BEIJING, July 19 (Xinhua) -- A widely aired expose of Beijing dumpling makers who used cardboard as a filling was a hoax and police have arrested the reporter, Beijing Television station has said.

    The station apologized in an evening news programme on Wednesday for airing the fabricated report produced with a home DVD camera by Zi Beijia, a temporary employee, on its Life Channel.

    "We should apologize to the public for the Life Channel's failure to strictly examine the content of the report, resulting in the airing of a faked report which in turn undermined public confidence," said the station announcement.

    The All-China Journalists' Association has released a statement which was aired by China Central Television Channel 1 (CCTV-1) on Thursday evening, denouncing the report and calling on all Chinese media workers to pursue genuine issues and preserve professional ethics.

    "Authenticity is key to journalism and ensuring authenticity of news reports is the basic professional ethic of journalists," said the statement, citing the banana virus rumour earlier this year, which resulted in a drop in Hainan banana prices and caused losses of as much as 20 million yuan (2.6 million U.S. dollars) per day.

    "This event rang an alarm in media circles ... journalists should safeguard their social image and ... fulfill their mission and responsibility endowed by the Communist Party and the people," said the statement.

    The investigative report about the so-called problematic meat buns done by Zi was aired in a slot known as "Transparency" on July 8, sparking a public outcry.

    Mayor Wang Qishan ordered an immediate investigation, and order those involved to be prosecuted if it were true.

    Beijing Municipal Food Safety Office organized an intensive inspection campaign from July 11 to 14 targeting breakfast stands in the city's Chaoyang District, where the report was shot, and areas on the urban outskirts.

    Food safety inspectors collected more than 100 samples of meat bun fillings, but failed to spot paper fiber or other illegal ingredients, said a spokesman from Beijing Municipal Food Safety Office.

    The office organized a group of specialists on July 15 to assess the report and they suggested scientific food analysis.

    Professor Chen Min, of the Food Science College of China Agricultural University, organized a simulation of the recipe from the TV report, and the specialists concluded it was impossible for the cardboard to go unnoticed.

    "Even if you mix a tiny proportion, to say five percent, of cardboard, the fiber substance can be easily seen, and the meat buns made this way could not be easily chewed," said the spokesman from the Beijing Municipal Food Safety Office.

    Local police began an investigation after municipal industrial, commercial and food safety officers questioned the credibility of the news report.

    Under interrogation, Zi, who joined Beijing TV as a temporary worker with the Transparency column this year, allegedly admitted fabricating the entire report, shot from June 15 to July 3.

    Police said Zi admitted he put forward a suggestion during an editorial meeting in early June to investigate the quality of meat buns and the Transparency producer showed great enthusiasm.

    "I focused my investigation on areas adjacent to the Fourth Ring Road. For half a month after the editorial meeting, I visited many stands selling baozi and usually spent one yuan on baozi at each stand," said Zi, according to police.

    But, he allegedly said, the pressure to produce a story built up over time as he realized he could not find anything to report.

    Pushed by the Transparency editor, Zi decided to take risks. Under the name Hu Yue, Zi twice went to the No.13 courtyard inside Shizikou Village, Taiyanggong Township of Chaoyang District, and asked four migrant workers who had been preparing breakfast there to make meat buns for other migrant workers at a construction site.

    The four meat buns makers were identified as Wei Quanfeng, Zhao Xiaoyan, Zhao Jiangbo and Yang Chunling, all from Huayin, a city in northwest China's Shaanxi Province.

    Zi allegedly invited a friend to act as the boss of the construction site, and bought pork and flour from a market in Chaoyang District and brought the materials to the courtyard.

    In order to film the process, Zi is alleged to have instructed Wei and his fellow villagers to make "baozi" or meat buns by soaking and crushing discarded cardboard he had collected and mixing it with pork. The baozi were said to have been fed to dogs.

    Zi used a home DVD camera to film the entire process and turned in his report after he edited it.

    The so-called cardboard meat buns gained more publicity after CCTV also broadcast Zi's report on July 11.

    Police sources said they had detained five other people, including the four migrant workers, to help with the investigation.

    Beijingers, however, remained suspicious of food quality on Thursday.

    "I would never let my family buy breakfast from street stalls again," said a Ms. Liu. "After all, health is paramount."

    Liu Qinghui, a worker with a supermarket in downtown Beijing, still doubted the quality of dumplings in street stalls.

    "The price of pork is on the rise, but meat buns are so cheap, usually 2.5 yuan (0.32 U.S. dollars) for ten," he said. "There must be some something going on."

    But stall owners were happy to see the alleged hoax exposed. "The taste of paper and meat are as different as chalk and cheese," said a Mr. Zhang who ran a dumpling stall. "Everybody would notice it."