Food adulteration continues to be a major concern in China as police in Xi'an, capital of Shaanxi province have detained two persons suspected of making noodles using toxic formaldehyde.

Meng Jiangwei, an officer at the Lianhu district Laodong Nanlu police station said two shops were found to be selling noodles mixed with formaldehyde as an ingredient.

Police detained the shop owners and seized two bottles of formaldehyde and more than 300 kilos of formaldehyde-poisoned noodles, state-run China Daily reported.

Formaldehyde is a highly toxic substance which according to the World Health Organization can cause cancer and birth defects.

Police said the shop owners, surnamed Zhang and Tang, confessed to making noodles with formaldehyde to keep them fresh in the hot summer days.

Chinese government has stepped up campaign against food adulteration as a series of scandals continue to rock the country eroding public confidence.

On April 7, the Central Cabinet ordered all localities and departments to continue their crackdown on the illegal use of food additives.

On May 2, the Ministry of Public Security announced five cases of crimes concerning meat that police across the country had discovered, and on May 3, the Supreme People's Court announced a number of criminal cases on food safety, including producing and selling fake liquor, selling sausage and ribs made from dead pigs, and the production and sale of gutter oil.

The most prominent food scare in China was the milk scandal of 2008 involving milk and infant formula adulterated with melamine with about 300,000 people falling sick, six infants died from kidney damage, and an estimated 54,000 babies were hospitalised.