SHANGHAI'S quality watchdog said yesterday it was investigating a local textile company after its silk quilts were found to contain less filler than stated on the label.

A 100 percent pure silk quilt made by Shanghai Homes Textile Co was found to contain 36.4 percent less silk filler than indicated on the label, the Beijing Consumer Association said last week.

The quilt actually contained 1,907 grams of filler, compared to the 3 kilograms marked on the label.

The Shanghai Quality and Technical Supervision Bureau said some silk quilts made by the company failed quality tests in 2012 and 36 substandard quilts were confiscated. The company was fined and illegal profits totaling 89,893 yuan (US$14,498) seized from them.

The Beijing association tested 40 silk quilt samples and found 19 of them substandard. Some contained less silk or used polyester fiber in place of silk.

Three silk quilt samples of the Shanghai Baolai Textile Co, which claimed to be 100 percent silk, were mostly stuffed with polyester fiber.

The Shanghai quality bureau said the company was registered in Shanghai, but its factory was in Nantong, Jiangsu Province. Its products are not sold in Shanghai.

Some other brands like Shengwei and Mianduo claimed their silk quilts contained 51 and 50 percent silk, but tests revealed the real content was actually 20.8 percent and 24.6 percent, respectively.

Since 2010, the city's quality watchdog carried out tests on 367 groups of silk quilt products and 84 percent passed the tests.

Most of the problem related to inadequate fiber content.

Some of the companies use poor and cheap materials in place of silk to save cost and maximise their profit.

Fabric companies also outsource to other factories and overlook quality, experts said.