Another food scandal has been uncovered in China.

A group of some 50 factories have been found to be manufacturing artificial sauces and flavourings, some with illegal ingredients, in the Chinese city of Tianjin, the Beijing News reports.

The investigative report revealed that the products were being falsely labelled as popular brands such as Nestlé, Knorr and Lee Kum Kee.

The factory in Duliu Image: The beijing news

It appears that one of the Nestlé products they were counterfeiting is Maggi seasoning sauce, commonly found in Asian supermarkets.

Image: taobao

Knorr is owned by Unilever, and makes chicken cubes and condiments; Lee Kum Kee is a well-known Hong Kong brand famous for its oyster sauces.

According to the Beijing News, about 100 million yuan ($14.5 million) worth of fake products are produced each year in Duliu, the Tianjin town in which the con was uncovered.

The products have been sold across the country, and the ring of factories were in operation for over a decade, said the report.

Ingredients for the fake food seasonings include tap water and industrial-grade salt, which is banned from human consumption in China because it can cause damage to the liver and kidneys due to the presence of cancer-causing agents and heavy metals.

Soy sauce is mixed in plastic vats such as these Image: the beijing news

Factories also bought spices and herbs that had already been used, such as star anise and pepper from nearby factories, then dried them and ground them into powder.

The operations are carried out in squalid conditions, with many factories operating inside dilapidated buildings.

Many of the used herbs are ground into powder to be used again Image: the beijing news

The Beijing News reporter accompanied a police raid of the factories, after years of successful evasion by the counterfeiters.

Many of the factories, which hire dozens of workers, have surveillance cameras installed outside their buildings and are alerted when strangers enter the premises. This has made it difficult for local police to crack down on them.

They goods are also moved immediately so as to avoid detection.

In the raid, police arrested several people caught in the act, and have also seized their materials and equipment.

This has not been the first time Chinese factories have been found manufacturing fake products.

Last year, thousands of cans of fake infant formula entered the Chinese market, with 1,000 cans of fake Similac milk powder seized by police in numerous raids.