"So many butchers began purchasing the cheap beef to make more money," said Zhou Tongbin, a police officer from Guanyuan County.

The beef was labeled with the English words "Manufactured in Brazil" and "Produced in 2013" to show its origin and production date. Some consumers bought the beef because of its price and did not notice the country of origin, and others may not have understood the English.

Police said some of the meat was smuggled into the Chinese mainland via Hong Kong and distributed to various provinces and regions in the country, highlighting loopholes within China's supervision system, the anonymous official told Xinhua.

"Whether the meat can enter farm produce markets or supermarkets depends on how much kickback you want to pay rather than the meat's quality," said a meat producer who declined to be named, adding that nobody cares where it comes from.

"During the investigation, we were surprised that no department wanted to help confiscate this beef in the county. Neither the health department nor the food and drug regulatory agency thought it was their responsibly," an anonymous investigator said.

Most suppliers and dealers are uneducated, police said. They knew the beef wasn't declared at customs, without knowing the potential risks and the penalties they would face.

China's current leadership made a promise at the third plenary session of the 18th Communist Party of the China Central Committee in November to establish a mechanism to trace the origins of food and safeguard food safety.

But several shocking scandals, including injecting clenbuterol into pork, recycling cooking oil from restaurant kitchen leftovers, and selling pork from sick pigs, have made headline news in China.

In the latest stomach-churning food scandal, police in east China's Zhejiang Province reported in August that 30,000 tonnes of chicken feet contaminated with hydrogen peroxide had been seized after police busted nine factories in the provinces of Jiangsu, Anhui, Henan and Guangdong.

"The general public are the people who most care about the food safety issue, since it is related to their health. Fortunately, that beef is safe, but we hope someone can really help ensure the safety of the food on our table," Olive Li, a Chinese citizen, wrote on Sina Weibo.