Beijing police raided a village where live pigs were force-fed wastewater to boost their weight before slaughter, state media reported.

Plastic pipes had been forced down the pigs’ throats and villagers had pumped each 220-pound pig with 44 pounds of wastewater, the Beijing Morning Post reported Thursday.

Paperwork showed the pigs were headed for one of Beijing’s main slaughterhouses and stamps on their ears indicated that they already had been through quarantine and inspection, the paper said. Suspects escaped during the raid and no arrests were made, it said.

Earlier this week, inspectors announced they had closed 180 food factories in China in the first half of this year and seized tons of candy, pickles, crackers and seafood tainted with formaldehyde, illegal dyes and industrial wax.

“These are not isolated cases,” Han Yi, an official with Wei’s quality administration, was quoted as saying in Wednesday’s state-run China Daily newspaper.

Han’s admission was significant because the agency has said in the past that safety violations were the work of a few rogue operators — a claim aimed at protecting China’s billions of dollars of food exports.