Dried fruits have highest sulphite levels, Hong Kong survey finds

A citywide survey in Hong Kong has found that dried fruits have the highest level of sulphites, a common type of food preservative, but researchers have said the risks are minimal given the population’s low dietary intake of the chemical substance.

The Centre for Food Safety on Friday released the results of a study conducted between February 2023 and January this year to assess residents’ dietary exposure to selected chemical substances of potential food safety concern.

Long-term excessive exposure to sulphites was found to cause stomach irritation and affect the central nervous system in experimental animals. For those sensitive to the substance, exposure could result in reactions such as constriction of the airways.

The study tested levels of sulphites in a total of 185 food items, and found 17 of them, or 9 per cent, contained detectable levels of the substance.

Among the items, dried fruits were found to contain the highest mean concentration of sulphites, at 240mg/kg, followed by 30mg/kg in button mushrooms, 27mg/kg in wine, and 23mg/kg in preserved vegetables.

The other food items that were also detected with the substance, such as bamboo fungus, shrimps and prawns and beef, were found to contain a mean concentration of 10mg/kg or below, according to the findings.

“Sulphites were not detected in the majority of the food items tested,” said Terence Cheung Yung-yan, a consultant of the centre.