Two pork samples have failed Centre for Food Safety tests as they contained sulphur dioxide, a preservative not permitted in fresh meat.

The centre has issued a warning to the vendors in Yau Ma Tei and Fa Yuen Street where the samples were collected, and prosecution action will be taken.

While the preservative is water-soluble and most of it can be removed through washing and cooking, people who are allergic to it may experience breathing difficulties, headaches and nausea.