The Centre for Food Safety found 15 out of 6,000 food samples tested in May to be unsatisfactory, mainly involving excessive or illegal use of food preservatives or colourings or metal contamination. The overall satisfactory rate was 99.7%.

It tested vegetables, fruit, meat, poultry, aquatic products, milk, milk products, frozen confections, cereals and grains.

Apart from the eight unsatisfactory food samples announced earlier, a Spanish sausage sample was also found to contain sorbic acid while a fresh beef sample contained sulphur dioxide. Three fresh oyster samples contained excessive cadmium.

A Chinese red bun sample was found to contain the non-permitted colouring matter Rhodamine B while a nopal juice sample contained excessive benzoic acid and sorbic acid.

The centre said today the exceedances or breaches are not serious. It has traced the source of food in question, stopped their sale and issued warning letters.