An official from China's State Administration for Industry and Commerce yesterday checked pigs at an illegal pork processing station in Beijing. The pigs were found to have been illegally injected with unsanitary water to increase their weight.

The state press reported yesterday that the closures came amid a nationwide crackdown on 'shoddy' and dangerous products which began in December. Since then it has uncovered the use of recycled or expired food.

Formaldehyde, illegal dyes, and industrial wax have been found in the production of candy, pickles, crackers and seafood, according to Han Yi, an official with the General Administration of Quality Supervision, Inspection and Quarantine, which is responsible for food safety.

"These are not isolated cases," said Mr. Han, director of the administration's quality control and inspection department,.

His admission was significant because the administration has said in the past that safety violations were the work of a few rogue operators, an assertion that is likely part of a strategy to protect China's billions of dollars of food exports.

Chinese wheat gluten tainted with the chemical melamine was recently blamed for dog and cat deaths in North America. Other products turned away by US inspectors include toxic monkfish, frozen eel and juice made with unsafe color additives.

Authorities in China have pushed for more stringent controls and increased publicity of their efforts to control the problem. Mr. Han said most of the offending manufacturers were small, unlicensed food plants with fewer than 10 employees, and all had been shut down. China Daily said 75 percent of China's estimated 1 million food processing plants are small and privately owned.