China said Friday it had shut down several firms at the heart of food and drug safety scares, its latest move to clean up those industries and salvage its reputation as a reliable exporter.

Li Changjiang, head of the General Administration for Quality Supervision, Inspection and Quarantine, said officials were focusing on stricter market access requirements for companies, conducting random checks and beefing up product testing.

But he stressed that China was not the only one with problems, citing comments by World Health Organization Director-General Margaret Chan this week that the agency receives about 200 reports of food safety problems every month from its 193 member states.

"This shows that food safety is not an issue of a particular country or region," Li said at a news conference.

In a statement released Friday, Li's administration said it had pulled the business license of Taixing Glycerin Factory, which has been accused of exporting diethylene glycol -- a thickening agent used in antifreeze -- and fraudulently passing it off as 99.5 percent pure glycerin.

The "TD glycerin" mix of 15 percent diethylene glycol, or DEG, and other substances eventually ended up in Panamanian medicines that killed at least 51 people.

"Its workshop and facilities have been closed down by the Jiangsu province and its business license revoked," the statement said. It was the first time action against the company had been publicly announced.

The statement also detailed punishments against Xuzhou Anying Biologic Technology Development Co. Ltd. and Binzhou Futian Biology Technology Co. Ltd., the two companies linked to melamine-tainted wheat gluten blamed for the deaths of dozens of dogs and cats in North America.

Xuzhou Anying, also in Jiangsu province, had its license revoked, its offices and workshops closed, and its right to import and export taken away, it said.

"It unlawfully added melamine in some of its products which could not meet the protein content requirement set in the contracts," the administration said. "This behavior of adulteration severely violated the feed quality and safety standards."

The business license for Binzhou Futian, headquartered in neighboring Shandong province, also was revoked and its offices and workshops closed, the administration said.

It "added melamine in some of its products which could not meet the protein content requirement ... constituting severe adulteration," the statement said. The company had also tried to avoid inspections, it said.

Melamine, used in plastics, fertilizers and flame retardants, has no nutritional value but is high in nitrogen, making products to which it is added appear to be higher in protein -- a way to cut costs for the manufacturer.

China also has accused the companies of illegally mislabeling their exported products to avoid inspections. All have been banned from exporting.

Legal action was being taken against managers of the companies, the administration said, but did not give any details.

Since the incidents, U.S. authorities have turned away or recalled toxic fish, juice containing unsafe color additives and popular toy trains decorated with lead paint. Chinese-made toothpaste containing DEG has also been rejected or recalled in Japan, Singapore and Australia.

U.S. Department of Health and Human Services and Chinese food safety authorities will meet in late July to discuss China's seafood exports.

Tensions were triggered last month after the U.S. Food and Drug Administration announced it would seize Chinese catfish, basa and dace, as well as shrimp and eel, after repeated testing turned up contamination with drugs that have not been approved in the United States for use in farmed seafood.

Li said an investigation has found that some fish farms "did use banned substances in those exports" and were not officially registered, allowing them to slip through without detection.

However, Li also said that the U.S. had an import system that relied on random tests and did not require quarantine certificates for customs clearance.

This week, Philippine authorities said a Chinese candy was found to be tainted with formaldehyde -- an allegation the maker denied on Wednesday, blaming counterfeit versions.

An official at the Shanghai branch of Swiss SGS, the testing company, said Friday that "the milk candy samples did not contain formaldehyde."

But the official, who gave only his surname, Zhang, said it was unclear if the products tested were the same as those found in the Philippines.

Li, the quality administration minister, said China has not received any official communication from the Philippines on the issue and that the country's embassy in Beijing has been unable to provide any information.

Li said the one of biggest problems in food safety is the regulatory nightmare of countless small and illegal food manufacturers that are springing up throughout the country.

"We will resolutely close down these small food manufactures ... who are engaged in producing substandard or fake or shoddy food and they will not be allowed to restart their business," Li said.