BEIJING, China (AP) – China executed a dairy farmer and a milk salesman yesterday for their roles in the sale of contaminated baby formula – severe punishments that Beijing hopes will assuage public anger, reassure importers and put to rest one of the country’s worst food safety crises.

The men were the only people put to death in a scheme to boost profits by lacing milk powder with the industrial chemical melamine; another 19 were convicted and received lesser sentences. At least six children died after drinking the adulterated formula, and more than 300,000 were sickened.

Beijing is eager to prove it has responded swiftly and comprehensively to eliminate problems in its food production chain that have spawned protests at home and threatened its export-reliant economy. The milk powder contamination struck a nerve with the public because so many children were affected, but was only one in a series of product recalls and other embarrassing disclosures of lax public health safeguards.

Melamine, which is used in the manufacture of plastics and fertilisers, has also been found added to pet food, eggs and fish feed, although not in levels considered dangerous to humans. The chemical, which like protein is high in nitrogen, fooled inspectors. It can cause kidney stones and kidney failure.

China has since tightened regulations and increased inspections on producers and exporters in co-operation with US officials, who have noted a drop in the number of product recalls on Chinese exports.

But Beijing continues to struggle to regulate countless small and illegally run operations, often blamed for introducing chemicals and additives into the food chain. The country has 450,000 registered food production and processing enterprises, but many – about 350,000 – employ just 10 people or fewer. The UN said in a report last year that the small enterprises present many of China’s greatest food safety challenges.

Zhang Yujun, the farmer, was executed for endangeringing public safety, and Geng Jinping for producing and selling toxic food, according to the official Xinhua News Agency.