Under the requirement of inspectors, a staff member at a KFC outlet in Yulin in Shaanxi province demonstrates the process of making fried food. The picture shows him adding magnesium trisilicate, a white odorless and tasteless powder additive, into the frying oil. [Photo: bjd.com.cn]

In response to reported food safety concerns over Kentucky Fried Chicken reusing its frying oil, China's Ministry of Health has ordered related departments to conduct further investigation.

KFC outlets in some Chinese provinces have been accused of repeatedly using same frying oil for up to 10 days and adding magnesium trisilicate to prolong its usage, which experts believe may cause cancer.

Ministry of Health spokesman Mao Qun'an said at a press conference that it has already made appraisals about the harmful effects of food fried with reused oil. It will report the test results to media as soon as they are completed.

In the meantime, KFC Corp (China) claimed it welcomes the Ministry of Health's tests. Adding magnesium trisilicate in fried oil complies with national food safety standards, it said.

According to national regulations on additives, magnesium trisilicate itself is safe, but whether harmful substances are produced after it is repeatedly heated needs further tests.