Since a clean-up was launched last month 10 people have been arrested, 95 companies without appropriate licenses closed, and the business licenses of another six firms revoked, according to figures released by vice minister of agriculture Gao Hongbin.

The Ministry of Agriculture is "targeting 100% surveillance of large- and medium-sized cities" in the hunt for illegal pesticides and feed additives, Gao told a press conference in Beijing.

Gao said authorities are also targeting the illegal production, sale and application of five types of pesticides.

Relatively few offenders
The ministry was attaching great importance to agricultural inspections. There will also be random checks for pesticide residue in farm produce. However, Gao stressed that offenders are in the minority.

"More than 93 percent of the vegetables are safe in terms of pesticide residue and more than 98 percent of meat products are up to scratch concerning the remains of clenobuterol hydrochloride," Gao said.

Clenobuterol hydrochloride is a muscle-developing drug some farmers feed to pigs before selling them. It has been abolished due to side effects, including human-heart problems.