CHANGCHUN, May 5 -- Fifty boxes of roasted seaweed imported from the Republic of Korea to northeast China's Jilin Province were found containing excessive levels of coliform bacteria, local authorities said Tuesday.

According to staff with the entry-exit inspection and quarantine bureau of Hunchun City, the levels of bacteria in the roasted seaweed reached 4,600 MPN / 100g, while the Chinese national standard stipulated coliform bacteria content should not be detectable in food.

Coliform bacteria is an important indicator of food hygiene quality. Eating food with excessive levels of the bacteria can cause infectious intestinal diseases or food poisoning.

Authorities in the city have destroyed the problematic imports according to law.

A report published last month by the General Administration of Quality Supervision, Inspection and Quarantine shows, substandard products have been discovered by Chinese authorities in almost all categories of imported foods during the last year.