A survey of imported Mainland food items found that seven contained chemicals exceeding the legal limits, the Food & Environmental Hygiene Department says.

Some 133 food items were collected last month from various outlets for testing for preservatives, additives and contaminants.

Three samples of sauce were found with benzoic acid at levels of 530 parts per million, 590 ppm and 750 ppm.

A sample of preserved food contained benzoic acid at 1,700 ppm while another type of preserved food contained chromium at 1.9 ppm. A sample of instant food was found to contain 660 ppm of sorbic acid.

Assistant Director of Food & Environmental Hygiene Dr Thomas Chung said except for the aflatoxins, the excessive levels of chemicals are unlikely to harm health.

Common preservatives

Benzoic acid and sorbic acid are common preservatives and widely used in food items including beverages, preserved fruits and sauces, he said.

Under the Hong Kong food law, they are allowed to be used in some food items to a level up to 1,000 ppm. They are of very low toxicity and the levels detected are unlikely to harm consumers.

"As for chromium, it is a naturally occurring element found in the environment. Chronic exposure to excessive chromium may affect the kidney and liver. But the level detected is unlikely to cause any acute toxicity," Dr Chung said.

Retailers have been asked to stop selling the products. The department has stepped up random inspections of similar products.

"We have also informed Mainland authorities about the findings on the seven products and checked with them whether any of these are exported to Hong Kong," he said.

Dr Chung urged food traders to ensure that all food for sale complies with the food laws and is fit for human consumption. Vendors should always obtain food from reliable suppliers.

While pledging to keep up the efforts in food surveillance, Dr Chung said the department will continue to attach great importance to enhancing food safety awareness.