investigations showed that the company had been adding milk minerals into the cheese product since December 2011. The product's packaging says it is for children aged one to three.

Milk minerals are banned in baby food because the substance has not been fully tested for potentially harmful effects.

Yang Jun, a spokeswoman for the Shanghai municipal government, said the company would face further penalties for changing the product's ingredients without authorization.