A company that supplies french fries to McDonald's Corp. in China has been fined a record 3.9 million yuan ($630,000) for water pollution.

Beijing Simplot Food Processing Co. Ltd., a joint venture between McDonald's, U.S.-owned J.R. Simplot Co. and the Beijing Agricultural, Industrial and Commerce General Co., said that it "respects and accepts" the decision of the Fengtai District Environmental Protection Bureau and has paid the fine.

The regulator took action after discovering that Beijing Simplot had been discharging contaminated wastewater that exceeded permitted levels. According to the official Xinhua News Agency, the company was upgrading its sewage treatment facilities at the time of the discharge.

Beijing Simplot said in a statement on Wednesday that it had acted promptly to address the problem.

"As soon as we discovered that we had a wastewater issue, we cooperated with the local environmental protection authority, shut down the wastewater discharge and transported excess wastewater to an approved facility for processing. We also conducted an internal procedural investigation and actively cooperated with the monitoring work of the local environmental protection authority to prevent this from happening again."

McDonald's told news agency AFP that it took the matter "very seriously" and would be monitoring Beijing Simplot's compliance in the future.

"All McDonald's suppliers must comply with all relevant local laws and regulations," the company said.