The warning came after the city’s Department of Health recently inspected 25 cold noodle products, 11 of which was selected from local convenience stores, three from hypermarkets and 11 from other stores and vendors.

The inspection was aimed at checking levels of bacteria, hydrogen peroxide and borax in cold noodle products, said Chiang Yu-mei, director of the department’s Food and Drug Division.

Initially, 10 of the samples failed to pass health standards, Chiang noted, adding that the health department demanded immediate improvements but later discovered that one noodle store’s product was still below acceptable safety standards.

Violators face fines of between NT$30,000 (US$977) and NT$100,000, according to Chiang.

She pointed out that none of the inspected products were found to contain hydrogen peroxide or borax, but reminded customers that cold noodles should be kept at temperatures below 7 degree Celsius.

Chiang warned that bacteria in cold noodles will quickly multiply if they are kept at room temperature for more than four hours, which can render them dangerous.

She called for good hygiene management at local stores and warned that the bureau will continue to conduct random checks to ensure food safety.

In July, the Consumers’ Foundation also conducted a similar check and found 80 percent of 20 cold noodle samples in the Greater Taipei area contained excessive levels of bacteria such as E. coli.

All of the products selected from local vendors failed to pass the health inspection at that time, the foundation pointed out.