Dutch authorities have said they are launching a month-long clean-up of farms affected by bird flu to prepare for a resumption of poultry operations now that the worst of the outbreak appears to be over.

The country’s poultry industry has been badly hit by the disease and is proceeding cautiously, wary of a new outbreak if operations are restarted too soon, reported Reuters. The last reported case of bird flu in the Netherlands, the EU’s largest poultry exporter, was on 23 May.

Most quarantine restrictions remain in place but these will gradually be relaxed if no new cases are discovered, said Agriculture Ministry spokesman Gerard Westerhof.

The first stage of the clean-up operations will be to remove infected manure from farms, said Westerhof. This stage is expected to last three weeks and will be followed by workers making sure all other traces of the virus are removed. Then test chickens will be brought in to some farms to see if they become infected with the highly contagious virus.

Around 255 Dutch farms were hit by the bird flu virus and around 26 million poultry were slaughtered in efforts to control the spread of the disease after it broke out in the central Gelderland province in early March.