A bakery chain in south China's Guangzhou City is being investigated after a former employee claimed workers had been recycling outdated bread to make new product for the past three years.

Guangdong provincial capital's Haizhu district bureau of quality and technical supervision announced it has set up a special task force to investigate Guangzhou New Sweetism Food Co Ltd.

The task force will be led by a deputy bureau chief and kicked off its inspection on Tuesday by visiting some of the company's production facilities.

In addition to looking at the company's order book and its purchase ledgers, the task force questioned managers and workers and collected evidence.

Samples of the company's products have also been collected for further analysis.

During the next few days, the task force will focus on studying the New Sweetism's documents and monitoring video tapes to find out what went on during the production process.

Meanwhile, the bureau has promised that it will roll out its inspection to all bakeries in the city and punish anyone found to have broken food safety laws and regulations.

The special investigation was launched after the New Express Daily published a story claiming five types of bread and cakes sold in Honey Cake outlets, which are run by New Sweetism, had been recycled from expired products.

The former worker, identified as Xiao Wen, told the newspaper that almost 70 percent of unsold expired bread that was returned to a plant was mixed with fresh flour to make new products.

The products, with prices ranging from 6 yuan to 12 yuan (US$1.84), were then relabeled with a new expiry date before they reached the shelves of the company's 15 Honey Cake outlets and some high-end ice cream shops in Haizhu District.

Xiao provided nearly 20 photos taken inside the plant to show the whole process.