The country's farm minister was responding to a television report which said sludge from slaughterhouses and toilets had ended up in Belgium's food chain.

The minister, Jaak Gabriels, said the practice had been halted in May when checks in Belgian food safety were stepped up.

Belgian chicken was the first product barred by importers

The Belgian Government is working hard to improve the image of the country's food trade after the crisis earlier this year when high levels of the chemical, dioxin, were discovered in eggs, meat and dairy products.

Now there are further revelations about sewage sludge contaminating the food chain.

Waste from toilets

The VTR television network has reported that waste from slaughterhouses, toilets and showers was mixed in with animal feed in Belgium.

Responding to the claims, Belgian Farm Minister Jaak Gabriels said the practice was illegal and had been stopped.

"Often we didn't realise what kind of filth was mixed into fodder," he said. "It is incredible how people used to be duped."

He promised that the government, which was only elected three months ago, would investigate why it had taken so long to clamp down on the use of waste products in animal feed.

EC wants sludge review

Jean-Luc Dehaene: his government knew the problems

The French-language daily Le Soir said the government of former Prime Minister Jean-Luc Dehaene was made aware of serious problems in the food industry before a crisis over dioxin contamination broke in May this year.

Similar practices have been investigated in France after a news report alleging that sewage sludge from septic tanks was being mixed into animal feed.

There has been growing pressure on the European Union to tighten controls on animal feed since the crisis over mad cow disease in Britain three years ago.

A spokeswoman for the European Commission said that an EU farm council next week would initiate a review of the use of sewage sludge in animal feed.

One of the tasks will be to achieve a common definition of what constitutes "sewage sludge", as current definitions differ in all EU member states.

At present waste from slaughterhouses is subjected to three processes - filtering, then chemical and biological treatment. Different member states accept the use in animal feed of material from different stages of this process.