The mainland's quality watchdog will set up a public blacklist of companies that fail to reach acceptable standards in an unprecedented measure to stem the flow of product safety scandals. Sun Bo , the head of the quality management department of the General Administration of Quality Supervision, Inspection and Quarantine, said a national network would be established to provide information on supervision, food, measurements, standards, approval, quarantine and inspection, Xinhua reported. Product quality problems, records of infringement of regulations and warnings would be available on the blacklist, Mr Sun said. A similar list exists for imported products. The blacklist is part of the administration's effort to build a quality credibility system within three years. So far the administration has established quality profiles for 89,699 companies in 17 categories. The administration also said a national standard for quality credibility would be implemented in November, the report said. The standard would provide detailed definitions on four levels of credibility, and companies would be rated accordingly. The announcement came amid a crisis in public confidence in mainland products ranging from toothpaste to food to medicine. Last year 22 dairy companies were found to have put poisonous melamine in baby formula powder that sickened 300,000 infants and killed at least six. Melamine is an industrial chemical used in the production of plastics and glue. It is added to substandard food, such as watered-down milk, to boost its nitrogen content, allowing it to pass testing for protein levels. As if to underscore the problems, one of the most popular bottled water brands, Nongfu Spring, is in the spotlight after an environmental monitoring agency announced last week its water source was too polluted to drink. According to a report by the National Environmental Monitoring Centre on the mainland's surface water, water quality in Zhejiang's Qiandao lake - claimed by the company as the main source of Nongfu Spring's water - fell to level four in January. Level four means the water is fit for industrial use, not drinking. The report also said its nitrogen level was higher than allowed. But an annual report on the quality of surface water by the province's environmental protection department said water quality in the lake last year was level two and fine for drinking. The department also defended the water quality in the lake as generally fine and 'one of the best' in the country through a Xinhua report yesterday. It said one of the three monitoring points - where water enters the lake - were recorded at level four because of its high nitrogen level, but quality at the other two was better than level three, the level suitable for a drinking water source. The department also defended the lake's nitrogen level as the lowest of all the country's key lakes and reservoirs.