BEIJING — Chopped cardboard, softened with an industrial chemical and flavored with fatty pork and powdered seasoning, is a main ingredient in batches of steamed buns sold in one Beijing neighborhood, state television said.

The report, aired late Wednesday on China Central Television, highlights the country's problems with food safety despite government efforts to improve the situation.

Countless small, often illegally run operations exist across China and make money cutting corners by using inexpensive ingredients or unsavory substitutes. They are almost impossible to regulate.

State TV's undercover investigation features the shirtless, shorts-clad maker of the buns, called baozi, explaining the contents of the product sold in Beijing's sprawling Chaoyang district.

Baozi are a common snack in China, with an outer skin made from wheat or rice flour and and a filling of sliced pork. Cooked by steaming in immense bamboo baskets, they are similar to but usually much bigger than the dumplings found on dim sum menus familiar to many Americans.

The hidden camera follows the man, whose face is not shown, into a ramshackle building where steamers are filled with the fluffy white buns, traditionally stuffed with minced pork.

The surroundings are filthy, with water puddles and piles of old furniture and cardboard on the ground.

"What's in the recipe?" the reporter asks. "Six to four," the man says.

"You mean 60 percent cardboard? What is the other 40 percent?" asks the reporter. "Fatty meat," the man replies.

The bun maker and his assistants then give a demonstration on how the product is made.

Squares of cardboard picked from the ground are first soaked to a pulp in a plastic basin of caustic soda -- a chemical base commonly used in manufacturing paper and soap -- then chopped into tiny morsels with a cleaver. Fatty pork and powdered seasoning are stirred in.

Soon, steaming servings of the buns appear on the screen. The reporter takes a bite.

"This baozi filling is kind of tough. Not much taste," he says. "Can other people taste the difference?"

"Most people can't. It fools the average person," the maker says. "I don't eat them myself."

The police eventually showed up and shut down the operation.