SEOUL, SOUTH KOREA - SHARES in South Korean food maker Nong Shim fell on Tuesday after what a government regulator said appeared to be a rat's head was found in a bag of its popular brand of shrimp cracker snacks.

Retailers across the country pulled bags of the top-selling snacks called 'Saewookkang' from their shelves following the release to the public late on Monday of pictures of the suspected rodent part.

By 10.31am Nong Shim shares were down 3.4 per cent to 185,000 won (S$250).

'The Korea Food and Drug Administration (KDFA) believes the suspected substance was mixed in during the half-finished manufacturing or packing process at a site located in China's Tsingtao,' the government regulator said in a statement.

'Based on results from the Nong Shim factory, we suspect that the substance is a rat's head,' KDFA said.

A Nong Shim spokesman said the company was not sure if the suspected rat's head entered into the production process in China or in South Korea.

'The company is fully responsible for this accident,' the spokesman said, and Nong Shim has halted sales of the cracker.

The shrimp crackers are a popular bar food served with beer and are also a favourite with children.

KDFA said, based on an inspection of the plant in the southern Korean city of Busan, there were no signs the suspected rat's head entered during the final manufacturing process.

'This accident is likely to affect Nong Shim shares temporarily because the shrimp snack accounts for only about 4 per cent of its overall revenues,' said Mr Lee Jeong Ki, an analyst at Daishin Securities. 'But it has obviously damaged the company's image.' -- REUTERS