The European Commission and the Belgian Federal Food Chain Security Agency are investigating the contamination of animal feed with poisonous dioxins, some exported to Germany and the Netherlands.

Hundreds of farms have been closed in the alert, caused by defective filters at Belgian chemical producer Tessenderlo Chemie.

It sold contaminated gelatine to at least three Belgian feed producers, who sold product to farms in Belgium, Germany and the Netherlands. The Commission is trying to discover whether human food supplies have been tainted.