In a statement, the Agri-Food & Veterinary Authority of Singapore (AVA) said it has tested 66 starch-based products from Taiwan and found maleic acid in 11 of them.
“Most of the affected products were tapioca starch balls used in the preparation of bubble tea beverages. AVA has informed the importers of the affected products to withdraw them from sale immediately and the withdrawal has been completed,” said the statement.
Maleic acid is not an approved additive in Singapore, and is rarely used in the manufacture of food products. Long-term consumption of high levels of the chemical can cause kidney damage, although occasional consumption at the levels detected does not pose any significant health risk, said the authority.
AVA said it would continue its surveillance of products from Taiwan to ensure that they do not contain maleic acid.
The announcement came shortly after the recall of Sun Right brand tapioca balls in Singapore, after the Taiwan Food and Drug Administration had detected maleic acid in some food products.
The affected Taiwanese products included fish paste products (oden), flat rice noodles and taro/yam balls, as well as the tapioca balls, which are commonly used in bubble tea.
This finding prompted AVA to inspect Taiwanese food products more closely for traces meleic acid, leading to the 11 product withdrawals.
Tapioca have reached craze-like popularity among the café-culture scene of Singapore, with the small, sweet and chewy “bubbles” forming a layer at the bottom of a beverage cup.
However, vendors have been told to stop serving the product if the bubble tea bubbles are sourced from any of the 11 proscribed Taiwanese brands.
According to an investigation by Singapore’s Straights Times newspaper, this affected one-quarter of the coffee shops and bubble tea vendors it surveyed.
This is not the first time bubble Taiwanese tea has found itself in hot water. Last September, a study by German researchers found that a random sample of tapioca balls from the Far East country for sale in a German coffee shop chain could include cancer-causing chemicals known as aspolychlorinated biphenyls.
"[What we found] includes in particular styrene, acetophenone, and brominated substances that shouldn't be in food at all," scientist Manfred Möller, of the Institute of Hygiene and Environmental Medicine at the University Hospital Aachen, told German newspaper The Local.
However, both a leading manufacturer of bubble tea drink ingredients and Taiwan's Food and Drug Administration subsequently disputed the researchers' claims, calling into question the authenticity of the test results.