Seoul, Dec 16 (IANS): Maeil Dairies, a major dairy product manufacturer, on Monday issued an apology over an accident involving the mixing of cleaning solution in one of its sterilized milk products during production.

Maeil Dairies CEO Kim Seon-hee said in a statement posted on the company website that a valve operation error momentarily caused cleaning solution to mix with the 200 milliliter sterilized milk product at the company's manufacturing plant in Gwangju, about 270 kilometers south of Seoul, on September 19.

"We sincerely apologize to our customers who have been shocked by this issue," Kim said.

The company said about 50 units delivered to a single specific client were affected by the incident, reports Yonhap news agency.

The issue came to light after some employees at a major corporate research center reported symptoms, such as stomach pain and discoloration, after consuming the product provided through the company cafeteria last Thursday.

The Ministry of Food and Drug Safety said it was conducting an on-site investigation into the case with local authorities to find the cause of the incident.

"We will appropriately respond under related laws when the investigation results come out," the food safety agency said.

Meanwhile, agricultural ministry here recently said that dairy farmers and businesses have reached an agreement to freeze the price of raw milk to alleviate the public burden amid ongoing inflation.

The agreement was reached after negotiations that began in June to address the rising production costs, according to the Ministry of Agriculture, Food and Rural Affairs.

As major milk producers, including Seoul Dairy Cooperative, Maeil Dairies Co. and Namyang Dairy Products, pledged to freeze the retail prices of their plain milk, the ministry added that the move will also help limit price hikes for other related goods that use milk as an ingredient.

Separate data compiled by Statistics Korea indicated that the production cost of milk increased by 4.6 won per litre from a year earlier.