HONG KONG • A carcinogenic substance was found in a sample of mooncakes made by a famed Hong Kong bakery, but it says it will continue to sell them.

Hang Heung Cake Shop, popular with tourists including Singaporeans for its trademark "wife biscuits", said it would not recall the mooncakes from its stores, according to a report by the South China Morning Post (SCMP).

Last Friday, the Macau authorities called for a halt to sales of the products, saying that a higher- than-allowed level of aflatoxin B1 was found in two mooncake samples, the SCMP reported. Besides the Hang Heung sample, the other was from a hotel in Macau, it said.

Aflatoxins are cancer-causing chemicals that can be produced by moulds. Aflatoxin B1 is said to be the most potent of these.

Some scientists have theorised that those with hepatitis B or hepatitis C have a higher risk of getting cancer from aflatoxin B1.

The Hang Heung mooncake sample had 7.48 micrograms of aflatoxin B1 for every 1kg of food, reported the SCMP. Macau bars the sale of any products with more than 5 micrograms per kg of the toxin.

However, in Hong Kong, 15 micrograms per kg or less of aflatoxin is allowed in food products, according to the Harmful Substances in Food Regulations law there.

Hang Heung executive manager Kazu Leung Chi-chung was quoted as saying by the SCMP that the company will keep selling the mooncakes as it had tried to call the Macau authorities but had not identified the problem. She added that its Macau bakery might not know Hong Kong had different standards from Macau, reported the SCMP.

Hang Heung has been in business since 1920. Though wife biscuits with winter melon paste are its signature product, it sells other Chinese confections like egg rolls.