BEIJING -?China's quality watchdog said Friday that nitrite was detected in?several batches of edible bird nests imported from Malaysia during the September to October period.

These products were found at entry ports in Guangdong and Fujian provinces, according to the General Administration of Quality Supervision, Inspection and Quarantine (AQSIQ).

Although widely used to cure meats, nitrite can cause health problems, including cancer, if ingested in large amounts.

One batch of the defective products from Malaysia during the period also tested positive for staphylococcus aureus, or golden staph, which can cause various diseases such as pneumonia and sepsis, the AQSIQ said.

During the same period, two batches of bird nests labelled as having originated in Hong Kong were found to contain nitrite, with one batch also found to contain sulfur dioxide, the AQSIQ added.

AQSIQ Spokesman Li Yuanping said all these unqualified products have either been returned or destroyed by the local entry-exit quarantine inspection authorities and didn't enter the domestic market.