A recent report on preservatives in hotpot meals may have you thinking twice about eating the traditional winter warmer this season, but how worried should you be?
Last week, a South China Morning Post cover story revealed that a report by the Market Supervision Administration of Shenzhen found unacceptable levels of preservatives in 38 of 200 samples collected from hotpot restaurants across our neighbouring city, a popular dining destination for Hongkongers.
The preservatives include benzoic acid, excessive levels of which could affect the central nervous system and liver, short-term studies in rats have shown, according to the World Health Organisation. Scientists also suggest that sodium benzoate - the sodium salt of benzoic acid - could cause DNA damage and neurodegenerative diseases such as Parkinson's disease.
The preservatives were found in beef tendon balls, pork balls, beef balls and mushroom balls, which the restaurants had bought from various supermarkets in Shenzhen, Xinhua news agency reported.
Mainland authorities have zero tolerance for the use of benzoic acid in fresh foods, such as the meatballs. In Hong Kong, benzoic acid - and its sodium, potassium and calcium salts - are permitted preservatives in specific food items, including beer, fruit juices and soy sauce, according to the Centre for Food Safety. The maximum permitted levels range from 70 to 10,000 milligrams per kilogram in different types of food.
Benzoic acid and sodium benzoate are on the US Food and Drug Administration's list of substances that are generally recognised as safe. Both may be used as antimicrobial agents, flavouring agents and as adjuvants with a current maximum level of 0.1 per cent in food.
The report provided no details about the level of preservatives found in the food samples. Also unknown was the source of the ingredients - and whether any of them had been exported to Hong Kong.
Benzoic acid was discovered in the 16th century and is used as a preservative in foods and found in cosmetics and drugs. In food, it is used as an antimicrobial additive primarily against yeast and moulds. It's particularly effective for preserving foods with high acidity, such as soft drinks, fruit juices, salad cream, tomato sauce and yogurt.
Traces of benzoic acid are found in cranberries, prunes, greengage plums, cinnamon, cloves as well as milk products. Naturally occurring benzoic acid usually does not exceed 40 milligrams per kilogram.
Benzoic acid is also used in cosmetics, pharmaceuticals, herbicides, flavours and antiseptic ointments for fungal infections of the skin.
According to the WHO, information concerning long-term oral exposure of experimental animals to the preservative is very limited. Hong Kong's Centre for Food Safety advises people to maintain a varied and balanced diet so as to avoid excessive exposure to benzoic acid and other food additives from a small range of food items.
So, don't only have hotpots or meatballs this winter - there are many other ways to warm up.