China's quality watchdog said Tuesday that its latest checks did not find excessive levels of aflatoxin in milk produced by Chinese dairy companies.

The checks, which ended on Jan. 9, covered the country's leading dairy companies, including Mengniu Dairy Group, Yili Industrial Group and Beijing Sanyuan Food Co., the General Administration of Quality Supervision, Inspection and Quarantine said in a statement on its website.

The country has intensified its efforts to step up inspections on dairy companies and strengthen the monitoring of their production process to ensure milk safety and quality, after milk products made by Mengniu were found to contain high levels of aflatoxin, a cancer-causing substance, in late December.

The aflatoxin test has been added to the country's fluid milk product monitoring system. Quality watchdogs across the country will destroy all tainted products if high levels of aflatoxin are found, the statement said.

Aflatoxin, which affects grains and other agricultural products, can increase the risk of cancer, including liver cancer, according to experts.