China's quality watchdog on Thursday refuted recent reports that Chinese soybean milk machines are using unhealthy industrial lubricants, saying a national inspection found no such problems.

The General Administration of Quality Supervision, Inspection and Quarantine (AQSIQ) said all the soybean milk machine manufacturers it has checked adhere to national quality standards.

The machines use food-grade lubricants in their engines and have no leakage problems, it said in a statement.

Earlier this month, Chinese media reported that household appliances, such as soybean milk machines and juice extractors, had been made with carcinogenic industrial lubricants.

The AQSIQ said its inspection included 30 major companies, including the two leading brands Midea and Joyoung whose combined market share exceeds 90 percent of the national total.