Industrial oils, wax, chemicals that can cause cancer and many other dangerous ingredients have been found in thousands of widely consumed foods in China, state press reported Wednesday.
A nationwide investigation by China's food quality watchdog found products such as baby milk powder, rice, flour, meat, biscuits, seafood, soy sauce and sweets had been contaminated.
More than 23,000 tainted or sub-standard foods were found and 180 food manufacturers closed in the crackdown from December last year to May, in what is believed to represent only a fraction of the problem.
"These are not isolated cases," the China Daily newspaper quoted Han Yi, a director with the General Administration of Quality Supervision, Inspection and Quarantine, as saying as he unveiled the findings on Tuesday.
The watchdog's probe focused mainly on China's countryside and Han said investigators now intended to turn their attention onto the cities.
The announcement of the investigation's findings come as China faces unprecedented international scrutiny over the quality of its food imports and other goods that have caused harm to buyers overseas.
Reports in the United States of tainted pet foods, dangerous toys, drugs, fish, cosmetics and other products from China have led to a spate of recalls and bans there.
In Panama, at least 80 people are believed to have died from taking a cough syrup contaminated with a toxic substance imported from China.
In the investigation by China's quality watchdog, one of the industrial products found in foods was formaldehyde, a chemical more famously used to embalm people, according to the China Daily.
Other industrial materials included paraffin wax and various dyes including malachite green, which can be carcinogenic, were also found.
Han said most of the sources of the contaminated foods were small, unlicensed food processing plants that employed fewer than 10 people.
However, about 75 percent of China's one million food-processing plants are small operations, according to the quality watchdog.