Thousands of protesters have marched in Berlin demanding changes in farming methods after cancer-causing dioxin was found in some eggs, poultry and pork in Germany earlier this month.
The scandal, caused by contaminated animal feed, has outraged consumers, triggered international health alerts and hit sales of German eggs and meat.
China, South Korea and Hungary have announced restrictions on German meat imports.
Investigators say they have traced the source of the dioxin to used chip fat which had undergone industrial processing.
Dioxins are poisons formed by burning waste and through other industrial processes, which have been shown to contribute to increased cancer rates and to affect pregnant women.
Organisers said 22,000 people took part in the demonstration, while onlookers put the turnout at close to 10,000.
German Chancellor Angela Merkel said in her weekly video podcast she welcomed her government's steps to close gaps in the system of checks and safety.
The government is separating the production of oil and fats for industrial and agricultural use, and introducing a new licensing system. Thousands of hens have been culled.