The Centre for Food Safety tested 12,800 food samples in July and August and found 79 to be unsatisfactory.

Six were vegetable samples with trace amounts of methamidophos while five had cadmium exceeding the permitted level. A green pea sample was found containing brilliant blue FCF, which is banned for fresh vegetables.

Twenty-five preserved vegetable samples were found to contain sulphur dioxide or benzoic acid, while 15 preserved fruit samples contained sulphur dioxide, benzoic acid or sorbic acid. All the preservatives detected had exceeded legal limits.

A chicken sample contained Staphylococcus aureus. Six fish samples had malachite green or nitrofurans, one spicy cuttlefish had Sudan dye, and a shrimp sample had salmonella.

An ice-cream mooncake, three ice-cream, nine watermelon juice-based bar and one milk beverage samples failed the tests for hygiene indicators. A rice cracker sample was found to contain acid red 52 while a corn chip had Sudan dye. A macaroni with egg and ham sample and a bean curd dessert contained Bacillus cereus.

The centre has traced the sources of the food and asked vendors to stop selling and dispose of the items, and issued warning letters. If there is sufficient evidence, prosecution will be taken.

Most of the breaches are not serious and will not pose immediate health risks. As a number of unsatisfactory samples related to the use of excessive or non-permitted food additives, the centre urged the food trade to use only permitted food additives, follow good manufacturing practice and comply with legal requirements.

People should thoroughly wash vegetables before cooking as most pesticides, such as methamidophos, are water-soluble.