Three types of mushroom, including one produced locally, as well as Chinese sauerkraut, were taken off Beijing's shelves on Wednesday due to excessive amounts of sulfur dioxide.

The Beijing administration of industry and commerce recently concluded a chemical check of 423 random food types in the capital, which included vegetables, fruit and meat.

The administration found Yunhong, Tianbao and Luze brand mushrooms, as well as Xingzhuangyuan Chinese sauerkraut, were not up to national standards. They all contained excessive levels of sulfur dioxide, which experts warned could damage health.

The result of the check was published on the administration's website (www.hd315.gov.cn) on Thursday, with a statement that consumers had the right to return their products, along with receipts and packaging, to claim a full refund.

The State standard for sulfur dioxide levels in mushrooms should be no more than 0.05 grams per kg. However, specific contamination details were not provided on the site about the affected goods.

"Sulfur dioxide is sometimes added as a whitening agent and is used in many foods," said Li Rong, a professor with the Nutrition and Food Safety Institution in the Chinese Center for Disease Control and Prevention.

Li told METRO excessive levels of sulfur dioxide are a recurring problem in the food industry, due to its ability to improve the appearance of vegetables and fruit.

Zhang Jing, a 29-year-old woman, said she was shocked at the news.

"I thought white mushrooms were the freshest, so I am actually surprised to find they are so bad for me," she said.

Zhang added that she was worried the sulfur dioxide her family had already consumed might harm their health.

"A little sulfur dioxide is safe because it detoxifies inside the body and is then passed out through urine," said Li Ning, a professor with the Nutrition and Food Safety Institution at the Chinese Center for Disease Control and Prevention.

However, Li said eyes and noses are affected in cases of acute poisoning, which can lead to asphyxia and coma, even death.

He noted that ingesting sulfur dioxide over an extended period can lead to nasal diseases and bronchitis, as well as stopping the body from absorbing calcium.